studies of new methods for the analysis of hydrazine …
TRANSCRIPT
STUDIES OF NEW METHODS FOR
THE ANALYSIS OF HYDRAZINE
COMPOUNDS AND THE USE OF HYDRAZINE
AS AN ANALYTICAL REAGENT
BY
HUGE E. MALONE B .A. (.WITTENBERG)
MSc CEDIN.BURGH
A
THES IS
SUBMITTED FOR THE DEGREE
OF
DOCTOR OF PHILOSOPHY
FACULTY OF PURE SCIENCE
UNIVERSITY OF EDINBURGH
FEBRUARY 1974
TWPT tiP ATT(ThT
This thesis has been composed by me; it is based on original
experimental work that I have conducted and includes details of, or
reference to, original experimental studies that I have conducted
in the University of Edinburgh and elsewhere.
This thesis does not include any work submitted by me for any
other degree or professional qualification at any time.
i
Table of Contents
INTRODUCTION
OXIDATION OF HYDRAZINES
BASICITY OF HYDRAZINES
HYDRAZINE AS AN ANALYTICAL REAGENT
Carbonyls
Anhydrides
Isocyanate and Isothiocyanate
DETERMINATION OF MIXTURES OF HYDRAZINE, MON OMETHYLHYDRAZ INE AND 1,1-DINE THYLRYDRAZIME
REACTIONS
EXPERIMENTAL
Preparation of Sample
Determination of Total Hydrazine and Monomethyihydrazine
Determination of Monomethyihydrazine
Analysis of Mixtures of Hydrazine and 1, 1-Dimethyihydrazine
Determination of 1, l-Dimethylhydrazine
CALCULATIONS
THREE HYDRAZINES
Analysis of Mixtures of Hydrazine, Monomethyihydrazine and 1,1-Dimethy1hydrazine
Preparation of Sample
Determination of Hydrazine, Monomethyl-Hydrazine + 1.1-Dimethylhydrazine
CALCULATIONS
RESULTS AND DISCUSSION
DISCUSSION
Section
1
Page
1
5
7
9
9
11
12
15
16
17
17
17
18
18
18
19
19
19
19
20
21
24
ii
Table of Contents (Continued)
Section
3 AN ACID-BASE ISOCYANATE METHOD FOR THE ANALYSIS OF ADMIXTURES OF HYDRAZINE WITH 1, 1-DIMETHYLHYDRAZINE, AND MONOMETHYL-HYDRAZINE WITH 1, l-DIMETHYLHYDRAZINE
REACTIONS
EXPERIMENTAL
Preparation of Sample
Determination of Total 1{ydrazines
Determination of 1,1- Dimethy1hydrazine
CALCULATIONS
RESULTS AND DISCUSSION
4 DETERMINATION OF ALDEHYDES, ANHYDRIDES,, ISOCYANATES AND ISOTHIOCYANATES
REACTIONS
EXPERIMENTAL
Preparation of Sample
Determination of Aldehydes, Anhydrides, Isocyanates
Determination of Isothiocyanates
5 THE ANALYSIS OF ISOCYANATE - ISOTHIOCYANATE ADMIXTURES USING HYDRAZINE
EXPERIMENTAL
Preparation of Samples
Determination of Total Isocyanate-Isothiocyanate Mixture
Determination of Isothiocyanate
CALCULATIONS
RESULTS AND DISCUSSION
Page
26
26
27
27
27
27
28
28
35
35
36
36
36
36
44
44
44
44
45
45
45
iii
Table of Contents (Continued)
Section
MISCELLANEOUS STUDIES
Page
52
GRAVIMETRIC
PRELIMINARY DATA
COLORIMETRIC
HYDRAZINE AS A REAGENT
PRELIMINARY DATA
52
52
53
55
55
59
62
7 CLOSURE
REFERENCES
iv
LIST OF TABLES
TABLE PAGE
1.1 Method for Hydrazine Determination (Oxidation) • . • • 2
1.11 Method for Hydrazine Determination (Basicity) ...... 7
1.111 Methods for Hydrazine use as an Analytical Reagent . . . . . . . . . . . . . . . . . . . . . . . . 8-
2.1 Reactivity of Various Aldehydes with N2H4 and MMH ...................... 21
2.11 Effect of Time, Temperature and Excess Aldehyde on N
2 H 4 and Mt'IH ................ 22
2.111 Analysis of N 2H4-MMH Mixtures .............. 23
2.IV Analyses of N2H4-MMH-UDMR Mixtures ........... 24
3.1 Effect of Isocyanates on Various Hydrazines in Alcoholic Medium using 0.1N HC1/Propanol ........ 28
3.11 Comparison of Acetic Acid and Dioxan as Non-Aqueous Solvents for the Analysis of Hydrazine-UDNH by the Isocyanate Reaction ................ 29
3.111 Effect of Time on the Reaction of Various ilydrazines with Phenylisocyanate (1.0 ml) at 19 0 . . . • 30
3.IV Effect of Various Concentrations of Phenylisocyanate .................... 30
3.V Effect of Time and Concentration of IJDMH with RCNO at 190 ..................... 31
3.VI Effect of Time and Concentration of 1JDMB with RCNOat39° .................... 31
3.VII Effect of Concentration and Time on UDMH at 190 for 18 H ....................32
3. VIII Effect of Acetic Acid .................33
3.IX Analysis of N2H4/UDMH Admixtures ............33
V
LIST OF TABLES (Con't)
TABLE PAGE
3.X Analysis of MMH/UDMH Admixtures ............ 34
4.1 Various Media for Aldehyde Determination ....... 39
4.11 Effect of Concentration of Acetic Anhydride on Hydrazine ..................... 40
..III Effect of Time on Acetic Anhydride .......... 41
4.IV Effect of Various Isocyanates with Hydrazine in Alcohol Medium .............. 42
4.V Analysis of Various Aldehydes, Anhydrides, Isocyanates and Isothiocyanates ............ 43
5.1 Effect of Isothiocyanates on Various Hydrazines in Alcoholic Medium using O.1N HC1/Propanol ...... 46
5.11 Effect of Isothiocyanate on Hydrazine in Various Solvents using Perchioric Acid in Dioxan as Titrant . . 47
5.111 Effect of Isothiocyanate on Hydrazine in Acetic Acid using 0.1N Perchioric Acid in Acetic Acid as a Titrant ..................... 48
5.IV Effect of Isothiocyanate on Hydrazine in Chlorobenzene and Ethanol using 0.lN Hydrochloric Acid in Propanol as a Titrant ..................... 48
5.V • Effect of Isocyanate in Chlorobenzene an Ethanol using 0.1N Hydrochloric Acid in Propanol as a Titrant . 49
5.VI Effect of Time on the Reaction of Naphthylisothiocyanate and Hydrazine ......... 50
5.VII Analysis of Isocyanate-Isothiocyanate Mixtures . . . . 51
6.1 Height of Precipitate vs Concentration of Hydrazine . . 53
6.11 Colorimetric Reactions of Hydrazines, and Amines with Dinitro Compounds ........... 54
6.111 Reaction of Various Iso and Diisocyanates with Hydrazines .................... 56
vi
SUMMARY
ft
This thesis presents the experimental work involved in developing
new procedures for the determination of hydrazines, their mixtures, and
the use of Hydrazine (N2H4) as an analytical reagent.
This thesis is divided into six sections each of which is complete
in itself. Cross references are made of the tables and equations.
Section I presents the references that pertain to (a) the analysis of
N 2 H 4 by oxidation and basic techniques and (b) the use of N 2 H 4
as
an analytical reagent.
Section II describes the procedures for determination of various
mixtures of N2H4 , monomethyihydrazine (MMH) and 1,1-dimethyihydrazine
(IJDNB). N 2 H 4 forms a precipitate with salicylaldehyde; MM and UDMH
do not. By proper combination of a total iodate titration, N 2 H
4
aldehyde precipitation and an acid-base technique, various mixtures
of all three hydrazines can be determined. Section III describes
the procedures for determination of N 9H4 /UDMH and NMH/IJDMH based on
the reaction rates of N 2 H 4 and MMII with isocyanates. Both N
2 H 4
and MMII react immediately; IJDMH does not. This selective reaction
coupled with an acid-base titration allows the mixtures to be deter-
mined. Section IV presents the procedures for determination of various
organic functional groups i.e. aldehydes, anhydrides, isocyanates and
isothiocyanates based on their reaction with hydrazine. Excess N 2 H
4
vii
is added to the functional groups and allowed to react. The excess
N 2 H 4
is titrated with perchioric acid. By use of this technique many
compounds, belonging to the above functional groups, can be determined.
Section V presents the procedures for the determination of phenyl
isocyanate and phenyl isothiocyanate mixtures. Other aromatic iso
and isothiocyanates can be determined also. Both iso and isothio-
cyanate compounds react with N2 H4
in alcoholic medium using alcoholic
hydrochloric acid as a titrant. Only the isocyanate reacts with N 2 H
4
in acetic acid using perchloric acid in dioxan as a titrant. By
proper selection of aliquots, medium and titrants, the iso and
isothiocyanate mixtures can be determined. Section VI presents several
potential procedures for hydrazine analysis and the use of N2 H4
as
an analytical reagent. (a) Both hydrazine and certain aldehyde form
precipitates with each other and hence can be determined gravimetrically
by proper selection of condition.(b) The reaction of hydrazines and
amines with certain dinitro compounds, produce highly colored com-
pounds. The colors are more pronounced with N 21-14 and MMII than with
the amines. As a result, determination of either hydrazine in the
presence of amine is feasible. (c) Also, iso and diisocyanates
react rapidly with N2 H4 * Based on the reaction rates, many combina-
tions of iso, isothio and diisocyanates (aromatic and aliphatic)
could be determined.
viii
SECTION I
INTRODUCTION
Hydrazine, monomethylhydrazine, and 1,1-dimethylhydrazine are
rocket fuels. Occassionally, they are blended in certain proportions
to obtain certain properties superior to those of the individual
fuels. The higher specific impulse of hydrazine (N2H4 ) and the lower
freezing point of 1,i-dimethylhydrazine (UDMH) are present in mixtures
of these fuels. The neat hydrazines find application as monopropellants
for small rocket engines. Hydrazines and their derivatives are also
used for plant growth retardants, drug manufacture and fertilizers.
Hence, the wide interest in hydrazine chemistry.
The subject of hydrazine chemistry has been amply covered by
Audrieth and Ogg's, "The Chemistry of Hydrazine" (Wiley, 1951), Clarks',
"Hydrazine" (Mathieson Chemical Corporation, 1953), Reed's Monograph,
"Hydrazine" (Royal Institute of Chemistry, 1957) and Malone's Monograph,
"The Determination of the Hydrazino-Hydrazide Groups" (Pergamon, 1970).
The analytical methods for the determination of hydrazine are numerous
and mixtures of hydrazine compounds, with each other and with other
compounds such as amines and hydroxylamines are presented in detail
in Chapter 8 of Malone's Monograph.
The methods presented herein supplements the latter referenced
work and pertain to the determination of N 2 H 4
in mixtures with
substituted hydrazines - namely monomethyihydrazine (MMH) and (UDMH)
and (b) to the use of N 2 H 4 as an analytical reagent to determine various
1
functional groups such as aldehydes, anhydrides, isocyanates, isothio-
cyanates and mixtures of isocyanates with isothiocyanates.
The methods are simple, require a minimum of equipment, are
relatively accurate and demonstrate quite satisfactorily both the
simplicity of analyzing the hydrazine mixtures and the versatility of
using N 2 H 4
as an analytical reagent.
Here the methods are based on two important chemical properties
of N2 H4- its reducing ability with oxidants and its basicity in
non aqueous media.
Previous methods for the analysis of N 2 H 4 based on its reducing
properties is summarized in Table 1.1.
TABLE 1.1
METHOD FOR HYDRAZINE DETERMINATION (OXIDATION)
Author
Koithoff
Kurtenacher & Wagner
Szebelledy & Madis
Sant and Mukherji
Yamamura & Sikes
Barakat & Shaker
Benrath & Ruland
Singh & Siefker
Singh & Singh
Komarowsky
Method Rpfprpnrp
Bromate in HC1 1
Bromate in H2 SO4 2
.Bromate phosphomolyhic acid 3
Bromate amperometrically 4
Bromate 5
N-Bromosuccinimjde 6
Ceric sulfate 7
Iodine Monochioride 8
Diethylenetetraa ammonium 9 Ceric sulfate
Chioramine T 10
2
TABLE 1.1 (Continued)
Author Method
Stolle lodometric
Rupp lodometric
Singh & Rehman Chioratnine T
Singh & Sood Chioramine T
Clark & Smith Chloramine T
Paul & Singh Chioramine B
Singh & Sood Chioramine B
Browne & Shetterly Copper oxide - Fehlings Soin
Bray & Cuy Copper oxide - Fehlings Soin
Browne & Shetterly Copper sulfate
Browne & Shetterly Copper sulfate
Browne & Shetterly Dichromate
Bray & Cuy Dichromate
Erdey Potassium Ferricyanide - Ascorbic acid
Dernback & Mehlig Alkaline Potassium Ferricyanide
Bray & Cuy Hypochiorous acid
Sant Ferricyanide - Zinc sulfate
Bray & Cuy Iodine
McBride & Kruse Iodine
Curtis & Shulz Iodine
Rowe & Audrieth Iodine
Browne & Shetterly Iodine
Stolle Iodine
Bray & Cuy Iodine
Gilbert Iodine
Koithoff Iodine
Penneman & Audrieth Iodine
Miller & Furman Iodate (UDNH)
Rimini Iodate
L.
