the synthetic use of metals in okganic...

THE

S Y N T H E T I C U S E O F M E T A L S

IN

O K G A N I C C H E M I S T E Y

ARTHUR J. HALE, B.SC. (LOND.) , A.I.O.FELLOW OF THE OHKMIOAL SOOU'lTY; LHOTURKK, A.TST)

IN CHicariaTRy AT THK crrY AND G U I L D S TEOiCOLLKGI', l

L O N D O N

J . & A . C H U K C H I L L

7 , a R E A . T M A R L B O K O U a i l S T R E E T

N

;Q<

P K E F A C E

THE student of Organic Chemistry will probably

be impressed at an early stage with the importance

of metallic sodium and its compounds in synthetic

work, and will subsequently mark the value of such

substances as acetoacetic-, malonic-, and cyanacetic-

ester and their sodium compounds.

He will notice the use of aluminium chloride in

the preparation of various aromatic compounds, will

hear the story of the discovery of the zinc alkyls,

and will possibly be attracted by those interesting

bodies, the organo-rnetals.

Various metals arid metallic derivatives have been

utilised in the development of Organic Chemistry,

and during recent years, much attention has been

given to the use of magnesium in the Grrignard

reaction and to the value of the carbides iu the

fixation of atmospheric nitrogen, wliilo tlio reduction

and synthesis of organic compounds in tlio presence

of reduced nickel and other metals has, by develop-

ment, led to the discovery of numerous catalytic

changes in the presence of certain metallic oxides.

VI PREFACE

In this volume an attempt has been made to

present an account of the uses to which the metals

and certain of their compounds have Tbeen put, and

the work is based upon a course of lectures, on this

subject, recently given by the author to the advanced

students of Finsbury Technical College.

Each chapter is supplemented by an appendix of

practical work exemplifying the methods mentioned

in the text.

Most of the preparations have been carried out in

the College laboratories, and in connection with fthis

part of the work the author desires to acknowledge

the valuable assistance of two advanced students,

Messrs. T. McLachlan and E. Mendoza. He is also

indebted to Mr. F. W. Streatfeild, F.LC., Senior

Demonstrator, for help during the reading of the

proofs.

A. J. H.LONDON;

February, 1914

C O N T E N T S

CHAPTER I.SODIUM AND POTASSIUM.

Synthetic Use of the Metals—Sodium ethylate—Sodamide—Sodium hydroxide—Potassium cyanide—Potassium"bisulphate—Potassium hydroxide —Potassium nifcrato—Potassium and sodium disulphates . . . . 1

CHAPTER II.COPPER AND SILVHXt.

Use of the Metals—Copper acetylene derivatives—Silvercyanide—Silver hydroxide 35

CHAPTER III.MAG-NESIUM, CALCIUM AND BARIUM.

Applications of the Grignard reagent—Carbides of Calciumand Barium—Nitrogen fixation—Calcium and Mag-nesium nitrides—Hydroxides of the metals . . . 42

CHAPTER IV.ZINO AND MERCURY.

Metallic Zinc—Zinc chloride—Mercuric oxido—Metallicmercury

V1U CONTENTS

CHAPTER V.

ALUMINIUM, TIN AND LEAD.PAGE

Aluminium chloride—Aluminium-mercury couple—Tin andlead organo-metallie compounds—Tin tetrachloride—Lead oxide—Antimony and the chlorides of antimony—Vanadium pentoxidc 11

CHAPTER VI.IRON, NICKEL AND PLATINUM.

Ferrous sulphate—Ferrous potassium oxalate—Iron andferric chloride—Reduction by reduced iron, nickel orcobalt 88

APPENDIX I.PRACTICAL WORK: SODIUM—POTASSIUM.

Ethyl benzene—Anisole—Benzoic anhydride—Hexamethy-lene—Trimethylene dicarboxylic acid—Chlorof ormicester—Carbonyl chloride—• Ethyl benzoate—Toluic ethylester—Aeetoacetic ester—Ethyl acetoacotic ethyl ester—Aceto-succinic ester—Malonic ester—Ethyl malonicester—Diaceto-succinic ester—Ethane tetra-carboxylicester — Acetyl-acetoacetic ester—Antipy rine—Methylsuccinic ester—Succino-succinic ester—Tin tetraphenyl—Lead tetraphenyl—Mercury diphenyl—Silicon tetra-phenyl—Oxalyl-acetic ester—Hydroxy-methylene cam-phor—Acetyl-acetophenone—Ethyl acetophenone—Fur-furol acrolein—Cinnamyl-vinyl-methyl ketone—Aceticanhydride — Benzoin — Desyl-acetophenone — Phonan-throxylene-acetoacetic ester 104

APPENDIX II.PRACTICAL WORK : COPP1R—SILVER.

Acrolein—Acrylic acid—/3-Iodopropionic acid—Adipic acid—Carbazole—o-Nitrophenyl-propiolic acid—Di-o-nitro-phenyl-diacetylene — o-Chlor -toluene — o-Chlor-benzoioacid—jp-Chlor-toluene—Formaldehyde . . . . 128

CONTENTS IX

APPENDIX III.

PRACTICAL WORK: MAGNESIUM—CALCIUM.PAOK

Benzoic acid—Phenyl-ethyl-carbinol—Trimethyl carbinol—Triphenyl carbinol—Camphoric anhydride—Homo-cam-phoric acid—Camphor—Pentamethylene—Cyanamide . 137

APPENDIX IV.PRACTICAL WORK : ZINC—MERCURY.

Citric acid—Use of Zinc alkyl iodide—Naphthalene—Iso-quinoline—ITuorescein—Malachite green—Acridine—a-Methyl-indole—Propyl chloride—a-Ethoxy-quinoline—Phthalic acid 144

APPENDIX V.PRACTICAL WORK: ALUMINIUM—TIN—LEAD.

Dimethyl-aniline-phosphor-chloride — jp-Tolxiic-aldehyde —Diphenyl-methane—a-Hydrindone—Triphenyl-methane—Acetophenone—o-Benzoyl-benzoic acid—Anthraqui-none — Hydrolysis of anisole—Toluene—Diphenyl—Oxalic acid 153

APPENDIX VI.PRACTICAL WORK: IRON—NICKEL.

o-Amino-benzaldehyde—o-Amino-cinnamic acid—Mannose—Hexahydrobenzene—Hexahydrophenol . . . 162

INDEX 167

A B B R E V I A T I O N S U S E D I N T H E

B I B L I O G R A P H Y .

Ann. =Ann. Ch. Phys. «Ber. =

Bull. Soc. chim. =Chein. Centr. =Chem. Zeit. =Compt. rend. ~

D.R.P.J. Am. Chem. Soc ~

J. Soc. Chem. Ind. =

J. prakt. Chem. =Monats. —Phil. Trans. =Proc. =Rec. Trav. Chim. «

Trans. =Zeit. ang-ew. Chem. =Zeit. phys. Chem. »

Liebig*s Annalen der Chemie.Annales de Chimie et de Physique.Berichte der deutsohen chemischen

G-esellschaft.Bulletin de la Soci6t6 chimique de Paris.Chemisches Centralblatt.Chemiker-Zeitung.Comptes rendus de TAcad&nie des

Sciences.German Patent.Journal of the American Chemical

Society.Journal of the Society of Chemical

Industry.Journal fur praktische Chemie.Monatshefte fur Chemie.Philosophical Transactions.Proceedings of the Chemical Sooiety.Recueil des travaux chimiques dos Payw-

Bas.Transactions of the Chemical Society.Zeitschrift fur angewandte Chomio.Zeitschrift fur physikalische Chomie.

T H E S Y N T H E T I C U S E O F M E T A L S

I N O R G A N I C C H E M T S T R Y

C H A P T E R S I

SODIUM AND POTASSIUM

ALMOST the first metal to Tbe used for organicsynthesis, sodium continues to hold a foremost posi-tk/Ai among all the metals utilised as synthetic agentsin organic chemistry. Although potassium was thofirst used, being applied by Frankland and Kolbein 1848 to the preparation of hydrocarbons by heat-ing the metal with alkyl nitriles^ yet sodium hasalways received a far wider application. Twenty-three parts by weight of sodium suffice to bringabout a chemical change which would require thouse of thirty-nine parts of potassium^ and thin fact,together with the lower price of sodium, gives thometal an economic advantage.

Another reason for the priority of this metal is thatin many cases the more electro-positive and niorochemically active potassium proves to be too violent

2 SYNTHETIC USE OF METALS

in its action, and renders the control of the reactiondifficult.

After the investigation of Frankland and Kolbementioned above, Frankland in the following yearheated metallic zinc with alkyl iodides, and besidespreparing paraffin hydrocarbons in this way, healso discovered the zinc alkyl s, the first of theorgano-metallic compounds.1

In 1850, Williamson prepared certain ethers bythe interaction of alkyl iodides and sodium ethoxide,a method of preparation which rendered evident theconstitution of these bodies :

C2H5I + C2H6O]Sra = ]STaI + C2H5.O.C2H5.

In 1855, Wurtz emphasised the importance ofsodium for preparing the paraffin hydrocarbons, andprepared di-isobutyl, by the action of the metalupon isobutyl iodide3:

2(CHa)2CH.CH2I + 2Na - (CH3)2CH.CHo.CH2.CH(CH3)3 + 2NaI.

A few years later, Fittig applied this reaction tothe synthesis of aromatic hydrocarbons by condensingaryl and alkyl radicles. The following reactionswill indicate the usefulness of this method8 :

C6H6Br + CH3Br + 2Na = C6HB*CH3 + 2NaBr.Brombenzene. Methyl Methyl benzene

bromide. (toluene).CBH4Br2 + 2C2HfiI + 4Na - C6H4(CaH6)a + 2NaI + 2NaBr

Dibrom-benzene. Ethyl iodide. Diethyl-benssene.

In these changes the alkyl groups take up thepositions occupied by the halogens in the benzenenucleus.

After 1850, various compounds were prepared by

SODIUM AND POTASSIUM 3

the agency o£ sodium and potassium, and tho follow-ing are examples of some of tho best known roaotionnoC tills class:

Phenol and other formation :

( l f ) oir,i » <yrfi.o.on3 .» NaiSodium phonato. AUIHOIO

(methyl phonyI othor).Tho samo exchango in offoctod by uning an alkyl

sulphate or an alkyl liydrogon Hulphato:CaH4OK + cairBnso4 car&.o.<uifi f- KHHO,

Ethyl hydrogonsulphato.

2C2II5OK + (<nr3)3so4 r- 2cyr&.o.air3 + Ka«o4

Mothyl Htilphato. Ethyl xnoihyl othor.

Tho following aro chai*actoriHtic roacjtionn ofalkyl potassium sulphates:

When hoatod alone they yield olofiuo.s :

When boiled with water Utoy yic ltl alcoliols:

oaiiftKso4 •»• nao i cyiftOH «- KHHO4.

When treated with Kl, KC5N, K^S, KHH, ilusyyield alkyl iodidos, nitrih^H, thio-ethern and mor-captans respectively:

2UKS<)4 + KM «« K.H.R - akjH()4KKHOt + KBU « K.S.U. 4 K9HO4.

When heated with tho alkali HHIIH of organic u<*itlN;

esters are obtained ;

RKSOj + OH8COOK t CirsCOOR 4 K.HO,

Sodium b(aizoato.

4 SYNTHETIC USB OF METALS

Acid anhydrides are produced by distilling amixture of the acid chloride with an alkali salt ofthe acid :

CH3COC1 + CH3COONa = (CH3CO)X> + NaClAcetyl chloride. Acetic anhydride.

C6H5COC1 + C6H5COOK - (CCH5CO)2O + KC1Benzoyl chloride. Benzoic anhydride.

Numerous hydrocarbons can be prepared by theaction of sodium upon halogen substitution products.

In addition to those already mentioned, un-saturated hydrocarbons can be synthesised in thisway:

2CH2: CH.CH2I + 2Na « CH2: CH.CH2.CH2.CH: CH2 + 2NaIAllyl iodide. Diallyl.

2CH2: CHBr + 2Na = CH-: CH.CH: OIL + 2NaBrVinyl bromide. Divinyl.

Sodium has played an important role in the pre-paration of many polymethylene hydrocarbons andtheir derivatives.

The first member of this series of hydrocarbonswas prepared by Freund (1882), by allowing sodiumto act upon trimethylene bromide4 :

yCH2Br y CILOH/ + 2Na == Oil/ I " + 2NaBr.

\CH2Br "\CH3

The same method was used in 1888, for preparing-methyl tetra-methylene from 1 : 4-dibrompentane5 :

CH3.CH. CH2

CH3.CHBr.CHo.CHfl.CH2Br + 2Na » | I +CH2.CH2

and again in 1894 for preparing hexamethylene fromthe corresponding dibromide :

. C 2I + 2NaBr,

2.CH


CH3.CH2.CH2Br CH2.CH2.CHS| + 2Na - | | + 2NaBr.OH2.CH2.CH2Br OH2.CH2.OH2

Cyclohexane.

Many polymethylene carboxylic acids can bo pro-pared by the aid of di-sodium malonato :

CIl.Br /COOC.JIs CIIjV /OOOO0II5 + 2NaBr

OH2Br \COOCaH5 OHo/ \COOCaUs

Triinetliylene dicarboxylio oatoir.

The condensation product when hydrolysod giventhe corresponding acid and the latter on heating,passes to a monocarboxyl compound :

CHo\ yCOOH Heat CPL>\I " NCX -> I " NCn.CO0H -i- COo.

CH2/ \COOH OIL/

Similar compounds are formed by using triinothy-lenc dibvomide and pentamothyloiio dibromido.0

Numerous acids may bo prcparod by tlie action ofcarbon dioxide upon aromatic halogen compouudsj inthe presence of sodium.

This method was first used by Kekule iu 18G0 forpreparing benzoic and toluic acids from brombonzouoand bromtoluene:

CoHfiBr + CO3 + 2Na == C(5HftCOONa + NaBr/OH3 .Qll,

C6H4< + COo + 2Na = C()II4< + NaBv.xBr XiOONa

Magnesium is now used instoad of sodium for thistype of reaction (see later).

Wurtz, by the aid of chloroformic ester, preparedthe corresponding esters of these itcids:

O6H5Br + 2N"a + CICOOC-II5 « CoU^COOC^ -I- NaCl + Kalir.

6 SYNTHETIC TTSJE OF METALS

USES OF ACETO-ACETIC ESTEB.

This useful reagent was discovered by G-euther in1863, who pi*epared it by the action of sodium uponethyl acetate.

About the same time Frankland and Duppa, usingthe same reaction, discovered that the hydrogenatoms of the raethylene group are replaceable bysodium and various organic radicles.

G-euther represented the substance as OH3.C(OH): CH.COOC2H6, that is /3-hydroxycrotonic ester, butFrankland and Duppa preferred the keto formulaOHg.CO.OHg.OOOOgHg, and represented it as aceto-acetic ester.7

The formation of the substance may be representedthus:CH3.COOC2H5 + CH3.COOC2H5 = CH3.CO.CH2.COOC3H6 + CaH6On«

Wislicenus had by 1877, investigated the substanceand shown that other substances contained methy-lene groups, the hydrogen of which could be replacedby sodium.9

A few years later, Conrad showed that an alcoholicsolution of sodium ethoxide would suffice, in place ofmetallic sodium or the dry ethoxide, for this type ofreaction; he applied his method in particular to thepreparation of alkyl malonic esters.10

Not only does condensation take place between twomolecules of an ester such as acetic ester, but also be-tween an ester and a ketonc. Acetyl acetone can beprepared, for example, from acetic oster and acetone :OH3.COOC2H5 + CH3.CO.CH3 « CH3.CO.CH2.CO.CH3 + C2H5OH.

Propionic and butyric esters undergo the sametype of condensation:


2CH3.CH2.COOC2H5 « CH3.CH2.CO.CH.COOC2H6 + C2H6OH

CH3Propio-propionic oster.

2C,HB.CHa.COOC3Hs == C,Hfi.CHa.CO.CH.CO0CaH5 + GftOHC2H5

Butyrobutyric ester.Iii both cases the carboxyl group of one molecule

of the oster attaches itself to the a-carbon atom ofthe other. The yields in both cases are lower thanthat obtained with acetic ester, which is about 25per cent, of that calculated.

Isobutyric and isovaleric esters were found byHantzsch11 to follow a different course.

The compound which might be expected whenusing isobutyric ester could not be isolated, and wasapparently reduced by the sodium present to eth-oxycaprylic oster, while simultaneously some of itbecamo hydroiysed to hydroxycaprylic acid thus :

(CHa)2CII.C(OH)(OC2H6).C(CH3)2.COOC2HsNot isolated.

Partly reduced to (CH3)2CH.CH.(OC2H6).C(CHJ)l,COOC2H6Etlioxycaprylic ester.

Partly hydroiysed to (CH3)2CH.CH(OH).C(Cir8)2.COOHHydroxycaprylic acid.

Similar changes occurred when using isovalericester and are represented by the following oquations :

2(CH3)2CH.CH2.COOC2H5 -•(CH3)2CH.CH.vC(OH) (OC2H6) .CILC3H7.COOR

Not isolated.(CXr3)2CH.CHo.CH(OC2H6).CILC3H7.COOCoH5 Ethoxycapvic ester.(CH8)2CH.CH2.CH(OH).CH.C3H7.COOH llydroxycapric acid.

Acetoacetic ester was tho first of those compoundsto be studied, which contain the grouping—00 —


CH2—CO— , the hydrogen of the methylene group(CH2) being replaceable, entirely or in part, bysodium. Around its constitution and principal re-actions much controversy was destined to take place,and even now the last word has not been heard con-cerning this important and interesting substance.

Geuther, endeavouring to show that a secondhydrogen atom of acetic acid could be replaced bysodium, caused the metal to act upon acetic ester.Hydrogen was evolved, sodium ethoxide was formed,and a solid sodium compound was isolated, having thecomposition C0H9O3Na, which on acidifying yieldedan oil capable of forming salts with bases. Geutheralso proved that by the action of alkyl iodides thesodium was replaced by alky], and this fact was con-firmed shortly after by Frankland and Duppa.

Wislicenus next showed that the product underdiscussion was acetoacetic ester and that two hydrogenatoms were replaceable by sodium in two stages.He represented the reactions in the following manner,adopting the formula of Frankland:

(i) CHa.CO.CHNa.COOCaH8 + C3H6I -CHs.CO.CH(C2H6).COOC2H6 + Nal

(ii) CH8.CO.CNa(C2H6).COOC2H5 + C2H5I =CH8.CO.C(C2H5)2.COOC2H5 + Nal

Geuther ascribed the enolic or hydroxylic formulaCH3.C(OH):OH.COOC2H6 to the substance, main-taining that it explained better its chemical nature.12

Claisen was the first to propose an important ex-planation of its mode of formation, and offered a viewwhich is still regarded with favour.13 This view is,that the condensation of acetic ester, and other con-


densations of this type, take place through thoformation and subsequent decomposition of an inter-mediate addition compound, in the formation of whichsodium ethylato plays an important role. Tho stagesof the reaction may therefore be represented thus :

.ONaCH3.OOOCvHfi + CJHsONa = Cl£3.C-OCallfi (Intoraodiato com-

cn 3 . c -ocyi , + c1i3.cooc.jir5

2 r )CH3.C(ONa): C1LOOOC.2H6 + 2CaiI5OJI.

Sodium dorivative.The sodium derivative is decomposed by weak acids

yielding acetoacetic ester, for which reason thoderivative is frequently represented with sodiumlinked to carbon directly and the liberation of thoester is then represented thus :CHj.CO.CHffa.COOC2H6 + HC1 - CH,.CO.CHa.0OOU3Ub 4- NaCl

The abovo intermediate compound has not boonisolated; but by tho interaction of bouzoic inolhyl-ostor and sodium benzylate an analogous compoundhas been produced and separated.

/

O6H5.COOCH3 + C0H6.CIL,ONa - CUHB.C -

Other compounds containing a motliyleno group ;

the hydrogen of which is replaceable by sodium ai)dby alkyl groups, are :

Acetyl acetone CJrjCO.ClI3.OOOH,Malonic esior 0.JUi,OOC.OH..OO()C<

2llAAcetono clicarboxylio estor C2llo000.(!ll2.C0,Cn340o0CaJI,,

Cyanacotio oator NC.CJTs.OC>OCaH6Benzyl cyaixido

Deoxybenzoin


A few applications illustrating the value of tliesesodium derivatives may now be outlined.

The sodium derivative of acetoacetic ester, pre-pared by treating the ester with an alcoholic solutionof sodium ethylate, is convorted into an alkyl sub-stituted ester by boiling with any alkyl iodide:

CH3.CO.CH2.COOaH5 -> CH3.CO.CII]Sra.COOC2H5 -*CH3.CO.CHR.COOC2H6

A second radicle II1 may be caused to replace thesecond hydrogen of the methylene group, by repeat-ing the treatment with sodium ethylate and an alkyliodide EaI.

CH3.CO.CHRCOOC0H5 -» CH3.CO.CNaR.COOC2H5 -»

These substituted esters, like aceto-acetic esteritself, can be hydrolysed in two different ways andthus yield a variety of ketones and acids of theacetic series.14

Boiling with dilute acid or dilute alkali bringsabout ketonic hydrolysis chiefly :

R

CH3.CO.C.COOCaH6 + Sift = CH3.CO.CHRR1 + CO2 + C2H6OH,I Kotone

while boiling with strong alkali favours acid hydro-lysis :

R

CH3.CO.C.COOCoH5 + 2H2O- C1I3COOH + CHRR^COOII + C2H3OH.I - Acid

R1

Malonic ester in particular can be used for pre-paring higher acids of the acetic series by first


replacing one or both of the methylene hydrogensby an alkyl group :

yCOOC2H5 /COOC2H5 yCOOC3H6CH2; -* CHRX or C&R1 (

\COOC2H5 \COOC2H5 \COOC2H5

On hydrolysis these substituted malonic estersgive the corresponding acids and the latter on beingheated to 200° lose carbon dioxide :

yCOOH /COOHCHEf -»B.CH,.CO0H; CKBF -» ERlCH.COOH

\COOH " \COOHThe monosodium derivative of aceto-acetic ester

on treatment with iodine undergoes condensation toa dibasic ester (diaceto-succinic ester).CH3.CO.CHNa.COOC,H5 CH3.CO.CH.COOC2H5

+ I2 » | + 2NaICH:j.CO.CHN*a.COOC2H5 CH3.CO.CH.COOC2H6

The mono-sodium compound of malonic estergives a tetra-carboxylic ester when similarly treated(ethane tetra-carboxylic ester):

COC2H5 CH(COOC2H6)2

+ Io == | + 2NaIOC3H6 " OH(COOC2H6)2

Acetyl aceto-acetic ester is prepared by the actionof acetyl chloride upon the compound 0H s .0O.0HNa.COO03H5, and on hydrolysis gives acetic andaceto-acetic acids :

CH3.CO.OH.COOC3HBI + 2H2O =COCH,

CH3.COOH + CH3.C6.CH3.COOH + O2HCOHIn a similar manner, by using a-monochloracetone,

the y-diketone, acetonyl acetone, is obtained afterhydrolysis15:


CHg.CO.CHN'a.COOCHg + CICHa.CO.CH,, =CHa.CO.CH.COOC3H5 + NaCl

OHo.COOH,

Heat ing with water a t 160° is sufficient to hydro-lyso the substitution compound and eliminate carbondioxide :

CUj.CO,Cn.COOHI |

c1i3.co.cuj cn s .co.ciijcn /co .c i r , OIL co.cir, + co3

Acetonyl acetone affords a means ol passing toi'urf urane, thiophone, and pyrrol derivatives. Hea tedwith dehydrat ing agen ts such as zinc chloride orphosphorus pent oxide, i t yields dimethyl furfurane,a change which is sometimes explained by thefollowing s teps :

/Oil ,ciio.co.cnj c n : c \ n T , ca: o v .01 ijI ^ 011 " I > °IC .cir,

Heated with phosphorus pentasulphide it yieldsthe corresponding thiophene compound, whilo theaction of alcoholic ammonia solution foims a pyrrolcompound:

SB*0U:0

CH • C< u' \ - J diniothyl-tliiopheno

/CHj

L / CH:C/.CH,' ^ dimothyl-pyrrol

SODIUM AND POTASSIUM 13The behaviour of sodium ethyl aceto-acetate to-

wards chloracetic ester and chloroformic ester respec-tive! jy indicates that the compound exhibits dynamicisomerism because in the first reaction it behavesas though sodium were directly united to carbon, andin the second reaction as though the sodium wereunited to oxygen :CH3.CO.CHNa.COOajT5 + C1CH2.COOC2H5 =rCH:}.CO.CH.COOC2H6CH?.COOC2H5Aceto-succinic ester, OCOOGftCH3.CONa : CH.COOC,H5 + C1COOC2HS = CH3.C £CH.COOC2Hfi/3-carbethoxy-crotonic ester

From acetyl-acetone a series of j3- or 1: 3-di-ketones can be obtained by treating the mono-sodiumcompound with alkvl iodides :

I3 + CHJE =CH3.CO.CH(C2HB).CO.CH3 + NalTreatment of the sodium derivative with iodine

gives tetra-acetyl ethane :CH3.CO.CHNa.CO.CH3 CH3.CO.CH.CO.CH3

CHa.CO.CHNa.CO.CH3 + * " CH3.CO.CH.CO.CHf

Aceto-acetic ester is technically valuable in thepreparation of antipyrine. The ester is first allowedto react with phenyl-hydrazine, and the ring com-pound formed is then convex'ted into antipyrin bymethyl iodide and sodium :

Cn3.CO.CH3.COOCsH5h


The hydrazone then loses C2H5OH and formsl-phenyl-3-rnethyl pyrazolon :

CH3.C : CH.CO

" L - J . Q . B .

which then passes to 1 : 2 : 3-phenyl dimethyl-pyra-zolon.