- -
11
12
13
14
15
16
17
18
19
18
18
18
19
20
21
19
22
19
23
24
25
18
11
19
26
1
27
28
29
3
TABLE 1.1 (Continued)
Author Method Reference
McBride & Kruse Iodate (UDNH) 23
Hale & Redfield Iodate / 30
Browne & Shetterly Iodate 18
Kurtenacher & Kubina Iodate 31
Maselli Iodate 32
Jamieson Iodate 33
Kolthoff Iodate 1
Lang Iodine Cyanide 34
Horvorka Mercuric Perchlorate 35
Singh & Ilahi Iodate 36
Smith & Wilcox Iodate 37
McBride, Henry & Skolnik Iodate 38
Olin Mathieson Personnel Iodate 39
Singh & Singh Periodate 40
Singh & Singh Periodate - Iodine Bromide 41
Singh & Singh Periodate - Iodine Cyanide 42
Peterson Permanganate 43
Sabanajeff Permanganate 44
Browne & Shetterly Permanganate 18, 45
Bray & Cuy Permanganate 19
Koithoff Permanganate 1
Roberto & Roncalli Permanganate 46
Medri Permanganate 47
Penneman & Audrieth Permanganate 25
Houpt Permanganate 48
Issa & Issa Permanganate (Thallium & Telluric Acid) 49
Suseela Selenious Acid 50
Berka & Busev Thalluim 51
Hoffman & Kuspert Vanadic Acid 52
Browne & Shetterly Vanadic Acid 18
Bray & Cuy Vanadic Acid 19
Singh & Singh Sodium Metavanidate 53
OXIDATION OF HYDRAZINES
Rimini (29)
found that the reaction between hydrazine sulfate and
potassium iodate (Kb 3 ) could be expressed by the equation:
5 N 2 H • HSO4 + 4 K103 -- 5 N2 + 12 H 2 0 + 2 K2 SO4 (1.1)
+ 3 HSO + 4 I
Jannasch and Jahn (54) stated that K10 3 solutions were easily re-
duced by hydrazine sulfate. Browne and Shetterly 8 experimented with
the Kb 3 - hydrazine sulfate reaction to determine the quantity of
ammonia and hydrazine acid formed. No hydrazoic acid was formed.
Hale and Redfield (29) conducted a series of experiments to prove that
the complete oxidation of N 2 H 4 was expressed as:
N 2 H 4 + 2 0 -* N2 + 2 1120 (1.2)
Kolthoff evaluated the Andrews-Jamieson (33) iodate method. In
the presence of HC1, the Kb 3 reacts with hydrazine according to the
equation:
N 2 H 4 + Kb 3 + HC1 - KC1 + Id + N2 + 3 H 2 0 (1.3)
Koithoff stated that carbon tetrachloride could be used in
place of chloroform as a visual indicator.
Penneinan and Audrieth 27 combined the oxidation titration of N 2 H 4
with an acidimetric titration method for rapid analysis of both
hydrazine and ammonia. They stated that the normality of HC1 should
be maintained within certain limits, preferably between 3 and 5 to
allow the formation of free iodine. Perineman and Audrieth 27 also
evaluated the use of Amaranth and Brilliant Ponceaux 5R for visual
indicators. McBride, et al (39) thoroughly studied the titrimetric
5
analysis of hydrazine sulfate using Kb 3 . They verified the work of
Penneman and Audrieth(27) concerning the HC1 normality limits. They
also oxidized N 2 H 4
quantitatively with Kb 3 to nitrogen in 0.5 to
2.ON sulfuric acid. The net reaction formulated by McBride et al (38)
is:
5 NH5 + 4 I0 - 5 N 2 + 2 12 + 11 H20 + H30+ (1.4)
McBride and Kruse (23) used a potentiometric end-point method to deter-
mine UDMH. They controlled the acidity, temperature, sample size and
concentration of UDMH. They found that the temperature had to be
maintained at -5 1 to +50 and the titration had to be completed in
10 min or side reactions would occur. A calomel electrode in a salt
bridge was required because of the low temperature involved.
2 (CH 3)2NNH + Kb 3 + 2 HC1 -- KC1 + Id + 2 1120 + (CH 3)2NN = NN (CH 3)2
(1.5)
Olin Mathieson (39) personnel adopted the potentiometric
titration method using Kb 3 to the determine monomethyihydrazine.
The reaction occurs according to equation:
CH3N2H4 + K103 + 2 HC1 -- KC1 + Id + CH 3OH + N2 + 2 1120 (1.6)
Singh and Ilahi 36 estimated hydrazine sulfate using potassium
iodate in the presence of hydrochloric acid by potentiometric titra-
tion. While Smith and Wilcox (37) used dyestuff internal indicators
for the same reaction in hydrochloric acid.
Jamieson (33) determined hydrazine salts with potassium iodate in
the presence of hydrochloric acid using chloroform. The Iodine formed
appeared in the chloroform layer. Continued titration of the iodine
with iodate formed iodine monochioride which was insoluble in the
chloroform layer.
Miller and Furman (28) showed that oxidation of hydrazine with
potassium iodate in the presence of mercuric salts resulted in direct
reduction of iodate to iodide. They detected the end-point potentio-
metrically. In Section 2, iodate is used to determine mixtures of hydra-
zines. The Jamieson (33) method for hydrazine and the modifications of
(23) McBride et al for UDMH are incorporated into a single method.
TABLE 1.11
METHOD FOR HYDRAZINE DETERMINATION (BASICITY)
L_.
Author
Gilbert
Penneman & Audrieth
Weed
Malone
Burns & Lawler
Serencha
Malone & Biggers
Malone
Dwiggins & Larrich
Malone & Barron
Malone & Barron
Method
Hydrochloric and Sulfuric Acids
Hydrochloric and Sulfuric Acids
Perchioric Acid
Perchioric Acid (Salicylaldehyde)
Perchioric Acid (Photometric)
Perchioric Acid (MNH - Sodium Acetate)
Perchioric (Acetic Anhydride)
Perchioric Acid (Salicylaldehyde)
Nitric Acid - Sodium Hydroxide
Hydrochloric Acid (Salicylaldehyde)
Hydrochloric and Perchioric Acids
Reference
26
27
55
56
59
59
59
60
61
62
63
BASICITY OF HYDRAZINES
Methods for the determination of hydrazine based on Its basicity
are shown in Table 1.11.
Perchioric acid has been the most widely used acid for the deter-
7 p
inination of the basicity of hydrazines. Conant and Hall (64) were the
first to use perchioric acid to titrate organic amines in acetic
acid. Since then, many papers have been written on the subject of
non aqueous titrations. Of interest here are those of Fritz and
(65) (66) Keen , and Riddick . By applying the reaction of salicylaldehyde
with primary amines in a non aqueous media, .Wagner et al(67) dis tin-
quished primary amines from secondary amines. Critchfield and Johnson (68)
modified their procedure using salicylaldehyde to determine primary,
secondary and tertiary amines.
Malone (60) adopted the aldehyde technique for determining mixtures
of aniline, N 2 H 4 and furfuryl alcohol.
The analytical methods presented herein are primarily conducted
in non aqueous media using either acetic acid or dioxan. Acetonitrile
(spectrograde) serves as a good medium also. For the most part
visual indicators have been used i.e. quinaldine red, ethyl red and
crystal violet. Glass-calomel electrode systems work satisfactorily.
Also, perchioric acid in dioxan or acetic acid is used as the titrant.
TABLE 1.111
METHODS FOR HYDRAZINE USE AS AN ANALYTICAL REAGENT
Author Method Reference
Siggia & Stahl Aldehydes 69
Riegler Alkali (Gasometric) 70
Schiotter Bromate 71
Riegler Iodide (Gasometric) 72
I
TABLE 1.111 (Continued)
Author Method Reference
Ebler Mercuric Chloride (Gasometric) 73
Van Slyke Iodates 74
Strecker & Shartow Selenium Dioxide 75
Lang Selenium Dioxide 34
Singh & Sood Selenium Dioxide 17
Panwar Permanganate, Cerium IV, Dichromate 76, 77 Carbonyls, Mercury, Peroxides et al
Stolle Iodine 11
Peterson Permanganate 43
Koithoff Permanganate 1
Shilling & Hunter Levulinic Acid 78
HYDRAZINE AS AN ANALYTICAL REAGENT
The methods for determining various compounds using hydrazines as
analytical reagents are shown in Table 1.111.
Carbonyls
The most widely used methods for determining aldehydes (carbonyl
compounds) are based upon their reaction with hydroxylamine to form the
corresponding oxime. The amount of hydroxylamine consumed is a
measure of the carbonyl compound present in the sample and is measured
by titration of the excess base with standard acid. Many modifications
of this method are listed in the literature. Ruch developed a method
for determining aldehydes in the presence of ketones using potassium
mercuric iodide. The aldehydes are oxidized to the corresponding
i
acid, effecting a quantitative liberation of mercury. The reduced
mercury is maintained in a finely divided state by using an agar
solution as a protective colloid. The reaction mixture is acidified
and the mercury is reacted with a measured excess of iodine. This
excess is determined using sodium thiosulfate. Hydrazines and
hydrazine derivatives have found wide use for determining carbonyl
compounds. Siggia et al (68) presented an acid-base method fcr
determining aldehydes by their reaction with 1,1-dimethyihydrazine.
An excess of the hydrazine reagent was added to the sample and after
the reaction was complete, the excess was titrated with standard acid.
Many workers used 2,4-dinitrophenyihydrazine (2,4 DNP) as a reagent
to determine qualitatively and quantitatively carbonyl compounds as
(81) hydrazones. Clift (80) determined ketonic acids; Houghton estimated
benzaldehyde; Iddles et al (82) extended the use of 2,4 DNP as a
quantitative reagent; Schoniger 8 applied 2,4 DNP to micro deter-
minations and Monty , Anet , Jart et al used chromato-
graphic techniques. Panwar et al (76) used hydrazine reagent
to determine carbonyl as well as many other compounds. Hydrazine
was used in iodometric titrations.
Here the author is using hydrazine similar to Siggia' 68 to
determine aldehydes. An excess hydrazine is added to the aldehyde
in acetic acid medium, after the reaction is complete, the excess
hydrazine is titrated with standard perchioric acid.
10
Anhydrides
The anhydrides of carboxylic acids are quite reactive, as a result,
they can be determined readily, usually with a compound containing an
active hydrogen group. The principal methods for analysis of anhydrides
depend upon the reaction of the anhydride with amine to form the
(87)
corresponding amide. Siggia et al developed a method using aniline
which reacts with most anhydrides to form one equivalent of carboxylic
acid and an equivalent of amide:
0 0 .0 II 11 II
C6H5NH2 + (RC) 20 -- RC - NHC 6H5 + RC - OH (1.7)
The carboxylic acid formed in this reaction and any free acid present
in the anhydride, can be determined by titration with standard sodium
hydroxide using phenolphthalein indicator according to the methods
of Radcliffe et al(88) and Smith et al (89)The difference between
the total acidity obtained by direct titration in the presence of
pyridine and the acidity after the aniline reaction is a measure of
the anhydride content of the sample.
Morpholine reacts with anhydrides to form amides and the corresponding
carboxylic acid according to the equation
0 0 0 II ,- II II
OJH + (RC) 2 0 - OSN -- C - R + RCOH (1.8)
(90) In this method by Johnson et al , morpholine is reacted with
anhydrides in methanol medium. The amount of morpholine used is
determined by titration with standard methanolic hydrochloric acid using
methyl yellow - methylene blue indicator. A third method for analyzing
11
anhydride and acid mixtures is that of Critchfield et al (67) which is
based on the reaction of an excess morpholine with the anhydride in
acetonitrile medium. Again, the reaction products are the same as
shown in equation 1.2. The acidity is determined using standard
sodium hydroxide using thymolphthalein indicator. Carbon disulfide is
added at the equivalance point and converts the morpholine to the
corresponding dithiocarbamic acid. Siggia et a1 9 I also developed
a method for determining anhydride in acetone using tertiary amines
such as tri-n-propylamine and N-ethyl piperidine.
In these procedures all of the anhydride is reacted with amines
to form amides. In the method introduced here, the author reacted
anhydrides with hydrazines to form hydrazides. The excess hydrazine is
titrated with standard perchioric acid. Since acetic acid can be
used as a solvent, the previous difficulty of determining anhydrides
in the presence of acids is overcome.
Isocyanate and Isothiocyanates
Isocyanates and isothiocyanates have been determined by a variety
of methods. Siggia et al (97) reacted primary amines with isocyanates
and isothiocyanates to form the corresponding ureas and thioureas.
A measured excess of butylamine in dioxan is reacted with the sample.
After the reaction is complete, the excess butylamine is titrated in
the presence of weakly basic ureas with standard sulfuric acid using
methyl red indicator. Beazley 93 used dimethylformamide as a medium
for dicyclohexylamine to determine allyl, n-butyl, cyclohexyl, phenyl
and toluene - 2-4-diisocyanates. Previously, other analysts
12
(94) (95) (96) (97) (98) Stagg , Siefken , Williamson , Navyazhskaya , Kubitz
Strongin et al 99 , Mikl °° , and Ryaakina and a1ika 0 used
n-butylamine, dibutylamine, diethylamine, diisobutylamine, and
piperidine as amine reagents and back titrated the excess amine with
hydrochloric acid.
Grehov et a1 02 determined isocyanates using benzoylhydrazide.
The reaction was conducted in benzene solution for 25-30 mm. at
50-600C, HCl and HBr were added and the excess hydrazide was back
titrated potentiometrically with sodium nitrite.
Several IR and gas chromatographic methods have been developed
to determine the isocyanate group. Using IR, Lord (103) and Finkel
et al(104) quantitatively differentiated toluene -2,4 diisocyanate
and toluene -2,6 diisocyanate at 780 and 810 cm -1 . Burns (105)
Greth et ai06), Zhokhova et al(107) and Kitukhina et al 08
determined the isocyanate group in polyurethane foams at 2000-2950
-i (109) (110) cm . Nebaver et al , Strepikheev et al , Hanneman and
(111) (112) (113) Robinson , Nikeryasova and Litovchenko and Ruth all
usedgas chromatographic techniques to determine aliphatic and aromatic
isocyanates.
Isothiocyanates were determined by Kjaer et al(114), Nagashima and
Nakagawa W5), Appelqvist and Josef sson 116 and Langer and
Gschevendtova 7 using IR and measuring the absorbances at 235-260 nm.
Ammoniacal silver reagent was used to. detect isothiocyanate by gravi-
metric and titrimetric techniques. Basically, the isothiocyanate is
13
reacted with ammonium hydroxide for several hours then treated with
silver nitrate, after a certain time the silver sulfide is precipitated
and weighed. The method of Dieterich (118)
developed in 1891 was
subsequently modified by many others. Roth (119) , Karten and Ma (120)
and Vinson (121)
used Di-n-butylamine and n-butylamine to determine
isothiocyanates.
Here an excess hydrazine is reacted with either the isocyanates
and isothiocyanates. After the reaction is complete, the excess
hydrazine is titrated with perchloric acid.
The following sections are complete in themselves and describe
a method or methods for determining specific compounds or groups of
compounds using hydrazines or possible new methods for analyzing hydra-
zine or hydrazines in the presence of amines.