From benzyl cyanide and deoxy benzoin alkylderivatives can be formed by the action of sodiumand alkyl halides:

C6H5.CH3.COCflH5 -> CCH5.CHR.COCGH6

The preparation of dimethyl succinic ester willillustrate the use of cyanacetic ester.16

The sodium compound is condensed with a-brom-propionic ester to form cyauo-methyl succinic ester :

CN CHa CN CH3

CHNa + Br.CH - CH CH + NaBr1 1 1 TCOOC2H5 COOCJHB COO2IIfi COOC2H5

This substance is then treated with ISTaOEt andOH3I and the product hydrolysed with loss of carbondioxide:

CN CH, CN CII,I I

+ CH8I « C.CH8 CH + NalCOOC2H5 6OOC2H5 COOCaHa COOC2H5

Hydrolysis COOH CH3 -CO2 CH3 CH3

"* 6.CH3 CH ~> CH CHCOOC2H5 COOC2H6 COOC2H5 COOCjHs

The synthesis of S-keto-hexahydrobenzoic acidfurther illustrates the use of cyanacetic ester.17

COOCoHr COC "


The di-sodium derivative is condensed with /3-iodo-propionic ester to form y-cyanopentane-a-ye-tricar-boxylic ester :

C2H5OOC.C(CN)NA2 + 2CH2I.CH2.COOC2H5

/CI12.CH2.COOC2II,

= C2H5OOC.C(CN) + 2TSM

\CH2.CH2.COOC2H5

Hydrolysis of this cyano-ester gives pentane-ayc-tricarboxylic acid, which on digestion with aceticanhydride and subsequent distillation yields S-keto-hexahydro-benzoic acid:

,CH2.CH2.COOH ,CH2.CH2

HOOC.CH = HOOC.CH NcO + CO2 + H2O.\CH2.CH2.COOII \ C

Further examples of the synthesis of cyclic com-pounds are :

The formation of butane tetra-carboxylic esterfrom ethylene dibromide and mono-sodium-malonicester:

OHjBr CH(Na) (COOC2H6)2 CH2.CH(COOC2H6)2I + I = | + 2NaBrCI!H2Br CH(lSra) (COOC2H5)2 CH2.CH(COOC2H5)2

When the sodium derivative of butane tetra-carboxylic ester is acted upon by bromine, the result-ing product is tetramethylene-1 : 2-tetracarboxylicester:

CH2.CNa(COOC2H6)2 CH2.C(COOC2H5)2

CH2.CNa(COOC2H5)2 + ^ " CH2.C(COOC2H5)2

The use of trimethylene bromide with sodium


malonic ester will make the following reactionspossible:

. CH2.CH(COOC2H5)2 y CH2.C(COOC2H5)2CH2 -» OHo J

\ CH2.CH(COOC2Hr,)a \ CH2.C(COOC2H6).2Pentametliylene-tetracarboxy] ic ester

Using methylene iodide instead of bromine, acyclohexane-tetracarboxylic ester results:

CHj + CHaI2

\cH2.CISra(COOC2HB)2

/CH2.C(COOC2H5)2

CH2

\cH2 .d(COOC2H f i)2

Succ ino - succ in i c e s t e r i s f o r m e d b y t h e c o n d e n s a -

t i o n of succ in ic e s t e r in t h e p r e s e n c e of s o d i u m : 1 S

C2H6OOC.CH2.CHo.COOC2H5 ,C2HfiOOC.CH2.CH;.COOC2l-I5 *

CJELfiOC.CE/ 2 \ C O + 2O,II5OH

OC CH.COOC2K5

and this on oxidation is converted into 2 : 5-dihydroxy-terephthalic ester:

C-COOCaTT6

HC ^C.OHII I

HO.C CH

C--COOC2H5

Succino-succinic ester can also be prepared by theaction of sodium upon a-bromaceto-acetic ester.19


COCH3.CO.CHBr.COOCoH5 / \

+ ^ H2C CH.COOC2H6

C2H5OOC.CHBi\CO.CHa C2H5OOC.HC CH2

CO

When hydrolysed with sodiam hydroxide the esterpasses to the corresponding acid; and this is decom-posed when heated to 200° into £>-diketohexaniethy-lene and carbon dioxide :

CO CO

H,C CH.COOH H2C CH2

I I -> I I + CO2

HOOC.HC CH2 H2C CH2

v v

The latter substance was used by Baeyer inpreparing dihydro-, tetrahydro-, and hexahydro-benzene.20

Succino-succinic ester was also used by Baeyerfor synthesising the terpene hydrocarbon p-men-thadiene.21

Succino-succinic ester, like phloroglucin, exhibitsdynamic isomerism (tautomerism), behaving undersome conditions as a keto-body; and under otherconditions as a hydroxylic, or phenolic body havingthis structure:

C.OH

II2C C.COOC2H6

C.OH

A furthor example oJ' ester and ketone condenaa-

CH3.CO.CH3 + j = CH3.CO.CH3.CO.COOC2H5 + C3H6OHcc

18 SYNTHETIC USB OP METALS

tion is afforded by the syntliesis of acetyl-pyroracemicester, from acetone and oxalic ester :

COOC2H5

iooc3H5

By using mesityl oxide and oxalic ester the con-densation product is mesityl-oxide-oxalic ester :

CH3V COOC2H5>C : CH.CO.CH3 + I

CK/ COOC3H5

CH3

C : CH,CO.CH2.CO.COOC2H6 + C3H8OH

CH3

A case of internal condensation similar to that ofsuccinic ester^ is the formation of keto-pentamethy-lene carboxylic ester from 1 : 4-butane dicarboxylicester:

CH3- CH2COOC3H5 CH2- CH.COOC2H6

= | NCO + C2H5OHCH2- CH2COOC3H5 CH2- CH3

Sometimes condensation products are formed bythe elimination of water. For example:

C6H6.CHO + CH3.COOC2H6 = C6H5.CH: CH.C0OCaH6 + H2OBenzaldehyde Acetic ester Cinnamic ester

C6H5.CHO + CH2 » C6H5CH : o / + H 8 °COOCjjHfi XCOOC3H5

Cyanacetio ester Benzylidene cyanacetic ester

Sodium has been widely used in the synthesis ofvarious organo-metals and organo-metalloids, bycausing the halides of the elements to react withorganic halogen compounds. The following are ex-amples of this type of reaction :23


S21CI4 + 4C6H5Br + 8Na = Sn(C6H5)4 + 4NaBr + 4Na01SiCl4 + 4C6H6Br + 8Na => Si(CcH5)4 + 4NaBr + 4NaCl.

Sometimes the sodium alloy of the metal is utilised,as in the preparation of tin, lead, and mercury com-pounds, by means of tin-sodium, lead-sodium, andsodium amalgam respectively :33

Pb + 4Na + 4O3H7I = Pb(C3H7)4 + 4NaISn + 4Na + 4C6H5Br = Sn(C6H6)4 + 4NaBr

I t is advisable to accelerate these reactions bymeans of a small quantity of acetic ester.

SODIUM BTHYLATE.

The value of this sodium derivative was firstextensively illustrated by Claisen.2*

I t may be used for condensing esters and ketones,and esters by themselves as well as with aldehydes,in much the same manner as sodium itself.

Benzoic ester and acetone yield benzoyl-acetone.C6H5.COOC2H6 + CH3.CO.CH3 = C6Hfi.CO.CH2.CO.CH3 + C2H6OH

Sucoinio ester and acetone yield teraconic ester.CH3.COOC2H5 (CH3)2C: C.COOC2H5

co+ 1 - I +H2O

CH2.COOC2H5 CH2.COOC2H8

Benzoic ester with acetic ester yields benzoyl-aceticester, while with acetophenone it gives dibenzoyl-methane :

06115.00.0^.0000^5 +C2H5OHC6H6.CO.CH2.CO.O0H6 + C2H6OH.

By condensing formic ester with other monocar-boxylic esters, aldehyde esters result, while by usingoxalic ester, ketonic dibasic esters are formed:


HCOOC2H5 + CH3.COOC.2H6 = HCO.CH.2.COOC2HS + C3H6OHFormyl acetic ester.

COOC,H5 CHaCOOC,H5 CO.CH2.COOC2H5| " + - | + 2C2H5OHOOOC.2H6 CH3GOOC2II5 CO.CH2.COOC2II5

Diacetyl dicarboxylic ester.Pormyl acetone may be prepared by using formic

ester and acetone:HCOOC2H5 + CH3.CO.CH3 = HCO.CHj.CO.CH3 + C2H5OII

This substance can be farther condensed by aceticacid to triacetyl-benzeno:

CH/CHO

H CH,.CO.CH8 CHaCO.C C.COCH3

I -> II I +3H2OOHO OHO HC CH

CHg.CO.CH3 C

COCH3Similarly acetophenouo and formic ester yield

formyl-acetophenone, which may bo condensedfurther to tribenzoyl benzone.

Bing condensations with oxalic ester are : Diketo-cyclopentane dicarboxylic ester from oxalic andglutaric esters :25

COOC2II5 CH2—COOC.J-I5 00—CH—C\ \

oir2 - oir2 +202H5OH.COOC2H5 OIL—COOO2H5 0 0 - OH— COOO2Hh

By using /3j3-dimethyl glutaric ester, Konnnpaobtained diketo-apocamphoric ester which was usedfor the synthesis of camphoric acid :26

OOO02H5 CH2.OOOC.2H6 CO—OH.COOC2ir6

O(CII3)2 ere:(0Ha)2

OHo.OOOC2H5 00—0H.0O002H6

SODIUM AND POTASSTUM 21

A methyl group was introduced into the lattercompound by the aid of sodium and methyl iodide,and the resultant compound reduced and thenhydrolysed to dihydroxy-camphoric acid:

CH3 CH,

CO—C—C00O>H5 CHOH—C—COOH

C(CH3)2 -> C(CH3)2

CO—CH—COOCUH5 CHOH—CH—COOH

On boiling the last product with phosphorus andhydrogen iodide, the result was dehydrocamphoricacid, which was then combined with hydrogen brom-ide to form j3-brom-camphoric acid. The last namedsubstance was reduced by zinc dust and acetic acidto racemic camphoric acid :

CH-, CH3 CH3

I I ICH—C—COOH CH2—C—COOH CH>—0—COOIt

C(CH:{)2 -» C

CH—CH—COOH CHBr—CH—COOH CH2—CH—COOII

Sometimes the oxalic ester only undergoes lialf-condensation as in the formation of oxalyl aceticester:

COOCJI5 CO.CIL,.COOC2Hr)

+ CH3.COOCjH6 =

COOC2H5 COOCaH6

+ C2ITr,OII.

By means of sodium ethylate or sodium, Claisenprepared hydroxymethylene camphor by condensingcamphor with amyl formate :27

22 SYNTHRTJC USE OF METALS

en. + Hcooc5Hn C.CHOH

-i- Cf>lInOH.\ \

CO COThis substance is strongly acid, forming salts and

esters, in which the hydroxyl hydrogen is replaced bymetals and by organic radicles respectively. Thereaction led to the discovery of many other hydroxy-methylene bodies possessing similar properties.

Olaisen also obtained nitroso-ketones by the useof amyl nitrite in tho presence of sodium ethylate :

CflH5.CO.CH3 + CfiH .O.NO * CC1I5.CO.CH: NOH + C6HnOH

An examplo of this class of condensation withelimination of water is the formation of a-phenyl-cinnamic nitrile, from benzaldehyde and benzylnitrile:

C(1H, CCH5.CTI: C.CJI,C(!H6.CHO + | « I + ILO.

CIT2.CN CN

SODAMIDB AS A SYNTHETIC AGENT.

This substance was utilised by Claisen in 1905, foralky latin g ketones and for preparing 1 :3-diketones.Its action seems to bo quieter and more regular thanthat of sodium or sodium ethylate.28

One or two ethyl groups may be introduced intoacetophenone by using ethyl iodide with sodamide :

CflH5.CO.CH3 + C2H6I - C0H5.CO.CH2.C2H6 + HICflH6.CO.CH3 + 2C2H6I - CflH^CO.CHCGft).* + 2HI.

By using benzyl chloride the benzyl group can beintroduced: f

C6H5.CO.CH3 + C6H6.CH2C1 ~ C6Hfi.CO.CH2.(CH2CfiHB) + HC1.


1: 3-Diketones are prepared by condensing ketoneswith esters.

Acetyl acetone from acetic ester and acetone:CH3.COOC2H5 + OH8.CO.CH3 = CH8.CO.CH2.CO.CH3 + GftOH.

Benzoyl acetone from acetic ester and aceto-phenone:CH3.COOC0H5 + CH3.CO.CCH5 = CH3.CO.CH2.CO.OGH5 + C2H5OH.

The powdered sodamide is added gradually to themixed substances, cooled in ice, and after standingfor some time, the mixture is treated Avith ice-coldwater and the product precipitated by acidifyingwith acetic acid.

Hydroxymethylene ketones are formed by usingformic ester:

CH3.CO.CH3 + HCOOR = CH3.CO.CH : CHOH + EOH.

Sodamide has been technically applied in at leasttwo instances, namely, the production of cyanide byCastner's process and also the production of indigo.

In the preparation of cyanide, the sodamide ismixed with carbon and the mixture subjected to a dullred heat, when the following reaction takes place:

NaNH2 + C =» NaCN + H2

Indigo can be synthesised according to theGerman Patent 158,089, by heating sodamide withtho diethyl ester, or the diamido-derivative, ofphenyl-glycocoll-carbonic acid, in benzene solution :

.NH.CH2.COOH .NHV4< -> CflH4< >CH2 + H.>0 + COo.

XJOOH MX)'Indoxyl

The indoxyl formed is converted into indigo byexposure to air.


Metallic sodium has recently received importantapplication as a polymerising agent in tho transfor-mation of isoprene into artificial rubber.29

The steps in this important synthesis, startingfrom starch, are as follows :

The starch is fermented to fusel oil and acetone,and from tho former liquid, isoamyl alcohol isseparated.

By treatment with hydrogen chloride, isoamylalcohol is converted to the monochloride, and thevapour of this when acted upon by chlorine gasleads to the formation of three isoamyl dichloindes :

(CH:02CH.CK,CH2OH + HC1 = (CII:l)oCH.CHo.CH2Cl + H3OS (CH:))2CH.CHC1.CH2C1 + IIC1

(CH.))3CH.CHn.CH2Cl + C l ^

^ :<N>CH.CHo.CH2Cl + HC1CHoCK

These isoamyl dichlorides, when heated with lime,lose hydrogen chloride and pass to isoprene (methyldivinyl) :

*\c.CH : CH2CH/ '

Isoprene on standing for some time with metallicsodium becomes converted into synthetic rubber.

SODIUM HYDROXTDE.

This sodium derivative is generally utilised inaqueous solution for condensation work, the concen-tration often being 10 per cent.

Schmidt30 was the first to use the reagent, in 10

SODIUM AND POTAflSTUM 25

per cent, aqueous solution, for condensing togetherfurfurol and acetaldehyde :

>CHO .CH : CH.CHOCH : c<( CH :| J>0 + CH3.CHO =fan : dH

Furfurol acrolein.Claisen, in the following year, used 10 per cent,

aqueous sodium hydroxide to condense furfurolwith acetone and thus obtained mono-furfurylideneacetone :81

C4II:iO.CIIO + CHn.CO.CH3 = C4H3O.CH : CH.OO.C1I3 + HUO.Using benzaldehyde and acetone, ho obtained

mono- and di-benzylidene acetone.Further examples of condensation of this class ai-e

the formation of indigo from o-nifcrobenzaldehydeand acetone, and the formation of quinoline fromo-aminobenzaldehyde and acetaldehyde:

.Clio vGHOH.CH».CO.cn»C H C O C H - C0H4<

o-nitrophenyl-lactic acid kotono.

This product is then decomposed by the excess ofsodium hydroxide :

yCHOH.CHo.CO.CH3

\NO2.CO v .CO x

C(5H4< > C : C < > C(1Ht + 2H«O + 2CHSCOOH:\ N H / \ m '

Baryta or ammonium hydroxide may also be usedfor this reaction.82

Quinoline and quinoline derivatives are obtainedby using o-amino-benzaldehyde :8S


CH

HC C.COH CH2.H HC C CH| II + | I II I

HC C.NHo CHOI + 2H3OCH

CH CHo-amino-benzaldeliyde. quinoline.

By substituting aceto-acetic ester for acetalde-byde, a quinoline derivative is obtained :

CH CH CH/' \ ^ \ / N

HC C.COH Cm.COOailfi HC C C.COOOJI5I II + I - I II J " +2H2O

HC C.NIL CO.CIT, 1IC C C.CH3

CH CH Nrt-metliyl-q[xiinoliiie-/3-carboxylic ostev.

Fischer made use of 1 per cent, sodium hydroxidesolution to polymerise a mixture of glyceric aldehydeand hydix)xy-acetone, in the formation of a-acrose.After allowing the mixture to stand for four or fivedays the transformation was complete :u

CH2OH CH2OH CH2OH CH2OH

CHOH + CO ~ CHOH CO

CHO CH2OH CHOH — OHOH(Q-lycerose). a-acrose (inactive fructoso).

By the same method; glycollie aldehyde has beenpolymerised to erythrose :

CH2OH CHO CH2OH CHO

CHO CH2OH CHOH - CHOH

Cinnamic aldehyde can be formed from benzal-

AND POTASSTTJM 27

dehyde **11 ^ c e t a l d e h y d e , and the product can beagain c°tX(*°nBecl w i th acetaldehyde or acetone :

Co l l"< j n° -+ OIT3.CHO = C6H5.CH : CH.CHO + H2O: CH.CHO + CH3.CHO =: CH.CH: CH.CHO + H2O

Cinnamyl acrolein.:: CH.CHO + CHVCO.CH, -

^ : CH.CH: CH.CO.CH> + H2OOinnamyl-vinyl-methyl ketone.

If tv^c> l u ° l o c u l a r quantities of cinnamic aldehydebeusodj ^ J ^ ° u i n t K e last case di-cinnamyl-vinyl ketoneresults.

Anot>l*ai* c n s o of quinoline formation is the con-^ T^enzoyl acetone and aniline, resulting in

CH C.C6Hr,

HCj. ,L... + C H *

CO.CH.ii C.CH,

+ 2II2O

It w ^ ^ n h o w n by V. Meyer, that solid sodiumhydroxi<lu i» b e t t e r than sodium ethylato for con-densing1 b e n z y l nitrile with methyl iodide :36

^I.i(JN . - CHaI + NaOH = CcH5.CHCISr + Nal + HaO.

CH8

Quitu>tios c a n be prepared by condensing 1: 2-diketonc^H by rtquoous sodium hydroxide.30

In ill o tivnij p l ace an unsaturated 1 : 2 : 5-triketoneis formed wliich. Tby further condensation passes to aquinom*# Diixcetjl gives first dimethyl-quinogen andthen jM-x


CO

CH3.CO.CO.CH, CH3.CCO.CH3 CHVC Oil-> * II ' -> ' II II

CH3.CO.CO.CH3 CH.CO.CO.Cir, HC O.CH,

Acetyl-propionyl condenses in this way, formingduroquinone :

CO

CH.}.CO.CO.CH>.CH, CH,.C 0.CH,' II II + 2TI>0.

OHn.CHo.CO.CO.CH.{ CTT,.C O.CTT,• ' Y •

The reaction may be expi*essed in a general wa}r

thus :CO

X.CHo.CO.CO.Y X.C.CO.CO.Y XC CY-» II -> II II

Y.CO.CO.CHo.X Y.C.CO.CH..X YC CX

A further example of condensation by sodiumhydroxide is afforded by ionone, used as a substitutefor essence of violets, -which is formed from citraland acetone.37

Pseudo-ionone is the first product, and this is thenconverted to a mixture of a- and j3-ionone by boilingwith dilute sulphuric acid :

(CH3)2C:CH.CH2.CH2.C(CH3):CH.CHO + CH3.CO.CH8 -(CH8)2C:CH.CH2.CH2.C(CH3):CH.CH:CH.CO.CH3 + H30.

The next stage is explained by the followingscheme:


CH3 CH3

c

H.Ic

CH3 CH3

<X>H/ +2H3O /HC CH.CH: CH.CO.CH3 > H,C CH2.CH : CH.CO.CH3

I | | XHXH3

V 0 H

CH2Ito

w

0 CH.CH: CH.CO.CH3 H2C C.CH: CH.CO.CH3

(C C.CH3 H2C C.CH3CHo

a-ionone /3-ionone.

POTASSIUM COMPOUNDS.

Potassium itself is rarely used in synthetic work,but the cyanide, acid sulphate, and hydroxide areoften made use of.

A commercial process in which potassium may berogarded as a synthetic agent is Beilby's process forpreparing cyanide, by heating a mixture of potas-sium carbonate and carbon in ammonia.

Potassamide is probably an intermediate compound,and the method corresponds to Castner's cyanideprocess:

KaCO8 + 2NH3 + 2C - 2KNH22C


While the action of carbon monoxide upon heatedpotassium results in the formation of the carbonyl,moist carbon dioxide reacts with the metal to formcarbonate and formate :

0K + 6CO » K6(CO)02K + H2O + 2CO2 = KHCO3 + H.COOK4K + H3O + 3CO2 = K2CO3 + 2H.C00K

POTASSIUM CYANIDE is especially useful for con-densing aromatic aldehydes (benzoin condensation) ,38

Benzoin is formed from benzaldehyde:2CCH5.CHO = C6H5.CHOH.CO.CCH5

Acetophenone condenses with benzoin in thepresence of alcoholic cyanide, giving desylaceto-phenone :

C6H5.CHOH C6H5.CH.CH2.CO.C6H6I + CH3.CO.C0H5 . I + H3O.

CO.CflH5 CO.C6H6

Mandelo-nitrile and benzyl cyanide condense inthe presence of aqueous potassium cyanide, givingdi-phenyl-succinic nitrile :

C6H5.CHOH CH2.C6H5 C6H5.CH-~CH.C6H8

I + I - I I +H2OON CN ON CN

It has been suggested that cyanhydrin formationis an intermediate stage in this class of condensation,and benzoin formation is represented by the followingscheme :89

C6H6.CHO + KCN -» C6H5.CHOKCN"

C6H5.CHOK 4 C6H6.CHO -> C0H5.COK—CH0H.CflH5

CN CNKON is then eliminated—

C6H5.CO.CHOH.CflH6 + KCN.


ACID POTASSIUM SULPHATE may be used for the

following condensations.The leuco-base of malachite green from benzal-

dehyde and dimethyl-aniline:C6H5.N-(CH3)2 /C6H4.N(CH3)2

= CgH5.CHC6H6.N(CH3)2 \C6H4.N(CH3)3

The resultant tetra-methyl-diamino-triphenyl meth-ane is then oxidised to the carbinol, which is convertedto malachite green by hydrogen chloride:

C6H5.CHO + = C0H5.CH' +HjO

/ \ H C I C 6 H , < + H 2 O\C6H4.N(CH3)2 \CCH4:N(CH3)2C1

Aromatic aldehydes condense with phenols, e. g.benzaldehyde and naphthol give hydroxy-dinaphthyl-phenyl methane:

CCH5.CHO + 2C10H7.OH = C6H5.CH(C10H6OH)3 + H2O.Pyruvic acid is formed by the removal of the

elements of water from either tartaric or glycericacids :

CH0H.COOHI = CH-{.CO.COOH + CO3 + H2OCHOH.COOH

CH2OH

CHOH - CH3.CO.COOH + HaO.

COOHBy a similar elimination of water, glycerin yields

acrolein and terpineol passes to dipentene:CH2OH.CHOH.CH2OH - CH2: CH.CHO + 2H2O

OHCH3.C*

\CHj—CH,/ \CH 3

8


POTASSIUM HYDROXIDE can often be used for thesame syntheses as sodium hydroxide, as for example,in condensing diketones with mono-ketones : Phen-anthraquinone condenses with either acetoacetic esteror acetone :40

C6H4.CO CO.CH3 C0H4.COI I + I - I I /COCH3 + H2O

4.0O CHo.COOC2HB C6II4.C<2 6

Plienanthroxylene acetoacetic ester.C6H4.CO CH3.CO.CH3 C8H4.C(OH).CH2.CO.CH3

C6H4.CO+ CH3.CO.CH3 ~ C6H4.C(OH).CH2.CO.CH3

Diacetone-phenanthraquinone.Potassium hydroxide, when heated in aqueous

solution with aromatic aldehydes, converts these inpart to acids and in part to alcohols :

2C6H5.CHO + KOH = CcH6.C0OK + C6H5.CH2OH

Certain aliphatic aldehydes undergo a similarchange. Isobutyric aldehyde, for example, is con-verted to isobutyric acid and di-isopropyl glycol:3(CH3)2CH.CHO + KOH = (CH3)2CH.COOK + (CH3)2CH.CHOH

(CH3)2CH.CHOH

This is a method for obtaining di-secondary glycolsfrom certain aldehydes by means of alcoholic potas-sium hydroxide solution.41

Potassium nitrate may be used for the preparationof acid anhydrides from acid chlorides, by distillingthe latter after mixing with the alkaline nitrate.43

Potassium and sodium disulphate bring about con-densation with elimination of water. The followingexamples illustrate the use of this method: ^

Triphenyl benzene from acetophenone, benzal


aniline from benzaldehyde and aniline,, benzal malonicacid from bonzaldehyde and malonic acid, benzalacotophenone from benzaldehyde and acetophenone.

BIBLIOGRAPHY.1 Ann., 1853, 85, 329.2 Ann., 1855, 96, 365.3 Ann., 1863,131, 301.4 Monats., 1882, 3, 625.5 Trans., 1888, 53, 201.R Ber., 1902, 35, 2091.' Ann., 1866,138, 204, 328.8 Phil. Trans., 1866,156,37.» Ann., 1877,186,163; 190, 257.«» Ann., 1880, 204,127.11 Ann., 1889, 249, 54.12 Ann., 1883, 219,123.13 Ber., 1887, 20, 646w Ann., 1877,190, 276.15 Ber., 1885,18, 58.lfi Trans., 1899, 75, 839.w Trans., 1904, 85, 416.w Ann., 1882, 211, 306.19 Ann., 1888, 245, 74.2° Ber., 1894, 27, 229.21 Ber., 1893, 26, 232.22 Ber., 1886,19, 1012.23 Ann., 1864,130,105 5 Bor., 1889,22, 2917.24 Ber., 1887, 20, 655.25 Ber., 1897, 30, 1470.26 Ber., 1903, 36, 4332.=7 Ann., 1897, 297,1.« Ber., 1905, 38, 693.a» X Soc. Chem. Ind., 1912, 31, 622.3« Ber., 1880,13, 2342.« Ber., 1881,14, 2468.32 Ber., 1882,15, 2856.33 Ber., 1882,15, 2574.

34 SYNTHETIC USJfl OF METALS34 Ber., 1887, 20, 3386.35 Ann., 1899, 250, 123.36 Ber., 1888, 21,1417.v Ber., 1898, 31, 808.38 Ber., 1892, 25, 293; Her., 1893, 26, GO.39 Trans., 1903, 83, 995.40 Ber., 1883,16, 276.41 Ber., 1896, Ref., 350.42 Ber., 1911, M, 3333.43 J. Amer. Chem. Soc, 1913, 35, 81.

C H A P T E R I I

COPPER AND SILVER

BOTH these metals bring about condensation bythe removal of halogens, for which they havo con-siderable affinity, and so function in this respect assodium, but the reactions are not so vigorous.

The formation of butane from ethyl bromido andof ethylene from methylene iodide are examples ofthis condensation :

2C2H5Br + Cu = CuBr2 + C2H5.C3H62CH2I2 + 4Cu « 2Cu.2I3 + C2H4

Copper or silver can be used to condense /3-iodo-propionic acid to adipic acid, and also for condensinga-brom-propionic ester to dimethyl succinic ester :l

CHo.CH3.COOH2CHoI.CHo,COOH + 2Ag = | + 2AgI

CH2.CH2.COOH2CH3.CHBr.COOR + 2Ag = | + 2AgBr.

CH3,CH.COOROther examples in which finely divided silvor is

used, are, the preparation of suberic ester fromy-brom-butyric ester, and di-isopropyl succinic esterfrom a-brom-isovaleric ester :2


CH2.CH2.CH2.COOK2CH3Br.CH3.CHc.COOR + 2Ag = I + 2AgBr.

CH3.CH3.CH3.COOE(CH,)20H.CH.COOR

2(CH3)2CH.CHBr.COOR + 2Ag - | + 2AgBr.(CH3)2CH.CH.COOR

Copper has been used to facilitate the removal ofhydrogen chloride and potassium chloride in thefollowing condensations.3

Anthranilic acid from o-chlorbenzoic acid andammonia:

• NH3 = C 6 H / ' 2 + HC1,

XJOOH

phenyl anthranilic acid is obtained if anilino bo usedin place of ammonia:

yCl yNH.C6H5C6H4< + C6H5.NH2 = C6H4< + HCL

\COOH \COOH

Further examples of the same class are :yCl yOC6H5

C6H4< + C6H5OH = C6H4< + HC1\COOH \COOH

o-chlor-benzoic acid plienol phenyl-salicylic acid./Cl /SO2.CGH5

CfiH4< + C6H5.SO2K » CGH4< + KC1\COOK \COOK

o-chlor-benzoie potassium phenyl-srilphi-benzoicacid phenyl sulphinate acid.

CH

HC^ C.C1

CH3O.C C.COOH +

l-dilor-4-methoxy- meth.oxy.phenyl-benzoic acid salicylic acid.

C6H5OK + C0H6Br - C6B[5.O.C6H5 + KBrDiphenyl ether.

COPPER AND SILVETf 37Copper is sometimes used to effect condensation by

combining with sulphur. The two following syn-theses of methane illustrate this reaction :

CS2 + 2HaS + 8Cu = CII4 + 4Cu2SCS2 + 2H2O + 6Cu = Cff4 + 2CIT2S + 2CuO.Carbazole is formed when thio-diphonylamino is

mixed with copper powder and the mixture distilledin carbon dioxide :

/C0H4v C0H#1vS< >NH + Cu = I >NH + CuS.

In a similar way j3-dinaphthyl carbazolo is formedfrom thio-j3-dinaphthylaraine :4

< S v CjoHb—CWIT(5

>C1UHC + Cu = \ / + CuS.The action of potassium ferricyanido upon copper

acetylene derivatives is interesting. Diacotylono-dicarboxylic acid is obtained from tlio copper deriva-tive of propiolic acid by troatment with forricyanido :r>

yC : C.COOH C : C.COOII\ C : C.COOH C; C.COOII

If the acid sodium salt of this bo digested withwater, carbon dioxide is liberated and tlio sodiumsalt of diacetylene-monocarboxylic acid is formed :

C; C.COOH C:CHI - 1 ' + CO,.C;C.COONa CjC.COONa

The copper derivative of this compound can nlsobe condensed in the presence of foiTicyamdo, nudtetr-acetylene-dicarboxylic acid resul ts :

yC i C.C: C.COOII C : CO : 0.000 IIc< ' -> r '

NCi0.C:C.C00ir C C.C ' C.COoll

38 SYNTHETIC FSB OF METALS

In using this method, the copper derivative (1. mol.)is added to a solution of potassium ferri cyanide (1 mol.)containing potassium hydroxide (1 mol.), and thomixture is allowed to stand some hours.0

By the same process it is possible to preparediphenyl-diacetylene from the copper derivative ofphenyl-acetylene :

CCH5.C j C.Cu.C i C.CJ-I-, -> CBHfi.C i C.C • C.CflH5.

Diphenyl-diacetylene is the parent hydrocarbonof indigo blue, and the dye itself can be prepared bymeans of this reaction; starting with o-nitro-phenyl-propiolic acid. By loss of carbon dioxide the acidbecomes o-nitro-phenyl-acetylene, the copper deriva-tive of which passes to di-ortho-nilrophcnyl-diacety-lene :

* -> Cel l / * ->NTO3 NNTOa

O j C.Cu.C ; Cv yC • C.C : Cv)>C8H4 -> O J T / \C8TT4

\NO2 ^0/ \NOo NO./The last substance is changed to the isomcric

di-isatogen by alkalis and this becomes indigo whenreduced:

C 6 H / \ c. c / \c f ln4 -> C ( ; H / C ° \ C :

The use of copper salts and of copper itself forthe replacement of the diazo-group of aromaticcompounds, by chlorine, bromine, cyanogen, etc., isimportant.