14
SECTION 2
DETERMINATION OF MIXTURES OF HYDRAZINE, MONOMETHYLHYDRAZINE AND
1, l-DIMETHYLHYDRAZINE
Mixtures of hydrazine (N 2H4 ) and monomethyihydrazine (MMH) were
determined by an oxidation-aldehyde method based on the selective re-
action of N 2 H 4 with salicylaldenyde and subsequent titration of MMH with
potassium iodate. Two aliquots were used, (a) for determining total
hydrazines, (b) for determining MMH, by titration with potassium
iodate. The N2H4 , precipitated as salicylidine azine, was determined
by difference.
In previous papers (56), (60), (63), Malone presented non-aqueous
methods for the determination of N 2 H 4 in admixtures with 1,1-dimethyl-
hydrazine (IJDMH) and secondary amines. These methods were based on
the acid-base titration of the UDMH and amines, using perchioric acid
as titrant, after the N 2 H 4 had been rendered neutral with either
salicylaldehyde or acetic anhydride (59). Clark and Smith (15) developed
a method for determining admixtures of N 2 H 4 and MMII by a differential
oxidation method. One sample aliquot was treated with excess chlorainine-T
and a second aliquot was treated with excess sodium hypochiorite in
the presence of potassium bromide and a phosphate buffer. The unreacted
oxidant was determined by back-titration with sodium thiosulfate.
Both hydrazines involved a four electron change with chloramine-T.
With sodium hypochiorite, N 2 H 4 involved a four electron change and
MMII an eight electron change. For this method, three standard reagents,
15
together with several other additives and buffer were required.
Serencha et al (58) extended Malone 's method (60) using salicylaldehyde
in the presence of excess perchioric acid to determine admixtures of
N2H4 /MMR. The excess perchloric acid was back-titrated with sodium
acetate. This non-aqueous acid-base method was simple and effective
and required the use of two standard titrants. Two gas chromatographic
techniques presented by Jones 22 and by Dee et al (123)
for -letermining
admixtures of N2H4/NNH and UDMH/MMH/N2H4 respectively are satisfactory,
but require good technique and a sound knowledge of chromatography.
The following work describes a simple, rapid, oxidation-aldehyde
method using the Jamieson (33) potassium iodate method with salicylaldehyde
for determining admixtures of N2H4 /MMH and N2H4 /UDMH. This procedure
can also be combined with the non-aqueous titration method described
(59) previously to give a method for the analysis of mixtures of
NNH and UDNH; effective removal of the hydrazine and MMH as the corres-
ponding hydrazides by adding acetic anhydride allows the UDMH present to
be determined in dioxan as solvent with perchloric acid in acetic acid
as titrant.
DV A ("PT11C
In acid medium, salicylaldehyde should react with N2 H4-% MMII and
UDNH to form Salicylidene Azine
0 H H viz. (-C-H
N2H4 + 2E,jIOH 1,j1 OH 11o1>.J-l- 2 H20 (2.1)
and Salicylidenemethyihydrazone
16
H viz. I - H C
+ O:OH
L)-OH
H C- 3 /i LV-jy. CH
Hfi I II (.0
OH HO,) (2.2)
and SalicylidenedimethyihydraZOfle
H H
cIr OH C=O •'-.
OH 2
H3C
CH ± 2H0 (2.3) N-N-H2 + --b,-
Under the conditions of this experiment, however, only the N 2 H 4
reacts completely. The salicylidinementyihydrazine and salicyledinedi-
methyihydrazone do not form.
EXPERIMENTAL
Preparation of Sample (Method A). Pipette 1.5 ml of the hydrazine
mixture into a tared 50 ml volumetric flask containing 20 ml of distilled
water and 10 ml of acetic acid. Cool to room temperature and weigh to
the nearest 0.1 mg, obtaining the sample weight by difference. Dilute
to the mark with distilled water and mix thoroughly.
Determination of Total Hydrazine and Monomethylhydrazine (Method A).
Pipette 5 ml aliquot of the hydrazine mixture into a 500 ml iodine
flask containing 50 ml of 6N. Add 25 ml of concentrated 12N hydrochloric
acid and 20 ml of chloroform. Titrate rapidly with 0.lM postassium
iodate 33 , while shaking, Until the dark brown solutioü lightens.
Then, add the potassium iodate dropwise until the liberated iodine in
the chloroform layer changes from purple to colorless and the solution
becomes yellow from the iodine monochloride formed. This gives titre "A 2 .
17
Determination of Monomethyihydrazine. Pipette 5 ml aliquot of the
hydrazine mixture into a 400 ml beaker containing 50 ml 6N hydrochloric
acid. Add 10 ml of salicylaldehyde in acetic acid solution (10% v/v).
Allow the yellow precipitate of salicylidine azine to set for 15 mm.
Filter through Whatman No. 40 filter paper on a Buchner funnel. Wash
the precipitate several times with distilled water and transfer the
filtrate to a 500 ml iodine flask with several rinsings of distilled
water. Add 25 ml of 12N hydrochloric acid and 20 ml of chloroform.
Titrate rapidly with 0.lN potassium iodate to the disappearance of
iodine in the manner described above. This gives titre "B 21.1-
Analyses of Mixtures of Hydrazine and 1,1-Dimethyihydrazine.
(Method B) Preparation of sample. Use the procedure outlined in
Method A. Determination of N 2 H 4 + UDMH. Use the procedure detailed
in Method A for N 2114 + NHH, but ensure that the temperature lies within
the range _100 to +100 by cooling in a carbon dioxide-acetone mixture.
The titration can also be carried out potentiometrically with a
platinum-calomel electrode system. This gives titre ttBtt.
Determination of l,l-Dimetriylhydrazine. Use the procedure detailed
in Method A for monomethylhydrazine, but maintain the temperature within
the range -10 to +10° . The potentiometric end-point lies between 0.67
and 0.70 V. To minimize side-reactions, complete the titration (23)
within 3-5 mm. This gives titre "B 2 tt .
18
CALCULATIONS
N2H4 +K103 +2 MCi = KC1+ IC1+N2 +
CH 3—NHNU2 +K103 +2HC1-KC1+ICl+CH3OFI+N2 +2H20
2 (CH 3 ) 2N-NH2 + Kb 3 + 2 MCi = (CH 3) 2 N-N = N -N(CH3 ) 2 + KC1+IC1+3H20
Let the Kb 3 molarity = M. Then:
3.20M [(A1 - A 2 ) or (B 1 - B2 )] x,10
% hydrazine sample wt. (g)
4.60MA2 x 10 %MMH=
sample wt. (g)
12.02M B 2 x 10 % UDNH = _______________________
sample wt. (g)
Analyses of Mixtures of three Hydrazines, Monomethylhydrazine, and
1,1-Dime thyihydrazine.
Preparation of Sample (Method C). By pipette, place 0.8 ml of
the mixture of hydrazines into a tared 50 ml standard flask containing
20 ml of acetic acid. Weigh to 0.1 mg, by difference. Dilute to
the mark with distilled water, and mix carefully.
Determination of Hydrazine + Monomethyihydrazine + 1,1-Dimethyl-
hydrazine. By pipette, add an aliquot (10 ml) of the hydrazine
mixture to a 500 ml iodine flask containing 50 ml of 6N hydrochloric
acid. Proceed exactly as described in Method A for the determination
of hydrazine + monomethylhydrazine with potassium iodate. This
gives titre "C 1".
/
19
Determination of Monomethyihydrazine + 1,1-Dimethyihydrazine.
By pipette, add an aliquot (10 ml) of the mixture of hydrazines to
a 400-ml beaker containing 50 ml of 6 N hydrochloric acid. Add
10 ml of a solution of salicyladehyde in acetic acid (10%, v/v)
and complete the determination of MMH + UDMH as described in Method
A above for the determination of MNH alone. This gives titre "C 2 t1 .
Determination of 1,1-Dimethyihydrazine. By pipette, add an
aliquot (2 ml) of the mixture of hydrazines to a 100-ml beaker
containing 20 ml of dioxane. Add 2 ml of acetic anhydride; both
the hydrazine and monomethyihydrazine react to give hydrazides.
Leave the reaction mixture for 30 mm, and then titrate with 0.1N
perchloric acid in acetic acid; conduct a blank determination
using the reagents only. The difference gives titre
CALCULATIONS
Let the Kb 3 molarity = N, and the HC10 4 normality = N. Then:
% NH4 M(C1 - c2) x 5 -
3.201 sample wt. (g) - X
%UDMII NC x25 -= 3 =Y
6.01 sample wt. (g)
MMH = 100 - 4.60[MC 1 - X + x 5 21
sample wt. (g)
20
RESULTS AND DISCUSSION
Fifteen aldehydes were investigated for their selective
precipitation with N 2 H 4 and MMII. UDNH was not investigated. Table 2.1
shows this reactivity as measured by the amount of 0.1 M potassium
iodate used. The reactions were conducted for thirty minutes at
ambient temperature using 5 ml of each hydrazine (1.5 ml N2 H4
Ln 50 ml).
TABLE 2.1
REACTIVITY OF VARIOUS ALDEHYDES WITH N 2 H 4 AND MMII
Ml Kb 3 Ml Kb 3
with N 2114 with MMII
Benzaldehyde 12.0 13.9
Furfuraldehyde 0.0 --
l-Naphthaldehyde 31.O 14.0
4-Hydroxybenzaldehyde 25.5 14.0
3-Hydroxybenzaldehyde 30.5 14.4
Salicylaldehyde 0.0 14.0
Veratraldehyde 0.0 13.8
Anisaldehyde 0.0 13.7
Vanillin 0.0 13.8
2-Ethyihexanal '30.0 14.0
TABLE 2.1 (Continued)
Ml Kb 3 Ml KI03
with N.)H, with MMH
3-Nitrobenzaldehyde 17.0 , 14.0
4-Dime thy laminob enzaldehyde 30.0 13.9
Piperonaldehyde 22.0 14.0
Cinnamaldehyde 0.0 0.0
Crotonaldehyde 0.0 0.0
Of these aldehydes, both cinnamaldehyde and crotonaldehyde, be-
cause of their double bonds, reduced the iodine from the chloroform layer
during the potassium iodate-hydrazine reaction.
Vanillin, veratraldehyde and anisaldehyde all formed precipitates
with N 2 H 4 but produced a yellow-orange to orange coloration in the
chloroform layer. As a result, these aldehydes interfered with the desired
colorless endpoint of the titration after the purple iodine color was
removed. These aldehydes were not purified for this experiment. For
salicylaldehyde, the colorless endpoint was easy to observe except when
the MMH-salicylaldehyde mixture was heated or when an excess of the
aldehyde was used. Heating the reaction (120 °F) for various times caused
the aldehydes to darken. The effect of time, together with the effect
of excess aldehyde, is shown in Table 2.11.
TABLE 2.11
EFFECT OF TIME, TEMPERATURE AND EXCESS ALDEHYDE ON N 2 H 4 AND NNH
Compound Temp. OF
Time Mm.
Salicylaldehyde ml
Iodate ml
N 2 H
4 75 15 2 0.0
N 2 H 4 120 30 2 0.0
N 2 H
4 120 45 2 0.0
22
Exterimental
N2114 MMH
82.5. 15.9 57.1 41.2 51.9 46.9 30.7 68.3 23.2 76.6 17.6 81.4
TABLE 2.11 (Continued)
Compound Temp. Time Salicylaldehyde Iodate OF Mm. nil ml
MMH 120 20 2 16.7
MMII 120 35 2 16.7
MNH 120 60 2 18.0
MMII 75 -- 0 14.0
MMII 75 15 2 14.5
MMII 75 30 1 13.8
1IMEI 75 50 1 13.7
For optimum results, only 1 ml of the salicylaldehyde was required.
This amount was dissolved in acetic acid prior to reaction with the hydra-
zines and was sufficient for precipitating all of the N 2 H4 .
The method was shown to be quantitative for NMH-salicylaldehyde in
the following manner:
ml MMII ml Kb 3
1.0 2.9
2.5 7.0
5.0 14.0
10.0 28.0
A series of mixtures of N 2 H 4 with MMII were prepared and were
analyzed by Method A. The results obtained are shown in Table 2.111.
TABLE 2.111
ANALYSIS OF N 2 H 4 - MMII MIXTURES
- Theoretical Variation in %
N2 H4 NMH N
-2 H4 MMII
82.5 15.9 0.0 0.0 57.6 41.3 -0.5 -0.1 52.2 46.8 -0.3 +0.1 30.5 68.9 +0.2 -0.6 22.8 77.3 +0.4 -0.7 18.0 81.7 -0.4 -0.3
23
A series of hydrazine with UDMH were prepared and were analyzed by
Method B. The results are shown in Table 2.IV.
Table 1.V shows the results obtained for all three components in
test mixtures by Method C.
The results in Table 2.111 indicate that the accuracy improved as
the hydrazine to N'II1 ratio increased. For greater accuracy, the
precipitate could be filtered directly into the vessel used for the
MMH determination, while the N 2 H 4 could be determined gravimetrically
as the azine. Since the azine is soluble in chloroform, the titration
could be conducted directly without filtering, by adding excess (50 ml)
chloroform. However, the azine colors the chloroform layer yellow.
TABLE 2.IV
ANALYSES OF N 2 H
2 - MMH - UDNH MIXTURES
Found (%) Theoretical (%) Difference (%) N 2 H 4 MMH UDNH N 2 H 4 MMH IJDNH N
2 H 4 NNH UDNH
35.9 32.5 29.8 36.9 31.9 29.1 -0.1 +0.6 +0.7
36.8 30.8 28.9 37.6 30.9 29.3 -0.8 -0.1 -0.4
Alternative analytical procedures for the reactions described
here are possible. For example, in the determinations depending on the
selective precipitation of one of more components, the precipitate
24
could be filtered directly into the vessel used for the determination
of MMH. The % hydrazine could also be determined gravimetrically as
the azine; since this is soluble in chloroform, the titration could
alternatively be conducted directly, without a filtration stage, by
adding excess (50 ml) of chloroform. Unfortunately, the azine gives
a yellow chloroform layer; the author prefers to remove the azine
precipitate by filtration. After this is done, the determination of
NNH and UDNH (in the ternary mixture case) can be conducted potentio-
metrically, provided that the platinum-calomel electrode system is
not coated by the azine nor by excess salicylaldehyde; rapid titration
(* 10 mm) within the temperature range _50 to +50 is necessary to
prevent side reactions from occurring between potassium iodate and
UDMH (23)
The well known disadvantages of methods in which one component
is found by difference apply here to the determination of the monomethyl-
hydrazine present. Ammonia and aniline are common impurities in
commercial hydrazine; nitrosodimethylamine, dimethylamine and other
compounds are found (59) in NNH and UDNH.