Halogen substitution products of benzene werefirst prepared by the aid of copper salts in 1884,

CGH4<(

COPPER AND SILVER 39

when Sandmeycr discovered the reaction which isstill named after him :7

CCH5.N:N.C1 -> C6H5C1 + N2.

G-attermann,8 in 1890, showed that the same reac-tion could be carried out, using copper powderinstead of the salts of that metal, and the methodwas applied in substituting by, -01, -Br, -ON, -N0 2

and -CNS groups.The yields by this method were superior to those

obtained by the Sandmeyer method, probably becausethe copper powder was added to the diazoniumsolution in the cold, whereas Sandmeyer recom-mended adding the diazonium solution to a hotsolution of the copper salt.

Later, Erdman, also Armstrong and Wynne (1892—93) used cold solutions of the copper salts and foundthe yiolds by Sandmeyer's method very muchimproved.9

Erdman also showed that there was a definiteoptimum temperature at which, by Sandmeyer'smethod, the maximum yield of halogen compoundwas formod, the optimum temperature referring tothe temperature of the copper salt solution whenthe diazonium salt was added.

Heller (1910) states that by increasing sufficientlythe amount of hydrochloric acid used, quantitativeyields of chlor-compounds are possible by Sand-meyer's method.10

Somotimes condensation takes place in the presenceof cuprous chloride, simultaneously with halogenationby Sandmoycr\s method. When, for example, o-nitranilino is diazotised and treated with cuprous

40 SYNTHETIC USB OF MKTALS

chloride a considerable quantity of Dinitro-diphenylresults as well as o-chlor-nitro-bonzeno.11

Heated metallic copper acts as a catalyst in thooxidation of primary alcohols to aldehydes by air oroxygen, but ifc has also been shown by Sabatior, thatmoderately heated copper in a finely divided statoeffects the dehydrogenation of primary and secondaryalcohols, yielding aldehydes and ketones respectively.

Powdered silver was found by Gomberg to yieldresults when sodium failed, in preparing the peculiarand interesting substance called by him triphonyl-methyl. Both triphenyl brom-methane and triphenylchlor-methane were used to effect the followingchange:

2(C6H5)3C.Br + 2Ag = (C6H5)3O.C(C()H5), + 2AgBr.The hexaphenyl ethane obtained was far more re-

active than was to be expected, and on account ofits properties Gromberg named it triphonyl methyl.Since then much work and discussion have centredaround this substance, which is now gonorally re-garded as being hexaphenyl-ethane.

Various constitutional formula have been sug-gested and the molecular structure of the hydro-carbon is still in dispute, but opinion appoars to givepreference to a formula which ascribes a quinonoidstructure to one or two of the phenyl rings.12

Silver cyanide seems capable of acting in thesame way as molecular silver. For example, itbrings about the condensation of iodo-acetoaceticester forming diaceto-succinic ester :13

CH8.CO.CH.COOC2Hr,ICir3.CO.CHI.COOC2H6 CH8.CO.CH,COOC2ir6

COPPER AND SILVER 41

Silver hydroxide is used in exhaustive methylation,a process often utilised in order to obtain an un-saturated cyclic hydrocarbon from an amino bytreating it with methyl iodide and silver hydroxide;the trimethyl-ammonium hydroxide obtained is thendecomposed by distillation.

Cyclo-butylamine, for example, is converted tocyclo-butyl-ammonium hydroxide, and this on distill-ing is decomposed into cyclo-butylene, trimethylamineand water :14

C H / ;CH.NH, -> C H / ;CH.N(CH3)8OH

/ O HCHo OH + N(CH3)3 + ILO.

Silver oxide suspended in water receives limitedapplication as a hydrolysing agent, and in alkalinesolution it is used as an oxidising agent, especiallyfor converting aldehydes into acids . u

BIBLIOGRAPHY.1 Ann., 1869, 1*9, 220;- Ber., 1895, 28, Kof. 4m.2 Bor., 1880, 13, 473; Ber., 1889, 22, 48.3 Ber., 1904, 37, 853.< Bor., 1886,19, 2243.5 Ber., 1885,18, G78, 2269.6 Ber., 1882,18, 57.7 Ber., 1884, 17, 1633.8 Ber., 1890, 2$ 1218.9 Trans., 1892,&*, 1072.

10 Zeit. angow. Oliom., 1910, 23, 389.« Ber., 1901, 3*, 3802.15 J. Amer. Chem. Soc, 22, 957; Bor., 1900, 33, 3150; Bor., 1901,

3S, 3818.' » Ann., 1889, 253, 182.

14 Ber., 1882,18, 1830.

C H A P T E R I I I

MAGNESIUM. CALCIUM. BAEIUM

THE great value of magnesium as a synthetic re-agent was'indicated in 1900, when Grignard showedhow various hydrocarbons and alcohols could beprepared from the confounds obtained by allowingthe metal to react with alkyl halides in the presenceof dry ether.1 In the previous year Barbior had!shown that by the interaction of methyl hoptcnonc,magnesium, and methyl iodide in ether, and subse-quent decomposition of the resulting product bydilute acid, a tertiary alcohol was obtained, dimethylheptenol :3

(CH,)2C: CH.CH3.Cir2.CO.GH:{ -> (CH3)3C: CH.CH2CH2.C(Oir)(Cir:,)o

The metal has to a great extent replaced zinc,which was used in 1849 by Frankland in tho prepara-tion of paraffin hydrocarbons and the zinc alkyls,and subsequently by Wagner for preparing secondaryalcohol from aldehydes, by Saytzeff in preparingtertiary alcohols from ketones, and by Butlerow inthe preparation of both ketones and tertiary alcoholsfrom acid chlorides.

The advantage of magnesium over zinc depends

MAGNESIUM. CALCIUM. BATJIUJff 43

upon the fact that the organo-magnesium compoundsare not spontaneously inflammable; it is not essentialthat they should be isolated during syntheses, whilethey are more readily prepared than the correspondingzinc compounds, and they are more reactive, andtherefore capable of much wider application.

In practice, tho metal in the form of ribbon orborings is added gradually to a solution of well driedalkyl or aryl halide in dry ether; a brisk reactionusually takes place, owing to the formation of themagnesium compound of type E.Mg.X (X=01,Br,I) .

When all the magnesium has been added and aclear solution obtained, the organic compound to beused in the synthesis (ketone, ester, etc.) is addedgradually, and the mixture cooled in ice to modifythe reaction if necessary.

When the vigorous roaction has subsided, it maybe completed by heating on the water-bath for halfan hour, or it may bo allowed to stand over-night.The next stago is to add ico-cold dilute acid to thoreaction mixture gradually, to decompose the complexintermediate compound formed, and tho end-productis thon isolated by suitable means. If magnesiumribbon is used, it must be first well cleaned withemery-paper, while borings muat be washed firstwith alcohol and then with ether to remove all oil,and then thoroughly dried.

All the reagents used must bo woll dried, and theroaction should be conducted under a reflux condenserfitted with a top tube containing calcium chloride toprevent access of moisture, and some soda-lime tokeep out carbon dioxide. The ether used should be

44 SYNTH HTIC USE OP ]\l RTAI/3

purified by treatment with powdered potassium per-manganate, followed by treatment with solid potashto remove aldehyde, alcohol, and most of thewater. The ether is then allowed to stand overcalcium chloride for two days, and finally over sodiumwire for about a week. Traces of moisture arc veryharmful, and the presence of moisture is indicated bya turbidity which appears when the magnesium isfirst added.

W h e n the magnesium albyl compound does notform readily, i. e. in using aryl halides, a crystal ofiodine is often added to start the reaction. Othersolvents than ether have been used, i. e. anisolc, phenylamyl ether, and dimethyl-aniline. The solvent appa-rently combines with the compound MgRX formingintermediate products R2O.MgllX and BoN.MgllX,and acts as a catalyst, since it has boon found that thereactions proceed in benzene or xylene provided asmall amount of ether or dimethyl-aniline be added.

The constitution of these compounds is represented,according to the suggestion of Bacyer and Villiger,3

by an oxoninm formula with the halogen directlyattached to quadrivalent oxygen, a suggestion sup-ported by Blaise. The dhneUiyl-aniline compound issimilarly represented:

CHr-N

Although the formation of the compound MgRXis the normal course, there is a tendency for themagnesium to form a hydrocarbon by the removal of

]MA<JNILSH!M. CALCIUM. BARIUM 15

halogen from two molecules of RX, which is moremarked as the molecular magnitude of R increases.When working with brom-benzene and benzyl chloridea considerable quantity of diphenyl and dibenzylresult, but this may be ayoided by adopting Barbier'soriginal method of omitting the first stage (prepara-tion of MgRX) and mixing all the reagents at once.This fact was emphasized by Kipping recently, and themethod has also been used with allyl bromide andiodide syntheses with success, although the allylhalides do not form a compound of the type MgRXin the presence of ether.*

The following syntheses wero carried out by meansof zinc, prior to 1900, and are now more convenientlyaccomplished by the aid of magnesium:

PARAFFIN HYDROCARBONS.

MgK3 + 2H2O = 2EII + Mg(OII)2EMgX + II2O = EII + MgX(OII)"EMgX + ENH2 = E.E + MgXNH2

= 2E,C "

SECONDAUY ALCOHOLS FROM ALDEHYDES.

/O.M*r.X + I I C

E.CIIO + R'.Mg.X -> R.C—E' • J>C1IOII + MgXCl.\ I X E ' /

If formaldehyde be used, a primary alcohol results :5

yOMg.X + n C 1

1I.CHO + E.Mg.X -> II.C—E > E.CHoOII + Mg-XCl.

46 SYN'LLIETIO UfciK OF METALS

TERTIARY ALCOHOLS FROM KETONE>S.

X)MgX 1IC1

E.CO.E + E'.Mg.X -> E.C—E > EoR'COlI + M-^

KETONES AND TiflliTIAliY ALCOHOLS l iOM ACIDCHLORIDES.

K.COC1 + E'.Mg.X -> E.C—Cl -> E.CO.14' + MgXOJ

With a second molecule of Mgli'X the followingchange takes place :

/>MgX , x /OMgX• E.C.—E'

TERTIARY ALCOHOLS FROM ESTERS.

+ E;/.Mg.X -> B < c — o R / "LjfJt E.C—I

E.C—E;/ > EE7/2COn + MgXCl.

With formic ester a secondary alcohol is obtained :

/OMgX vOMgXH.COOE + E'.Mg.X -> II.C—OE -> H.C—E' ~> E'aCHOII.

\ E 7 \ E /

A dicarboxylic ester like oxalic ester may have onlyone carboxyl group acted upon at a time :

MAGNIUfcJJUM. CALCIUM. BAH HIM -17

yOMgX MgCOOK , « / / \ , , R'3C.OIICOOK N&' SR' OOOE

COOE COOEDialkyl glycollic

ostor.

Since 1900 various syntheses have been added, ofwliicli the following are typical examples :

TIIJBTIARY ALCOHOLS VROM OAKBONYL CuLorjDjyj.

COC], + 3E.Mg.X = KjCOMg-X + 2MgXClR3C0MgX + IIC1 = R3C.OH + MgXCl.

ALDEHYDES PKOM FORMIC AND ORTUO-POUMIC ESTEUS.

/ O M - X + HCI

1I.COOE -1- li'.Mg.X -> H.C—Oli > R'CIIO + EOH + MgXCl.

/ 0 K +R'MgX / 0 E + ILO11,0—011 > II.C—OH --> E'.CHO + 2K0II.

KBTONES PROM CYANOGEN, JSTITRILES, AND AMIDES.0

^NMgX +M-EX 7/NMgXN -. C.C i N + ll.Mg.X -» N: C.C\ > R.cfCyanogon R Mi

.NMgX + 11,0 + IIC1E.CT : > E.CO.E + NiL< + MgXOl.

\E

^ g + IJ.,0 + IfClR.CN + ti'MgX > ll.Cf '* >Niirile XE'

E.C0.E; + NIL, + MgXCl.

+ 2E'M^X-> E.C— U' + It'll

48 SYM'IIKTK! UriK OK

+ NIL, + 2MgXCl.

DIAZO-AMINO COMPOUNDS FROM AZOIMIBES.

+ K/Mg-X ~-> E.N(MgX)N: N.R'

ANILIDES FROM AKYL OABBIMIDES.

.OMgXCoHa-N: CO ~> C6HVN : C< -> C0H3.NH.COK.

HYDEOXYLAMINB DERIVATIVES FROM ABIYL NITRITE.

C5HU.O.NO + 2MgEX = Eo TOMgX + MgOC5H13X+ HC1 = iySTOH + MgXCl.

Esters of the type R.COOK aro obtained by theaction of MgRX upon esters of meta-carbonic acid :

.OMgX ^oCO(OEt)k> + EMgX -> (EtO)oC<; -> EtO.C<

Triplienyl methyl chloride in benzene solution re-acts with an ether solution of RMgCl thus :7

(C6H5)3C.C1 + RMgCl = (CGH6)3C.EHydrocarbons are formed by the action of methyl

sulphate upon E M g X :(CH3)3SOi + EBTgX = B.CII3 + CII3(MgX)SO4.

Unsaturated hydrocarbons may be obtained fromaromatic aldehydes via the carbinols, which on distil-lation sometimes decompose, as phenyl-benzyl-car-binol does; into stilbene and water :8

MAGNESIUM. CALOIUM. BARIUM

C6H5.CHO + CflH5.CHj.MgBr -» CoH5.C

Sometimes the unsaturated hydrocarbon is formeddirectly, as with benzyl chloride and anisic aldehyde :

MgC6H6CHoCl + CoHX -> CGH5CH: CH.C6H4.OCH.,.

Benzyl alcohol may be obtained from benzylchloride by the action of oxygen:CcH6CH2.MgCl + O -» CflH6CHs.O.MgCl -» C6H6CH2OH + Mg(OH)Cl.

Tertiary alcohols and ketones result from acidanhydrides:

R.CO K.CO\ o -> No -> E.COOH + B.CO.E + Mg(OH)X.

R.CO R.C—OMgX\R

P r o m s u c c i n i c a n h y d r i d e a d i t e r t i a r y g l y c o l r e s u l t s :

CH2.CO CH2.CR2OH

CH2,2,CO CH0.CR0OH

From phthalic anhydride similai^ly dimethyl-^diethyl-, and dipropyl-phthalide are obtained:

>CO >CB2

CCH4 No + 2EMgX -> C6H, ^OH -» C6H4

\CO ^COOH

C a m p h o r i c a n h y d r i d e w i t h b e n z y l c h l o r i d e g i v e s

t w o i s o m e r i c c a m p h o l i d e s :

. 0 0 X(CH2C6Hr))2 .COV " ~ ~ V ^ and CdHM N o

50 SYNTHETIC USE OP METALS

a-Diketoncs give ditertiary glycols, as in the caseof benzil to tetraplienyl glycol:

CfiH5.CO C((H5C(OH)K

C6H5.CO C,lTr)C(OH)K

If only one carbonyl group be attacked, phony]benzoin results:

C(JH5CO.CEOH.CGHf,

Acids are formed by the action of carlbon dioxideupon E.Mg.X:

<MgX + HC1> R.COOH + MgXCl.

Many organo-rnetallic compounds can be preparodby digesting- an etliereal solution of tlio magnesium^alkyl or aryl halide with the metallic lialogon com- -•pound.

The following compounds have been preparod in tin'sway:

Sn(C2H5)45 Sn(CflHG)4, Pb(C0H5)4, Pb(CHr{)4, I^(OuH0)^

and an optically active silicon compound in whichfour different radicles are present, Si(C3HG) (C3II7)

(OflH6)(OH2CfiH5)-9

Pivalic (trimethylacetic) acid is formed from tertiarybutyl chloride and magnesium (yield, 30 por cent.) :

+ Mg + CO2 /O(CH3)3C.C1 > (CH3)3C.Mg.Cl > (CHa),CC<

Tetramethyl-methylene-glycol from succinic estor:

MAGNESIUM. CALCIUM. BARIUM 51

.OMgXCH2.COOR CH2.C -R + 2MgRX

OROMgX+ 2R.Mg.X -

CH2.COOR CH2.Cc-R CH2.C -:

- \ -,OMgX

+ 2HC1 CH2.CR2.OH

k + 2MgXCl.c2.CE2.OH

(A ditertiary glycol is also obtained from oxalic ester.)By the same reaction this can be obtained from

acetonyl acetone:

CH2.CO.CH3 CH2.C^R CH2.C(CH3)R.OHXCH3.OMgX •*

,CO.CH3 CH2.C -R CH2.C(CH3)R.OHXCH3

The ketonic group of a-tetonic esters is attackedin preference to the carboxyl group. Prom pyruvicester is obtained a-methyl lactic ester:

yOMgXCPI3.CO.COOR + MeMgX -> CH3.C^COOR ->

NvteCH3.C(Me)(OH).COOR

y-Ketonic esters, such as laevulinic ester; behavein the same way:

OHCH3.CO.CH2.CHo.COOR -> CH3.C -CH2.CH2.COOR

XR

j3-Ketonic esters, such as acetoacetic ester, show asomewhat different behaviour. The ethyl and menthylesters both react with MgRX as if possessed of anenolic structure, and the magnesium compound fox'med

52 SYNTHETIC TTSE OF METALS

is decomposed by dilute acid, giving the originalacetoacetic ester :10

CH3.C(OH) :CH.COOE + E'MgX = CH3.C(OMgX): CH.COOE + E'HCH3C(OMgX):CH.COOE + HCl « CH3.CO.CH2.COOE + MgXCl

When, however, enolisation is retarded by an alkylsubstituent in the methylene group, the reaction fol-lows the same course as a- and y-ketonic esters :

CH3.CO.CHE.COOE -» CH3.CE'(OH).CHE.COOE

If the carboxyl group be next attacked by MgR'X,the following change takes place, resulting in a sub-stituted trimefchylene glycol:

CH3.CE'.CHE.COOE CH3.CE'.CHE.CE'2

OH ~* OH OH

The tendency to form organo-metallic compounds,seen in the metals of group 1 (alkali metals) reachesa maximum in the metals of group 2 ; it diminisheson passing through groups 3, 4 and 5, and none ofthe metals in groups 6 and 7 combines with organicradicles. The property reappears in group 8, whichcontains the transitional elements.

Aluminium, thallium, indium and lithium formcomplexes with alkyl or aryl halides, which are de-composed by water, with the formation of hydro-carbons.

These compounds are not produced in the presenceof ether, but by heating the halogen derivatives withthe metal.11

Two important applications of the Grignard reagentto synthesis in the terpene series may be mentioned.

The formation of dipentene from S-keto-hexahydro-benzoic acid (see p. 14) by Perkin involved the

CALCIUM. UAlilUM 53

following stages : Tho ester was troalod with mag-nosium methyl bromido, and tlio addition compoundgave on hydrolysis S-liydroxy-lioxahydro-p-toluicostor:

yCiia.cii3v xjjT8.cxrav xOiiKOOC.CII CO -> ROOC.OH C

This ostor was then converted into §-brom-hoxa-liydro-_2>toluiocstoi% by tlio action of hydrogen bromido,and from this, by romoval ot II Br with alkali orpyridino, AR-tetra-hydro-y-toluic ostor was obtained;

>CII2.CILjV y\\t yCili.CiLEOOC.CII C -> KOOCJ.CII C.OU3

Troatmonb oi: this ostor with 2MgMoBr gavetcrpinool, which was converted into dipontono bydehydration with acid potassium sulphate :

o i r , \ / O i /1 ;c(on).ou " ecu , -> " . ecu coir ,

Tho synthesis of A:J:B(0)-2^monthadiono from ethyl-A8-totrahydro-j>-toluato involved tho following stages:

OIL, CLT3 0HH

on on ctn

iiac Clio u^' ojr2 nBo on.

nac on *"> ua<! e n ""v n^o on\<s \ \

0 0 COOOR 0 0

/ I \ <ifia ona

Oil CUaCIIj

5 4 SYNTHETIC USE OF METALS

CALCIUM AND BABIUM.

These metals, so alike chemically and physically,have been closely associated together in the solv-ing of the problem of atmospheric nitrogen fixa-tion.

Calcium has received some application in organicsynthesis similar to that of magnesium; alkyl andaryl compounds, CaR2; have been prepared, and itseems likely that many of the magnesium syntheses,already mentioned, could be accomplished by the useof calcium.

The compounds of calcium and barium, instru-mental in bringing about nitrogen fixation, are thecarbides, the preparation of which has been renderedpossible by the advent of the electric furnace. Thismeans of attaining very high temperatures came intogeneral use during the eighties of last century, andrendered possible the preparation, on a largo scale,of many new and useful substances.

In 1895, Erank and Caro found that when bariumcarbide was heated to redness in air the main productwas barium cyanide, but simultaneously a cortainamount of barium cyanamide was formed. Thesetwo reactions, therefore, proceeded side by side:

» Ba(CN)3 ; BaC2 + N2 = BaN.CN + C

These workers subsequently found that when cal-cium carbide was used the cyanamide was the mainproduct, while the cyanide became the by-product.

These efforts to prepare a nitrogenous land ferti-lizer promised success, since the cyanamido decoin-

MAGNESIUM. OALCJUM. J3AKJUM 55

posed easily in the presence of water, yielding am-monia and lime :

CaN.CN + 3H3O « CaCO3 + 2NH3

Later work has shown that cyanamide o£ lime isnot only a valuablo fertilizer product, but that itcan be used for a variety of purposes and trans-formed into various useful products.

Eleven European factories were making the sub-stance in 1909, and their yearly output was estimatedat 166,000 tons, while in the same year the AmericanCyanamide Company erected at Niagara, plantcapable of yielding 20,000 tons per annum. Thesubstance is sold for agricultural uses under thename of nitrogen lime (Gorman, Kalkstickstoff), andhas been shown to be equal in value to an equivalentof calcium nitrate.

Since 1901 it has boon found unnecessary to preparethe carbide itself in tho first place, and necessary toexclude oxygen, so that now the process involves theheating together, in an electric furnace, of lime andcarbon in atmospheric nitrogen, when the followingchange takes place:

CaO + 2C + N3 = CaN.CN + CO.

The complete decomposition of the cyanamide intocalcium carbonate and ammonia may be accomplishedin stages by suitably arranging the conditions, so thatthe first substance to bo formed is cyanamide itself,which is then transformed into urea, and the thirdstage involves the hydrolysis of urea into carbondioxide and ammonia :

56 SYNTH KTIC USE Ol1 MKTALS

CaN.ON + 2II3O = Ca(OH)s + NH2.CNNHS.CN + H3O - CO(NH2)2

CO(NH8)4 + H3O = CO2 + 2NH3

Under ordinary soil conditions all tlio above stagesare realised, but by heating with, water under pres-sure, complete decomposition into calcium carbonateand ammonia takes place.

The chief uses of calcium cyanamide are as follows :(1) By decomposition with steam it is used for

preparing ammonia and ammonium salts.(2) When fused with sodium carbonate, or chloride,

and carbon it yields sodium cyanide :

CaN.CN + Na.2CO3 + C = CaCO3 + 2NaCN.

Hundreds of tons of cyanido arc manufacturedannually in this way in Europe, and in Mexico it ismade in the mining districts.

(3) I t roceives some application in the caso-hardon-ing of steel.

(4) By the action of dilute acids, dicyanamido isformed :

2CaN.CN + 4.11*0 = 2Ca(OH)2 + (CN.NH2)a

Dicyanamide is used in largo quantities by dyersand explosive manufacturers. Its presence in gun-powder tends to lower the temperature of the gun-barrel.

(5) Artificial urea made from cyanamido is usedin large quantities for certain pharmaceutical pre-parations :

CaN.CN + 31LO » Ca(OII)2 + CO(N1I2)2

(6) Large quantities of guanidino are made fromcyanamide. Two methods aro available for this

MAQNHSJLUM. CALCIUM. BARIUM 57

preparation ; either the cyan amide may bo treatedwith ammonia, or it may bo reduced with zinc andhydrochloric acid. In the latter method, mcthyla-mine is produced at the same time by reduction ofthe hydrogen cyanide formed :

CN.NII, + NUj ~ II

.NIL,2C3ST.NII2 + II) = UN: C< + IICN

NNH3

HCN + 2H3 - CHj.NII2.

(7) Creatino is prepared by combining cyanamidewith sarcosino (methyl glycine) at 100° 0. :

CN.NH2 + ClIy.NH.CIL COOH = \c.N(CH3).CH3.COOH.

(8) Another method for proparing cyanide dependsupon the heating of dicyanamide with alkaline car-bonate and carbon. Ammonia is formed at tho sametime and is generally absorbed in sulphuric acid.

2(CN.NII2)2 + 2K2COa + 4C = 4.KCN + 2NHa + II3 + 6CO + N2

A process patented in 1903 by the Amp&re Electro-Chemical Co. (U.S. patent 71922C) for tho prepara-tion of barium cyanide and acetone is as follows:

Barium hydroxide and carbonate are heated withcoke in a revolving electric furnace. Tho bariumcarbide formed, rolls down into a cooler region andthere comes into contact with a stream of atmo-spheric nitrogen, and the resulting cyanide is with-drawn :

58 SYNTHETIC USE OJi1 METALS

Tho cyanide is next treated with acetic acid toliberate the hydrogen cyanide, which is then passedinto alkali:

Ba(CN)3 + 2Cn3COOH «= (CII3COO)2Ba + 2HOT

The acotato is thon submitted to distillation, where-by acetone is formed,, and the barium carbonate isusod. over again :

(CH3C00)aBa = CHj.CO.CH3 + BaCO3

The "by-product of the first stage, barium cyanamide,is separated from the cyanide and converted intoalkali cyanido by fusion with carbonate :

BaN.CN + Na2CO3 + C = BaCO3 + 2NaCN\

The preparation of nitrides from atmosphericnitrogen making use of calcium or magnesium, hasboon the subject o£ much investigation and o£ manypat outs.

Tho nitrides are easily decomposed by the weakestacids, oven by carbonic acid, liberating ammonia, andoften they can bo decomposed by water.

Some processes depend on the fact that the oxideof a nitride-forming metal is reduced to the metalliccondition, when heated in the electric furnace withcarbon in tho requisite quantity, and if a streamof nitrogen be thon blown through the fused mass,nitride is formed.

Magnosium has, for example, been utilised in thisway :

23%O + C - 2Mg + CO2 j 6Mg- + 3N3 = 2Mg3N2Mgstfa + 6H2O - 8Mg(OH)2 + 2N"H3

The French Patent, 350966, depends upon theproduction of calcium hydride which is formed by

MAGNESIUM. CALCIUM. BA1UUM 59

heating tlio metal in hydrogen ; the hydride is nextconverted into the nitride by a stream of nitrogen,ammonia being formed at the same time :

Ca + II2 » CaH2 ; 3CaH2 + 2N2 - CaJST2 + 2NHjCagNs + 6H2 = 3CaH2 + 2NH:{

The nitride is then heated in hydrogen to decom-pose it in the manner indicatod above; the methodis one., therefore, of continually fixing atmosphericnitrogen and converting it into ammonia. In de-veloping this method it has been found that eithercalcium or magnesium may be used, or a mixtureof the two metals ; also that it is immaterial whetherthe hydrogen and nitrogen pass over the metalseparately or together ; and instead of hydrogen itis possible to use water-gas.

The reaction may, therefore, be regarded as asynthesis of ammonia from its elements in thepresence of magnesium or calcium.

Another process for the fixation of atmosphericnitrogen is the subject of an English Patont, 1894,13315.

A heated air-blast is passed into the bottom of avertical furnace containing a mixture of alkalinecarbonate and coal (the carbonate may be replacedby or mixed with oxide, hydrate or nitrate), wherebya cyanide results, which is carried up in the form of afume and at a suitable height is decomposed by ajet of steam, into carbonate and ammonia, the latterbeing collected in condensers :

IC3CO:, + 40 + Ns = 2KCN + 300KOT + 2H2O = H0ONII2 + K01I

HCONiJ2 = CO + NIL,00 + O » COjj 5 G02 + 2K01I «'K3COJ' h 1I2O.

60 SYNTHETIC U8K OF METALS

Tlio K20O3 is allowed to fall down to the "bottomof the furnace and the process is repeated. Theentire reaction may be represented by the followingequation :

2KCN + 3H2O + O2 - K2CO3 + 2NH3 + CO2

This process may evidently be used to yioldammonia and formic acid if the reaction is rogulatedto bring about the following change :13

KCN + 2H2O = HCOOK + NH3

Two applications of the calcium and barium saltsof various organic acids are common and of greatimportance.

Firstly, the calcium and barium salts of organicacid are frequently used in the preparation of theacids themselves, by treatmont with mineral acidssuch as sulphuric, hydrochloric or phosphoric. Thismethod was first utilised by the Swedish chemist,Scheele (about 1770), who discovered by this meanstartaric, citric, malic and oxalic acids.