25
SECTION 3
AN ACID-BASE-ISOCYANATE METHOD FOR THE ANALYSIS OF ADMIXTURES OF
HYDRAZINE WITH 1, l-DINETHYLHYDRAZINE, AND MONOMETHYLHYDRAZINE WITH
1, l-DIMETHYLHYDRAZINE.
A rapid chemical method based on the differential reaction rate
method of l,l-dimethylhydrazine (UDMH)-hydrazine(N 2H4 ), of mono-
methylhydrzine (MMH)-N 2H4 with e.ther phenylisocyanate or
naphthylisocyanate (RNCO) is described.
In alcoholic solution, with ethanolic hydrochloric acid as
titrant, N2H4 , MNH, and UDMH all react with isocyanates at about the
same rate to form semicarbazides. In anhydrous acetic acid, however,
N 2 H 4 and MMII react rapidly (MMH slightly slower than N 2 H 4 ) with
isocyanates, but UDNH does not react appreciably in less than 2 h
at room temperature.
flfl A flrflrrayfl
In acid medium, phenyl and naphthyl isocyanate react with N 2H4 ,
MMII and UDNH to form seniicarbazide
viz.
N2H4 +RCNO-3N112 . NH CO NH R
(3.1)
viz.
H3C N - NH + RCNO +3 . NH • NH CO Nil R (3.2)
H
26
viz.
HC ' -N - NH + RCNO (CH ),)N NH Co NH R (3.3)
H 3 C-'--- 2 /
Under the conditions of the experiment, only the N 2 H 4 and 1'IMH
react completely. The UDMH reaction rate is very slow.
EXPERIMENTAL
Preparation of sample. By pipette, add the mixture of hydrazines
(0.4 ml) to a tared volumetric flask (50 ml) containing about 30 ml of
anhydrous acetic acid; obtain the sample weight by difference. Make up
to the mark with the acetic acid and mix carefully.
Determination of Total Hydrazines. Add an aliquot (5.00 ml) of the
mixture of hydrazines to a 50 ml beaker containing 20 ml of a mixture of
acetic acid and dioxan (1:1). • Add 4 drops of quinaldine red indicator,
0.2% in acetonitrile. Titrate to a colourless end point with 0.1 N
perchioric acid in dioxan to obtain titre "A". T'itrate a blank for the
reagents and indicator to obtain titre "a".
Determination of 1,1-Dimethylhydrazine. Add an aliquot (5.00 ml)
of the mixture of hydrazines to a 50 ml beaker containing 20 ml of the
acetic acid-dioxan mixture and 1 ml of either naphthylisocyanate or
phenylisocyanate. (Use 2 ml for MMH/UDMH.mixtures). Set aside for
30 min ( white precipitate forms). Add 4-drops of the quinaldine
red indicator, and titrate to a colourless end point to obtain titre "B".
By titrating a blank similarly, obtain titre "b".
27
CALCULATIONS
% N 2 H (ffl) = (A-a) - (B-b) HClO 3.20 (or 4.60) , 10
(sample weight)
% UDNH = (B-b) N HC104 6.01 ' 10
(sample weight)
RESULTS AND DISCUSSION
In alcoholic solution with ethanolic hydrochloric acid as titrant,
N2H4 , MMII and UDNH all react with naphthylisocyanate at approximately
the same rate as shown in Table 3.1.
TABLE 3.1
EFFECT OF ISOCYANATES ON VARIOUS HYDRAZINES IN ALCOHOLIC MEDIUM USING 0.1 N HC1/PROPANOL
Compound Non-Aqueous Additive Titrant HC1/Propanol 1 ml/50 ml Ethanol Solvent *RCNO ml (0.1 N) ml used
1 in]. aliquot
N2114 Ethanol 6.40
N2}14 Ethanol 1.0 0.20
UDMH Ethanol 6.27
UDMH Ethanol 1.0 0.80
EM Ethanol 4.10
MMII Ethanol 1.0 0.02
Indicator was meta Cresol Purple 0.2%/Ethanol
*Naphthylis ocyanate
The various hydrazines were reacted with phenylisocyanate in
both acetic acid and dioxan using 0.1 N HC10 4 in acetic acid as
titrant. Table 3.11 shows that either solvent could be used.
28
TABLE 3.11
COMPARISON OF ACETIC ACID AND DIOXAN AS NON-AQUEOUS SOLVENTS FOR THE ANALYSIS OF HYDRAZINE - IJDMII BY THE ISOCYANATE REACTION
Compound Non-Aqueous Additive Titrant 1 ml/50 ml HAc Solvent 1 ml used 0.1 N HC10 4 /HAc 1 ml aliquot ml used
N H Acetic Acid 8.08 2 4 N 2 H
4 Acetic Acid *RCNO 0.10
UDNH Acetic Acid 6.96
UDNH Acetic Acid RCNO 7.10
NNH Acetic Acid 5.05
NMH Acetic Acid RCNO 0.66
Titrant 0.1 HC104 /Dioxan
ml used
N 2 H 4
Dioxan 8.10
N 2 H 4
Dioxan RCNO 0.30
UDMH Dioxan 7.25
UDME Dioxan RCNO 7.17
MMII Dioxan 5.50
MMH Dioxan RCNO 0.60
Quinaldine Red 0.2% in Acetonitrile was used as indicator.
*Phenyljsocyanate
The effect of time and of the isocyanate concentration on the
reaction is shown in Tables 3.111 and 3.IV at least 0.4 ml of phenyliso-
cyanate and a reaction time of 15 min must be used for the effective 0.04 ml
of hydrazine used here. For MM, however, 2 ml of the isocyanate and
30 min reaction time is required.
29
TABLE 3.111
EFFECT OF TIME ON THE REACTION OF VARIOUS HYDRAZINES WITH -- PHENYLISOCYANATE (1.0 ml) AT 19 0
Time (mm) ml HC10, (0.1 N) For NNH For UDNH used
For N 2 H 4
7.90*
5
0.26
15
0.19
30
0.15
45
0.16
60
0.18
75
0.17
* Without phenylisocyanate
5.00*
7.10*
1.90
7.10
1.19
7.08
1.05
7.09
0.77
7.10
0.70
7.08
0.30
7.05
TABLE 3.IV
EFFECT OF VARIOUS CONCENTRATIONS OF PHENYLISOCYANATE*
Phenyliso- ml HC104 (0.1 - N) For NNH For UDNH
cyanate (ml) used For N 2 H
4
0.0 8.20 5.06 7.05
0.2 3.00 2.05 7.05
0.4 0.17 1.25 7.05
0.6 0.18 0.75 7.05
0.8 0.14 0.80 7.03
1.0 0.21 0.55 7.00
2.0 -- 0.10 7.00
3.0 0.06 --
* 20-40 min allowed for the reactions aj 19 0
The effect of time, temperature and concentration of naphthyliso-
cyanate on UDMH is shown in Table 3.V.
30
TABLE 3.V
EFFECT OF TIME AND CONCENTRATION OF UDNH WITH RCNO AT 19 ° C
Time Compound Non-Aqueous Additive Titrant 1 ml/50 ml HAc Solvent ml RCNO 11C104 /HAc (0.1 N) 1 ml aliquot ml used
15 TJDMH Acetic Acid/Dioxan 0.5 3.50
30 UDNH Acetic Acid/Dioxan 0.5 3.48
60 UDNH Acetic Acid/Dioxan 0.5 3.45
120 UDNH Acetic Acid/Dioxan 0.5 3.48
15 UDME-I Acetic Acid/Dioxan 1.0 3.50
30 UDNH Acetic Acid/Dioxan 1.0 3.50
60 IJDMH Acetic Acid/Dioxan 1.0 3.48
120 UDMH Acetic Acid/Dioxan 1.0 3.48
15 UDNH Acetic Acid/Dioxan 2.0 3.52
30 IJDNH Acetic Acid/Dioxan 2.0 3.48
60 UDNH Acetic Acid/Dioxan 2.0 3.50
120 UDNH Acetic Acid/Dioxan 2.0 3.40
When the temperature was increased to 39 ° C the UDNH reacted with the
RCNO as shown in Table 3.VI and formed a precipitate.
TABLE 3.VI
EFFECT OF TIME AND CONCENTRATION OF UDNH WITH RCNO AT 39 °C
Time Compound Non-Aqueous Additive HC1O A /HAc 1 ml/50 ml HAc Solvent ml RCNO (0.1 N) 1 ml aliquot ml used
15 UDNH Acetic Acid/Dioxan 1.0 3.50
30 TJDNH Acetic Acid/Dioxan 1.0 3.25
45 UDNI-I Acetic Acid/Dioxan 1.0 3.49
60 IJDMR Acetic Acid/Dioxan 1.0 3.45
The UDMH was reacted with the RCNO and allowed to remain 18 h
at 19 0C. The results shown in Table 3.VII indicate that the UDNH does
-
31
react. A white precipitate of 1,1-dimethyiphenyl semicarbazide
formed; however, the solution still titrated basic.
TABLE 3.VII
EFFECT OF CONCENTRATION AND TIME ON UDNH WITH RCNO AT 19 0C FOR 18 H.
Compound 1 ml/50 ml HAc 1 ml aliquot
tsJiIi
UDNE
UDMH
UDi
Non-Aqueous Solvent (1 / lv)
Acetic Acid/Dioxan
Acetic Acid/Dioxan
Acetic Acid/Dioxan
Acetic Acid/Dioxan
Additive Titrant ml RCNO HC104 /HAc (0.1 N)
ml used
0.0 3.47
0.5 3.25
1.0 2.75
2.0 2.20
Water affects the analysis of hydrazines with isocyanates by
causing the end point of quinaldine red (red to colourless) to revert
to red. The reason for this is shown in the equations below; hydrolysis
of the isocyanate gives the amine which eventually reacts with sufficient
isocyanate to give a substituted urea derivative.
R . NCO + H2O -* R • Nil CO 2H - R NH + Co2 (3.4)
R NH + R . NCO R NH . CO . NH • R (3.5)
Several tests were conducted to substantiate this. As long as
phenylisocyanate was present with acetic acid regardless of the
solvent or titrant the red colour of quinaldine red returned - Diglyme-
HC104 /HAc, HAc-HCl/ROH, ROH-HC10 4 /HAc, Methyipropionate Acetonitrile
and dioxan. Without acetic acid i.e. dioxan - HC104/dioxan with
isocyanate, quinaldine red remained colourless. On addition of
acetic acid, the solution reverted to red. The time of the indicator
change from colourless to red is shown in Table 3.VIII.
32
TABLE 3.VIII
EFFECT OF ACETIC ACID
Compound Non-Aqueous Acetic Acid RCNO Time 1 ml/50 ml ROH Solvent ml ml mm 1 ml aliquot
N 2 H 4 Djoxan 1.0 0.4 4
N 2 H 4 Dioxan 2.0 0.4 2
N 2 H
4 Dioxan 3.0 0.4 1.5
N 2 H 4 Dioxan 4.0 0.4 C.75
N 2 H 4 Dioxan 5.0 0.4 0.75
Because the end-point was not sharp using a dioxan - HC104/dioxan
system a small amount of acetic acid was added. The red colour
returned immediately. Upon addition of acetic anhydride to the UDMH
acetic acid system prior to the addition of isocyanate, the quinaldine
red remained colourless because the water in the acetic acid was pre-
vented from reacting with the isocyanate. Since acetic anhydride
reacts rapidly with both hydrazine and MMH it would interfere in
the quantitative analysis of these two hydrazines. The molecular
sieve technique developed by Burns (57) was used satisfactorily to
remove the water from acetic acid. Potassium cyanàte, potassium
cyanide, lead thiocyanate, phenyl and methylisothiocyanates gave no
reaction with N2H4 , MtYIH or UDNH in acetic acid media.
TABLE 3.IX
ANALYSIS OF N2H4 /UDMH ADMIXTURES
Experimental (%) Theoretical (%) Variation (%) N 2 H 4 UDNH N
2 H 4 UDMH N 2 H 4 UDNH
82.4 13.9 82.6 14.0 +0.2 +0.1
74.0 23.6 73.4 23.5 -0.6 -0.1
33
TABLE 3.IX (Continued)
Experimental (%) Theoretical (%) Variation (%) N2 H4 IJDNH N2114 UDMH N
2 H4 UDNH
64.7 32.6 65.1 32.2 +0.4 +0.4
60.1 37.6 59.6 37.9 -0.5 +0.3
54.1 44.0 53.6 44.3 -0.5 +0.3
48.9 49.4 48.4 39.6 -0.5 +0.2
42.5 55.8 42.2 56.0 -0.3 +0.2
32.7 66.0 32.0 66.7 -0.7 +0.7
20.2 78.5 19.5 79.0 -0.7 +0.5
TABLE 3.X
ANALYSIS OF NNH/UDNH ADMIXTURES
Experimental (%) Theoretical (%) Variation (%) NMH UDNH MMH UDMH MMH UDI'IH
76.1 23.7 76.8 23.2 +0.7 -0.5
85.6 13.6 85.8 14.2 +0.2 +0.6
11.2 88.7 10.8 89.2 -0.4 +0.5
25.5 74.0 25.8 74.2 +0.3 +0.2
47.0 52.4 47.5 52.4 +0.5 -0.0
51.4 47.5 51.8 47.1 +0.4 -0.4
A series of mixtures of N 2H4 /UDMH and MMEI/IJDNH were prepared for
test analyses; the results are shown in Tables 3.IX and 3.X.
For industrial-grade hydrazines, greater accuracy can be obtained
if the "contaminant titration values" for each of the hydrazines is
known. Malone and Biggers (59) reported contaminant titration values of
0.20, 0.12, and 0.04 ml for N2114 , NNH, and UDNH respectively; these
are corrections for any impurities in N 2 H 4 and MMII which behave
similarly to another hydrazine (UDMH) and vice-versa.
34
SECTION 4
DETERMINATION OF ALDEHYDES, ANHYDRIDES, ISOCYANATES AND ISOTHIO-
CYANATES USING HYDRAZINE REAGENT.
A method is presented for determining aldehydes, anhydride,
isocyanates and isothiocyanate by reaction with hydrazine. An excess
hydrazine reagent is added to a sample, and after the reaction is
complete, the excess is titrated with standard acids. Hydrazine can
be used as a reagent to determine various functional group compounds.