Secondly, by the dry distillation of the calcium andbarium salts of organic acids, ketones are formed:

(CH3COO)aCa = CaCO, + CH8.CO.CH3

If the salt of formic acid be mixed in molecularquantity with the other salt then an aldehyde isproduced:

(HCOO)2Ca + (CHjCOO)aCa = 2CH3.CHO + 2CaCOy

Certain cyclic ketones have been formed in thisway, and from them, the cyclic hydrocarbons.

For example, the calcium salt of adipic acid yieldson distillation, adipoketone (keto-pentamethylone),

MAGNESIUM. CALCIUM. BARIUM 61and this by reduction and subsequent use of hydrogeniodide gives pentamethylene:CHo.CHo.COOCH2.CH2.COO (

CH2.CH2 r(-» 1 Sco -CH2.CH23Ho.CH« ^>r rocluc\OHICH2.CH3

+ HIjduce CH2-CH2

CH2~CH2CH2.CH2-> ")CH2CH2.CH2

In a similar manner hexamethylene can be pre-parod from pimelic acid, and heptamethylene fromsuberic acid :

.CH2.CH2.COO .CH2.CH2 .CHCHCIL \ca -> CH3 ScO -»CH2\CH2.CH2.COO \CH2.CH2CH2.CH2.CH2.COO CH2.CH2.CH2\ S2 \c

2.COOICIL,.CII,.CII2." - CH2.CH2.CH2

CH2.CH2.CH2

By means of this reaction Haller obtained camphorfrom camphoric acid.13

The complete process was as follows; camphoricanhydride from camphoric acid was reduced withsodium amalgam to campholide, and this combinedwith potassium cyanide gave homocamphoric nitrile.The nitrile was hydrolysed, and the calcium salt ofthe resulting homocamphoric acid, on heating, gavecamphor :


—II >O reduced + TCCN.coon "0,11,/ -> C

\ c o o nhydrolyse

>CHo.ON /CII..COOH /CT-Lcy*, / " -> cbnn<; - -> CSITU<; i -

XI00K XJOOH \ COThe Lydroxides of magnesium, calcium and barium,

liavo played an important part in the synthesis ofsugars.

In 1801, Butlorow digested an-aqueous solution ofcalcium hydroxide with trioxy methyl one (a polymerof formaldehyde) and obtained a sweet yellowishsyrup.14

In 188G, Loow prepared a syrup which he termedformoso, by shaking a 4 per cent, solution of formal-dehyde with milk of lime and then filtering.After standing for live or six days, the solution wasevaporated and a syrup obtainod.15

A few years lator (1889) ho used magnesiumhydroxide, and by the same method obtained a sweetsyrup which was fermentable and which ho termedmothosc.10

The above throe syrups all appear to have con-tained a-acrose, which Emi] Fischer isolated in a purestate in 1887, by the action of baryta water uponacrolein bromide, when a mixture of a- and /3-acrosewas obtained.17

SCjHiOBra + 2Ba(OII)2 = C(5ir]20(, + 2BaBr2

Fischer subsequently obtained a-acrose alone, bytho polymerising influence of one per cent, sodiumhydroxide uponj^glycerose, an oxidation product ofglycerol.18

MAGNFSIUM. CALCIUM. BARIUM 63

CILOII CH,OII cn>on CB\OIII - I - I - I *

CHOH + CO -v CHO1I CO

CHO CHoOH CIIOH CHOTI

BIBLIOGRAPHY1 Compt. rend., 1900, 130, 1322.2 Compt. rend, 1899, 123, 110.{ Ball. Soc. Chim, 1907 (iv), 1, 6104 Bei\, 1909, 52, 435.r> Compt rend., 1902,134, 107.G Compt. rend., 1901,133, 299.~' Ber., 1906, 39,1461.8 Ber., 1904, 37, 453.q Trans., 1901, 79, 451; Proe, 1903, 290; Trans., 1907, 91, 209

10 Trans., 1906, 89, 380.11 Ber., 1905, 38, 905; J. prakt. Chom., 1908 (ii), 78, 97.12 Zeit. angew. Chem, 1912, 25,12G8>3 Compt. rend., 1896,122, 446.»4 Ann., 1861,120, 295.11 J. prakt. Chem., 1844, 33, 321.1(' Ber., 1889, 22, 475.V Ber, 1887,20,1093, 2566, 3384 ; 1890, 23, 21251S» Ber, 1891, 27, 3190.

C H A P T E R I V

ZINC AND MERCURY

TEE use of zinc for preparing ketones and tertiaryalcohols from acid chlorides, has received widerapplication since Michael showed how it might beused in a similar manner to magnesium, withoutisolating spontaneously inflammable organo-zinc com-pounds. It has been used largely by Blaise and hisco-workers in synthesizing ketones and cyclo-acetals ;it is less reactive than magnesium, and is, therefore,complementary to that motal in synthetic work.

The zinc organo-halide is prepared for use byheating together the zinc-copper couple, the alkyl oraryl halide, ethyl acetate, and toluene for about anhour, the reaction being started if necessary with acrystal of iodine. All the roagonts must be welldried, and the colourless viscous liquid which resultsis utilised by adding to it the acid chloride dissolvedin toluene, and when the required amount has beenadded the intermediate zinc complex is decomposedby the addition of dilute sulphuric acid.1

Blaise synthesised aj3-unsaturated ketones, andketone-alcohoLs as follows: A |3-liydroxy-aliphaticester is prepared by condensing a kctone with an

ZINC AND MKBOTRY 65

a-halogen substituted ester by means of zinc (liefor-niatsky's reaction) :

R.CHBr

COOR

The j3-hydroxy-aliphatic acid is then acetylatedand converted to the acid chloride by thionyl chloride,,after which the acid chloride reacts with ZnRX, toproduce an acetoxy-kctone which is liydrolysod to ana/3-unsaturated ketone :

HO.CHR.CHE'.COOH -> A.cO.CIIE.CIIir.COCl —->"-» AcO.CHR.CHE'.GOE" -> RCH: CR'.COR''

If however, there is no hydrogen atom in thoa-position, a saturated koto-alcohol results:

AcO.CHjj.CRo.COR" ~> HO.CH2.CE2.COE'7

)3-hydroxy-a«-dimetl]yl propionyl chloride, forexample, changes in this manner.2

The semi-acid chlorides of succiuic and glutaricacids yield keto-acids by treatment witli ZnRl :

CHo.COOE CHo.COOE CIL.COO1I

OII2.COC1 CJIo.COB cna.COR

Diketones are obtained from tho acid chlorides ofadipic acid and higher acids of tho scries :

/COC1(0Ha)< ->

This change is not applicable to saccinic andglutaric acids.3

Compounds of tho type E.CO.O.CLILl.COC] givecyclo-acetals, probably by the following change :

/O—C<KZnIO.CRa.O.CHRCOCl -> lUlS


These cyclo-acetals may be hydrolysed, forminghydroxy-acid and aldehyde :4

Cnru_o^>CHR' + H2O = KCHO + R'CHOH.COOH.

The use of zinc in those syntheses which are nowgenerally carried out by the aid of magnesium, hasalready been mentioned, p. 45.

A further application of zinc is seen in a reactionfirst carried out by Reformatsky in 1887, in whichhalogen substituted esters are condensed with ketonesor with ketonic esters. An example is afforded bythe production of j3-hydroxy-isovaleric ester fromacetone and iodo-acetic ester; a zinc addition com-pound is probably formed; and on the addition ofdilute acids is decomposed. This reaction is there-fore represented in the following manner:

CHav / I CHjv yOZnL>CO + CH< -> >C<

CEL/ " XJOOCgH* CIV XCH2.C0OaH5

CHav .OZnl CH3v /OH>C< + HC1 - >C< 4 ZnlCl.

CH,/ \CI-L.COOGoH5 CH/ \C

Citric ester has been synthesised in this way frombroni-acetic ester and oxalyl-acetic ester :5

CH.,Br CO.COOCH, CH, C(OH) CH,

COOC.2H3 CH3.C00C0H5 OOOCoHs COOC0H5 COOC2H3

Another esamplo is camphoronic acid (aa/3-tri-niethyl-tricarballylic acid), an oxidation product olcamphoric acid, which can be synthesised froma-broin-isobutyric ester and acetoacetic ester.5

ZINC AND MERCURY 67

(CH3)oC.Br CO.CH3

"| + 1 ->

COOC2H3 OHo-COOUjlI,,

(CH8)3C C.CH, CH2

COOC3H3 OH COOC2H3The liydroxyl group of this hydroxy-trimethyl

glutaric ester is replaced by chlorine, this again bycyanogen, and the nitrile gives the required acid onhydrolysis, dl-camphoronic acid:

(CH3),C C.OH3 CJrLI I I ->

CN COOG2li5

I ICOOCH C

(CH3),C C.CII3 GIL

(JOOH COOII COOH

Magnesium has been used in place of zinc for thistype of synthesis.0

Zinc is frequently used for bringing about con-densation by the elimination of halogen or ofhydrogen lialide.

For the preparation of hydrocarbons it may re-place sodium in the Wurtz-Fittig reaction :

2GoHrjI + Zn = Znl> + CHu,.Ill reactions where hydrogen halide is eliminated,

zinc plays a somewhat similar role to that of alu-minium or aluminium chloride in the Friedel-Craftsreaction (Chapter V).

Naphthyl-phcnyl-ketone is obtained from naphtha-lene and benzoyl chloride, in the presence of zinc :7

C1()LL3 + O(,HdCOGl =- eiulJr.OO.C()Ll, -1- Jit1].Phenyl-tolyl-metluino L'rom bouzyl chloride and

toluene is another example :C6H6.CII2CI + cji.,.01^ =- c0uo.0Ji3.0(,ii1.ciitl \ un .


A recent and interesting use of zinc is found inthe preparation of keten, the simplest of the ketides,from brom-acetyl bromide.8

After an unsuccessful attempt to remove thechlorine from chlor-acetyl chloride, it was foundpossible to remove the bromine from brom-acetylbromide by treatment with zinc turnings, in etherealsolution. Tor this purpose the brom-acety] bromide(50 gms.) was dissolved in ether (250 gms.) or in aceticester (200 c.cm.), and the mixture was then droppedon to zinc turnings, in a distillation flask. A vigorousreaction took place and the product was allowed todistil over, in a current of hydrogen gas.

The keten was isolated by passing the mixedvapours through a vessol immersed in liquid air andwas found to be a gas at ordinary temperatures,which liquefied when cooled to — 56° and solidifieda t — 1 5 1 ° :

CII.Br.COBr + Zn = CH3: CO + ZnBr2.Methyl and ethyl keten can be prepared by tho

same method using a-brom-propionyl bromide anda-brom-butyryl bromide respectively, but the yieldsare smaller than with keten itself :

CH3.CHBr.COBr + Zn - CII,.CII: CO + ZnUr8C2H5.CHBr.COBr + Zn = C2H5.CH: CO + ZnBr3.

Carbon suboxide (03O3) may be regarded as ketenin which the two hydrogens of the methylene grouphave been replaced by the carbonyl group :

H2C : CO CO : C : COKeten Carbon suboxide.

This substance was prepared in 1906, by heatingmalonic acid with phosphorus pentoxide at 300° under

ZINC AND MERCUKY 69

reduced pressure (12 mm.). Carbon suboxide is acolourless gas at ordinary temperatures, its boilingpoint is + 7° and the melting point of the solid is— 108°. I t is to be regarded as malonic anhydride,since it is formed by the removal of two moleculesof water from malonic acid and because it recombineswith water, forming malonic acid :9

XJOOII >;COCH< = C, + 2H,O.

" XX)0II CO

This oxide of carbon can also be prepared by theaction of zinc turnings upon di-brom-malonyl bromide:

.COBr -COCBi\< + 2Zn = O{ + 2ZnBr,.

^C ^

Zinc is a valuable reducing agent in acid, alkaline,or neutral solution, and in the dry state it is used toremove oxygen from phenols and other oxygen-containing bodies. By mixing alizarin with zinc dust,and heating the mixture, Graebe and Liebermann in1886, reduced the dye-substance to its parent hydro-carbon^ anthracene.

In effecting the reduction of oxygen compoundsby this method, zinc dust ii mixed with the substanceto bo reduced, and the mixture is then heated in acombustion tube. The reduction is often facilitatedby passing a stream of hydrogen or carbon dioxidethrough tho heated mixture :

C0I-I5OH + Zn = C,,Hb + ZnO ; C10H7OH + Zn = C,OHS + ZnO.

By this method succinimide can bo converted topyrrol, and hoino-phthalimide to isoquinoline :


CH2.00 CH: CIIT I 2Zn N

OIL CO OHrCIL2ZnO

,/PI, 00 ^\ + 2r/n = r.,11, | + 2ZnO.

Homophthalimidc itself is produced by reducingphthalic anhydride and then hjrdrolising the cyano-nddition product; the ammonium salt of the acidformed is then heated :

CO CTI2 + I C 0 N CH2CN(^H,^ j>0 -v C()Tl/ V) > C([T, ->

CO CO N'OOIC.CH,.COOJI

CIL.COONIT, CHj.COi^ - \NI-T + Nfla + 211,0.

Ct(II(.CO

ZINC

This substance is used to effect condensation bythe elimination of water, ammonia, or hydrogenchloride.

I t was used by Groves in 1874, to prepare ethylchloride by the interaction oF ethyl alcohol andhydrogen chloride : ]0

C^OII + HC1 = 0,11,01 + II2O.

Illustrative of the power of zinc chloride to elimi-nate the elements of water, is the fact that many ofthe higher primary alcohols when heated with thisreagent, become converted into olefine hydrocarbons.

ZINC AND MTUKOimY 71

Homologues of the phenols can be prepared byheating a mixture of the phenol with a primaryalcohol and zinc chloride at 200°; thus, from phenoland isobutyl alcohol is obtained isobutyl-phenol, whilefrom cresol tho analogous isobutyl-crcsol results :11

CV,H5OII + (cn:,)2cH.rH3on — (CF:i):tc.o,H4.oir + TT.,O.CH, OIL,

I I + (CH3)2CH.CILOII = I + HoO.

Alkyl ethers of the phenols are formed simul-taneously.

The production of phthaleins by zinc chloride isexemplified by the condensation of phthalic anhydrideand dimethyl-aniline :

CfiH4.N(CTT3)attO+ 2OGH5.N(CH3)a = | | \C,,H4.

co —. oThe leuco-base of malachite green is formed by

condensing benzaldehyde with dimethyl-aniline in thepresence of zinc chloride:

CCIT5.CHO + 2C(1Hri.N(CH3).. = C6\Lt.CE<( + IIaO.\ o n N c r

Acid chlorides condense with acid anydrides,hydrogen chloride being eliminated in tho presenceof zinc chloride :^

CV,H5.COC1 CGH5.CO Q.lira.CO.C,1H4CO+ >O = No + 2HO1.

Cfin5.COCl CfiHB.CO QHB.CO.CTlIT.iCO

Acvidine and its homologues are fomned by heating


the acidyl derivatives of diphenylamine with zincchloride :13

c a o XJH^

The method of Groves for preparing alkyl chlorideshas been improved by Delm and Davis, who recom-mend the use of phosphorus trichloride instead ofhydrogen chloride.

The reaction is represented by the followingequation :14

PC13 + ZnCl2 + 3C3H7On = 3C3H7C1 + 2HC1 + ZnHPO3.

While the maximum yield by Groves' method, usinghydrogen chloride, was 28 per cent., they obtained bythe above modification a yield of 90 per cent, ofpropyl chloride, and with isobutyl and isoamylchlorides tho yields were 60 and 70 per cent, respec-tively.

Many condensations are brought about with theelimination of ammonia, by zinc chloride.

Naphthylamine and methyl alcohol yield naphthyl-methyl-cther:

C1()1I7.NII2 + CIT3OII - CJ0II7.O.CH, + NII3.

Phenyl-hydrazoncs of aldehydes and ketones loseammonia and form indol derivatives.15

Acetono phenyl-hydrazone gives a-metliyl-indole,whilo tho hydrazone of propaldehyde gives j3-methyl-indole :

O(lII6.NTI.N : C( = CcH/ )C.CH3

\ NH/C.cn3v\ NH /

ZINC AND MERCURY 73

Zinc chloride may bo used to assist the introduc-tion of acetyl groups by means of acetic anhydride,10

A saturated alcoholic solution of tlie chloride maysometimes be used instead of the solid itself. Forexample, by warming o-amino-cinnamic ester in analcoholic solution saturated with the chloride, wateris eliminated and n-ethoxy-quinoline results :17

/CH:CH.COOaH5 / CH/ " = cyau' | + ir8o.

coa i i

Metallic zinc may be used as an oxidising catalyst.When the vapour of alcohol, mixed with air, ispassed through a tube containing heated zinc, a yieldof aldehyde amounting to 80 per cent, may beobtained.

MERCURY AND MKRCURY COMPOUNDS.

The use of mercury and its compounds is confinedto the substitution of halogens and to oxidation.

The aluminium-mercury couple (prepared by im-mersing aluminium foil in mercuric chloride solution)is a halogen carrier of some value, and is used to facili-tate substitution in. the aromatic series of compounds,by chlorine and bromine.

For this purpose the hydrocarbon or the body in (,owhich it is desired to introduce bromine is placed ina flask and a few pieces of the couple added ; thebromine is then added slowly and the substitution isaccompanied by a vigorous reaction.18

Mercuric oxide is utilised when iodino is to be

74 SYNTHETIC USE OF MTSTALS

introduced ; the easily reducible oxide forms mercuriciodide with the liberated hydrogen iodide which itis essential to remove from the sphere of action.

The following avo examples of this method :Phenol is converted to iodo- and di-iodo-phenolby

adding gradually, iodine and mercuric oxide to analcoholic solution of phenol and agitating :10

2CfiHr,0I-I + IlgO + 2L = 2CJT.1(OH)I + Hg-r, + R,020(.H:)OH + 2HgO + 4I« - 2C{5Ha(OH)I2 + 2HgI3 + 2IIX>.

lodo-dnrene is obtained by adding iodine andmercuric oxide to durene dissolved in petroleumd,lier; and allowing the mixture to stand some time."0

As an oxidantj mercury may be used in thepresence of sulphuric acid. One of the most impor-tant examples of this is the oxidation of naphthaleneto phthalic acid; used on the large scale in the first-stage of the process for preparing indigo from the*hydrocarbon.

The phthalic acid is next converted into anthranilicaoid; and this is condensed with chloracetic acid ;the stages are indicated by the following formula?:

.COOH /CO /CONJLclon8 -> c f iH/

<COOH XJO >COOII

.NH.CH3.COOH

•COOJI " "'NCOOH

The phenyl-glycine-carbonic acid is fused withcaustic soda and the aqueous extract from the fusedmass oxidised by air.

ZTNO ANT) MBRCTTflY 75

The use of mercuric oxide as a ruild oxidant isshown in tlie following examples.

Salts of phenyl-hydrazino are oxidised to thecorresponding diazo-eomponnds :

(OCM5.NH.NH2)2 H2SO4 + 2O2 — (OCH> N : N)2 SO, + 4ir2O.

Di-ethyl-hydrazine is oxidised to tetra-ethyl-tetrn-zone :

2(CoHr,)2N.NHo + O2 = (CJI-,): N.N : N.N(CJI3)3 + 2JLO.

This action differs from that of Fehling's solution,which in the first case gives benzene and in thesecond case diethylamine :

2OflH:,.NH.NTr2 + O2 .-- 2CJl{] + 2N2 + 2IT2O4(Coirr,)>N.NIL, + 0.2 ~ ^(ailOiNTT + 2N2 + 2EL.O.

The addition oC the elements of water io variousacetylenes takes place in the presence of mercuricbromide and other mercury salts.21

Acetylene is converted to acetaldehyde, allyleneto acetone, and valerylene also to a ketone :

C.TL + TLO -r CTT3.CnO; CH,.C : CH + lT3O-CH3.rO.CJT.,.

BlBLIOGRAPnT.1 Bull. See. Chim., 1911 (iv), 9 (i-xxv).2 Compt. rend., 11)07, 1$5, 73.:< Compt. rend., 1909, 148, 489.4 Compt. rend., 1912, 154, 596.•r> Trans., 1897, 71, 457.(( Bor., 1902, 35, 2140 j J. prakt. Chom., 1908 (ii), 78, 97." Ann., 1888, 247, 1807.8 Ber., 1908, 41, 59 i, 906.'•' Ber., 1906,39,689.1(1 Ann., 1874, 174, 372.11 Bov., 1881, 14, 1842 ; BLT., 1894, 27, 1(>14.


12 Ber., 1881,14, 648.13 Ber., 1884, 17, 101.14 J. Amer.Cliem. Soc, 1907, 29, 1328.15 Ber., 1886, 19, 1503.1G Ber., 1889, 22, 1465.V Ber., 1882, 15, 2103.13 Trans., 1899, 75, 893.w Chem. Contr., 1870, 63.20 Ber., 1892, 25, 1522.21 Ber., 1881,1$, 1542; Ber., 1884,17, 28.

C H A P T E R V

ALUMINIUM. TIN. LEAD. ANTIMONY.VANADIUM

The use of aluminium chloride for bringing aboutcondensation by the elimination of hydrogen chloridewas first made known by Friedel and Crafts in 1877,?/ho applied it to the preparation of benzene hydro-carbons by the treatment of benzene with alkylchlorides, in the presence of anhydrous aluminiumchloride :

C,H6 + CH3CI = CfllI5.CH:{ + 1101C6II6 + C2H5Br = CGH5.C2H3 + HBr.

Its nse has been greatly extended^ and aromaticketones may be prepared by using acid chlorides andbenzene hydrocarbons. For example, benzene withacetyl chloride gives acetophenone, while benzenewith carbonyl chloride gives benzophenone:

C6Hf) + CH3.COCI = C6H6.CO.CII3 + HC12cGi-rG + c6cia = cGn5.co.cGH5 + 2HC1.

Aluminium chloride condensations aro effected bymixing tho reagents in a suitable solvent (carbon


bisulphide, petroleum ether, etc.) and graduallyadding powdered, dry, and freshly prepared aluminiumchloride. If desired the procedure may bo alteredby placing the whole amount of aluminium chloridein the solvent and then adding the reacting substancesgradually.

The reaction, which is vigorous, is completed byheating the mixture on the water-bullJ, smd thenpouring the contents into cold water previous toextracting the end-product with benzene, ether orother suitable solvent.

Acids can be prepared by using carbonyl chlorideor carbamic chloride; in the formor case an acidchloride is obtained in the first instance, and in iliolatter case an amide :l

C6H0 + COCLj = CbH3.COCl + 1101CGHG + CICONH* = C6H3.CO.NH3 + HOI.

Aldehydes of phenols and of phenol-ethers can beobtained by passing gaseous hydrogen chloride andhydrogen cyanide into the phenolic substance, mixedwith aluminium chloride :2

•OCH,CbH5.O.CH3 + C1CH: NH = CbH< + 1101.

Xtti: NilThe intermediate imino-compound is acidified and

distilled with steam :

NC±i : JNH XCI1O

Aldehydes can be formed by acting upon aromatichydrocarbons with a gaseous mixture of carbonmonoxide and hydrogen chloride :3

ALUMINIUM. TIN. LEAD. ANTIMONY. VANADIUM 79

Q,uo.cn, + cicon = C ( I H / + HOI.\0HO

The following are examples of internal condensa-tion brought about by A1013 :'

A

Plienyl propionyl chloride -»• hydrindone :

/ GH'2 \c o c i /

Plienyl valeryl chloride -> pheno-keto-heptamethy-lone :

>CHo + HOI.

> GIL—OHo v jCKr—CH-v- " >CH, -> Q H / " >CHo + HOI.

COCl—CIV " ^CO—CHXyimilarly phenyl-butyryl chloride passes to «-keto-

Lolrahydro-naphthalenc.Sometimes direct combination of two molecules

'"results without any elimination taking place, as forcxaurplo, in the union of phthalic anhydride andbenzene to form o-benzoyl benzoic acid :5

\ / \COOH

Auotlior example is the formation of benzaniliclcfrom plionyl carbimide and benzene:

C0H6 + CGH5N : CO = CbH3.NH.CO.CClH5.

/>Diketones (1 : 8-diketones) may be obtainedFi'oiu acid chlorides, and here again, an intermediateaddition compound appears to bo formed and thendecomposed !>y treatment with water. The forma-tion oi% acetyl acetone from acetyl chloride will serveto illustrate this typo of synthesis :


CH3COV3CH3COC1 + AICI3 = >CH.CClo.O.AlCl2 + 2HC1

CH3CCK

>CH.COOII + 1IC1 +CRfiO'

CH3CO.CH2.COCH3 + COo.

Benzene is converted into benzene snlpliinic acidby sulphur dioxide, in the prcsonce of anhydrousaluminium chloride, while oxygen will bring aboutthe formation of phenol :(5

c()n() + sex, -= c,,irvso,u2C,,irb + O3 = 2C()[15OII.

When substances containing hydroxyl g]*oups arcused with aluminium chloride, it is necosary to protecttheso groups from attack by the metallic chloride andthis is accomplished by estoritying them. For ex-ample di-benzoyl-quinol is prepared by the action ofbenzoyl chloride upon quinol dibenzoato and subse-quent hydrolysis of the product:cjitCO.co.cyir,). + 2Cbiir,.ooci -=• (cl)n)(JO)o<j(,ir,(o.co.cl>fi))l>

% 21 LCI.(CcII5CO),C()IL(O.C0.06n5)o + 21LO - (C,,lI>CO)»Cflir«(011)o

+ 2CUI5.COOU.The function of aluminium chlorido in these various

condensations appears to be catalytic.7

Sometimos relatively small quantities of thochloride are sufficient to coinplete the reactions and


at other times larger quantities are necessary; com-plex compounds are generally formed and thus thechloride is removed from the sphere of action.Anhydrous ferric chloride, which brings about thesame kind of condensation, does not exhibit tho sametendency to form complex intermediate compoundsand therefore acts as a catalyst.

The following are examples of the complex inter-mediate compounds which have been isolated :8

ALJClG.CbHG; Al2Clfi.CfiH3(CH3)3.6Ct>nG; AI,Cl,.CaTI],.6C0ir,.

Compounds of oxygen-containing bodies have alsobeen isolated : With ether C4H10O.A1C13 ; with anisoloC7H8O.A1C13; with ethyl benzoate C9H10Oo.AlCi3.All of these are crystalline solids.

A study of the reaction between anisole and benzylchloride indicates that the change is unimolecular andthat the chloride of aluminium acts as a catalyst, sincethe velocity of reaction is proportional to its concen-tration.9

The formation of aromatic kofconos has been ex-plained as proceeding in tho following stops :10

R.COC1 + AICI3 - R.COCI.AICI3R.COC1.A1C13 + I1B' = RCCR'Alda + 1TO1

K.CO.K/.AICI3 + uiloO = E.CO.R' + AICI.JIHOO.

Anhydrous zinc chloride as well as forric chloridocan often be used instead of aluminium chloridein these condensations.

I t is interesting that the rovorsc reaction can boaccomplished in the case of the alkylation of benzene.All the hydrogen atoms of the hydrocarbon can boreplaced by methyl groups, and conversely hoxa-methyl-benzene can be converted into benzene.n

82 SYNTHETIC USTO OF METALS

The alkyl groups can also be made to pass fromone hydrocarbon to another, toluene in the presenceof aluminium chloride yielding both benzene andmeta- and yara-xylene.

The fact that small quantities of the aluminium-mercury couple can bring about similar condensa-tions, indicates that the chloride acts as a catalyst;the formation of diphenyl-methane from benzylchloride and benzene is an example of this.12

Inorganic radicles may be condensed with hydro-carbons as in the formation of antimony triphenyland dimethyl-amino-phenyl-phosphine-dichloride :13

SbCl3 + 3CfiHG = Sb(CflH6), + 3HC1PC13 + CGH5.N(CH3)2 = PCla.CcH4.tf(CH3)2 + HC1.

Aluminium trichloride can be used for hydrolysingthe alkyl ethers of phenol and its derivatives :14'

q«Hs.O.CH3 + HC1 = C(5H5.OH + CH3C1

+ CH3C1

TIN AND LEAD.

Both metals form compounds with organic radicles,in which the metals themselves are tetravalent.

These compounds are prepared by treating thesodium alloy of the metal with the required halogencompound, and in the case of tin two other methodsare available,namely, the treatment of tin tetrachloridewith sodium in the presence of the halogen organiccompound, and the action of organo-magnesium com-pounds upon tin tetrachloride.

These reactions may be represented by the follow-ing equations (X represents 01, Br or I) :

ALUMINIUM. TIN. LEAD. ANTTMONY. VANADIUM 83

Sn + 4Na + 4RX = SnE4 + 4NaXS11CI4 + 8Na + 4RX = SnR4 + 4NaCl + 4NaX

SnC]4 + 2MgRX » SnRaCl2 + MgX2 + MgCl2.By the action of iodine upon the tetra-alkyl com-

pounds one or more alkyl radicles can be replaced :

PbR4 + I2 = PbR3I + El.