Panwar et al (76) used hydrazine in conjunction with iodine to deter-
mind permanganate, copper sulfate, chlorate, bromate and iodate,
periodate, peroxide, ferricyanide, ferrocyanide and both mercurous
and mercuric mercury. In another paper 7 , they determined carbonyl,
thiourea, semicarbazide, several aldehydes, ascorbic acid and
isonicotinic acid hydrazine. In most cases, the iodine was allowed to
react with the compound being analyzed, then the excess iodine was
back titrated with hydrazine. Siggia et al (68) used l,l-dimethyl-
hydrazine (IJDNH) as a reagent for determining aldehydes. An excess of
UDMH was allowed to react with the aldehydes for 30-60 min then the
excess UDNH was back titrated with alcoholic HC1 in ethylene glycol
solvent.
Dt' A ("PT (K1C'
In dioxan medium, hydrazine reacts to form 1,2-diacetyihydrazine
with acetic anhydride as shown in equation 4.1
35
0
o H - CH
N2H4 + 2
CH - 0 2CH3COOH 1
N - CH 3 (4.1)
CH - C H U
0
and salicylidene azine with salicylaldehyde as shown in equation (2.1).
Hydrazine reacts with isocyanates to form semicarbazides as shown
in equation 3.1; hydrazine reacts with Isothiocyanates to form thio-
senticarbazides as shown in equation 4.2 but only in alcohol medium.
N2114 + RCNS Cs NH . R
(4.2)
EXPERIMENTAL
Preparation of Sample. Add 1.0 ml or 1 gram (dissolve in acetic
acid if solid) of the functional group to be analyzed to a tared
volumetric flask (50 ml) containing about 20 ml of dioxan or acetic
acid. Use chlorobenzene for both isothiocyanates and isocyanates.
Obtain the sample weight by difference. Make up to the mark with the
dioxan or chlorobenzene and mix. carefully.
Determination of Aldehydes, Anhydrides, Isocyanates. Add an
aliquot (5.00 ml) of the desired functional group to a 50 ml beaker
containing 20 ml of dioxan or acetic acid and an aliquot (2.00 ml) of
hydrazine reagent. Add 1 drop of quinaldine red indicator 0.2% in
acetonitrile. Allow to react for 20 mm., then, titrate to a colourless
end-point (yellow end point for aldehyde) with O.lN perchloric acid in
dioxan to obtain titre "B". Titrate a blank for the reagents and
indicator to obtain titre "b". Titrate a 2 ml aliquot of hydrazine
reagent with perchloric acid to a colourless end-point to obtain
titre "A"
Determination of Isothiocyanates. Add an aliquot (5.00 ml) of
the isothiocyanate to a 50 ml beaker containing 20 ml of propanol and
an aliquot (2.00 ml) of the hydrazine reagent. Add 2-3 drops of meta
36
cresol purple 0.2% in ethanol. Allow to react for 20 mm., then,
titrate with O.1N hydrochloric acid in propanol to obtain titre "B".
Titrate a 2 ml aliquot of hydrazine reagent with hydrochloric acid in
propanol. Titrate a blank for the reagents and indicator to obtain
titre "b".
CALCULATIONS
% Functional = A - (B-b) x N HC10 4 x N.W. compound x 100 x 25 Group
sample weight (g) x 1000
RESULTS AND DISCUSSION
A series of experiments were conducted with aldehydes (primarily
salicylaldehyde) to determine the best medium and titrant for analyzing
aldehydes. In Table 4.1 acetic acid was used as the non aqueous
solvent and 0.1 N perchloric acid in acetic acid was used as the titrant.
The results show that the milliliters of hydrazine available for back
titration with perchloric acid is reduced. Using perchloric acid in
propanol and propanol, chlorobenzene, ethylene digol and benzene as
solvents and varying the salicylaldehyde added, the milliliters of
perchioric acid is also reduced. However, the endpoint is difficult
because precipitates are formed. On changing the solvent to acetic
acid and the titrant to 0.1 N perchloric acid in dioxan, the endpoint
becomes sharp and the titration proceeds smoothly. The reaction
time of salicyladehyde with hydrazine was determined as 20-30 mm.
A similar series of experiments was conducted with acetic acid
and hydrazine in various solvents namely, ethyl acetate, dioxan and
acetic acid using 0.1 N perchloric acid in dioxan as a titrant.
37
Tables 4.11 and 4.111 shows the effect of concentration and time on
the anhydride - hydrazine reaction. They also show that the excess
hydrazine added to the anhydride sample is reduced proportionately to the
amount of anhydride added. These experiments were conducted between
10-40 mm. Dioxan gave a sharper endpoint than ethyl acetate and the
anhydride-N2H4 reaction occurred more rapidly in dioxan. Acetic acid
gave as good an endpoint as dioxan. Table 4.111 shows the effect of
time on the anhydride - hydrazine reaction in ethyl acetate using
perchloric acid in dioxan as titrant. A time of 20-25 min is adequate
for the acetic anhydride to react.
38
TABLE 4.1
VARIOUS MEDIA FOR ALDEHYDE DETERMINATION
Compound Non Aqueous 1 ml Aldehyde! Titrant 1m]. N2H4/5() mi/HAc Solvent 50 ml HAc HC1O4 /llAc
aliquot ml aliquot ml' O.1N
ml used
2 Acetic Acid 0 7.65
2 Acetic Acid 1 6.50
2 Acetic Acid 2 5.50
2 Propanol 2 10.0
2 Ethylene Digol 2 (no color
9.5 change)
2 Chlorobenzene 2 10.0
2 Propanol 2 (yellowish) 9.4
2 Propanol 4 (ppt) 7.5
2 Propanol 6 (ppt) 5.25
2 Propanol 8 (ppt) 2.1
2 Benzene 2 (ppt) 8.5
• 2 Benzene 4 (EP difficult) 6.2
2 Benzene 6 4.0
HC104/Dioxan
2 Acetic Acid 0 11.15
2 Acetic Acid 2 7.15
• 2 Acetic Acid 4 6.60
2 Acetic Acid 6 5.0
39
TABLE 4. 11
EFFECT OF CONCENTRATION OF ACETIC ANHYDRIDE ON HYDRAZINE
Time Compound Non Aqueous Additive Titrant mm. 1 ml N2H4/50 ml Solvent Acetic 0.1N HC104/Dioxan
Acetic Acid Anhydride ml used
ml aliquot g.
-- 5 Ethyl Acetate 0 4.8
20 5 Ethyl Acetate 0.25 2.9
35 5 Ethyl Acetate 0.25 2.7
24 5 Ethyl Acetate 0.30 2.4
36 5 Ethyl Acetate 0.30 2.6
25 5 Ethyl Acetate 0.40 2.1
25 5 Ethyl Acetate 0.40 2.2
25 5 Ethyl Acetate 0.50 1.7
-- 5 Ethyl' Acetate 0.50
10 5 Ethyl Acetate 0.25 4.1
25 5 Ethyl Acetate 0.25 3.1
34 5 Ethyl Acetate 0.25 2.5
20 5 Ethyl Acetate 0.01 4.85
20 5 Ethyl Acetate 0.02 4.85
20 5 Ethyl Acetate 0.04 4.1
20 5 Ethyl Acetate 0.08 3.8
20 5 Ethyl Acetate 0.12 3.5
20 5 Ethyl Acetate 0.20 3.1
40 5 Dioxan 0.02 3.0
30 5 Dioxan 0.02 2.95
30 5 Dioxan 0.04 2.75
40 5 Dioxan 0.04 2.40
40 5 Dioxan 0.08 1.90
30 5 Dioxan 0.08 2.1
40
TABLE 4.111
EFFECT OF TIME ON ACETIC ANHYDRIDE
Hydrazine Reaction
Time Compound Non Aqueous Additive mm. i ml N2H4/50 ml Solvent 1 ml AcAn/50 ml
Acetic Acid Ethyl Acetate m
ml aliquot l aliquot
Ti trant O.lN HC104 /Dioxan
ml used
5 Ethyl Acetate 0 4.9
5 5 Ethyl Acetate 2 3.9
10 5 Ethyl Acetate 2 4.1
15 5 Ethyl Acetate 2 3.4
20 ' 5 Ethyl Acetate 2 32
25 5 Ethyl Acetate 2 3.3
30 5 Ethyl Acetate .2 3.2
35, 5 Ethyl Acetate 2 3.3
40 5 Ethyl Acetate 2 3.5
45 5 Ethyl Acetate 2 3.3
15 5 Acetic Acid 2 3.3
15 5 Acetic Acid 4 1.2
A series of experiments were conducted with isocyanates and
isothiocyanates to determine the conditions for their analysis. In
Table 4.IV propanol was used as the solvent and hydrochloric acid in
propanol was used as the titrant. As shown both the isocyanate and
isothiocyanate react with hydrazine as indicated by the reduction
in milliliters of the alcoholic HC1. This agrees with the data shown
in Tables 3.1 and 5.1 where ethanol was used as the solvent. However,
to keep the use of hydrazine as an analytical reagent simple, whenever
41
possible, perchioric acid is used as the titrant and dioxan or acetic
acid as the solvent. Isothiocyanates can not be determined in acetic
acid medium using perchioric acid as the titrant. The data to sub-
stantiate this is shown in Tables 5.11 and 5.111.
Selected aldehydes, anhydrides, isocyanates and isothiocyanates
were weighed and analyzed by the method described. The results are
shown in Table 4.V as indicated, aliphatic iso and isothiocyanates can
not be determined under the condition described here. Aromatic
isothiocyanates must be analyzed using alcoholic hydrochloric acid as
a titrant and alcohol as a medium as described.
TABLE 4.IV
EFFECT OF VARIOUS ISOCYANATES WITH HYDRAZINE IN ALCOHOL MEDIUM
Time Compound Non Aqueous Additive 1 ml N2H4/50 ml Solvent 1 ml/50 ml Chlorobenzene Titrant
Propanol 20 ml ml aliquot O.lN HC10 /HAc 4
ml aliquot Cyanate ml used
1 Propanol 1 ml Cychiohexyliso 6.0
1 Propanol 1 ml Cychlohexyliso 5.62
1 Propanol 1 ml Cyclohexyliso 5.62
1 Propanol 1 ml Naphthyliso 5.70
1 Propanol 1 ml Naphthyliso 5.40
1 Propanol 1 ml Phenylisothio 4.50
1 Propanol 1 ml Phenylisothio 4.60
1 Propanol 2 ml Cyclohexyliso 5.05
1 Propanol 2 ml Cyclohexyliso 5.05
1 Propanol. 4 ml Cyclohexyliso 4.90
1 Propanol 4 ml Cyclohexyliso 4.90
1 Propanol 6 ml Cylohexyliso 2.80
1 Propanol 6 ml Cyclohexyliso 2.60
42
TABLE 4.V
ANALYSIS OF VARIOUS ALDEHYDES, ANHYDRIDES, ISOCYANATES AND ISOTHIOCYANATES
% Determined By % Determined By Hydrazine Method Other Methods
Artisealdehyde 93.8
Cinnamaldehyde 96.4
Salicylaldehyde 97.6 981b
Crotonaldehyde 92.8
Naphthaldehyde 98. 99 . 31
Heptaldehyde 94.5
Proprionic Anhydride 97.8 98.2 Succinic Anhydride 99.1
Phthalic Anhydride 92.2
Maleic Anhydride 9514
Acetic Anhydride 97.2 991b
Trifluoroacetic Anhydride 95.7
Naphthylisocyanate 98.2 99.3
Phenylisocyanate 97.0
Toluene Diisocyanate 99.1 99.0 c
acyc1ohelisocyanate
aDimeryl Diisocyanated
Naphthylisothiocyanate 98.3
Phenyl Isothiocyanate 99.1 986b
aAllylisothiocyanate
Could not determine under conditions described.
b Chemically Pure
C United Technology Corporation by Di-n butylamine method
d c42H66 (NCO)
43
SECTION 5
THE ANALYSIS OF ISOCYANATE-ISOTHIOCYANATE ADMIXTURES USING HYDRAZINE
A method for the analysis of Isocyanate-Isothiocyanate admixtures
based on their reactions with N 2 H 4 is presented. Both naphthyl
and phenylisocyanates and isothiocyanates react with hydrazines in an
alcoholic medium using alcoholic hydrochloric acid as a titrant. Only
isocyanates react with hydrazines (N 2H4 and MMII not UMDH) in an acetic
acid or dioxan medium using perchloric acid in acetic acid as a titrant.
EXPERIMENTAL
Preparation of Samples. Pipette 0.5 ml of the isocyanate-isothio-?
cyanate mixture into a tared 50 ml volumetric flask containing 20 ml
of chlorobenzene. Weigh to the nearest 0.1 mg, obtaining the sample
weight by difference. Dilute to the mark with chlorobenzene and mix
thoroughly.
Determination of Total Isocyanate-Isothiocyanate Mixture. Pipette
a 5 ml aliquot of the mixture into a 50 ml beaker containing 20 ml of
methanol and 10 ml of (0.3 M) hydrazine *(lO g of hydrazine/acetic acid)
in acetic acid solution. Allow 30 minutes for the reaction to occur.
Titrate the excess hydrazine solution with alcoholic HC1 (0.1 N) either
potentiometrically using a glass-calomel electrode system or visually
using meta cresol purple indicator 0.2% in methanol. Call this value "A"
*When adding hydrazine to acetic acid, be careful to add the hydrazine
slowly as the reaction is exothermic. Cool to room temperature before
diluting.
Determination of Isothiocyanate. Pipette a 5 ml aliquot of the
mixture into a 50 ml beaker containing 20 ml of dioxan and 10 ml of
(0.3 M) hydrazine in acetic acid solution. Allow 30 minutes for the
reaction to occur. Titrate the excess hydrazine solution with perchioric
acid (0.1 N) in acetic acid either potentiometrically using a glass
colomel electrode system or visually using quinaldine red indicator 0.2%
in acetonitrile. Call this value "B". Conduct a titration of the
10 ml of (0.3 N) hydrazine as a blank.
CALCULATIONS
(Ml 1-IC1 for sample) - (ml HC1 for blank) x N HC1 x M.W. x 100 X 10 - A sample wt. (g) x 1000 -
(Ml HC104 for sample) - ml HC10 4 for blank x N HC104 x M.W. x 100 x 10
sample wt. (g) x 1000
RESULTS AND DISCUSSION
Chlorobenzene was used as the sample solvent for both isocyanate and
isothiocyanate because of its inertness with these compounds. Isocyanate
and isothiocyanate were reactive with dioxan, acetic acid, methanol and
ethyl acetate as indicated by the formation of a white precipitate. For
the titration solvent using hydrochloric acid, ethanol was used in preference
to chlorobenzene. For the titration solvent using perchloric acid,
solutions of perchioric acid in acetic acid were used. Using dioxan as the
titration solvent gave sharper end points than using solutions of perchloric
acid in dioxan with acetic acid as the titration solvent. The water content
in all reagents should be reduced as indicated in reference (57) because
of the reactivity of water with isocyanate as shown in equations (3.4) and
(3.5).