Compounds of the type PbR3I and SnR3I are con-verted into the corresponding hydroxides by treat-ment with the hydroxides of silver or sodium :

PbR3I + AgOH = PbR3OH + Agl.

The stannonium and plumbonium hydroxides arestrongly basic crystalline substances which form saltswith acids.

Optically active tin compounds have been preparedby combining the metal with four different groupsand then resolving the racemic compound produced.The following scheme will indicate the method adoptedby Pope and Peachy in separating active methyl-ethyl-propyl tin iodide :16

2Sn(CH3)aI + Zn(C2H5)2 = 2Sn(CH3)3(CaH5) + Znl2Sn(CH3)3(CaH5) + Ia = Sn(CH8)9(CaH5)I + CH3I

2Sn(CH3)a(Cya6)I + Zn(C3H7)a = 2Sn(CH3)a(CaH5)(C3H7) + ZnlaSn(CH3)2(CaH5)(C3H7) + Ia - Sn(CH3)(CaH5)(C3H7)I + CH3I

(Faint yellow oil, b.p. 270°.)

Resolution was effected by treatment with thesilver salt of d-camphor-sulphonic acid and subsequentdecomposition of the camphor-sulphonate formed, bymeans of potassium iodide :

Sn(CH3)(CaH6)(C3H7)I + C]0H]6OSO3Ag -Sn(CH3)(C2H5)(C3H7)SO3OCltiH16 + Agl

Sn(CH8)(CaH5)(C3H7)SO3OC10H16 + KI - Sn(CH3)(C2H6)(C3H7)I+ C10H16OSO8K


Tin is used as a reducing agent in acid or alkalinesolution, and after reduction the metal may be sepa-rated from the solution as sulphide by hydrogensulphide, or if the reduced compound be a base, causticsoda may be added in excess and the base then ex-tracted by some suitable solvent.

When using stannous chloride and hydrochloricacid for reduction, the usual proportions are 40 partsSnCl2 and 100 parts HC1 (1*17). This mixture maybe used in alcoholic solution since stannous chlorideis soluble in alcohol.16

Alkaline stannous chloride is largely used in pre-paring azo-compounds and particularly for trans-forming diazo-compounds into hydrocarbons :17

C0H5N: N.OH + H2 » CttHc + N2 + H3O

The entire reaction may be represented thus :

C6H5N:NC1 + SnCl, + H20 = C6H6 + Na + SnOCl2 + IIC1

Tin tetrachloride is very efficient in bringing aboutthe formation of phthaleins; for this purpose thechloride is heated with the reacting substances toabout 120°.

The formation of phenol-phthalein and of salicyl-phenol will serve to illustrate this method :18

2C6H6OH

HO.C6H4.COOH + C6H5OH « HO.C6H4.CO.C6H4.OH + H2O

The separation of organic acids by means of thelead salt which is subsequently decomposed by


hydrogen sulphide, is a method much used, and maybe illustrated by reference to formic acid :

(HCOO)2Pb + H2S - PbS + 2H.C00HLead monoxide, like silver oxide, may be used in

the presence of water, for hydrolysis. Fats, forexample, are saponified (hydrolysed) by boiling themwith water containing PbO in suspension ; the result-ing products are glycerol and a lead soap :

2(C15H31COO)3C3H6 + 3PbO + 3HaO » 3(CI6H31COO)aPb +Palmitin. Load palmitato.

2C8H5(OH)3G-lycerol.

Lead monoxide is also used as an oxidant, gener-ally by mixing it with the compound to be oxidisedand heating, or passing the vapour of the compoundover heated lead oxide.

By this method benzil is oxidised to bonzophe-none, acenaphthene to acenaphthylene, and o-ainino-diphenyl-methane is converted into acridino :10

CaH5.CO,CO.C0H6 + PbO = C0II5.CO.CJT5 4- CO2 + PbOH2 yCliI + PbO - CXOHZ|| + H2O + PbCH2 ^CH

0 FTH5 + 2PbO * C6H4/ I \COH4 + 2HaO + 2Pb

OH6<

Lead peroxide is used for oxidising leuco-bodies.For example, leuco-malachite groon (obtained by con-densing bonzaldehyde with dimethyl-anilino) is con-verted to the base of malachite groon by lioating1

with PbO 2 :

C0H6.CH/ 6 *' * a -> C0H6.C(OII)/ ° * " 2

\C6H4.N"(CH8)a NC0H4.N(CII3).i


The peroxide is utilised on the large scale for thispurpose. [Germ. Patent 50782.]

ANTIMONY.

The chief use of antimony and its chlorides is foraccelerating the chlorination of organic compounds.Chlorination is also accelerated by the chlorides ofiron, aluminium, molybdenum or thallium, and themetals themselves may be used.

Just as the trichloride and pentachloride of anti-mony are suitable, so also are the two chlorides ofmolybdenum, MoCl3 and Mo015, and the two chloridesof thallium, T1C1 and T1O13.

20

Nitrobenzene is converted intom-chlor-nitrobenzeneby chlorine in the presence of antimony trichloride.21

According to the German Patent 32564, phthalicanhydride is converted into the tetra-chlor-derivativeby passing chlorine into a mixture of the anhydrideand antimony pentachloride heated to a temperatureof 200°:

.CO yCO

>O + 4C12 = CeCl4/ No + 4HC1

30 X!OAntimony trichloride is used to facilitate pyro-con-

densations such as that of dinaphthyl from naphtha-lene. Only a small quantity of the product isobtained by passing naphthalene alone through ared-hot tube, but the yield is very much improvedby mixing the vapour of antimony trichloride withthe vaporised hydrocarbon :

6C10H8 + 2SI)C13 = 2Sb + 6H01 + 8Cl0H7.CloH7


The vapour of stannic chloride appears to be stillmore efficient in this type of condensation. By itsmeans a good yield of diphenyl is obtained frombenzene.

VANADIUM PENTOXIDE has received limited applica-tion as an oxygen carrier. Its presence acceleratesthe oxidation of ethyl alcohol to aldehyde and aceticacid, when effected by air or by oxygen.

The oxidation of cane-sugar to oxalic acid by con-centrated nitric acid is facilitated by the presence ofa small quantity of vanadium pentoxide.32

BlBLIOGBAPHY.1 Ann., 1888, 244, 50.2 Ann., 1906, 347, 347; Ann., 1907, 357, 320.3 Ber., 1897, 30, 1622.4 Trans., 1894, 65, 484; 1899, 75, 144; 1901, 79, (502.5 J. prakt. Oheni., 1890,149, 147, 301.6 Ann. Ch. Pliys. (6), 14, 433.7 Trans., 1903, 83, 1470.8 Compt. rend., 1903,136, 1065; Trans., 1904, 83, HOG.8 Zeit. phys. Chem., 1904, 48, 430.l° Rec. Trav. Chim., 1900,19,19.11 Ber., 1885,18, 339, 657.12 Trans., 1895, 67, 826.13 Ber., 1888, 21, 1497.14 Ber., 1892, 25, 3531.1& Proa, 16, 42,116.lB Ann., 1891, 264, 131 ; Her., 1882, 15, 1422.V Ber., 1885,18, 29J2.18 Ann., 1880, 202, 68 ; Ber., 1883,16, 2298.19 Ber., 1883,16, 502 ; Ber., 1893, 26, 3085.20 Ann., 1884, 225, 199.al Ann., 1876,182,102.22 J. prakt. Chem., 1907, 75,146.

O H A P T E E V I

IEON. NICKEL. PLATINUM. PALLADIUM

THESE metals have all been used as catalysts,particularly in oxidation and reduction processes, andin this connection the value of nickel and platinumis well known.

Certain iron compounds have been used forreduction. Ferrous sulphate in aqueous solution,with ammonia, baryta, or sodium hydroxide, may beused for reducing, as also may ferrous potassiumoxalate in neutral, alkaline, or weakly acid solution.

The following are examples of the reduction ofnitro-compounds by ferrous sulphate : nitro-phenylpropiolic acid1 and nitro-dichlor-benzaldehyde2; themethod has been used to reduce several nitro-acidsto the corresponding amino-acids.s

Ferrous potassium oxalate can be utilised in thesecases with good results.4

The value of iron and of ferric chloride as halogencarriers is well known. Ferric chloride or ferrichydroxide may be used for oxidising purposes, theoxidant being in each case reduced to the ferrouscondition.

IRON. NICKEL. PLATINUM. PALLADIUM 89

The oxidation of ethyl indoxylate to ethyl indox-anthinate5 and of naphthol to dinaphthol6 may beaccomplished by ferric chloride :

2C10H7OH + 2FeCl3 = C2()H12(OH)o + 2HC1 + 2FeCl2

Ferric hydroxide is sometimes used for oxidisingleuco-bases.7

The oxidising action of hydrogen peroxide in thepresence of ferrous sulphate, was first used by Fentonand applied by him in the conversion of the poly-hydric alcohols to the corresponding aldehydes.

In the first instance, the reagent was used toprepare di-hydroxy-maleic acid from tartaric acid :

CH(OH).C00H C(OH).COOH2 | + Oa - 2 || + 2H3O

CH(OH).COOH C(OH) .COOH

Glycerol, erythrite and mannitol can be convertedto the corresponding aldoses by this oxidant:8

The first indication of the value of reduced nickelfor accelerating the reduction of organic compoundsby hydrogen, was obtained by Sabatier and Senderensin 1897, when studying the compounds obtained bypassing acetylene or ethylene over heated reducednickel. I t was subsequently shown that many organicsubstances could be reduced in this manner, the chieffactors which determined the success of the reactionbeing, the temperature at which the nickel was firstprepared from the oxido by hydrogon, and thetemperature at which the mixture of tho substanceand hydrogen was allowed to pass over tho metallicnickel.

Generally, the catalyst (nickel) is prepared byheating pumice, impregnated with nickel oxide, in a


current of dry hydrogen at about 300°. Whenreduction is complete the temperature is allowed tofall to between 160° and 200°, and the mixture ofthe substance to be reduced, with hydrogen, is passedthrough the reduced nickel.

The following is a brief summary of the resultshitherto obtained by this method, and a collectionof references to the original papers will be found atthe end of the chapter. I t will be seen thatalthough nickel is the metal most used and the onewhich generally yields the best results, yet othermetals, namely, copper, cobalt, iron and platinum,

' have been utilised.In 1897 it was found that by passing ethylene

over reduced nickel at about 325°, a gaseous mixturewas obtained consisting of 10 vols. of hydrogen, 60vols. of ethane and 30 vols. of methane. At highertemperatures the volume of ethane was diminished,and the nickel was found to be most active when thenickel oxide was reduced at 300°. A mixture ofethylene and hydrogen at a temperature of 150° gavea quantitative yiold of ethane.

In 1899 and during subsequent investigations, itwas shown that when acetylene and hydrogen arepassed over reduced nickel at ordinary temperaturesthe gases combine, a rise in temperature takes placespontaneously, and ethane is the chief product, butthe composition of the product depends upon thetemperature, the proportion of acetylene to hydrogen,and the velocity of the gas current. Olefines, paraffinsand benzene are found in the product and the liquidconstituents increase with rise of temperature, while

IKON. NICKEL. PLATINUM. PALLADIUM 91

a diminution of hydrogen also favours the formationof liquid hydrocarbons, especially benzene com-pounds.

Metallic iron, copper and cobalt behave in asimilar way, and the formation of liquid hydrocarbonssupports the idea that petroleum may have beenformed naturally, by the gases evolved from the actionof water upon carbides of the alkalis and alkalineearths, passing through layers of heated metals inthe earth's interior.

The metals copper, iron and cobalt produce thefollowing changes in mixtures of acetylene andhydrogen on the one hand, and mixtures of ethyleneand hydrogen on the other hand.

If acetylene be passed over copper at 180-250°,a mixture of hydrogen, unchanged acetylene, andvolatile hydrocarbons results ; the copper swells up,owing to a deposit of yellowish highly condensedhydrocarbon of composition (C7H6)n which has beennamed ciiprene. If the acetylene bo first mixed withexcess of hydrogen and the temperature 200°, themixture resulting, contains 3 per cent, of define(ethylene) and 18 per cent, of ethane; a morecompact form of copper at 170° causes the definecontent to increase ninefold while the ethane isreduced in quantity. If the mixture contains halfits volume of acetylene and the reaction proceeds at150° the amount of ethylone in the product is stillfurther increased and tho cthano decreased.

Reduced iron at ordinary temperatures docs notaffect a mixture of acotylene and hydrogen, butabove 180° ethane, ethyleno (and higher olofines),


and a small amount of benzene hydi^ocarbons r e -sult.

Reduced cobalt accelerates the reduction o facetylene to ethane by hydrogen above 180°, a t x dsome liquid paraffins result at the same t i m o -Evidently those three metals bring about different*rosults under similar conditions.

While copper favours ethylene formation, i r o i *and cobalt, when a sufficently high temperature i sreached, favour ethane formation accompanied in o a ©case by benzene hydrocarbons and in the other c a s oby liquid paraffins.

As regards mixtures of ethylene and hydrogen.^the reaction, 0 2H 4 + H 2 = O3H6, is not induced b ycopper below 180°, but between 180-300° this is t h emain reaction. Metallic iron has no effect on t h pmixture at ordinary temperatures, and when heatecLto 180° the reaction soon ceases owing to the meta/1becoming carburised.

Reduced cobalt induces the reaction, C^H^ + H 3

= O2H6, at first and the metal becomes spontaneouslyheated, but it soon becomes carburised and inactive.If heated to 100°—150° the reaction proceeds, yielding*ethane mixed with unchanged ethylene and hydrogen,together with traces of higher acetylenes. At 300°much unchanged ethylene and hydrogen are foundwith ethane, together with small amounts of methanoand liquid hydrocarbons; the cobalt still becomescarburised and its activity declines.

The reaction between ethylene and hydrogen isonly temporary in the presence of platinum black a tordinary temperatures, but at 100—120° slow com-


bination takes place, and at 185° the yield of ethaneis almost quantitative. Spongy platinum behaves ina similar manner at 180°.

Acetylene with excess of hydrogen, in the presenceof platinum, black at ordinary temperatures givesonly ethane, but if acetylene is in excess then ethyleneis also formed, while at 180° some liquid hydrocarbonsalso result.

The passage of acetylene alone, over the metalsnickel, platinum, cobalt and iron gives the followingresults.

A rapid current of acetylene when passed overreduced nickel causes intumescence, and this isapparently due to occluded hydrogen in the metal,because when displaced by a stream of nitrogen gasno reaction is observed below 180°. At highertemperatures no intumescence is observed if theacetylene current be sufficiently slow, and theproducts are hydrogen, ethane, ethylene and liquidhydrocarbons containing benzene with higher olefines.A. rapid stream of gas gives rise to intumescence, andthe issuing gas is made up of hydrogen 51*4 percent., ethane 36f3 per cent., ethylene 2 per cent.,benzene and homologues 10*3 per cent.; at the sametime a liquid condenses which contains unsaturatedhydrocarbons.

Finely divided platinum induces no effect withacetylene at ordinary temperatures, but above 150°intumescence is observed, and the gas is partly de-composed into carbon, ethylene, benzene, ethane, andhydrogen, the last three in small quantity.

Cobalt free from nickel has no action upon acety-


lene at ordinary temperatures, but above 200° thegas is almost completely decomposed into hydrogen,ethane and carbon while small quantities of benzonoand its homologues are formed.

Iron behaves similarly but much loss ethane results,while olefines and benzone accompany the gases.

Ethylene is not affected by finely divided platinumor copper below 400°, but cobalt above 300°, partlydecomposes the gas into ethane, methane, hydrogenand carbon, no acetylene being formed. Iron above350° has less action, but decomposes some of the gasinto ethane, hydrogen and carbon.

The following are some of the results obtained byreducing aromatic substances in this manner:

Benzene and its homologues are reduced by hydro-gen in the presence of nickel at 180-200° yieldingthe corresponding cyclohexanes. If the side-chafabe long, then a certain amount of disruption accom-panies the reduction, and lower homologues are pro-duced as well as the normal cyclohexane. At ahigher temperature, decomposition of the reducedproducts may occur; cyclohexane itself, for example,is decomposed if the temperature is 300°, into methaneand carbon. The hydrogenation of benzene seemspeculiar to nickel, since cobalt and platinum blackhave only a transitory effect, while spongy platinum,iron and copper are quite inert.

Limonene, sylvestrene and terpinene are all re-duced to l-methyl-4-isopropyl-cyclohexane by thismethod, naphthalene gives tetrahydro-naphthalene,and acenaphthene behaves similarly.

Nitrobenzene, o- and m-nitrotoluene, are all re-


duced to the corresponding amino-compounds in thepresence of copper at 300°-400°, and the reducingaction of platinum black is similar. Reduced nickelacts more vigorously and reduction takes placenormally at 200°, but at 250° the products obtainedfrom nitrobenzene are benzene, cyclohexane andammonia, as well as aniline, while at 300° benzeneis the chief product.

Reduced iron and cobalt act in a similar mannerto nickel when heated to 450°—500°.

Reduced copper does not effect hydrogenation inhydrocarbons unless at least one unsubstituted (:0H2)group is present; styrene is reduced to ethyl benzene,and limonene O10H16 passes to C10H18, but limonenebecomes still further reduced by nickel to liexahydro-cymene C10H20."* Hydrogen in the presence of reduced nickel con-verts phenol into cyclohexanol and cyclohexane.Poly-phenols are affected similarly, while aniline andits homologaes become reduced to cyclohexylamines;quinones are reduced to quinols and nitriles to amines.

The catalyst remains active in continual use, oftenfor a month, but is poisoned by halogens or sulphurand also by the decomposition of carbonaceous matterwhen working at too high a temperature.

The following reactions are also important :Carbon monoxide (1 vol.) and hydrogen (8 vols.)

react in the presence of nickel at 250° to fonnmethane and steam, CO + 3H2 = CH4 + H2O.Carbon dioxide is also reduced at a higher tempera-ture, CO2 + 4HS = CH4 + 2HSO.

Hydrocarbons of the ethylene series up to a carbon


content of C8, are reduced to the correspondingparaffins; below 160° the product is practically pure,but above 200° partial decomposition takes placeand hydrocarbons of lower molecular weight result.

The liquid product obtained from acetylene andhydrogen at temperatures not above 200° is fluor-escent, not attacked appreciably by a mixture ofsulphuric and nitric acids, and presents the character-istics of American petroleum. Acetylene alone, yieldsa green-coloured liquid which resembles Russianpetroleum.

Dehydrogenation takes place when the vapour ofprimary alcohols is passed over reduced copperat250°—300° and aldehydes result, while secondary alcoholsare converted by the same method into ketones.

Nickel and cobalt effect the same changes, but intoo vigorous a manner generally.

Tertiary alcohols are decomposed into defines andwater by the agency of reduced nickel and copper.

For the catalytic reduction of aldehydes, nickelreduced at as low a temperature as possible is mostefficient; a quantitative yield of alcohol from acetal-dehyde is obtained at 140°, while the optimum tem-perature for reducing formaldehyde is 90° and forpropaldehyde 102°-140°.

Eeduced cobalt, platinum sponge, and copper arenot suitable for aldehyde reduction.

The reduction of oleic acid to stearic acid by thismethod is of technical importance and is one exampleof the reduction of unsaturated aliphatic acids to thecorresponding saturated acids.

Iron, nickel, zinc or lead may be used, according

UtON. NICKEL. PLATINUM. PALLADIUM 97

to the German Patent 185932,, for reducing formicacid to formaldehyde by hydrogen at 300°.

Sabatier and Maihle have studied the catalyticaction of various metallic oxides upon the vapours ofcertain organic compounds. They find that alcoholsare oxidised to aldehydes by manganous oxide andthat they are dehydrated by alumina, thoria or theblue oxide of tungsten, with the formation of olefincsand ethers. Those changes arc explained in thecase of thoria by the following equations :

ThO2 + 2Cnn2n+i.OH = ThO(OOnn.jn+i)a + H,0Below 300° ThO(OCnHto+1)a = ThO2 + (CuHou+T)20

Above 300° ThO(OCnH2n+I)a = ThO, + H2O + 2CnH2n.

The rosults obtained by passing the vapour ofprimary alcohols over various heated metallic oxideshave been summarised, and the oxides used have been

•*arranged in four classes as follows :°(1) Tho oxidation is limited to the formation of

aldehyde and wator; tho metallic oxide used has noeffect upon tho aldehyde and the metal or loweroxide which results has no catalytic powor. To thisclass belong Sb2O3 and Bi2O3.

(2) The aldehyde formed may be partly oxidisodeither to the corresponding acid, or with the forma-tion of carbon dioxide and water. Mercuric oxideat 150° oxidises alcohol to acctaldehydo with thesimultaneous formation of carbon dioxide, but noacetic acid is produced.

Manganese dioxide at 200° oxidises alcohol toaldohyde and is itself roduccd to Mn2O3; at 250° theMn2O3 brings about further oxidation and tho pro-ducts are acetaldohyde, carbon dioxide, and acetic acid.

7

98 SYNTHETIC USE OF MKTALS

(3) The oxides catalytically dehydrate the alcohol,and ethylene is the chief result. To this class belongFe2O3; A12O3, and ThO2.

(4) The largest class consists of those oxides whichare reduced to the metal, or a lower oxide, capable ofproducing a catalytic effect which is superposed uponthe initial oxidation. The oxides of nickel and cobalt,of lead (PbO2, P b ^ , PbO), of copper (CuO, Cu2O),at 350° belong to this class; the reduced metals inthese cases have a dehydrogenating effect upon thealcohol, and aldehyde results.

Mn2O3 is reduced at 350° to pale green MnO,which converts the alcohol to aldehyde by dehydro-genation.

Tungstic oxide at 350° is reduced to a blue oxidewhich has a dehydrating effect and ethylene resultsas well as aldehyde and acetic acid.

The oxides TJO3 and V2O5 are reduced to UO2 andV2O3 respectively, aldehyde and carbon dioxideresulting. The further action of UO2 or V2O3 givesaldehyde, hydrogen, ethylene and water.

Mixed ethers result when alcohols and phenols areused with thoria at 390°—420° and esterification takesplace when alcohol and acid interact at 350°-400°.Esfcerification10 is more complete in the presence oftitanic oxide at 280°—300°. One molecule of acid isused with twelve molecules of alcohol, and in this waymethyl, ethyl, propyl, butyl, and benzyl esters havebeen prepared from acetic,propionic and butyric acids.

In the case of formic acid it is necessary to workat 150° with titanium oxide and at 200° with thoriato avoid decomposition of the acid.

IKON. NIOKia. PLATINUM. PALLADIUM 99

Hydrolysis is effectod under similar conditions ifthe ester and oxcess of steam are passed over thesecatalysts.

defines are obtainod by passing the vapour ofparaffin monohalides over reduced nickel or copper,heated to 250°; the resulting products are the olefineand the haloid acid, which are prevented from recom-bining by passing them through potash. The chlorinederivatives decompose thus below 260°, but a highertemperature is required for bromo- and iodo-com-pounds.11 The bivalent chlorides of nickel, cobalt,cadmium, iron, lead and barium produce the sameeffect at 300°; barium chloride is the most efficientcatalyst. Chlorides of univalont metals are not ableto bring about this change, and the following equationspossibly represent the reaction in the case of thebivalent chlorides:

(1) MCI, + CnnJn+lCl =* MCl.CnllonCl + HOI.(2) MCl.CnHonCl = OnHon + MCL.

Tho reduction of nitrilos by hydrogen in thepresence of reduced nickel or copper usually givesprimary, secondary and tertiary amines together withammonia, and the changes aro probably representedby the following equations :12

Q) K.CN + 2Hs = K.CHaNIIa(2) 2R.CHjNH9 - (R.CH,)9NH + Nil,(3) 3R.CH2NH2 « (Jft.CHa)3N + 2NH3.

Aldoximes are reduced to amines by hydrogen at180—220° in the presence of reduced nickel or copper;with benzaldoxime, however, the chief product isbenzaldeliyde when copper is used, and toluene whennickel is used.13

100 SYNTHETIC (JSK 01' MKTALS

Primary alcohols are converted into primary, sedary and tertiary amines, by ammonia, in the presoncM *of heated tungstic oxide or thoria.

A mixture of reduced nickel and alumina may l>t*used to effect reduction by hydrogen and tlio simul"taneous fission of water ; thus fenchenol is converted"by this method into fenchane and bornool is t r a n ^formed into iso-caniphane :1<J;

CJ0H17OH —> CIOH]0 -> C]0H18.

PLATINUM is not only suitable for accelerating reduc-tion processes, "but is also an excellent catalyst who**oxidation is effected by air or oxygen. Formalde-hyde was first prepared by passing the vapour olmethyl alcohol and air over a heated platinumspiral.15

Later, copper gauze was found equally effectivesand formaldehyde is now manufactured by passing*the vapour of wood spirit mixed with air, over finelydivided platinum or copper distributed over anearthenware surface. The following processes furmanufacturing ammonia and nitrates or nitritort(substances essential for the synthesis of the highlycomplex plant and animal bodies), depend largelyupon the use of platinum as a catalytic agent.

Ammonia is formed when nitric oxide and hydro-gen are mixed and passed over platinum sponge at80°. The hydrogen used may be that present inDowson-gas or water-gas and the reaction involvedis indicated by the following equation :16

2NO + 5H2 = 2NH3 + 2H2O.

If ammonia and air be passed over red-hot finely


divided platinum (or one of the platinum metals),onitric acid is formed,17 and nitrous acid is producedi n the same way if ferric oxide at 700° be substitutedf o r platinum.18

Ammonia is now made by the Badische Anilin•und Sodafabrik, by passing nitrogen and hydrogenove r heated platinum at a temperature of 80°; underct pressuro of about thirty atmospheres. Othercatalysts used in the process are manganoso, uraniuma n d osmium.

Keten has been prepared from acetic anhydride,"by exposing the vapour of the anhydride to the<~lehydrating influence of a white-hot platinumwire :1(J

CI-T3.CONo = 2cn2:co + irao.

CH3.COPlatinum and palladium in colloidal solution arc

•used for effecting the Uydrogonalion of substances* inaqueous or alcoholic solution. llydrogon is passedthrough the solutions and it is often advantageous towork under slightly increased pressure; the colloidalmetals are obtained from palladious chloride or pot-assium platinichlorido, in tho presence of gum arabic.

By this method unsaturated aldehydes and ketonesnre converted into the corresponding Hat united com-pounds, while benzene, toluene and benzoic acid may"bo converted into cyclohcxane, methyl-cyclohexnnoand cyclo-hexanc-carboxylic acid respectively.20

Tho reduction of nitro-compoumls in solution byspongy copper depends upon tho precipitation of thocopper from copper wulplinte solui-ion )>y sodium

102 RYNTTTBJTTC URTC OF METALS

hypophospliite and tho simultaneous decomposition ofwater, with evolution of hydrogen.21

The nitro-compound is usually dissolved in alcohol,spongy copper added^ and an aqueous solution ofhypophosphito is gradually run into the mixture.

Tlio presence of halogen or hydroxyl groups in thenitro-compound is no disadvantage and good yieldsare obtained.

I Ber., 1882,15, 214.7.- Bor., 1884,17, 75-1.3 Bor., 1879,12,1946.* Monats., 1880,1, 1137.r' Bor., 1882,13, 775.c Ber., 1888, 21, 728.7 D.E.P. 19484.8 Trans., 1899, 73, 1.9 Conipt. rend., 1908,147, 16.

1(1 Compt. rend., 1911,152, 358, 494,1044.» Chom. Zoit., 1906, 30, 37.la Chom. Zoit., 1900, 30, 458.I1 Compt. rend., 1905,150, 3091.1' Bor., 1912, 45, 3205." Ann., 1868,145, 358."> D.R.]?., 1572876.17 Eng. Patent, 1903, 698.'« Proncli Patent, 1903, 335220.1{) Trans., 1907, 91, 1941.2() Ber., 1912,45, 3579.21 Bull. Soc. Chim., 1910 (iv), 7, 952.

References to the papers of 8dbaticr and Scnderens in * Gotnptesrcnd%B do VAcademie des Sciences/ Paris.

1897,124, 616, 1358; 1899,128,1173 j1900, 130, 250, 1559, 1701, 1028 j1900,131,40, 187,207;


1901, 132, 210, 566, 1254; 133, 321;1902,134, 514, 1127, 689, 1185 ; 135, 87, 225 j1903,136, 738, 921, 983 ; 137, 301, 1025,-1904,138, 457, 1257 ; 1905, 140, 482;1906, 142, 1394;1908, 146, 457, 1193 ; 147, 106 ;1909,148, 898, 1734; 1910,130, 823 ;1911,152, 358, 494, 669, 1212 s

Also 'Ann. Qhim. Pliys.,'—

1905,4, 319, 433 ;1909, 16, 70.

A P P E N D I X T

PEACTICAL WOEK: SODIUM POTASSIUM

ETHYL BENZENE from brom-benzene and ethyl bromide.[Ann., 1864,131, ,304 Ann., 1869,149, 342 ]

The brom-benzene (60 gms.) and ethyl bromide(50 gms.) are mixed in a 1-htro flask fitted with areflux condenser, and double the volume of dryether added.

The sodium (18 gms.), in small piccos, or in theform of wire, is added gradually, and a few dropsof acetic ethyl ester may bo added to accelerate thereaction.

When all the sodium has been added the mixtureshould stand for four or five hours (preferably over-night), and then be boiled on the water-bath for halfan hour. After cooling, the liquid is decanted fromthe sodium bromide and the residue washed twicewith dry ether. The washings are addod to theoriginal liquid, and after distilling off the other theresidual oil is fractionated. That fraction is collectedwhich distils between 132°-135°, Yield, about20 gms.

PRACTICAL WORK : SODIUM. POTASSIUM 105

ANISOLE from sodium phenate and methyl iodide.[Ann., 1851, 78, 226^

Sodium (5 gms.) in small pieces is dissolved inmethyl alcohol (100 c.cm.) contained in a ^-litreflask fitted with a reflux condenser. When thesodium has all dissolved, phenol (20 gms.) andmethyl iodide (40 gms.) are added, and the mixtureheated on the water-bath until it gives no alkalinereaction (about three hours).

The alcohol is then distilled off and water addedto the residue to precipitate the anisole, which isextracted with ether. After drying the etherealextract over calcium chloride, the ether is distilledoff and the residual oil fractionated, that fractionbeing collected which boils between 150°—155°. Yield,about 16 gms. of a colourless oil with agcoablcodour, b.p. 154°.

BKNZOTC ANITYPKIDK from sodium bonzoale and benzoylchloride.

Bonzoyl chloride (10 gms.) is added to powderedsodium benzoato (10 gms.) in a small retort and thomixture is heated strongly. The distillate, which iscollected in a receiver, solidifies and may be recrystal-lised from bonzene, and the odour of bcnzoyl chloridemay be removed from tho crystals of benzoic an-hydride by placing them in a desiccator over solidpotassium hydroxide for a few hours.

Yield, about 12 gms. Rhombic prisms; m.p.42°, b.p. 360°.

106 SYNTHTSITC USE 01? METALS

HEXAMETHYLENE from the dibromide.

[Trans., 1894, 65, 599.]

The preparation of hexametltyleno dibromide fromoK^-cliloro-brom-propane, which is itself prepared fromallyl chloride, is as follows:

Allyl alcohol may be converted into allyl chlorideby heating with cone, hydrochloric acid in a sealedtube at 100° for several hours.

Allyl chloride is then converted to chloro-brom-propane by heating in a sealed tube with a slightexcess of cone, hydrogen bromide solution at 100°for seven to eight hours. The mixture is thenwashed, dried and fractionated.

The boiling point of the product is 140°—142°.Chloro-brom-propane (1 mol.) is next dissolved in

a little methyl alcohol; and the calculated amount ofsodium (1 atom in twelve times its weight of methylalcohol) is added in three portions, the mixture beingboiled after each addition.

As soon as the vigorous action ceases the productis cooled and mixed with twice its volume of water,the oily layer extracted with ether and the etherealsolution washed with water to remove alcohol. Afterdrying the extract over calcium chloride it is distilledwith a fractionating column: the portion boiling at115°-118° is chlor-methoxy-propane, yield 50-60 percent.

Chlor-methoxy-propane (20 gms.) is next dissolvedin 60 c.c. of light petroleum (b.p. 50°-60°) andheated to boiling under a long reflux condenser.

PEACTTCAL WOKK : SODIUM. POTASSIUM 107

The flame is removed and small pieces of potassiumadded gradually, the very violent action after eachaddition being allowed to subside before addinganother piece. The mixture soon thickens owing tothe separation of potassium chloride, and when themetal is no longer acted upon the whole is boiled forhalf an hour, any unchanged metal being removedby alcohol.

The product is then poured into water, the oilylayer separated and dried over calcium chloridebefore fractionating. Most of the liquid distilsbetween 100°—150° and is unchanged chlor-methoxy-propane, while the liquid boiling above 150° is chieflydi-methoxy-hexane, which is next digested under areflux condenser for three hours with fuming hydro-bromic acid. The dark-coloured product is pouredinto water, the oily layer extracted with ether, andafter removing the ether from the dried extract, theresidue is heated in a sealed tube with hydrobromicacid for two hours at 150°—160°. The product ispoured into water, extracted with ether, and thedark-coloured hexamethylene dibromide fractionatedunder reduced pressure (20 mm.). That portion iscollected which boils between 125° and 140°.

The heavy colourless dibromide (30 gms.) is nowmixed with meta-xyloiiQ (30 gms.), and added througha funnel drop by drop to a mixture of sodium(15 gms.) in small pieces, and 70 c.c. of m-xylene.The reaction is vigorous, and if a condenser be fittedto the side-tube of the reaefcion-flask, the resultinghexamethylene distils over between 70° and 100°;this may be refractionatcd over sodium and that part

108 SYNTHETIC USE OF MKTALR

collected which distils at 77n-80°. Yield about10 gms.

TRIMBTTIYLENE DlCAKBOXYLtC ACID.

[Bor.,1884.,17,61..]

Di-sodium malonic ester is prepared by dissolvingsodium (13*5 gins.) in alcohol (150 gms.) andadding malonic ester (45 gms.) gradually. Ethylenedibromide (54 gms.) is then slowly added, and thesolid mass which forms is thon heated under a refluxcondenser to 100° for twenty hours; the mass becomesliquid soon after heating, and at the end of thistime should be no longer alkaline to litmus. Theexcess of alcohol is next distilled over and theresidue mixed with water to dissolve sodium bromide,after which it is extracted with ether and theextract dried over calcium chloride. The driedextract is now freed from ether by distillation, andthe residual yellow-coloured oil fractionally distilledin a flask with a long neck and the fraction collectedwhich distils between 195°~225°. This fractionshould again be distilled and the portion boiling at203°~210° collected.

To separate malonic ester still present and whichamounts to 15 to 20 per cent, it must be convertedinto the higher boiling derivative, benzyl-malonicester. For this purpose half a gram of sodium inalcohol is added to every 20 gms. of the oil collected,and to this mixture 2*5 gms. of benzyl chloride isadded and the whole heated until neutral.

Water is then added and the esters extracted with

PRACTICAL WOltK : SODIUM. POTASSIUM 109

ether, and after removing the ether the remainingoil is fractionatod. Benzyl-malonic ester boils at300°, so that tho frrimethylene ester may be separatedby collecting the distillate which passes over at 206°—210b.

The ester is hydrolysed by boiling with alcoholicpotash for three hours, and after boiling off allalcohol tho residue is dissolved in water, and -onacidifying with sulphuric acid the trhnothyleno di-carboxylic acid is extracted with ether. Crystallinesolid, m.p. 140°. By heating to 200° carbon dioxideis evolved and tho mono-carboxylic acid results,which is a liquid, b.p. 188o-190°.

CHLOROFORMIC ESTER.

[UOI\, 1885, 18,1177.]

Liquid carbonyl chloz'ide is placed in a flask whichis immersed in a freezing mixture. The flask is fittedwith a reflux condenser through which a stream ofice-cold water circulates. The upper end of thecondonser is closed by a cork through which passesa calcium chloride tube, and into which is fixed adropping funnel. The calculated quantity of methylalcohol is slowly added from the dropping funnel; avigorous reaction follows the fall of each drop andhydrogen chloride is evolved and passes out throughthe calcium chloride tube. When tho addition ofalcohol produces no further action the ester is pouredinto water, washed with soda carb. solution, separatedand dried over calcium chloride; b.p. 70°.

r . n n ii' i .»i «»» MI i \i

iJtt., I MM, 20, m*o.

For tlii;* ]»tir{t«t.ii* Milphur friovide i allowed tourtmvhuu tt-f ruchl<>rttlt*. (VI , i *JS< \ C!<K* 1»

The pyroMtlphur^ I eh!«»rido !'ofiuf<l traeL't withthe sulphuric acid present I hits : N^M'I , f J|(4S()^

Tho ntrln»uflu* \\atcr*lmt!i utut^r n ( j y<»»r having thrrp or l'«»ur lnilh* <«tt the iimor luhi'),with a nitlr-ttthn i'u vtl inft» tin* l«»p part, ami itdropping fumu*l ititvil in Ihrupi u nul , thmu^h which*»() c.c\ fittuuijjr Milphtirit* arit! (M) pt*r c«»ut. M\\) v\(ln»ppi*<l .4tnvly. Tlu* vapt»u»*.M which u ccutl flu*cundctthpr pav;s <»ut throti^h IIu* adc-iubc ittitl amwanhctt hy pa.i^in|( through rtiuc. sulphuric uc-id(well coolctl) ; they then pa:n inin a n ro ivr r iittmrn oilin a. fnH'zin^ xuiHturo when* tin* carhtmyl chturicl^{*t»Uoc*t«. \Va:4tiu^ through c«»nr. ^tilphuric ncUlHVVVVH io rentnvt* HO:l nnd HS^sVl^ from flu* vapours.

Wluni all the? hunting sulphuric acitl ha;i heenintihul the ila^k may \H\ warmed l't»r Iivt* minuteiiover the Ilium* to drive out nil (*<)t'l,. Weight <•!ermle product i\ lia IH) gun, Thi* tuny In* puriliedby redistilling thnai^h rotuf. sulphuric acitl, tlit*warmth of the hand being MiiHrii*ttt t<* product*boilitig, h,p. j Hf\

PRACTICAL WORK: F>O]>JUM. POTASSIUM 111

METHYL BENZOATE.

[Ann., Suppl. 7, 125.]

Brom-benzenc (30 gms.) and chloroformic ester(20 gms.) are mixed with 1 per cent, sodium amalgam(1200 gms.) and heated for several days at 110°under a reflux condenser. Tho mercury is thenpoured off, tho residue extracted with ether andtho extract fractionally distilled.

B. p. of methyl benzoate is 199°.

TOLUIC ETHYL ESTEI?.

This may be prepared in the same manner asmethyl benzoate, using brom-toluene (34 gms.) ;

chloroformic ethyl ester (20 gms.), and 1 per cent,^sodium amalgam (1500 gms).

ACETOACETIC ESTER.[Ann., 1877,186,101.]

Acetic ester (200 gms.) is placed in a round flaskand sodium in thin slices (20 gms.) is quickly added.After this a reflux condenser is fitted to the flask, andif the reaction becomes too vigorous the latter mustbe immersed in cold water. When the reactionsubsides the mixturo is boiled on the water-bathuntil no sodium remains, and after cooling, the mixtureis made acid by adding 50 per cont. acetic acid(about 100 c.c.); an equal volume of saturated brineis then added to salt out any acetic ostor, whichcollects at the top with acetoacetic ester. This layeris placed in a distilling flask and distilled over wire

112 SYNTHETIC XTSK Ol1 METALS

gauze until the temperature reaches 100°, to removeall acetic ester. The remaining liquid is distilledunder reduced pressure to avoid decomposition ofthe acetoacetic ester.

Tho boiling points under various pressures are asfollows :

88° at 29 mm. . . 97° at 59 mm.94° „ 45 „ . . 100° „ 80 „

The yield is about 35 gms. ; b.p. 181°.

ETHYL ACETOACETIC ETHYL ESTER.

[Ann., 1878,192, 153.1

Aceio-acotic ester (32 gms.) is added to a solutionof sodium (5'5 gms.) in alcohol (70 gms.), and to thismixture is gradually added ethyl iodide (40 gms.).The mixture is then heated on the water-bath till itgives no alkaline reaction with litmus (about 2£hours). Most of the alcohol is then distilled off, thoresidue is mixed with water to dissolve the sodiumiodide and then extracted with other. After dryingthe ethereal extract over calcium chloride, tho ethoris distilled off and tho ronminiug oil fractionallydistilled. Yield about 25 gms., b.p. 198°.

Tho yield may bo improved by distilling underreducod pressure. B. p. at 140 mm. pressure is 140°,at 100 mm. 127°, at 40 mm. 106°.

Acid hydrolysis of the ester by concentrated potash.[Ann., 1877,190, 270.]

The ester (20 gms.) is boiled with 22 per cent,alcoholic potash (made by dissolving 20 gms. of

PRACTICAL WORK: SODIUM. POTASSIUM 113

potash in 90 c.c. of alcohol) for four hours under areflux condenser. When cool, it is extracted withother to remove any ketone formed, and then againextracted after acidifying with sulphuric acid, toremove butyric acid. After drying the extoact overcalcium chloride the ether is distilled off.

Yield of butyric acid about 8 gms., b.p. 163°.

Ketonic hydrolysis of the ester by dilute sulphuricacid.

CHaCO.CI-LCOOC2H5 + H3O = CH3CO.CHa.CaH5 + CO2 + C2H5OII.

C9H5

The ester (20 gms.) is boiled with 200 c.c. of dilutesulphuric acid (1 part acid to 2 parts water) forthree hours under a reflux condenser. The cooledmixture is then extracted with ether, and after dryingthe extract over calcium chloride, the ether is distilledoff and the remaining oil fractionally distilled. Yieldabout 10 gms. B.p. of propyl-methyl-ketone is 102°.

ACETO-SUCCINIC ETHYL ESTER.

A mixture of aceto-acetic ester (33 gms.) withsodium (5 gms.) dissolved in alcohol (70 gms.) istreated with mono-chlor-acetic ester (32 gms.) whichis added gradually. The mixturo is then boiled onthe water-bath until no alkaline reaction is shown(about two hours), afbor which it is treated withwater to dissolve sodium chloride, extracted withother*, and the ethereal extract dried over calciumchloride and distilled. Yield 12—15 gms. of a paleyellow oil, b.p. 256°.

ft

114 SYNTHETIC URK OK MKTAI.H

MALONIt'

[Ann., IHHO, 204, 120. |

Jti this preparation ehlor-ucotic acid is convertedinfo potassium cyanaeotato, which is then hydrolysedand ostoriliod in one operation :

t K(1N ^ <)

• ICHSO, h (NH,)HHOt.(Jhloracoiic acid (*t() f(inH.) tnixod with water (80

(\c.) is hoatud to 50—(K)n wltilo potass, carh. (U2is addcnl until tho licpiid in noutral and elTorvCCMISOH. Powdcnnl poiassium eyanido (* 2 fifniH.) innow added and tho whole wc»ll wtinvd. AI*UT tlu»iirsl redaction iw over the niasH in carefully heated tilltho temporal tiro reaches Itf5n and then allowed tocool. rV\n\ Holid is then broken up, and tho oyan-ncetafo ]>r(^sont is himultaneounly hydrolynod andeHierilied by ilrnt mixing with 10 c.e. of alcohol, andthen adding a mixture of alcohol (05 c.e.) and cone,sulphuric acid (05 c.e.) gradually, during Urn minuter.fPho flask in tlwxi Incited on the water-bath for onohour tinder a roflux condenHtvi', after which tho coolmixture is treated with HO c.e. of wator, filteredfrom insoluble matt.cn', and tho filtrate extractedseveral times with other, Tho ethereal extract iswashed with sodium carbonate solution and thendried over calcium chloride. After dintilling off thoother, tho remaining oster is distilled under reducedpressure. B.p. at ordinary pressure is J95°. B.p.at 80 mm. is 12?°; at 00 mm. 120°, at SO mm. 108°,Colourless liquid, Yield, *i5—4*0 gms.

PRACTICAL WORK : SODIUM. POTASSIUM 1 1 5

MONO-ETHYL MALONIC ESTER.

Malonic ethyl ester (20 gms.) is added gradually toa solution of sodium (3 gms.) in ethyl alcohol (40 c.c.).The solid sodium salt separates out, and when all themalonic ester has been added the solid mass is mixedwith ethyl iodide (25 gms.), which is added graduallyand which causes the mass to become liquid. Themixture is then heated on a water-bath for one and ahalf hours, by which time sodium iodide has separatedout and no alkaline reaction is obtained.

The alcohol is next distilled off, water added, andthe mixture extracted with ether. After drying theextract over calcium chloride, the ether is removedand that portion of the remaining oil collected whichdistils at 206°-208°. Yield, 10-15 gms.

Hydrolysis and Conversion to Butyric Acid.

The ethyl malonic ester (10 gms.) is hydro!ysedby boiling for an hour on the water-bath with strongaqueous potash containing 15 gms. of potash. Theproduct is treated with moderately strong hydro-chloric acid till neutral, and the acid is then pre-cipitated as the calcium salt by adding a concentratedsolution of calcium chloride. The salt is filtered anddecomposed by strong hydrochloric acid and the freeethyl malonic acid extracted with ether. The etherextract deposits crystals on evaporation, and thesemay be recrystallised from a small quantity of boilingwater. Colourless prisms, m.p. 111*5°. Yield, about5 gms.


If some of the acid be heated over a small flame,carbon dioxide is liberated and butyric acid remains.

/COOHC,H5.CH< = C3H7.COOH + CO2

XIOOH

DrAOETO-suociNic ESTER.

[Ann., 1880, 201, 142.]

Solid sodium acetoacetic ester is first preparedby dissolving 5 gms. of sodium in 40 gms. of alcohol,and after adding an equal volume of dry ether,acetoacetic ester (28 gms.) diluted with its ownvolume of ether, is gradually added with shaking.

To the mixture 1 c.c. of water is then added andthe whole well s t irred; this causes the sodium com-pound to separate, and it is filtered and drained onthe pump. Yield, 20-25 gms.

The sodium compound is mixed into a thin pastewith ether, and an ethereal solution of iodine thenadded till no more sodium iodide precipitates. Themixture is allowed to stand some hours and thenfiltered. The ethereal solution is shaken withmercury to remove iodine, after which it is crystallisedfrom dilute alcohol or 50 per cent, acetic acid. Whitecrystals, m.p. 78°. Yield, 10 gms.

ETHANE TETRA-CAKBOXYLIC ESTER.

[Ber., 1884,17, 2781.]

Sodium (2*3 gms.) is dissolved in alcohol (30 gms.)3

and to the cold solution is added malonic ethyl ester(16 gms.). To the clear mixture, ether is added tilla turbidity appears, and then iodine (12'7 gms.),


dissolved in ethor, is added gradually with shaking.After standing a short time, wator is added to dissolvesodium iodido,and the separated ethereal layer shakenwith thiosulphate solution to decolorise it. Afterseparating and drying over calcium chloride, the etheris removed and tho remaining oil solidifies on cooling.Oolourloss prisms, m.p. 76°. Yield, about 8 gms.

ACBTYL ACETOACETIC ESTER.[Ber., 1884,17, Eef. 604.]

Dry sodium acetoacetic ester (20 gms.), which isprepared according to the method given under di-acoto-succinic ester, is dissolved in ether, and acetyl-chlorido (12 gms.) is added slowly. A vigorousreaction takes place, which may be completed bywarming, after which a little water is added todissolve sodium chloride, and the ethereal layerseparated. After removal of the ether tho remainingoil is distilled under reduced pressure. B.p. at 50 mm.is 122-124°. Yield, about 20 gms.

ANTIPYRINE.

[Ann., 1887, 238, 147,160.][Ber., 1883,16, 2597.]IDEP. 20429.]

Phcnyl hydrazino (10 gms.) is added to acoto-acctic ethyl ester (12*5 gms.) and well shaken; muchheat is evolved, and when the reaction is over thooily product is separated from tho water formed, andheated on the water-bath till a samplo poured intowater becomes solid (2 hours). Tho whole is pouredwhilo fetill warm into ether, tho white precipitate


collected, well washed wi th e ther , and thon d r i edrecrystall ised from alcohol.

The phenyl-methyl-pyrazolon is then methyl ,by heat ing wi th t h e calculated amount of m eiodide in methyl alcohol a t 100°—ISO0, in a scaled 1for one or two hours . T h e hydriodido of an t ipypresent in the contents , is decomposed by aqu«potash, and the an t ipyr ine obtained is t h e n cry*Used from toluene or e ther . M.p. 114°. Yiabout 10 gms.

MONO-METHYL SUCCINIC ESTER.

[Trans., 1899, 75,839.](3-Mothyl-cyano-succinic ester is first p repared

mixing cyan-acetic ester (28*5 gms.) with 5*7 gmssodium dissolved in 70 gms . of alcohol, and tadd ing very carefully to t h e thick pas te , 42 gmsa-brom-propionic ester. The sodium compodissolves with evolution of heat , and sodium b r o nseparates. After an hour on the water -ba th ,neu t ra l liquid is cooled a n d poured into water , :t h e oil which separates is ex t rac ted wi th ether . 'e ther extract is washed wi th dilute sodium carborsolution and t h e n with water , and after d ry ing ocalcium chloride t h e e the r is distilled off; t hemaining yellow oil is fract ionated under 24 rpressure. The g rea te r por t ion distill ing befcw1 4 0 ° - l 65° is collected and refract ionated under 17npressure, and t ha t pa r t collected which passes ovoi160°-165°. Yield, 60 p e r cent.

The cyano-succinic ester t h u s obtained, is hydlysed by boiling wi th six t imes its volume of co


hydrochloric acid under a reflux condenser for fivehours. Any acid which scparatos on cooling isfiltered, the liquid is made alkaline with ammonia,and boiled with 25 per cent, calcium chloride to pre-cipitate the calcium salt of tho acid, which is filteredand treated with hydrochloric acid to separate thomethyl succinic acid.

SUCCINO-SUCCINXC EsTEJt. -DlKETO-HBXAMKTUYLKNK.

[Ann., 1882, 211, 308.][Ann., 1885, 229, 45.][Ber., 1889, 22, 2168.]

Sodium (10 gms.), cut into small pieces, is addedto succinic ester (38 gms.) containing two or threedrops of alcohol. The mixture soon becomes semi-solid, and is allowed to stand for ten days withoccasional shaking.

At tho end of this time the mass is brokon up,acidified with dilute hydrochloric acid, and tho in-soluble ester is then filtered and recryatallised fromalcohol. Colourless crystals, m.p. ]26°. Yield, about20 gms. N.B.—A smaller quantity can be obtainedin less time if a little ether be added to the mass, andtho mixture be heated on the water-bath for abouttwenty hours, during throo days.

To obtain p-dikoto-hexamethyleiic, tho ester ishydrolysed with sodium hydroxide, and the acid(succino-Hiiccinic) precipitated by acidifying. Thisacid is then heated to 200°, when it loses carbondioxide and the diketo-body remains; ni.p. 78 \

Another method is to hydrolyao the ester with con-

120 bYNTRimC USE OF METALS

centrated sulphuric acid, when it loses carbon dioxideand passes directly to p-diketo-hoxamethylene.

TIN TETRAPHENYL.

[Ber., 1889, 22, 2917.]Twenty-five gms. of tin-sodium alloy (25 per cent,

sodium) is prepared by adding sodium in smallpiccos to strongly heated molten tin, in an ironcrucible. Tho alloy when cold is broken up intosmall pieces and mixed with 30 gms. of brombenzenoin a flask, and 1 to 2 gms. of acetic ester added.Tho mixture is then boiled under a reflux condonserin an oil-bath for ton hours. Tho brown semi-solidmass is next extracted with benzene and the extractcrybtallised. Colourless prisms; m.p. 226°. Yield,10—15 gms.

LEAD TETKAPHENYL.

[Ber., 1887, 20, 710.]This is prepared in the same manner as tin tetra-

phonyl, using 25 gms. of powdered lead-sodium(8 per cent, sodium) and tho same quantity of broxn-benzene. The mixture should be boiled for fifteenhours and then extracted with benzene. Pale yellownoodles; m.p. 224°. Yield, about 18 gms.

MERCURY DIPHENYL.

[Ann., 1870,153, 93.]Brombenzene (31*5 gms.) is dissolved in an equal

volume of xylene, and heated with 400 gms. of sodiumamalgam (2 per cent, sodium) at 160° in an oil-bath.A small amount of acetic e&ter (about 1 gin.)

I'KACTh'AL WORK : MUHUM. POTASSIUM 121

accelerates tlio reaction and boiling* is continuedduring four hours. rI1ho clear liquid is then filteredhot, and tho crystalline substance which separatesfrom tho jcylono on cooling is reorystallisod frombenzene.

Colourless needles; ni.p. 120°. Yield about 15 gins.

tfu.U'ON TWTKANIKNM,.[H<n-., IHHf), 18, inu.|I Nor., lHhtt, 19, IO1^J

Silicon tolraolilorido (20 gins,) is mixed withdilorbon/jono (56 gins.) and four MimiH tho volumo ofdry ctht'i^ nnd a Hnui.ll (iiumtidy of acolic cisUir (I to2 gtns.) addod. rPho iln.sk ih> attachort to a rolluxcoudonsor, and iilum sodium (2^ gms.) in small piocosis gradually added. A vigorous reaction follows andtho flask should bo repeatedly shaken. When Mmreaction is completed, water is addod to remove anyunattaekod sodium, and thon enough to dissolve thosodium chloride, after which the mixture in extractedwith hot bonzono. White crystals separate from thebenzene solution, m.p. 22H°.

\\Uw.y lhH(i, 19, iil f). 1

Oxalic ester (20 gins.) M mixed with ether(100 gms.) anil sodium Q) gms.) in thin slices.Acetic ester (12 gms.) in then added From adropping-runnel, slowly, nnd nflcu" tw(*lvre hours tlu^ masswhich has solidified is treated in the mime way as

122 SYNTHETIC! USE OF WKTALS

for tlio separation of acetoacciic osier (see p. 111).Yield, 50 to 60 per cent. A colourless oil, whichcrystallises with difficulty.

Method 2.[Ann., 1893, 277, 375.]

Sodium ethoxido (9 gms.) is prepared by dissolving3 grm. of sodium in a small quantity of etliyl alcoholand then distilling off the latter in a stream of dryhydrogen gas. The distillation should be conductedin an oil-bath and the temperature allowed to rise to200° in order to drive off all alcohol. Oxalicester (20 gms.) is then added and enough ether togive a clear solution; acetic ester (12 gms.) is nextadded, and the whole is boiled under a reflux con-denser for one hour.

After this, the cool mixture is decomposed withcold dilute sulphuric acid, the ester is extracted withether, and after drying over calcium chloride theethereal solution is allowed to crystallise. Yield,about 50 per cent.

HYDROXYMETHYLENE-GAMPHOR.

[Ann., 1894.., 281, 328.]

In a litre-flask, dry ether (20 c.c.) is mixed withsodium (8 gms.) in thin slices. The flask is attachedto a reflux condenser fitted with a dropping-funnel,and camphor (50 gms.), dissolved in 200 c.c. of dryether, is added to the ether and sodium, after whichamyl formate (45 gms.) is added gradually from thedropping-funnelto the well cooled mixture in the flask.

PRACTICAL WOIMC : SODIUM. POTASSIUM 123

Tlio reaction is allowed to moderate after eachaddition of 4 or 5 gms. of the formate, and thoflask is shaken occasionally. About half an hour istaken to add all the formate, and the mixture isthen allowed to stand for two hours, by the end ofwhich time most of tho sodium will have dissolvedand the mixture will be semi-fluid and brown. Afterstanding another four hours to allow the sodium saltto separate, the wholo is poured into 200 c.c. of icedwater. The yellow aqueous layer is extracted twicewith ether to remove any camphor or borneol in it,and finally air is blown through it to remove all ether.The aqueous solution is then treated with ice-coldacetic acid (30 per cent.) until the deposition of oilceases, and after an hour, when the oil has solidified,it is filtered and dried. Yield, about 20 gms.; m.p.,70°-76°:

yC: CHONa2Cl0IIIbO + 2Na + IICOOC.Hn-CsH.Z | + CluHi70Na

+ cBnn0H

ACISTYL ACETOPHENONE.[Bor., 1905, 38, C95.][D.R.P. 49642.]

Acetic osier (19 gms.) and acotophenono (24 gms,)are mixed with 150 gms. of dry ether and tho mixturecooled in ico, whilo powdered sodamido (16 gms.) isgradually added. When tlio sodauiide has all beenadded, the mixture is allowed to stand for a day,during which time a thick paste <>C sodium salt sepa-rates. At tho end of thin period ice-water is added;the aqueous layer is separated from the ether, aud nil

124 SYNTHETIC USK OF METALS

traces of ether blown out of i t ; it is then acidifiedwith acetic acid, and the precipitated ketone filtei^edoff. Crystals; m.p., 60°~61°; yield, about 25 gms.

Preparation of Sodamide.

[Trans., 1894, 65, 504.]

Ammonia gas is passed over sodium heated ina glass tube to a temperature of 300°~400°. Sincethe glass is attacked, the sodium should rest in atrough of nickel foil. When powdering the sodamide,it should first be moistened with benzene, since it isvery hygroscopic.

ETHYL ACETOPIIENONE.

[Ber., 1905, 38, 698.]

Acetophenone and ethyl iodide in molecular quan-tities are mixed, and sufficient dry ether added todissolve them (several volumes). One molecularquantity of sodamide is then added gradually withcooling, and after a while ammonia gas is evolvedand the ether boils. After standing twenty-fourhours, ice-water is added and the ethereal layerseparated. This contains acetophenone, together withmono- and di-ethyl derivatives, which are separatedby fractional distillation. B.p. of ethyl acetophenono,227°-233°.