As shown in Section 3, Table 3.1, N 2H4 , MMLI and UDMH all react
45
with isocyanate in an ethanol solvent system using HC1 in propanol as a
titrant. This same experiment using isothiocyanate Instead of isocyanate
is shown in Table 5.1. Again all of the hydrazines react as indicated
by the decrease in total ml of 0.1 N BC1 required.
TABLE 5.1
EFFECT OF ISOTHIOCYANATES ON VARIOUS HYDRAZINES IN ALCOHOLIC MEDIUM USING 0.1 N HC1/PROPANOL
Compound Non Aqueous Additive Titrant 1 ml/50 ml ROH Solvent ml RCNS 0.1 N HC1/ROH 1 ml aliquot ml used
N2. H4 Ethanol 5.90
N 2 H
4 Ethanol 1.0 0.13*
UDNH Ethanol 6.10
UDMH Ethanol 1.0 2.50
NMH Ethanol 4.10
MMR Ethanol 1.0 0.02
Indicator m cresol purple 0.2% in Ethanol
*White precipitate formed. Solutions were allowed to react for 45 mm.
Also shown in Section 3, Table 3.11, the hydrazines, except UDNH,
reacted with isocyanates in both acetic acid and dioxan using perchloric
acid in acetic acid as a titrant. A series of experiments were conducted
to determine if N 2 H 4 reacts with isothiocyanate in acetic acid medium
and/or dioxan using perchioric acid in dioxan as a titrant. Table 5.11
shows that the N 2 H 4 was unreactive with isothiocyanate in chlorobenzene
and acetic acid. However, in dioxan evidence of reactivity is indicated
by the slight decrease in (ml) required of 0.1 N HC10 4 /Dioxan.
46
TABLE 5.11
EFFECT OF ISOTHIOCYANATE ON HYDRAZINE IN VARIOUS SOLVENTS USING PERCHLORIC ACID IN DIOXAN AS TITRANT
Compound Non Aqueous Additive Titrant 1 ml/50 ml HAc Solvent -1 ml RCNS/ 0.1 N HC10 4/Dioxan 1 ml aliquot 50 ml Chlorobenzene ml used
ml aliquot
N 2 H 4 Chlorobenzene 0 3.30*
N 2 H 4 Chlorobenzene 1 3.30
N 2 H
4 Chlorobenzene 2 3.25
N H 2 4 Chlorobenzene 3 3.25
N 2 H
4 Chlorobenzene 4 3.20
N 2 H 4 Acetic Acid 1 3.30
N 2 H 4 Acetic Acid 2 3.30
Acetic Acid 3 3.30
N 2 H Dioxan 0 3.45
N 2 H 4 Dioxan 1 3.00
N 2 H 4 Dioxan 2 2.82
N 2 H 4 Dioxan 3 2.60
*30 min reaction time
Upon changing the titrant to 0.1 N Perchioric acid in acetic acid
as shown in Table 5.111, there was little evidence of reaction between
N 2 H 4 and isothiocyanate. Because of this, perchioric acid in acetic acid
was adopted as the titrant for the rest of the experiments.
47
TABLE 5.111
EFFECT OF ISOTHIOCYANATE ON HYDRAZINE IN ACETIC ACID USING 0.1 N PERCHLORIC ACID IN ACETIC ACID AS A TITRANT
Compound Non Aqueous Additive Titrant 1 ml/50 ml HAc Solvent RCNS, 0.1 NHCl04/HAc
aliquot ml ml used
1 ml N 2 H 4 Acetic Acid 1 4.20
2 ml N 2 H 4 Acetic Acid 1 8.33
3 ml N2 H4Acetic Acid 1 12.50
4 ml N 2 H 4 Acetic Acid 1 16.60
A series of experiments were conducted to compare chlorobenzene
and ethanol solvents for the isothiocyanate-N 2H4 reaction and the
isocyanate-N2H4 reaction using 0.1N HC1 in propanol as titrant. Tables
5.IV and 5.V show that both reactions proceed smoothly in either
chlorobenzene or ethanol.
TABLE 5.IV
EFFECT OF ISOTHIOCYANATE ON HYDRAZINE IN CHLOROBENZENE AND ETHANOL USING 0.1N HYDROCHLORIC ACID IN PROPANOL AS A TITRANT
Compound Non Aqueous Additive Titrant 1 1 nil/50 ml R011 Solvent 1 ml RCNS/ 0.1 N HC1/ROH 1 ml aliquot 50 ml Chlorobenzene ml used
ml aliquot
N 2 H
4 Chlorobenzene 0 3.10
N 2 H
4 Chlorobenzene 1 1.85
N 2 H
4 Chlorobenzene 2 1.15
N 2 H 4 Chlorobenzene 3 0.70
N 2 H 4 Chlorobenzene 4 0.50
48
--
TABLE 5.IV (Continued)
Compound Non Aqueous Additive 1 ml/50 ml ROH Solvent 1 nil RCNS/ 1 ml aliquot 50 ml Chlorobenzene
ml aliquot
Ti trant 0.1 N HC1/ROH*
ml used
N 2 H 4
N 2 H
4
N 2 H
4
N 2 H
4
N 2 H
4
*30 min reaction time
Ethanol 0 3.15
Ethanol 1 2.45
Ethanol 2 2.05
Ethanol 3 0.90
Ethanol 4 0.60
TABLE 5.V
EFFECT OF ISOCYANATE ON HYDRAZINE IN C}ILOROBENZENE AND ETHANOL USING 0. iN HYDROCHLORIC ACID IN PROPANOL AS A TITRANT
Compound Non Aqueous Additive Titrant 1 ml/50 ml ROH Solvent RCNO 0.1 N HC1/ROH* 1 ml aliquot ml ml used
O 3.14
1 2.25
2 1.30
3 0.45
4 0.25
0 3.15
1 2.20
2 1.45
3 0.48
4 0.20
N 2 H
4 Chlorobenzene
N H Chlorobenzene 2 4
N H Chlorobenzene 2 4
N H Chlorobenzene 2 4
N H Chlorobenzene 2 4
N H 2 4 Ethanol
•
N 2 H
4 Ethanol
N 2 H 4 Ethanol
N2114 Ethanol
NH Ethanol 2 4
*30 min reaction time 49
The effect of time was observed in a series of experiments
shown in Table 5.VI. Hydrazine and MMII reacted between 30-45 mm
with naphthylisothiocyanate. The UDMH was incompletely reacted
even after 75 min using 0.5 ml of RCNS.
TABLE 5.VI
EFFECT OF TIME ON THE REACTION OF NAPHTHYLISOTHIOCYANATE AND HYDRAZINE
Time Compound Non Aqueous Additive Titrant min 1 nil/50 ml ROH Solvent Naphthylisothiocyanate 0.1 N HC1/ROH
1 ml aliquot ml ml used
15 N 2 H
4 Ethanol 0.5 1.65
30 N 2 H
4 Ethanol 0.5 0.37
45 N 2 H Ethanol 0.5 0.17
60 N 2 H
4 Ethanol 0.5 0.11
75 NH Ethanol 0.5 0.08
15 UDMU Ethanol 0.5 5.0
30 UDNH Ethanol 0.5 3.93
45 IJDNH Ethanol 0.5 3.62
60 UDNH Ethanol 0.5 2.59
75 IJDNH Ethanol 0.5 1.92
0 MMII Ethanol 0.0 4.0
15 MMII Ethanol 0.5 1.19
30 MMII Ethanol 0.5 0.23
45 .MMH Ethanol 0.5 0.10
60 MMII Ethanol 05 0.10
75 . MMII Ethanol 0.5 0.10
50
Mixtures of phenylisocyanate and phenylisothiocyanate were
prepared and analyzed by the described method. The results are
shown in Table 5.VII.
TABLE 5.VII
ANALYSIS OF ISOCYANATE-ISOTHIOCYANATE MIXTURES
Experimental Theoretical Variation in % RCNO RCNS RCNO RCNS RCNO RCNS
71.0 16.6 71.7 16.1 -0.7 +0.5
63.5 34.1 63.0 34.7 +0.5 -0.6
48.5 49.5 48.1 50.1 +0.4 -0.6
32.0 65.3 32.4 65.0 -0.4 +0.3
24.1 74.4 24.7 73.8 +0.6 +0.6
UR
51
SECTION 6
MISCELLANEOUS STUDIES
Several additional techniques have been investigated and are
discussed here for the determination of hydrazines.
GRAVIMETRIC
As described in Section 2, hydrazine forms a precipitate of
Salicylidene Azine with Salicylaldehyde. The formation of this precipi-
tate lends itself to a gravimetric procedure both for the determination
of hydrazine in the presence of other hydrazines but also for the
determination of several aldehydes - those that form precipitates
such as Verataldehyde, Anisealdehyde, Cinnamaldehyde, Naphthaldehyde,
piperonaldehyde and nitrobenzaldehyde.
PRELIMINARY DATA
A sample of N2H4/TJDMH (5.0 ml) was added to a 100 ml volumetric
flask and diluted to the mark with glacial acetic acid. Approximately
(4.0 ml) of Salicylaldehyde (SA) was added to various aliquots of the
hydrazine mixture in 15 ml centrifuge tubes. After setting for 20
minutes, a yellow precipitate formed. Acetic acid was added to keep
the volume constant. The tubes were centrifuged for 5 min and the
height of the precipitate was recorded. Table 6.1 shows the pre-
liminary results.
52
TABLE 6.1
HEIGHT OF PRECIPITATE VS CONCENTRATION OF HYDRAZINE
ml SA N2114 /UDMH N 2 H 4 Height
ml aliquot g of precipitate ml
4 0.5 0.26 0.40
4 1.0 0.52 0.7 - 0.8
4 1.5 0.78 1.30
4 2.0 1.05 1.5 - 1.6
4 2.5 1.31 1.6 , - 1.8
3.0 1.57 2.0
For a practical gravimetric method the following variables must
be determined: the centrifuge time, the proper ratios of aldehyde
(excess) to hydrazine, proper selection of a solvent (not necessarily
acetic acid) proper order of adding reagents, and the limits of these
variables to prevent packing. The method would be readily applicable
for rapid, field type use.
COLORIMETRIC
Hydrazines, as do primary and secondary amines, diamines and
triamines, form highly colored compounds with dinitro compounds. By
proper selection of solvent, and concentrations of hydrazines, and
amines, mixtures of hydrazines in the presence of amines is possible.
In Table 6.11, only concentrated compounds were used, hence the
intensity of the colors and the reactivity of others producing
reddish-black and brownish-black compounds. It appears that hydrazine
can be determined readily in the presence of primary, secondary and
53
• 6.11. CDWR.DTRIC. REACTIONS 'OP HYDRAZINES, .LND ANES WITH DIbTITRO COO1JNDS DIETTr TriEt
1L UD1IL nBNL2 n1ilR2 DMNR2 TBNH2 NetAn DMAn ETDiNH2 NH2 Tet NH2
2,4DNTo P B YG B B C Y R R BC BC DC
nDNB P RP 0 R R (P1) 0 Y RBr RBR P P P
2,6DNT0 P Bur RBr RBr RBr Pi Y 0 RRr BC DC DC
2,4 DN 0 Y-0 Y Y Y Y Y RBr R3r Y Y Y
ODNB BrC BrG Y Y Y Y C RBr RBr RO 0 Y
ONAn 0 Y0 Y Y Y '1 Y Y y y y y
pNAn YG C C Y Y Y C Y Y C C C
1,4DNOPIP C C C C C C C C C C C C
1 Cl 2,4 DNB RBr CB1 DR Y Y0 Y Y REl RB]. RB1 Rhi Y0
4 Cl 3,5 DNBCN BrBl* B1* BrBl* 0 0 0 Y , RBr RB]. RO 0 0
4C12NTo
2,4 DNAnis B]. GB]. YBr Y Y 0 C 0 0 DR DR 0
' NH 2 2C1NPYR RBr •Y Y Y Y Y C Y Y RBr Y Y
2NH2 3NPY B]. Y Y Y Y Y Y Y Y Y 'I
4NH2 3NHT' R Y Y Y Y Y Y Y Y Y Y Y
1,5 DF 2,4 DNB BrBr R0* 0* Y* Y YG R R Y R* Y
2,4,7 TNBAL GB]. RB]. RB]. RB]. RB]. RB]. C BrB]. BrB1 RB]. RB]. RB].
1,3 DNNAPTH RB]. RP RB]. RB]. RB]. RB]. BrB1 RBr RBr RB]. RB]. RB1
]. Cl 2,4,6 TNB HP Bur DR DR DR R Y BrBl BrB1 HP RP HP
2,4 DNFB PB]. B]. BrB]. RO RO Y Y BrB]. BrB]. BrBl* • RO RO
2,4,7 TN 9 FONE BrB]. BrBl RBr Y Y 0 Y DR DR RY DR R
D Di HAL Benza].dehyde P Purple Pi Pink , *Reacts
T Tri Cl Ch].oro B Blue B]. Black
To Toluene AIS Aniso].e Y Yellow Bur Burgundy • S
B Benzene •
.' Diuiethylamine C Green D Dark
DN Nitri].e Net,An N-ethy]. Aniline C Colorless
NH Amine EtDINH2 Ethylene • Br Brom
NAPH - Naphthaldehyde am • 0 Orange
TriEtTetNH - Triethylone tetrenina • 54
• •. :
tertiary amines. Whereas the diamines, triamines and tetramines
might offer some difficulty because of the deep blues and greens
formed. Determining MMH or UDMH in the presence of the amine
groups could be accomplished using o-dinitrobenzene, p-nitroaniline,
1-chloro-2,4-dinitrobenzene, 4-chloro-3,5-dinitrobenzonitrile,
2 ,4-dinitroanisole and 2,4, 7-trinitrofluorene. Compounds containing
the chioro and fluoro groups reacted readily.
The high coloration of the compounds was dependent on the nitro
groups, nitro < dinitro < trinitro and the number and location of the
amine groups in mono < di < tri < tetramine as expected.