FURFUROL ACJROLEIN.[Ber., 1880,13, 2342.]

Furfurol (1 part) is mixed with acotaldehyde(2 parts), water (100 parts), and 10 per cent, sodiumhydroxide (5 parts).

PEACTICAL WOEK : SODIUM. POTASSIUM 125

By gradually heating the mixture to 50°—60° ayellow oil first separates, passing to a brown solid,and when the latter appears, the liquid is neutralisedwith sulphuric acid. The liquid is next distilled, andthe distillate (containing needle-crystals) is extractedwith ether, the ethereal extract distilled, and whenthe temperature has reached 210° the residual oil isallowed to solidify. The brown needles of furfurolacrolein are recrystallised from Tboiling water. Paleyellow needles; m.p. 51°; yield, about 60 per cent,of furfurol used.

ClNNAMYL-VINYL-METHYL IClSTONE.[Bor., 1885,18, 2320.]

Acetone (30gms.) is shaken with water (3600 grns.)till dissolved, and then cinnamic aldehyde (40 grns.)is added and shaking continued till a white emulsionis obtained. Sodium hydroxide (40 gms. of 10 percent. aqueous solution) is then added,, and the wholeis allowed to stand forty-eight hours, with occasionalagitation. At tho end of this time the kotono willhave completely crystallised. I t may bo recrystallisedfrom ether. Rhombic plates; m.p. 08°.

ACETIC ANHYDKIDE.

[Bor., 1911, U, 3333.]

Acetyl chloride (40 gms.) is mixed with potassiumnitrate (7 gms.) in a flask attached to an uprightcondenser, which is closed by a calcium, chloride tubo.A vigorous reaction is accompanied by tho evolutionof chlorine and nitrosyl chloride, and after standing

126 SYNTHETIC USE OF MKTALS

for half an hour, the mixture is heated on a water-bath and gradually raised to boiling temperature, atwhich it is maintained for two hours. The colourlessliquid mass is then extracted with other to romovothe potassium chloride, and the othoroal extractfractionally distilled. Yiold, 15 to 20 gins.; l).p., 138°.

PROM BENZALDEHYDE.

[Ann., 1840, 34, 186.]

Bonzaldohydo (25 gms.) mixed with potassiumcyanide (5 gms. in 20 c.c. of water) and absolutealcohol (50 c .c) , is heatod on a water-bath under areflux condenser for half an hour. At the end ofthis time tho benzoin crystallises out and may befiltered, washed with a little alcoliol and rocrystallisedfrom spirit. Oolourloss prisms, m.p. 137°. Yioldabout 20 gms.

DESYL-ACBTOHIHNONE.

[Trans., 1890, 57, 644.]

Acetophonono (18 gms.) is mixed with benzoin(31 gms.), potassium cyanide (4 gms.), water(75 gms.) and alcohol (75 gms.). The mixture isboiled on tho water-bath and if necessary a littlemore alcohol may bo added to dissolve tho benzoin.After half an hour, dosyl-acetophonone separatos asan oil, and after 1^ hours, tho boiling is stopped, andthe oil?allowed to settle and separate. On cooling,the oil solidifies, and after draining on a plate is re-crystallised from alcohol. Pale-yellow crystals; m.p.126°. Yield, about 18 gms.

PRACTICAL WOEK : SODIUM. POTASSIUM 1 2 7

PHENANTHROXYLENE ACETOACETIC ESTER.

[Ber., 1883,16, 21Q.~]

Finely powdered phenanthraquinone (33 gms.) ismixed in a flask with acetoacetic ester (30 gms.)and 150 c.c. of potassium hydroxide solution (onepart KOH to six parts water) added. The mixtureis gently warmed with continual shaking, heat isevolved, and the red colour of phenanthraquinonegives place to the light grey of the crude product.

This is boiled with water, washed with alcohol andrecrystallised from benzene. Yield, about 30 gms.

White silky needles, which blacken and decomposeat 185°.

A P P E N D I X I I

PEACTICAL WOES: COPPEK AND SILVEE

ACJIOLEIN -> /3-IODOPROPIONIC ACID.

Acrolein is prepared from glycerol by mixing thelatter substance with twice its weight of powderedacid potassium sulphate, and after standing two days,distilling the mixture in a retort ; two layers collectin the receiver, the upper of which is acrolein. Thisaqueous distillate is shaken up with powderedlitharge until no more lead sulphite is produced, andit is then distilled on a water-bath. The moistacrolein which collects, is allowed to stand overcalcium chloride for two hours and then redistilled.B.p. 52°. Yield, about 35 per cent.

The acrolein is next oxidised to acrylic acid asfollows : An alkaline silver oxide solution is preparedby dissolving silver nitrate (1 part) in water (10parts), and mixing with sodium hydroxide (1 part) ,also dissolved in water (10 parts)."*

Ammonia solution is then added gradually till theprecipitated silver hydroxide just dissolves. A quan-tity of this solution, sufficient to oxidise the acroleintaken, is warmed to 60°—70° on the water-hath, and

* These quantities should not "be departed from and the solutionshould not be allowed to evaporate, otherwise silver fulminate maybe formed and a dangerous explosion may result.

PRACTICAL WORK: COPPER AND SILVER 129

the acrolein, dissolved in the minimum amount ofwater, is added gradually; when all has been addedthe heating is continued for half an hour, withoccasional shaking.

After this the mixture is acidified with hydro-chloric acid and the acrylic acid separated bydistillation with steam.

The acid distillate is neutralised with lead car-bonate, heated and filtered, after which, the dry leadsalt is decomposed by heating it in an inclined tube,through which passes a current of dry hydrogensulphide. B.p. 140°.

2CH2:CH.CHO + 3Ag2O = 2CH2:CH.COOAg + 4Ag + H2O

The acrylic acid is now dissolved in the minimumquantity of water, and the calculated amount of con-centrated hydrogen iodide solution gradually added,shaking well after each addition. When all hasbeen added, the mixture is warmed on the water-bath for one hour and then evaporated to crystallisa-tion ; the resulting /3-iodopropionic acid melts at 82°.

ADIPIC ACID.

[Ann., 1869,149,220.]

/3-Iodopropionic acid is melted in a small flaskwith finely divided silver in slight excess of thatcalculated from the equation :

2CH2I.CH2.C00H + 2Ag = 2AffI + (CH2)4(COOH)a.

The silver is prepared by suspending silver iodideor silver chloride in water, and adding the necessaryamount of zinc dust. The precipitated silver isfiltered, washed with diluto hydrochloric acid to


remove any zinc, and then dried by heating graduallyto 150°.

The molten mixture of iodo-acid and silver ismaintained at 100°—120° until it thickens and thetemperature is then raised to 150°-160°, Afterremaining at this temperature for two or tliree hoursthe mixture is cooled and then extracted with boilingwater. The aqueous extract, on evaporation, depositsa considerable crust of adipic acid which is separated.A further quantity of adipic acid is obtained byevaporating the mother-liquor, and the whole may berecrystallised from hot water. Colourless crystals;m.p. 148°-149°.

Adipic acid is more conveniently prepared by thefollowing method, from ^y-chlorobutyronitrile (C1.CH2.CH2.CH2.CN), which is itself prepared from trimethy-lene chlorobrornide as follows:

To a hot solution of potassium cyanide (80 gms.)dissolved in 125 gms. of water, hot 96 per cent,alcohol is added (500 c.c), and to thi§ clear, hotmixture, trimethylene chlorobromide (200 gms.) isadded; the whole is then boiled for 1\ hours on thewater-bath under a reflux condenser. The alcoholis next distilled off, and carries with it most of theunchangedtrimethylene chlorobromide. Water is thenadded to the residue in the flask to dissolve potassiumsalts, and the oily layer is distilled after drying overcalcium chloride. After two or three fractionationsthe portion boiling at 192°—205° is taken as y-chloro-butyronitrile. B.p. 195°-197°. Yield, 50 per cent.

[Ber., 1890,23,1771.][Trans., 1901,79,130.]

PRACTICAL WORK : COPPER AND SILVER 131

The nitrile, prepared as above, is next digestedwith the calculated amount of sodium malonic ethylester, on the water-bath, till no alkaline reaction isobtained. After removal of the alcohol and sodiumchloride, the cyano-propyl-malonic ethyl ester isfractionally distilled under reduced pressure. B.p.170°-175° at 40 mm.

This substance, CNXH2.CHS.CH3.CH(COOOSHB)2,is then boiled with dilute sulphuric acid (1:2) forfive hours ; the resulting adipic acid is extractedwith ether and purified by recrystallising from water.

CARBAZOLB FROM THIO-DIPHENYLAMINE.

[Ber., 1886,19, 2243.]

Thio-diphenylamine is prepared by heating amixture of diphenylamine (30 gms.) and sulphur(12 gms.), at a temperature of 250°—280° for one houror until hydrogen sulphide is no longer evolved.The mixture is then distilled (in a retort) ; any un-changed diphenylamine boils at 310°, while thio-diphenylamine distils at 370°. The distillate may becrystallised from alcohol. Yellow plates; m.p. 180°.Yield, over 50 per cent.

To prepare carbazole, the thio-diphenylamine ismixed in a retort with excess of copper powdor anddistilled in a stream of carbon dioxide. If thedistillate has a yellow colour (due to thio-diphenyl-amine) it should be again mixed with copper powderand distilled. Colourless crystals, m.p. 238°; b.p.355°. Yield, C0-70 per cent.


Dl-ORTIIONJTROPHENYL-DIACTCTYLENE.[Ber., 1882,15, 50.]

It is necessary to prepare first, o-nitro-phenyl-propiolic acid, which is itself obtained from o-nitro-cinnamic acid. Cinnamic ester (50 gms.) is nitratedby pouring gradually into cooled nitric acid (sp. g.1-5).

After completing the nitration by warming on thewater-bath for twenty minutes, the mixture is pouredinto water, and the mixed o- and j9-nitro-estersseparated by digestion with a little alcohol, in whichonly the ortho-compound dissolves. The substancemay then be obtained in a pure state by pouring thealcoholic solution into cold water and filtering.

Bromination of o-Nitro-cinnamic Ester.[Ann., 1882, 212,125.]

The ester (20 gms.) dissolved in carbon bisulphide(300 gms.) under a reflux condenser, is treatedgradually with bromine (15 gms.) and warmed. Thebromine soon disappears, and if the 0S2 be quite dry,no hydrogen bromide will be evolved. After warm-ing a short time, part of the 0S2 is distilled off andthe remainder evaporated. Pale yellow crystals willseparate; m.p. 71°. Yield, 30 gms.

The ester is next treated with alcoholic potash asfollows:

Di-brom-o-nitrocinnamic ester (12 gms.) is dis-solved in alcohol, and potash (6 gms.), also dissolvedin alcohol, is added slowly. Potassium bromide at

VHA.CTICAL WOIUC : COPPER AND SlLVEti 133

once separates, and when all the potash has beenadded tho liquid is filtered from bromide, part o£ thealcohol distilled off, and the romainder evaporatedover sulphuric acid. The dark brown liquid depositscrystals (mixed with resin), which are poured into waterand extracted with ether to remove impurities, afterwhich the nitro-phenyl-propiolic acid is precipitatedby sulphuric acid fractionally. A brown precipitateis first thrown down and removed, further additionof sulphuric acid throws down nitro-phenyl-propiolicacid, and more is obtained by extraction with ether.The slightly red crystals melt at 157°, and whensubjected to a steam distillation give nitro-phenyl-acetylene.

The last-named compound is converted into thecopper derivative by dissolving it in much alcoholand adding an ammoniacal solution of cuprouschloride. The rosulting precipitate is washed withammonia, then beaten to a pulp and air bubbledthrough it to remove ammonia; it may be recrystal-lised from chloroform.

In the final stage of the process this copper com-pound (1 part) is addod to a solution of potassiumferricyanide (2£ parts) and potassium hydroxide(0*4 part) in water (9 par ts ) ; this mixturo is allowedto stand till the red colour of the copper compounddisappears (24 hours). The green-brown rcsiduo isseparated and after drying, extracted with chloroform;the di-phenyl-diacetylene uitro-compound crystallisesin yellow needles.

13-i SYNTJ1KT1C USE OF MWTALK

O-CllLOE-TOLUENE.[Zoit. angow. Chem., 1910, 23, 389.]

o-Toluidine (53 gms.) is dissolved in a mixture of170 gms. of 23 per cent, hydrochloric acid and 500gms. of ice-cold watei\ I t is diazotised by addinggradually, sodium nitrite (37 gms.) dissolved in water(80 gms.). The ice-cold diazo-solution is then addedto a solution of cuprous chloride (50 gms.) in 23 percent, hydrochloric acid (380 gms.) diluted with water(830 gms.). The temperature of the copper solutionshould be kept at + 5° during the mixing, and thoprocess should occupy fifteen minutes. After stand-ing a short time, the mixture is heated on the water-bath to drive off nitrogen and is then stoam-distillod.The distillate is extracted with chloroform, thoextract dried over calcium chloride, and after removalof chloroform the oil is distilled. B.p. 157°. Yiold,about 50 gms.

O-CHLOR-BENZOIC ACID.

o-Chlor-tolacne is boiled in a flask under a refluxcondenser, with a solution of potassium permanganatocontaining a weight of the oxidant equal to that ofthe chlor-toluene used. The time required is aboutten to twelve hours and the permanganato solutionmay be added gradually. When the liquid hascooled two methods of treatment aro possible : Eitherit may be filtered from precipitated manganese oxideand then acidified with hydrochloric acid to precipi-tate chlor-benzoic acid, or sulphur dioxide may bepassed in straight away without filtering. The latter

PRACTICAL WORK : COPPER AND SILVER 135

process will dissolve the oxide of manganese and atthe same time precipitate the chlor-benzoic acid.Colourless crystals ; m.p. 137°. Yield, nearly quanti-tative.

(G-attermann).[Ber., 1890, 23, 1218.]

p-Toluidino (36 gms.), dissolved in a mixture of40 per cent, hydrochloric acid (225 gms.) and water(150 gms.), is diazotised by 25 gms. of sodium nitritedissolved in 100 c.c. of water. Copper powder (40gms.) is then made into a paste with water andadded gradually to the above diazo-solution duringhalf an hour. After standing a short time themixture is steam-distilled and the _p-chlor-tolueneseparated by extraction with chloroform. B.p. 160°.Yield, about 35 gms.

FORMALDEHYDE.

[J. Eaiss. Phys. Chora. Soc, 1913, 53, 286.]Methyl alcohol (100 c.c.) is placed in a flask

which is kept at a temperature of 40°, and connectedto a horizontal combustion tube in which a roll ofcopper foil (5 cm. long) is placed. The other endof the combustion tube is connected to a condenserand a well cooled receiver.

A stream of air is driven through the alcohol causinga mixture of air and alcohol vapour to pass throughthe copper coil, which should bo hoated until it justglows. The reaction will proceed without furtherheating and a solution of formaldehyde in methylalcohol will collect in the receiver.


Small explosions on t h e copper do no l iarm ; b u tthe tempera ture should not exceed a dull r ed hea tor some of tho a ldehydo will be decomposed.

A much improved yield (about 80 per cent.) maybe obtained by subs t i tu t ing pumice, coated wi th amixture of silver and copper , for the roll of copperfoil.

For a method of es t imat ing the percontage offormaldehyde obtained, see c Volumetric Ana lys i s /b y Sutton.

A P P E N D I X I I I

PRACTICAL WORK: MAGNESIUM. CALCIUM

BENZOIC ACID.

A solution of magnesium phenyl bromide in etheris proparod by mixing Ibrombenzene (16 gms.) withdry ether (50 c.c.) and gradually adding magnesiumribbon (2*4 gms.). The reaction, which is fairlyvigorous, may require to be started by the additionof a crystal of iodine. When all the magnesiumlias dissolved, the solution is cooled in iced water anda atroam of well dried carbon dioxide passed throughit for about three hours, at the end of which timetho flask contains a solid mass of the addition pro-duct CcH5.COO.MgBr.

Tho solid mass is treated with 50 c.c. of ice-waterwi th shaking, and then 40 gms. of cold 20 per cent.hydrochloric acid is added gradually. This processliberates bonzoic acid, which may then be extractedwi th other and crystallised.

Yield, about 10 gms.

1 3 8 SYNTHETIC USE OF METALS

PHENYL-ETHYL-CARBINOL.

[Compt. rend., 1900,130,1322.]

Magnesium ethyl iodide is prepared by mixingethyl iodide (40 gms.) with dry ether (100 c.c.) andthen adding magnesium ribbon (6 gms.). When allthe magnesium has dissolved, the solution is cooledin ice, and benzaldehyde (25 gms.) in 50 c.c. ofdry ether added gradually. The solid magnesiumcompound which separates is allowed to stand over-night and then ice-cold water (200 c.c.) is added,followed by sufficient hydrochloric acid (1 :1) to justdissolve the magnesia. The ethereal layer is removedand washed, first with sodium carbonate solution,and then with sodium bisulphite to remove iodine,after which it is dried over potassium carbonate.The ether is distilled off and the phenyl-ethyl-carbinoldistilled under reduced pressure. Yield, about 20

TRIMETHYL CARBINOL.

Magnesium methyl iodide is prepared from methyliodide (25 gms.), and magnesium (4 gms.) in dryether (15 c.c).

To this solution is added, gradually, acetone(10 gms.) in an equal quantity of ether, and themixture is allowed to stand over-night. After this,dilute acid is added and the two layers which resultare separated.

The ether is distilled from the ethereal layer andthe trimethyl carbinol which remains is added to theacid aqueous solution; this is distilled with steam

PRACTICAL WOKK : MAGNESIUM. CALCIUM 139

until the addition of solid potassium carbonate ceasesto "sa l t o u t " the carbinol. From tlio aqueous dis-tillate the carbinol is salted out with potassium car-bonato, separated, and dried over lime or bariumoxide.

Yield, about 60 per cent.; b.p. 83°.

TUIPHENYL CARBINOL.

Magnesium phonyl bromide is prepared bydissolving brom-benzeno (16 gms.) in ether (80 c.c.)and adding gradually magnesium ribbon (2*4 gms.).The solution when ready, is treated with benzo-phenone (18 gms.) in ether (50 c.c) , and when themain reaction is over it is completed by boiling onthe water-bath for half an hour.

A few lumps of ice arc then added to the wellcooled liquid, followed by diluto sulphuric acid.The ethereal layer is separated, washed with sodiumcarbonate solution and then dried over potassiumcarbonate, after which the ether is distilled off andtho solid rccrystallised from benzene. Yield, about20 gms. ; m.p. 159°.

CAMPHOR FKOM CAMPHORIC ACID.

[Compt. rend., 1896, 122, 293, 448.]

Camphoric Anhydride -> Campholide -> Homo-camp] i or ic Acid.

Camphoric anhydride is proparcd by mixingcamphoric acid (100 gms.) with acetic anhydride

140 SYNTHETIC TT8JM OF MKTALfl

(70 gins.) and acotyl chloride (11 gins.) and boilthe mixture under a reflux condenser for halfhour. After cooling, the anhydride is washed wwator and rocrystallisod from alcohol. Yield, £90 per cent. ; in.p. 221°.

The camphoric anhydride is dissolved in alcoand an excess of 5 per cent, sodium amalgam adogradually during 3 days, keeping the mixturo 1and continually acid by addition o£ cone, sulphuacid. Tlio resulting campholide may bo rocrystlised from benzene. M.p. 21G°.

The campholide is next heated in a scaled tuwith the calculated amount of potassium cyanide230° for six hours. When cold, the mass is traiferred from the tubo to water, in which unchangcampholido is insoluble, and the aqueous solutionextracted with other to remove traces of catnpholi*at'lor which it is acidified with sulphuric acidprecipitate homocamplioric nitrilo. This substaiis colloctcd, rocrystalliwod from alcohol or other ahydrolysod by boiling with 30 per cont. potash iammonia is no longer ovolved. Tho mixture is thacidified and tho precipitate of homocainphoric acfiltered. M.p. 234°.

Homocamplioric acid is now neutralised with sosolution and precipitated with load acetate ; tho lesalt of tho acid is collected, dried, and thon packinto a long combustion tubo and hoatod gontCamphor sublimes and may be collected.

CAMPHORIC ACID is proparcd from camphorheating 50 gms. with a inixtu.ro of 400 gms. nitiacid (1*4) and 260 c.c. of wator for twenty hours

PRACTICAL WOBK: MAGNESIUM. CALCIUM 141

a boiling water-bath. The mixture should be in alitre-flask, with a boiling tube, which contains coldwater, fitted in the neck.

At the end of this time the mixture is well cooled,and the camphoric acid which separates is filteredoff—about 30 gms.

The mother-liquor, about 600 c.c., is mixed with afurther 80 c.c. of cone, nitric acid and camphor(50 gms.) added, and after heating for a furthertwenty hours, camphoric acid is separated as before(about 40 gms.). The mother-liquor is again treatedwith 130 c.c. of cone, acid and 60 gms. of camphor,and after a further twenty hours' heating, about40 gms. more of camphoric acid is separated. Inthis way from 160 gms. of camphor, about 110 gms.of camphoric acid will be obtained—70 per cent,yield [Amer. Chem. Journ., 1894, 16, 500].

PENTAMETHYLENE.

[Ann., 1893, 275, 312.]

Adipo-ketone is produced by distilling the calciumsalt of adipic acid in an iron or glass tube. Thedistillate is re-distilled, and that portion collectedwhich boils at 128°-132°.

The ketone is then reduced by mixing it with anequal volume of ether in a flask fitted with a refluxcondenser; an equal volume of water is then addedand sodium in small pieces dropped in. When therequired amount of sodium has been introduced, theethereal layer is removed, dried over potassiumhydroxide and the ether distilled off. The remaining

142 SYNTHETIC USE 01 METALS

oil is fractionated and the portion collected whichboils at 135°—145°; this is refractionated. The re-sulting cyclo-pentanol boils at 139°.

The alcohol is next cooled to 0° and saturatedwith hydrogen iodide; after standing ovor-night theliquid is shaken with dilute sodium hydroxide. Acolourless oil separates, which can be distilled withlittle decomposition in a current of carbon dioxide at164°-165°.

The iodide is now reduced to pentamethylene bymixing it with five times its weight of alcohol andsome granulated zinc in a flask fitted with refluxcondenser.

Fuming hydrochloric acid is added drop by drop,and after some time the solution becomes turbid andan oil separates, which, after standing during somehours with the zinc and acid, is separated, andany iodide present removed by shaking with amixture of concentrated sulphuric and nitric acids.The liquid after separation is dried and distilled.B.p. 50°.

CYANAMIDE; G-UANIDINE.

[J. angew. Cliom., 1910, 23, 2405.]

Sodium cyanamide (50 gins.). is gradually addedto concentrated hydrochloric acid (1'19), 74 gms.while well cooled, and the water is then removed bydistillation in vacuo. The residue, which solidifieson cooling, is extracted with ether, and the etherevaporated; the cyanamide solidifies when cooled.Yield, about 10 gms. M.p. 40°.

PRACTICAL WORK : MAGNESIUM. CALCIUM 143

From calcium cyanamide the procedure is asfollows : The calcium compound is dissolved in waterand the calculated amount of aluminium sulphateadded in solution; this liberates cyanamide^ and aprecipitate of calcium sulphate and a]umina is formed.The filtrate is evaporated in vacuo and the cyanamidecrystallised from ether. By this method about 20 gms.of cyanamide is obtained from 200 gms. of the calciumcompound.

A good yield of guanidine nitrate is obtained bytreating dicyanamide (obtained by heating cyanamidejwith a mixture containing 25 per cent, of hydrochloricacid (1 •]9) and 35 per cent, of nitric acid (1*38), inwater.

A P P E N D I X I V

PEACTICAL WOEK: ZINC. MEBCURY

OITRTC ACID.

[Trans., 1897, 71, 457.]

Oxalyl-acetic ester (20 gms.) is mixed with mono-bromacetic ester (17 gms.) in a flask of 300 c.c.capacity, fitted with an air-condenser. Enough zincturnings to cover the end of a spatula are added andthe mixture becomes brown, while the temperaturequickly reaches 50° and the zinc dissolves. Additionof a second portion of zinc is attended by boilingand the reaction is moderated by cooling; the metalis added in excess, and the mixture is then heated onthe water-bath for a short time. After cooling, themixture is treated with cold dilute sulphuric acidand ether, well shaken to get a clear solution, andthe ethereal layer removed, washed with dilutesodium carbonate and dried over calcium chloride.The ether is next distilled and the remaining oilfractionated under reduced pressure; most of itpasses over below 200° at 35 mm. That portiontaken as citric ester (b.p. 212°~216°) is hydrolysed

WOKK : /INC. MICUCURY 145

l)y alcoholic potash. From tho neutral solutioncalcium citrate is precipitated. Yield, about 5 gins.

KETONTBS OU THRTIARY ALCOHOLS FROTH ACID CHLORIDES.

[Bull. Soc. Claim., 1911 (iv), 9, i-xxv.]Tho zinc alkyl reagent is prepared as follows:Twice the amount of zinc-copper couple theoreti-

cally required, is mixed with the alkyl iodide (1 rnoh),ethyl acetate ($• niol.), and dry toluene equal to twicetho weight of ethyl acetate used. This mixture isheated under a reflux condenser at 100°, and thereaction started, if necessary, by adding a crystal ofiodine.

About forty-five minutes' heating is required, andtowards the end, the temperature may be raised to110°; the flask should be occasionally shaken. Whenrefluxing has stopped, the contents of the flask arecooled, an amount of toluene equal to that first used isadded, and the viscous liquid is decanted into a dryflask or bottle. Yield, about 80 per cent.

For use with acid chlorides the procedure is asfollows :

An amount of the above reagent (zinc-alkyl-iodido)is taken (25 per cent, in excess of tho calculatedamount), and while cooled to 0°, the acid chloridedissolved in dry toluene is added drop by drop withshaking. When all the acid chloride has been run in,the mixture is cooled and dilute sulphuric acidadded. Tho toluene layer contains the requiredproduct, and often a* small quantity of zinc which may"be removed by shaking with ammonia. After this the

10

IU) SYNTHETIC USE CW MlflTALK

toluene solution is washed with NallCC^ and also withthiosulphate; it is then dried over sodium sulphatebefore separating the ketone or tertiary alcohol.

NAPHTHALENE PROM JS-OKTAFHTHOL.

A combustion tube is half filled with a mixture ofzinc dust and /3-naplithol (10 gins.). The remainderof the tube is filled with granulated pumice impreg-nated with zinc dust, and this (the front end) is con-nected to a receiver. The other end of the tube isconnected to a generator for providing a stream ofdry hydrogen. The combustion tube should bebetween 50 and 60 cm. long, and rest in a furnace.When all air has been expelled by hydrogen, the zinc-pumice is heated to redness and then the naphtholmixture is heated.

In the receiver, naphthalene and water collect, andwhen the distillation is complete, the aqueous distillateis extracted with ether and the ethereal solutiondried over calcium chloride. On evaporating theether, naphthalene remains.

ISOQUINOLINE.[Ber., 1888, 21, 2299.][Ber., 1884,17, 2178.]

Phthalic Anhydride -» Fhthalide -»Ilomophthalimide.

Phthalic anhydride (200 gins.) is dissolved inglacial acetic acid (1 kilo.), and while heated on thewater-bath, zinc dust (300 gms.) is gradually added.

PRACTICAL WOlHv : ZINC. MERCURY 147

Tho zinc dissolves rapidly with evolution of hoat andwhen the reaction becomes sluggish; heat is applied.

Needles of diphthalyl—

xwhich deposit on cooling are filtered oil, and ondiluting the mother-liquor a mixturo of hydro-diphthalyl and hydrodiphthal-lactonic acid is pre-cipitated. After filtering these off, the phthalideis extracted from the mothor-liquor with ether.Prisms; m.p. 73°. Yield, about 30 per cent.

The phthalide is next converted to cyanotoluicacid by heating it in a scaled tube with the calculatedamount of potassium cyanide at 230°-240°, for five orsix hours.

Tho contents of tho tube are then transferredto water, filterod from any insolublo matter, and thonitrilo precipitated by sulphuric acid. When filtered,it is hydrolyscd by boiling with 30 por cent, potashtill no more ammonia is evolved, after which homo-phthalic acid is precipitated by sulphuric acid. M.p.175°.

Homojohthalic Acid -» Homophthalimide.[Ber., 1886,19, 1653.]

The ammonium salt is preparod by neutralisationwith ammonia, and then distilled, when it decomposesinto homophthalimide, wator and ammonia. The twolatter substances pass over first, and leavo behindhomophthalimido, which melts at 223°.

The homophthalimide is then mixed with zinc dust

148 SYNTHETIC TJBiS OP METALS

in a combustion tube and heated in a stream ofhydrogen, at a dark red heat.

A deep-brown liquid distils over which smells ofisoquinoline, and this is saturated with hydrogenchloride, the hydrochloride of the base filtered anddried, and it may then bo decomposed by aqueouspotash. The isoquinolino, which may be obtained byextraction of the alkaline liquor with ethor, or dis-tillation with steam, may fc0 furthor purified byformation of the picrate and its subsequent decom-position. M.p. 23°. B.p. 241°.

[Ann., 1876,183, 3.]Rosorcinol (7 parts) i s m i x c ( j w i t h phthalic

anhydride (5 parts), and powdered anhydrous zincchloride (3 parts) is gradually added to tho mixture,with stirring, at a temperature of 180°. When allthe zinc chloride has been added, the mass is heatodto 210° for two hours. The cooled mass is thenpulverised and boiled with dilute hydrochloric acidfor ten minutes, after which the solid fluorescein isfiltered and washed. It m&y be purified by re-crystallising from alcohol. Yield, about 80 porcent.

MALACHITE GREEN.

[Ann., 1881, 206,122.]

Dimethylaniline (5 parts) is mixed with benzalde-hyde (2 parts) and powdered anhydrous zinc chloride(4 parts).

PRACTICAL WORK : ZINC. MERCURY 149

This mixture is heated on the water-bath, in abasin, until it no longor smells of benzaldehyde (fourto five hours).

The product is then transferred to a large flaskand distilled with steam to remove unchangeddimethyl-anilino; the leuco-base is filtered whencool and recrystallised from alcohol. Almost a quanti-tative yield is obtained. The zinc chloride doublesalt of the dye is prepared as follows : Ten. gms. ofthe base is dissolved in diluto hydrochloric acidcontaining 2*7 gms. of HOI; the liquid is diluted with800 c.c. of water and 10 gms. of 40 per cent, aceticacid added; it is then cooled with ice, and a thin pasteof 7"5 gms. of lead peroxide added gradually withshaking. After standing a few minutes, the lead isprecipitated by adding 20 per cent, sodium sulphate,and to the filtrate from lead sulphate is added 8 gms.of zinc chloride dissolved in a little water. The dyeis then salted out by addition of common salt. Yield,about 7 gms.

ACRIDINE.[Ber., 1884,17, 101.]

Diphonylamino (1 part) is mixed with chloroform(1 part) , zinc chloride (1 part), and zinc oxide (J apart). The mixture is placed in a sealed tubeand heated to 200°—210° for seven to eight hours.The mixture is then digested with cone, hydrochloricacid and the filtered solution poured into water toprecipitate any unchanged diphcnylamine, the hyclro-chlorido of which is dissociated by water. Prom the


filtered solution, acridine is precipitated by sodiumhydroxide, and may be recrystallised from hot waterafter separating by steam distillation. Fine leaflets.M.p. 110°. Yield, about 50 per cent.

a-MsTHYL-INDOLE.[Ber., 1886,19,1563.]

Acetone phenyl-hydrazone is first prepared bymixing phenyl-hydrazine (30 gms.) with, acetone(18 gms.). The mixture becomes warm and waterseparates; it is then heated on the water-bath forhalf an hour, and at the end of this time heated ina dish on the water-bath, to drive off acetone andsteam. The hydrazone is then mixed with five timesits weight of anhydrous zinc chloride, and heatedunder a reflux condenser in an oil-bath at 180°. Avigorous reaction takes place, and when completed,the dark-coloured mass is distilled with steam. Thea-methyl-indole collects in the receiver and soonsolidifies to a pale yellow mass. I t may be purifiedby recrystallising from ligroin. M.p. 59°. Yioldis over 60 per cent, of that calculated.

PBOPYL CHLOEIDE.

[J. Am. Chem. Soc, 1907, 29,1328.]

Anhydrous zinc chloride (30 gms.) is melted in around flask (£-litre), which is rotated so that thecooled chloride forms a layer inside, with a largesurface exposed. The flask is fitted with a three-holed cork through which pass two dropping funnelsand a fractionating column ; the last is fitted with a

PRACTICAL WOKK : ZTNC. MRRCUEY 151

thermometer and the side tube passes into a verticalspiral condenser. Through a second hole at thetop of the condenser, a tube is passed for droppingcold water, so that hydrogen chloride may beabsorbed. Propyl alcohol (54 gras.) is required andphosphorus trichloride (30 gms.). One half of thetrichloride is run in from the funnel which reachesto the bottom of the flask, and while heating gently,one third of the alcohol is admitted drop by dropthrough tho second funnel which reaches just abovethe level of the mixture. When this portion hasbeen added the remaining phosphorus trichloride andalcohol are added simultaneously and at the samerate. Propyl chloride distils over, mixed withhydrogen chloride continuously, but the latter isprovcnted from escaping into the air, by droppingwater at a suitable rate into the condenser. Thedistillation (hitherto conducted on a water-bath) isfinished over a flame, and the propyl chlorideseparated and driod over calcium chloride. Yield,80-90 per cent. B.p. 44<°.

a-ETJTOXY-QUINOLINK.

[Bcr., 1882,13, 2103.J

o-Aanino-cinnamic ester (20 gms.), prepared byreducing o-nitro-cinnamic acid and then esterifyingthe resulting ammo-acid (see p. 162), is warmed witha saturated alcoholic solution of zinc chloride forsome hours at 80°—90°. The mixture is then madealkaline and distilled with steam, when the quinolinederivative passes over and may bo extracted from


the distillate with other. After drying the extractover potassium carbonate and removing the ethor,the remaining oil is distilled, B.p. 256°.

PHTUALIC ACID.

[D.R.P. 91202.]

Naphthalene (20 gins.) is mixed with mercuricsulphate (10 gins.) and concentrated sulphimc acid(300 gms.) in a retort which is fixed upright, andwarmed until the naphthalene has dissolved. Theretort is then turned, connected with an air-condenserand heated strongly. Eeaction commences at 200°-250° and becomes vigorous at 300°, while the pro-ducts distilling over, consist of phtlialic acid, sulpho-phthalic acid, naphthalene, and water, accompaniedby sulphur dioxide and carbon dioxide. The distil-late is collected in 250 c.c. of cold water and hoatingcontinued till the retort is nearly dry, after whichthe distillate is filtered. The precipitate is washedwith water and then dissolved in sodium hydroxide,filtered from unchanged naphthalene, and the phtlialicacid re-precipitated by hydrochloric acid. I t may berecvystallised from water or alcohol. Yield, about70 per cent.

153

A P P E N D I X V

PRACTICAL WORK: ALUMINIUM. TIN. LEAP

DlMTDTHYL-ANILINE-PKOSPHOR-CTILOKTDE

[Bor., 1888, 21, 1407.]

Phosphorus trichloride (33 gms.) is mixed withdimethyl-aniline (23 gms.) in a. flask fitted with areflux condenser.

Anhydrous aluminium chloride (7 gms.) is tlionadded, through the condenser, a little at a tiniowhereby a vigorous reaction ensues. When n.11 thechloride has been added, the flask is hoatotl on awater-bath for three hours, and then when cool, Lhooily liquid is extracted two or throe tinws withpetroleum ether (until the residue in tlio flask isnearly solid).

On distilling the clear extract over a water-bath,the petroleum ether is removed, and the residue oncooling separates in tables. I t may be purified byrecrystallisation from ether or benzene.

Yellow crystals; m.p. 06°. Yield, about 50 per

154 SYNTHETIC USK OF METALS

J0-TOLUIC-ALDEIIYDE.[Ber., 1897, 30, 1622.]

Toluene (30 gms.) is mixed with anhydrousaluminium chloride (45 gms.) and cuprous chloride(4 gms.) in a flask, and into the mixture a stream ofcarbon monoxide and hydrogen chloride gases ispassed; while the flask is continually shaken and thotomperature maintained at 20°-25°. Tho carbonmonoxide may be stored in a 10-litre bottle and isenough to pass steadily for about three hours. Thehydrogen chloride should pass at half the rate ofthe carbon monoxide. The escaping gases may becollected in a second bottle and used over again.

At the end of three hours the reaction-product ispoured into ice-water; an oily layer separates, andthe mixture is distilled with steam to remove tolueneand toluic aldehyde. The aqueous distillate isshaken with saturated sodium bisulphite, and undis-solved toluene separated from the aqueous layer.If the aldehyde bisulphite separates at this stage itmust be dissolved by adding more water.

Finally, the separated aqueous solution is madealkaline with sodium hydroxide and distilled withsteam; the aqueous distillate is then extracted withether, and after drying over calcium chloride thoether is removed by distillation. Yield, about 20gms. of oil; b.p., 204°.

DIPHENYL METHANE.

[Trans., 1895, 67,826.].Benzene (60 gms.) is placed in a flask under a

reflux condenser and half a gram of aluminium-

PRACTICAL WORK : ALUMINIUM. TIN. LEAD 155

mercury couple added in strips. The couple isprepared by immersing aluminium foil in concentratedmercuric chloride solution for a minute ; the mercury-coated strips are first washed with water, then withalcohol, and lastly with benzene, and dropped quicklyinto the benzene in the flask. Benzyl chloride(30 gins.) is then added slowly, from a tap-funnel inthe top of the condenser, during one hour. Effer-vescence is caused by the evolution of hydrogenchloride, and when all has been added the flask isheated for a short time on the water-bath (quarterof an hour).

The liquid is then shaken up with dilute sodiumhydroxide solution, the benzene layer separated andfractionally distilled. When the temperature reaches100°, the distillation is continued under diminishedpressure (80 mm.) and the fraction collected whichpasses over at 170-176°. On cooling, this forms amass of colourless needles (diplienyl methane). M.p.25°. Yield, about 14 gms.

O-HYDRINDONH.

[Trans., 1894, 65, 484.]

Hydrocinnamic Acid -> fi-Phenyl-propionyl Chloride,

Cinnamic acid (1 part) is mixed with water (10parts) and neutralised with sodium hydroxide. Tothis solution, 2£ percent , sodium amalgam (17*parts)is gradually added with shaking, after which theliquid is poured off from the mercury, and the


hydrocinnainic acid precipitated by hydrochloric acid.Yield, 80-90 per cent.; m.p. 47°*

The acid chloride is prepared by treating the acid(50 gnis.) in a flask, gradually, with phosphoruspentachloride (69 gnis.) ; the reaction may bo com-pleted by warming on the water-bath. To removephosphorus oxychloride, the liquid is distilled underdiminished pressure; subsequently the pressure isreduced to below 35 mm. boforo the /3-phenyl-propionyl chloride can be distilled without decomposi-tion. B.p. 125°-135° at 33 mm. and 117°-119° under13 mm. Yield, about 90 per cent.

/3-Phenyl-propionyl chloride (25 gms.) is dissolvedin petroleum ether (b.p. 60°—70°); and after addinganhydrous aluminium chloride (25 gms.) the mixtureis heated gently, under a reflux condenser, on thewater-bath, till the mixture boils and a vigorousevolution of hydrogen chloride takes place; the flaskis then removed till the reaction subsides.

This heating on the water-bath and subsequentcooling, is repeated until the evolution of hydrogenchloride is small (20-30 mins.). After treatmentwith ice-cold water the mixture is steam distilled, andthe hydrindone in the receiver is extracted withpetroleum ether, washed with sodium carbonate andcrystallised.

Colourless crystals; m.p. 41°. Yield,about 10 gms.

TKIPIIENYL-METHANE.

[Bor, 1893, 26, 1961.]Dry benzene (160 gms.) is mixed with dry chloro-

form (32 gms.) in a flask connected with a reflux

PRACTICAL WORK : ALUMINIUM. TIN. LEAD 157

condenser, and powdered aluminium chloride (25 gms.)is added gradually; with shaking.

Hydrogen chloride is evolved, and when all thealuminium chloride has been added, the flask isheated to boiling for half an hour.

When cold, the mixture is added to an equal volumoof cold water, and tho upper benzene layer which con-tains the triphenyl-methane, is separated and driedover calcium chloride. Benzene is then distilled offand tho temperature finally raised to 200°, aftorwhich any diphenyl-mcthano is removed by di&tillingunder 80 mm. pressure. B.p. 175°. When thethermometer rises above 180°, tho distillation isstopped and the residue, when cool, extracted withwarm benzene.

Tho crystals obtainod from this liquid containbenzene of crystallisation which is removed byheating on tho water-bath; the triphcnyl-mothancmay bo rocrystallised from alcohol. Colourless plates;m.p. 92°. Yield, 20-25 gms.

ACETOHIENONE.

Aluminium chlorido (60 gms.) is powdered, andcovered with benzene (36 gins.) in a half-litro flaskfitted with a reflux condonser, and acotyl chlorido(42 gms.) is gradually added to tho well cooledmixture through a tap-funnel. A vigorous ovolutionof hydrogen chloride takes place and the mixture isallowed to stand for an hour, after which it is stirredand poured into 300 c.c. of ice-cold water. Thealuminium compound decomposes with evolution of

158 SYNTHETIC USE OV METALS

heat, and the dark oil which separates is extractedwith benzene. The benzene extract, after washingwith dilute caustic soda and then with water, isdried over calcium chloride and distilled. Benzenepasses over first and the thermometer then risesrapidly to 190°; that portion is collected as aceto-phenone which distils at 195°—200°. The pale yellowoil solidifies on cooling. Yield, about 25 gins.Colourless plates ; m.p. 20°, b.p. 202°.

O-BENZOYL-BINZOIC ACID.

[Ber., 1880,13,1612.]

Phthalic anhydride (25 gras.) is dissolved in warmbenzene (250 gms,), and dry aluminium chloride (40gms,) is gradually added during three quarters of anhour* After standing for a short time the cooledbenzene layer is poured off and decomposed by dilutehydrochloric acid, when a yellow mass separates,which, is washed with water and then treated withwarm sodium carbonate solution, whereby most ofthe solid dissolves. The acid (benzoyl-benzoic) isreprecipitated by acidifying the solution of thesodium salt, and may be recrystallised from xylene.Yields about 15 gms.

Phenyl-benzoyl-benzoic acid—

4 \ X > O H

may be prepared similarly, using diphenyl andphthalic anhydride.

[J. Prakt. Chem., 1890,1*9,147.]

PRACTICAL WOKK : ALUMINIUM. TIN. LEAD 159*

Benzoyl-benzoic Acid ~> Anthraquinone.

The acid is dissolved in cone, sulphuric acid andheated to 100° for half an hour. On pouring intowater, a white precipitate of crude anthraquinone isformed, which is washed with water and then withsodium hydroxide solution.

I t is then recrystalliscd from glacial acetic acidand further purified by sublimation. Yellow needles;m.p. 275°.

HYDROLYSIS OF ANISOLE BY A1C]3.

[Bei\, 1892, 23, 3531.]Anisole (10 gms.) is mixed gradually with

powdered anhydrous aluminium chloride (15 gms.),A vigorous reaction ensues, and crystals of aluminiumdouble compound separate; the flask is then heatedin an oil-bath to 120° for three hours, when methylchloride is steadily ovolvod. At the end of this timethe aluminium phenolate is decomposed by cold wateracidified with hydrochloric acid, and the phenol ex-tracted with ether.

Unchanged anisole is removed from the phenolthus obtained, by dissolving the' latter in sodiumhydroxide and re-precipitating with acid, and againextracting with ether. Yield, about 5 gms.

TOLUENE PROM ^-TOLUIDINE.

[Ber., 1889, 22, 587.]

p-Toluidine (15 gms.) is dissolved in 45 c.c. cone,hydrochloric acid diluted with 90 c.c. of water, and

160 SYNTHETIC IF.SK OH1 METALS

diazofciscd with sodium nitrite (10*5 gms.). Thediazonium solution is poured into caustic soda solu-tion made by dissolving 22 gms. of sodium liydroxidein 75 c.c. of water, and the mixture is kopt below 10°all the time. This alkaline mixture containing thediazonium salt is next added slowly, through a con-denser, to alkaline stannous chloride solution, in aflask which is immersed in ice. The alkalino tinsolution is prepared by dissolving tin chloride (45 gms.)in water (110 gins.), and adding 50 por cent, causticsoda solution till the precipitated tin hydroxidealmost dissolves. A vigorous evolution of nitrogentakes place after each addition of the diazo-solutionand impure toluono separates; this is removed bysteam distillation, and the toluone in the distillateseparated and dried over calcium chloride. Yield,about 8 gms.

DlPHJENYL.

[Bor., 1870, 9, 407.]

Benzene (100 gms.) is boiled and the vapourpassed through an iron or glass combustion tube 1metre long, which is filled with granulated pumiceand heated to redness in a furnace. The vapoursissuing from the combustion tube (consisting ofdiphenyl, unchanged benzene, and hydrogen) arepassed through a condenser so arranged as to bringthe diphenyl, etc., back to the flask o£ boilingbenzene. A glass tube fused into the lower end ofthe condenser serves for the escape of hydrogenwhich is liberated during the reaction. By this

PEACTICAL WORK : ALUMINIUM. TIN. LEAD 161

arrangement, the vapours pass repeatedly through thered-hot pumice, and after two hours, the contents ofthe flask may be distilled and that portion boilingbelow 150° rejected. The remainder, in the distillingflask, solidifies on cooling and may be re crystallisedfrom alcohol. M.p., 71°.

OXALIC ACID.

[J. Prakfc. Chem., 1907, 75, 146.]Concentrated nitric acid (140 c.c.) containing

vanadium pentoxide (0*1 grm.) is warmed gently ina litre-flask; it is then placed in a fume-cupboardand powdered cane-sugar (20 gms.) is added.

As soon as the reaction becomes vigorous andbrown fumes are evolved, the flask is placed in coldwater to moderate the reaction. The mixture isallowed to stand for twenty-four hours, by whichtime the oxalic acid will have crystallised; thecrystals are drained and recrystallised from water.Yield, about 16 gms.

11

162

A P P E N D I X V I

PRACTICAL WORK: IRON. NICKEL. PLATINUM

O-AMINO-BENZALDEHYDE.

[Ber., 1884,17, 456, 754.]

o-Nitro-benzaldehyde (10 gms.) is suspended in alitre of water, containing 100 gms. of ferrous sulphatein solution, and excess of ammonia solution is added.The mixture is then heated to 100° for ten minutesand afterwards steam-distilled; the amino-benzal-dehyde is extracted from the distillate with ether.M.p. 39°.

O-AMINO-CINNAMIC ACID.

[Ber., 1882,15, 2299.]

o-Nitro-cinnarnic acid (30 gms.) is reduced byferrous sulphate (270 gms.) as above. Instead of steam-distilling, it is advisable to filter from ferric hydroxideand to precipitate the amino-acid in the cold solutionby adding glacial acetic acid. Bright yellow needlesof amino-cinnamic acid separate. Yield, 54 per cent.M.p. 158°.

PRACTICAL WORK : IRON. NICKEL. PLATINUM 1 6 3

MANNOSE FROM MANNITOL.

[Trans., 1899, 75, 9.]Mannitol (40 gms.) is dissolved in water (100 c.c.),

and powdered ferrous sulphate (10 gms.) added.When this has dissolved, the clear solution isoxidised by added " 20-volume " hydrogen peroxide(120 c.c.) gradually. After standing for two hoursthe solution is divided into two parts, one of whichis used for isolating the mannose as follows : Thesolution is treated with excess of barium carbonateand filtered from iron oxide, etc. I t is thendistilled under diminished pressure at 50° to removewater, and the syrup obtained is then transferred to adish and allowed to crystallise. Yield of mannose,8-10 gms.

The second half of the above solution is againdivided and one part used for preparing the hydra-zone, while the other part serves for preparing theosazone.

The hydrazone is prepared by making the solutionalkaline with sodium carbonate and then acidifyingwith acetic acid; to this solution is added phenyl-hydrazine (5 gms.) which has been dissolved in 25per cent, acetic acid. After standing for forty-fiveminutes the hydrazone is filtered off, washed with avery little acetone and recrystallised from water.Pale yellow crystals; m.p. 181°. Yield, about 5 gms.

The portion used for preparing the osazone is madealkaline with sodium carbonate, then acidified withacetic acid, and phenyl-hydrazine (10 gms.) dissolvedin 25 per cent, acetic acid is added together with 10


gins, of sodium acetate in a little water. This mixtureis digested on the water-bath for three hours, afterwhich the osazone is filtered, washed with water, andrecrystallised from alcohol. M.p. 195°; yield, about8 gms.

HEXAHYDRO-BENZENE.

[Compt. rend., 1901,132, 210.]A 50 cm. combustion tube is loosely packed with

pumice, which has been previously mixed with anequal weight of nickel oxide and a little water, andgently dried.

This is then placed in an air-bath and heated toabout 300° while a stream of hydrogen gas is passedthrough, to reduce the oxide. When no more steamis produced the tube is allowed to cool, and to oneend is attached a distilling flask, containing 30 c.c. ofbenzene, through the neck of which, a glass tubepasses connected with a hydrogen-generating appa-ratus. The hydrogen is allowed to pass through thetube, driving out all air, and is then made to bubblethrough the benzene warmed to 30°, while the nickel-pumice is heated to 180°—190°. About six hours isrequired to pass all the benzene through and toconvert it into hexahydro-benzene. Any unchangedbenzene is removed by nitrating the distillate. Yield,80 per cent. B.p. 80°-82°.

HEXAHYDRO-PHENOL.

[Compt. rend., 1901,132, 210.]

About 40 gms. of phenol may be reduced byhydrogen in the presence of reduced nickel, by the

VliAOTXCAh WORK : IKON. NICKBL, PLATINUM 165

&o>***e method an hoxahydro-bontfeno in prepared. Thetoxnpora tu ro of the nickel Rhould bo 160°—170° and•fclxo phenol may bo hoaiod nearly to ita boiling pointyyixilo a fairly rapid current of dry hydrogenbubblon

h it. Tho diHtillnto ultnnately obtained, IBwith oaimtic Hoda nolution to remove un-

c g phenol, extracted with other, and afterd r y i n g tho extract over potaHHiutn carbonate, it isf rac t iona l ly dintillod,

B.p. of hoxahydro-phenol in 170°.

I N D U X

pAcoiio anhydride, J*2, 125Aootoacotio nht<U\ 0, 111

liydrolyMH of, 10A colony 1 acetone, 12Aootophonono, K>7AeetoHUceinic out or, 1 111Awtyl-acotoacoiio onior, 11, 117Aflotyl-aectophouono, 1 %SAAcotyl-ncntono, 0, 2<'iAcwtyl'pyroraeomic o.-iter, J8Acid anhydride format ion, 4, U2,Acid itotiiHhium Miilpliato, i)JAori(limi,7l, 1 1UAcrolom, lil, 128rt-AoroHO, L*<K 02Aoryliu* acid, liJHAdipuwicid, :m, 00, liii>, 1-UA i i h h 7My p

82Aluminium chloride, 77, ir»i']

oxtdo an ('atalynt, i)7, KK)Amino-)M»n/,»ldohy<l<s 102Amino-citinnuiic acid, 102Ammonia, Hynili<Mih of, UX)Aniwdo, !()o, lfi'JAnihranilic acid, JJ<i, 7l<

Antimony, M»oxido, i>7

Anti|)yrin<*, 13, 11

H<ui/.o)ilu»Jion<>, 77H« nzoyl aeotouo, 2ttUtm'Auyl-lnm'/inv acid, 79, 158UonzyJ ryiuiido, M<BiHnatth oxidtt an catulynt, 97

lhiiano toinusarboxylic OHIOV

acid, 1U7anhydride, lor»

ji(l<», 02, i;J9('amphor, 01, i:tf)((am]»lioric acid, 20, (U, I'M)( iinphoronic a.cid, 00(Wl.azohs Jl7, t.'M(4ar!>idoKT fi'j.Carbon i uhox'uh*, OSCnrljotiyl chlori<l<\ 101)C'aHincr <'yani<lo prociMH, 2'i(•'hloi'bonzoic acid, I .'It(Milorobroui-pt'itpat s 1OI5(Miloroformic owtcr, fi, 109o~('lilor(olu(»u<i, III IfMiiloHoluono, 1«'$5(1innamic aldehyde, 20

nator, 18(1iunntuyl-\ inyl-m<»lhyl K(i

Ciliic < 1( r, 00, M 1(4lai »»n, 8, 19Coba 11, a,i calaly t, til'oppcr an cataly. U 91

Cynnncotic oHtoi, 1 1<'yntmmi<l<«, T»r>, 1 12Cyclo-iirctnl.i, (JOCycl<t-litiiyl<»ius 11

I>««oxyh(Ui'/t«in, 11

168 INDEX

Desyl-acetophenone, 30, 126Diaceto-succinic ester, 11, 40,116Diaeetyl-dicarboxylic ester, 20Diacetylene dicarboxylic acid, 37Diazo-compounds, 38Dibenzoyl methane, 19Di-isatogen, 38Bi-isopropyl succinic acid, 35Di-keto-hexamethylene, 17, 119Diketones by ZnRI, 65/3-Diketones by A1C13,79Dimethyl-aniline-phosphor-chlo-

ride, 82,153glutarie ester, 20succinic ester, 14, 35

Di-o-nitrophenyl-diacetylene, 38,132

Dipentene, 31, 52Diphenyl, 160

diacetylene, 38methane, 154

Di-tertiary glycols, 50

Esterification by catalysts, 98Ethane tetracarboxylic ester, 11,

116Ethoxy-quinoline, 73,151Ethyl acetophenone, 124Ethyl benzene, 104Exhaustive methylation, 41Fats, hydrolysis by PbO, 85Ferric chloride, 88Ferrous sulphate, 88, 162Fluorescein, 148Formaldehyde, 100,135Friedel-Crafts' reaction, 77,153Furfurane, 12Furfurol acrolein, 25,124

Gattermann, 39,135Glycerose, 26Grignard reagent, 41,137Guanidine, 56,142

Hexahydrophenol, 164Hexamethylene, 4, 61,106,164Hexaphenyl ethane, 40Hydrindone, 79,155

Hydrogen peroxide, 89, 163Hydrolysis by A1C13, 82,159

by catalysts, 99Hydroxymethylene camphor, 22,

122ketones, 23

Indigo, 23, 25, 38, 74p-Iodopropionic acid, 35, 128Ionone, 28Isoprene, 24Isoquinoline, 70,146

Keten, 68, 101£-Keto-hexahy drobenzoic acid, 14,

52Keto-pentamethylene, 60, 3-41

carboxylic ester, 18Komppa, 20

Lead monoxide, 85organo-compounds of, 19, 50,

83,120peroxide, 85,149tetraphenyl, 50,120

Magnesium syntheses, 45,137Malachite green, 31, 71,148Malonic ester, 11,16, 114Manganese dioxide, 97Mannose, 162Mercury diphenyl, 50,120Mercuric oxide, 74^-Menthadiene, 53Mesityl-oxide-oxalic ester, 18Metallic oxides as catalysts, 97Methane, synthesis of, 37Methyl benzoate, 111

succinic ester, 118indole, 72,150

Molybdenum, 86

Naphthalene, 146Naphthyl-phenyl-ketone, 67Nickel as catalyst, 89,164Nitrides, 58o-Nitro-cinnamic ester, 132Nitro-compounds, reduction of,

88, 94,101,162

INDEX 169

Nitrogen fixation, 54Nitroso-ketones, 22defines from alkyl chlorides, 99Organo-metals, 19, 50, 52, 82,120Oxalic acid, 161Oxalyl-acetic ester, 21,121

Palladium, 101Pentamethylene, 61,141Petroleum formation, 91, 96Phenanthroxylene acetoacetic

ester, 32,127Phenyl-ethyl-carbinol, 138Phenyl salicylic acid, 36Phenyi-tolyl-methane, 67Phloroglucin, 17Phthalic acid, 74,152Phthalide, 146Pivalic acid, 50Platinum as catalyst, 93Polymethylenes, 4Potassium alkyl sulphate, 3

cyanide, 30, 126ferricyanide, 37, 133hydroxide, 31,127nitrate, 32, 125

Propiolic acid, 37Propyl chloride, 72, 150Pyrazolon, 14,118Pyrrol, 12, 69Pyruvic acid, 31

Quinoline, 25, 27Quinones, 27Keformatsky's reaction, 65, 66,

144Rubber, artificial, 24

Sabatier and Senderens, 89, •'"Sandmeyer's reaction, T *

Silicon tetraphenyl, 19, 50, 121Silver cyanide, 40

hydroxide, 41Sodamide, 22, 124Sodium cyanide, 23, 57

ethylate, 19, 122hydroxide, 24, 124

Stannous chloride, 159Suberic ester, 36Succino-succinic ester, 16,119

Teraconic ester, 19Terpineol, 31Tetra-acetyl ethane, 13Tetramethylene carboxylic ester,

15Thiophene, 12Thoria as catalyst, 98Tin tetrachloride, 87Tin tetraphenyl, 19, 50, 82, 120Toluene, 159Toluic aldehyde, 154Triacetyl-benzene, 20Trimethyl carbinol, 138Trimethylene, 4

dicarboxylic acid, 109Triphenyl benzene, 32

carbinol, 139methane, 156methyl, 40

Tungstic oxide as catalyst, 98

Vanadium pentoxide, 87,161

Wurtz-Fittig reaction, 2, 104

£inxj atkyl syntheses, 64, 145l ^ ^ agent, 69, 146

AD LAUD AND SO.

the synthetic use of metals in okganic...

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