HYDRAZINE AS A REAGENT
As shown in Sections 3 and 5, isocyanate compounds, especially
aromatic isocyanates, react readily with both hydrazine and Monomethyl-
hydrazine respectively.
PRELIMINARY DATA
From the preliminary data, as shown in Table 6.111, Isopropyl
isocyanate reacts very slowly, and Toluene diisocyanate reacts immediately
with hydrazine in dioxan. As a result of the larger difference in
reaction rates, it would be feasible to develop analytical methods
for determining, (1) aromatic isocyanates in the presence of aliphatic
isocyanates, (2) Diisocyanates in the presence of aliphatic isocyanates
and aromatic thioisocyanates and (3) diisocyanates in the presence of
diisocyanates (not verified) depending on the location of the isocyanate
group. Table 6.111 also indicates that the proper selection of a solvent
is critical because of the reactivity of the isocyanates. By changing
55
from dioxan to chlorobenzene, a 2 milliliter difference for the
same time was observed. Also, both acetonitrile and nitrobenzene
reacted with the diisocyanate. Normally, the isocyanate reacts
faster than the isothiocyanate and the diisocyanate would react
faster than the isocyanate.
TABLE 6.111
REACTION OF VARIOUS ISO AND DIISOCYANATES WITH HYDRAZ.NE
'ime Compound Solvent Additive Titrant tin. 1 ml N2H,/50 ml HAc 1 ml Isocyanate/ 0.1N HC104 /Dioxan
ml aliquot 50 ml Chlorobenzene ml used ml aliquot
4 Dioxan 0 9.3 20 4 Dioxan 2 ml TDI 6.4 15 4 Dioxan 2 ml TDI 6.7 20 4 Dioxan 4 ml IPI 9.1 20 4 Dioxan 4 ml IPI + 2 ml TDI 6.4 25 4 Dioxan 4 ml IPDI + 2 ml TDI 5.9 5 4 Dioxan 4 ml NAPI + 2 ml TDI 4.2 15 4 Dioxan 4 ml NAPI 7.75 5 4 Chlorobenzene 4 ml NAPI + 2 ml TDI 6.00 20 4 Chlorobenzene 4 nil NAPI + 2 ml TDI 6.00 58 4 Chlorobenzene 4 ml ATI +2 ml TDI 6.00 58 4 Chlorobenzerte 4 ml OTI + 2 ml TDI 3.50 58 4 Dioxan 4 ml TI 3.50 58 4 Dioxan 4 m ATI 7.25 10 4 Acetonitrjle 4 ml DDI Reacts with 10.2 10 4 Acetonjtrjle 4 ml IPDI 11.6 10 4 Acetonitrile 4 ml IPrI
Acetonitrj le 11.2
TDI = Toluene Diisocyanate NAPI = Naphthylisocyanate TPI = Isopropylisocyanate ATI = Allylisothiocyanate IPDI = Isophoronedlisocyanate OTI = phenylisothiocyanate
DDI = Dimeryl Dilsocyanate
56
APPLICATIONS
The additional techniques investigated here offer considerable
benefits.
(1) As mentioned the gravimetric method could.be adopted for a
rapid, field type method for determination of N 2 H 4 or by use of
N2H 4 as an analytical reagent for determination of aldehydes; (2)
precipitates of aldehydes and hydrazines produce three colors,
white, yellow and yellow orange. Identification of an aldehyde might
be feasible based on its precipitate color; also, (3) here N 2 H 4 was
gravimetrically separated from MMEI and UDHR, N 2 H 4 could readily be
separated from amines, diamines and triamines using the same technique.
The highly colored compounds formed between hydrazines, amines
etc. and dinitro and trinitro compounds can be used as a method to
distinguish N2114 from other hydrazines, amines, diamines, triamines
and tetramines. The N 2 R 4 color was always more intense. Both amines
and hydrazines are presently detected using dimethylaminobenzaldehyde
which produces a yellow coloration. This colorimetric reaction suffers
because it can not distinguish amines from each other or amine from
hydrazines. By proper selection of conditions, colorimetric methods
for air pollution measurements of hydrazines and amines, diamines and
triarnines might be feasible. Also, identification of primary from
secondary and tertiary amines and secondary from tertiary amines might be
be feasible. Glass tubes containing a substrate impregnated with
57
selective dinitro,. trinitro or chloro, fluoro containing dinitro
compounds could be prepared. Known volumes of air containing amines
could be drawn through the glass tubes. The color produced would be
indicative of the amino group as well as the concentration of the
amine.
3. The reaction rate difference between N 2 H 4 and isocyanates,
isothiocyanates (aromatic and aliphatic) and diisocyanates could form
the basis for many varied techniques for the analysis of their mixtures.
Changing solvents and titrants, and adding catalyst to increase
reaction rate, offer ways in which analytical problems involving
isocyanates, diisocyanates and isothiocyanate can be solved.
58
SECTION 7
CLOSURE
In this Thesis, the versatility of using N 2 H 4 as an' analytical
reagent has been demonstrated. Hydrazine is simple to use and is
of high purity. It has been used both as a reducing agent and as a
basic agent. It is hygroscopic and highly reactive with strong
oxidizers but, when properly handled, is a powerful analytical
reagent.
Complete references for the analysis of hydrazine compounds by
oxidation methods and acid-base methods are presented.
Mixtures of N2H4 /MMH and N2H 4 /UDMH have been analyzed by a
titrimetric method in which two aliquots are titrated with potassium
iodate: (a) directly to determine the sum of the hydrazines present
and (b) to determine the NMIi or UDNH after selective reaction of the
hydrazine with salicylaldehyde. For ternary mixtures, three aliquots
are required: the sum of the hydrazines is determined with potassium
iodate; the sum of MMH and UDMH is found after selective reaction of
the hydrazine present with salicylaldehyde; and the UDM1-I content is
obtained by non-aqueous solvent titrimetry after reaction of both
hydrazine and MMII with acetic anhydride in dioxane.
Mixtures of N2R4 /UDMH and NNI-l/UDMIi have been determined by the
reaction of hydrazines with naphthyl or phenylisocyanate in non-
aqueous medium. In anhydrous acetic acid, N 2 H 4
and MMH reacted
rapidly with isocyanates but UDNR did not react appreciably in less
than 2 h at room temperature. From a total base titration using
perchioric acid the sum of the hydrazines is determined. The UDMH
content is determined by perchioric acid titration after the N 2 H 4 or
MMII have reacted with the isocyanate.
Various aldehydes, anhydrides, isocyanates and isothiocyanates
have been determined using hydrazine as an analytical reagent.
Compounds from the above functional groups were allowed to react at
room temperature for 30 min with excess hydrazine reagent. The
excess hydrazine was back-titrated with perchioric acid in dioxan.
This simple single method can be substituted for 3-4 different
methods presently used.
Mixtures of phenylisocyanate with phenylisothiocyanate have been
determined using hydrazine as an analytical reagent. Both isocyanates
and isothiocyanates react with N2114 to form semicarbazides and semi-
thiocarbazides in an alcohol medium using alcoholic HC1 as a titrant.
Only isocyanates react with N 2 H 4 in an acetic acid medium using
perchioric acid in dioxane as a titrant. Two aliquots are titrated:
(a) to determine the total isocyanate--isothiocyanate content using
alcoholic HC1 to back-titrate the excess N 2 H4reagent; and (b) to
determine the isocyanate content using perchloric acid in dioxan to
back-titrate the excess N21i4 reagent. From the difference in the two
titrations, the isothiocyanate content can be determined.
Ideas for new methods have been presented: (a) Because N 2 H 4 forms
a precipitate with certain aldehydes, rapid analytical methods for
either N 2 R 4 or these aldehydes could be developed. The height of the
precipitate in a centrifuge tube is a measure of the concentration
provided the proper test conditions are established. (b) Experiments
conducted by reacting hydrazines, amines (primary, secondary,
tertiary), diamines, triamines and detramines with dinitro, trinitro,
chiorodinitro and fluorodinitro compounds to select those dinitro
compounds which would allow development of methods for determing
hydrazines in the presence of each other and hydrazines in the presence
of amines. Highly colored compounds are produced by reacting the
hydrazine and amines with dinitro compounds; different hydrazines and
amines produce different colors. Preparation of glass tubes containing
glass beads impregnated or coated with selected dinitro compounds
could allow differentiation of one amine group from another or
hydrazine groups from amine groups. Establishment of proper test
conditions for this differentiation is required. (c) Preliminary
experiments were conducted with N 2 R 4 and aromatic and aliphatic
isocyanates, diisocyanates and isothiocyanates. Hydrazine reacts
rapidly with aromatic diisocyanates, isocyanates and isothiocyanates;
diisocyanates > either isocyanates or isothiocyanates. Based on
reaction rates of the different functional groups and the location of
the isocyanate group on the hydrocarbon chain, analytical methods
could be developed for their mixtures. Hydrazine because of its two
amine groups reacts faster than amines and could show a significant
improvement over amines as an analytical reagent for isocyanate
analysis. -
61
R1TC1c
I. I. N. Kolthoff, J. Axner.Chem. Soc. 46, 2009 (1924). A. Kurtenacher and J. Wagner, Z. anorg. Chem. 120, 261 (1921). L. Szebelledy and W. Madis, Mikrochim. Acta 57 (1937). B. R. Sant and A. K. Nukherji, Anal. Chim. Acta 20, 476 (1959). S. S. Yatnamura and D. H. Sikes, Anal. Chem. 35, 1958 (1963). N. Z. Barakat and M. Shaker, Analyst 88, 59 (1963). V. A. Benrath and K. Ruland, Z. anorg. Chem. 114, 267 (1920). S. Singh and J. R. Siefker, Anal. Chirn. Acta 36, 449 (1966). B. Singh and S. Singh, Ibid. 14, 109 (1956). A. S. Komarowsky, W. F. Filonowa, and I. N. Korenrnan, Z. anal. Chem. 96, 21 (1933). R. G. Stolle, J. prakt. them. 66, 332 (1902). E. Rupp, Ibid. 67, 140 (1903). B. Singh and A. Rehman, J. Ind. Chem. Soc. 17, 169 (1940). B. Singh and K. C. Sood, Anal. Chim. Acta 13, 301 (1955). J. D. Clark and J. R. Smith, Anal. Chem. 33, 1186 (1961).
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Mj
I. H. Issaand R. M. Issa, Anal. Chim. Acta 14, 578 (1956). B. Suseela, Ber. 88, 23 (1955). A. Berka and A. I. Busev, Anal. Chim. Acta 27, 493 (1962). K. A. Hoffman and F. Kuspert, Ber. 31, 64 (1898). B. Singh and R. Singh, Anal. Chim. Acta 10, 408 (1954). P. Jannasch and A. Jahn, Ber. 38, 1576 (1905). A. F. Weed, J. E. Zarembo, and L. H. Diamond, Food Machinery and Chemical Corp. C. A. 106 (1960). H. E. Malone, Anal. Chem. 33, 575 (1961). E. Burns and E. Lawler, Anal, them. 35, 802 (1963). N. Serencha, J. C. Hanna, and E. J. Kuchar, Anal. Chem. 37, 1116 (1965). H. E. Malone and R. A. Biggers, Ibid. 36, 1037 (1964). H. E. Malone, WADC TR 59-172 WPAFB, Ohio (1959). R. D. Dwiggins and B. F. Larrick, R & D. Symposium Report FRO 205/3 (1953) H. E. Malone and R. Barron, Anal, them. 37, 548 (1965). H. E. Malone and R. Barron, SSD-TRD-62-41, Edwards AFB, Calif. (1962). J. R. Conant and N. F. Hall, J. Am. Chem. Soc. 49, 3062 (1927). J. S. Fritz and R. T. Keen, Anal. Chem. 22, 565 (1952). J. A. Riddick, Anal. Chem. 28, 679 (1956). C. W. Wagner, R. H. Brown and R. H. Peters, J. M. Chem. Soc. 69, 2609 (1947). F. E. Critchfield and J. B. Johnson, Anal. Chem. 29, 957 (1957). S. Siggia and C. R. Stahl, Anal. Chem. 27, 1975 (1955). E. Riegler, Z. anal. Chem. 41, 413 (1902). M. Schlotter, Z. anorg. Chem. 164 (1903). E. Riegler, Z. anal. Chem. 46, 315 (1907). E. Ebler, Z. anorg. Chem. 47, 377 (1905). D. D. Van Slyke, A. Hiller, and K. C. Berthelsen, J. Biol. Chem. 74, 659 (1927). W. Strecker and L. Shartow, Z. anal. Chem. 64, 218 (1924). K. S. Panwar, N. K. Mathur, and S. P. Rao, Anal. Chim. Acta 24, 541 (1961). K. S. Panwar, S. P. Rao, and J. N. Gaur, Ibid. 25, 218 (1961). W. L. Shilling and B. T. Hunter, Anal. Chem. 37, 1421 (1965). J. E. Ruch and J. B. Johnson, Anal. Chem. 28, 69 (1956). F. P. Clift and R. P. Cook, Biochem. J. 26, 1800 (1932). R. E. Houghton, Amer. J. Pharm. 106, 62 (1934). H. A. Iddles and C. E. Jackson, Ind. Eng. Chem., Anal. Ed. 6, 454 (1934). W. Schoniger, H. Lieb, and K. Gassner, Mikrochim. Acta 38, 165 (1951). K. J. Monty, Anal. Chem. 30, 1350 (1958). E. F. L. J. Anet, J. Chromatog. 9, 291 (1962). A. Jart and J. Bigler, Ibid. 23, 261 (1966). S. Siggia and J. G. Hanna, Anal. Chest. 23, 1717 (1951). L. G. Radcliffe and S. Medofski, J. Soc. Chem. Ind. (London) 36, 628 (1917). D. N. Smith and W. M. D. Bryant, J. Am. Chest. Soc. 58, 2452 (1936). J. B. Johnson and C. L. Funk, Anal. Chest. 27,1464 (1955). S. Siggia and Floramo, Anal. Chem. 25, 797 (1953). S. Siggia and J. C. Hanna, Anal. Chem. 20, 1084 (1948). P. M. Beazley, Anal. Chest. 43, 148 (1971).. H. E. Stagg, Analyst London 71, 557 (1946). W. Siefken, Ann. 562, 99 (1949).
63
A. G. Williamson, Analyst London 77, 372 (1952). E. A. Navyazhskaya, Khim. Prom. 432 (Chem. abstr. 51), 8585 (1956). K. A. Kubitz, Anal. Chem. 29, 814 (1957). G. A. Strongin, A. N. Bodrovaand V. I. Smirnov, Anal. abstr. 9, 4755 (1961). 0. Mikl, Kozarstvi 15, 224; (Chem. abstr. 65, 12350) (1965). A. M. Ryadkina and A. S. Kalika, Chem. abstr. 67, 17654 (1966). A. P. Grehov, V. V. Shevchevko and K. A. Kornev, Zh, Anal. Khim 21, 1398 (1966). S. S. Lord, Anal. Chem. 29, 497 (1957). A. I. Finkelshtein and E. N. Boitsov, Zavod. Lab. 26, 959 (1960). B. A. Burns, Anal. Chem. 35, 1279 (1963). G. G. Greth, R. C. Smith and G. 0. Rudkin, Jr., J. Cell. Plast. 1, 159 (1965). F. A. Zhokhova and V. V. Zharkov, Plast. Massy 63; (Chem. abstr. 67, 82587) (1967). C. S. Kitukhina and V. V. Zharkov, ibid. 60 (Chem. abstr. 69, 36620) (1968). N. R. Nebauer, G. Skaeckoski, R. C. White and A. Kany, Anal. Chem. 35, 1647 (1963). Yu. A. Strepikheev, R. A. Semenova and A. N. Ushakov, Zh, Anal. Khim. 20, 757 (1965). W. W. Hanneman and L. L. Robinson, J. Gas Chromatogr. 6, 256 (1968). S. V. Nikeryasova and G. D. Litovchenko, Zh. Anal. Khim. 23, 309 (1968). G. W. Ruth, J. Gas Chromatogr. 6, 513 (1968). A. Kjaer and K. Rubinstein, Acta. Chem. Scand. 7, 528 (1953). Z. Nagashima and M. Makagawa, (Chem. abstr. 54, 774) (1957). L. A. Appelqvist and E. Josefsson, Acta. Chem. Scand. 19, 1242 (1965). P. Langer and K. Gschwendtova, J. Sci. Food Agr. 20, 535 (1969). E. Dieterich, Pharm. Z. No. 79.2. Anal. Chem. 45, 262 (1900). H. Roth, Mikrochim. Acta. 766 (1958). B. S. Karten and T. S. Na, Nicrochem. J. 3, 507 (1959). J. A. Vinson, Anal. Chem. 41, 1661 (1969). R. M. Jones, Anal. Chem. 38, 338 (1966). L. A. Dee and A. K. Webb, Anal. Chem. 39, 1165 (1967).
64
Analylica Chimica Acts 87 Elsevier Publishing Company, Amsterdam Printed in The Netherlands
THE DETERMINATION OF MIXTURES OF HYDRAZINE, MONOMETHYL-HYDRAZINE AND i,i-DIMETHYLHYDRAZINE
H. E. MALONE* AND D. Al. W. ANDERSON
Chemistry Department, The University, Edinburgh EH9 3ff (Scotland)
(Received July 29th, 2969)
Mixtures containing hydrazine and monomethyihydrazine (MMH) can be analysed by a differential oxidation method'. Non-aqueous methods for analysing admixtures of hydrazine with i,i-dimethylhyd.razine 2 (UDMH) or with secondary amines 34 have also been described; the UDMH or secondary amines were titrated with perchioric acid after the hydrazine had been removed by reaction with salicyl-aldehyde 2. If the salicylaldehyde is replaced by either acetic anhydride 5 or phenyliso-cyanate 6, both hydrazine and MMH can be removed from activity in the solution, and therefore the analysis of other combinations of hydrazines becomes possible. SERENCHA et al. 7 extended MALONE'S method 2 by using salicylaldehyde in the presence of excess of perchioric acid to determine admixtures of hydrazine and MMH. Such mixtures can also be analysed by gas chromatography 8 ' 9 .
Nevertheless, simple rapid chemical methods are still useful, e.g. in the analysis of mixtures of hydrazines blended for use as rocket fuels. This paper describes simple procedures for analysing admixtures of hydrazine with MMH and of hydrazine with UDMH. The total hydrazine content is found by titration with iodate'°; addition of salicylaldehyde converts the hydrazine to salicylaldazine (disalicyihydrazine) which is removed by filtration, and subsequent titration with standard potassium iodate gives the MMH or UDMH content. This procedure can be combined with the non-aqueous titration method described previously 5 to give a method for the analysis of mixtures of hydrazine, MMH and UDMH; effective removal of the hydrazine and MMH as the corresponding hydrazides by adding acetic anhydride allows the UDMH present to be determined in dioxane as solvent with perchloric acid in acetic acid as titrant.
EXPERIMENTAL
Analyses of mixtures of hydrazine and monomethyihydrazine (Method A) Preparation of samples. By pipette, add 1.5 ml of the mixture of hydrazines to
a tared 50-ml standard flask containing 20 ml of distilled water and io ml of acetic acid. Cool to room temperature and weigh to o.i mg, by difference. Dilute to the mark with distilled water and mix carefully.
Determination of hydrazi'ne +monomethylhydrazine. By pipette, add an aliquot (5 ml) of the hydrazine mixture to a 500-ml iodine flask containing 50 ml of 6 N hy-drochloric acid. Add 25 ml of 12 N hydrochloric acid and 20 ml of chloroform. Titrate * Permanent address: Air Force Rocket Propulsion Laboratory, Edwards, Calif.
Anal. Chim. Acta, 48 (1969) 87-91
88 H. E. MALONE, D. M. W. ANDERSON
rapidly with o.i M potassium iodate'°, with shaking, until the dark brown colour becomes pale. Then add the iodate dropwise until the purple colour of the chloroform layer becomes colourless and the aqueous solution is yellow. This gives titre "A1".
Determination of monomethylhydrazine. By pipette, add an aliquot (5 ml) of the mixture of hydrazines to a 400-ml beaker containing 50 ml of 6 N hydrochloric acid. Add io ml of a solution of salicylaldehyde in acetic acid (io%, v/v). The hydra-zine gives a yellow precipitate of salicylaldazine. After 15 nun, filter through Whatman No. 540 paper on a Buchner funnel, wash the precipitate several times with distilled water, and then transfer the filtrate to a 500-ml iodine flask, rinsing with several small portions of distilled water. Add 25 ml of 12 N hydrochloric acid and 20 ml of chloroform. Titrate rapidly with o.i M potassium iodate as described above for hy-drazine +monomethylhydrazine. This gives titre "A2". For calculation, see below.
Analyses of mixtures of hydrazine and I,I-diinethylhydrazine (Method B) Preparation of sample. Use the procedure outlined in Method A above. Determination of hydrazine + i,r-dimethylhydrazine. Use the procedure detailed
in Method A for hydrazine +monomethylhydrazine, but ensure that the temperature lies within the range _100 to + io° by cooling in a carbon dioxide—acetone mixture. The titration can also be carried out potentiometrically with a platinum—calomel electrode system. This gives titre "B1".
Determination of i,I-dimethylhydrazine. Use the procedure detailed in Method A above for monomethyihydrazine, but maintain the temperature within the range
I00 to + 100. The potentiometric end-point lies between 0.67 and 0.70 V. To mini-mise side-reactions, complete the titration" within 3-5 mm. This gives titre "B 2".
Calculations N2H4 + K103 + 2HC1 = KO + ICI + N2 + 3H20 CH3 .NH.NH2 + K103 + 2HC1 = KC1 + Id + CH3OH + N2 + 2H20 2[(CH3 ) 2N.NH2] +K103 +2HC1 = (CH3)2N.N = N.N(CH 3)2 + KC1 +ICJ +3H20 Let the K103 molarity = M. Then:
% hydrazine = 320M [(A1 —A 2) or (B 1 —B2)]
sample wt. (g) X 10
% MMH = 4.60MA2
sample wt. (g) X 10
%UDMH = I202M B2 sample wt. (g) x ro
Analyses of mixtures of hydrazine, monomethylhydrazine, and i,r-dimethylhydrazine (Method C)
Preparation of sample. By pipette, place o.8 ml of the mixture of hydrazines into a tared 50-ml standard flask containing 20 ml of acetic acid. Weigh to o.i mg, by difference. Dilute to the mark with distilled water, and mix carefully.
Determination of hydrazine +nzonomethylhydrazine +I,r-dimethylhydrazine. By pipette, add an aliquot (io ml) of the hydrazine mixture to a 500-ml iodine flask con-taining 50 ml of 6 N hydrochloric acid. Proceed exactly as described in Method A above for the determination of hydrazine +monomethylhydrazine with potassium iodate. This gives titre "C,".
Anal. C/jim. Ada, 48 (1969) 87-91
THE ANALYSIS OF HYDRAZINE MIXTURES 89
Determination of mon.oinethylhydrazine + i,i-dimethylhydrazine. By pipette, add an aliquot (io ml) of the mixture of hydrazines to a 400-ml beaker containing 50 ml of 6 N hydrochloric acid. Add io ml of a solution of salicylaldehyde in acetic acid (io%, v/v) and complete the determination of MMH + UDMH as described in Method A above for the determination of MMH alone. This gives titre "C2".
Determination of i,i-dim ethylhydrazi'ne. By pipette, add an aliquot (2 ml) of the mixture of hydrazines to a ioo-ml beaker containing 20 ml of dioxane. Add 2 ml of acetic anhydride; both the hydrazine and monomethyihydrazine react to give hydra-zides. Leave the reaction mixture for 30 mm, and then titrate with 0.1 N perchioric acid in acetic acid; conduct a blank determination using the reagents only. The difference gives titre "C3".
Calculations. Let the K10 3 molarity=M, and the HC104 normality =N. Then:
% hydrazine - M(Ci -C2 ) =x 3.201 - sample wt. (g) x 5
% UDMH - NC 3 6.oi - sample wt. (g) X 25
MCI -(x+.'ul % MMH = Ioo_4•6o 11 [sampiewt (g)
X5 2/i
RESULTS
Experiments with a large number of aldehydes showed that salicylaldehyde was the most suitable for the selective precipitation of hydrazine; it was also established
TABLE I
ANALYSES OF HYDRAZINE-MONOMETHYLHYDRAZINE MIXTURES
Found (%) Theoretical (%) Difference (%)
N2H4 MMH N2H4 MMH N2H4 MMH
82.5 15.9 82.5 15.9 0.0 0.0
57.1 41.2 57.6 41.3 -0.5 -0.1
51.9 46.9 52.2 46.8 -0.3 +0.1
30.7 68.3 30.5 68.9 +0.2 -o.6 23.2 76.6 22.8 77.3 +04 -0.7 17.6 81.4 18.o 81.7 -0.4 -0.3
TABLE II
ANALYSES OF HYDRAZINE-DIMETHYLHYDRAZINE MIXTURES
Found (%) Theoretical (%) Difference (%) N2H4 UDMH N2H4 UDMH N2H4 UDMH
71.0 27.8 71.2 27.6 -0.2 +0.2 50.9 47.7 50.5 48.1. +0.4 -0.4 45.2 54.4 45.3 54.1 -0.1 +0.3 31.3 66.6 31.8 67.1 -0.5 -0.5
Anal. Chim. Ada, 48 (1969) 87-91
90 H. E. MALONE, D. M. W. ANDERSON
that only i ml of salicylaldehyde was required for the conditions described in Methods A and B.
Series of test mixtures of (a) hydrazine with MMH and (b) hydrazine with UDMH were prepared and analysed by Methods A and B. The results obtained are shown in Tables I and II respectively.
Table III shows the results obtained for all three components in test mixtures by Method C.
TABLE III
ANALYSES OF HYDRAZINE-MMH-UDMH MIXTURES
Found (%)
Theoretical (%)
Difference (%)
N2H4 MMH UDMI-]
N2H4 MMH UDMH
N2H4 MMH UDMH
35.9 32.5 29.8 36.9 31.9 29.1 -1.0 +0.6 +07 36.8 30.8 28.9 37.6 30.9 29.3 —o.8 —o.i -0.4
DISCUSSION
Alternative analytical procedures for the reactions described here are possible. For example, in the determinations depending on the selective precipitation of one or more components, the precipitate could be filtered directly into the vessel used for the determination of MMH. The % hydrazine could also be determined gravimetrically as the azine; since this is soluble in chloroform, the titration could alternatively be conducted directly, without a filtration stage, by adding excess (5o ml) of chloroform. Unfortunately, the azine gives a yellow chloroform layer; the authors prefer to re-move the azine precipitate by filtration. After this is done, the determination of MMH and UDMH (in the ternary mixture case) can be conducted potentiometrically, provided that the platinum—calomel electrode system is not coated by the azine nor by excess salicylaldehyde; rapid titration (I,. 10 mm) within the temperature range _50 to
+5° is necessary to prevent side-reactions from occurring between potassium iodate and UDMH".
The well-known disadvantages of methods in which one component is found by difference apply here to the determination of the monomethylhydrazine present. Ammonia and aniline are common impurities in commercial hydrazine; nitrosodi-methylamine, dimethylamine and other compounds are found 5 in MMH and UDMH.
We thank the Olin Corporation, New Haven, Conn., and the F.M.C. Corpora-tion, Princeton, N.J. for providing quantities of hydrazine, monomethylhydrazine, and i ,i-dimethylhydrazine. We acknowledge the award of an American Air Force Systems Command Study Fellowship (to H.E.M.) which allowed these studies to be carried out in the University of Edinburgh.
SUMMARY
Admixtures of hydrazine and monomethylhydrazine (MMH) and of hydrazine with i,i-dimethylhydrazine (UDMH) can be analysed by a titrimetric method in which
Anal. Chim. Ada, 48 (1969) 87-91
THE ANALYSIS OF HYDRAZINE MIXTURES 91
two aliquots are titrated with potassium iodate: (a) directly to determine the sum of the hydrazines present, and (b) to determine the MMH or UDMH after selective reac-tion of the hydrazine with salicylaldehyde. For ternary mixtures, three aliquots are required: the sum of the hydrazines is determined with potassium iodate; the sum of MMH and UDMH is found after selective reaction of the hydrazine present with sali-cylaldehyde; and the UDMH content is obtained by non-aqueous solvent titrimetry after reaction of both hydrazine and MMH with acetic anhydride in dioxane.
RESUME
Des mélanges d'hydiazine et de monométhylhydrazine (MMH), d'hydrazine et de i,i-diméthylhydrazine (UDMH) peuvent être analyses par dosage titrimétrique. Cette méthode consiste a titrer deux parties aliquotes a l'aide d'iodate de potassium: (a) directement pour determiner le total des hydrazines présentes et (b) pour deter-miner MMH ou DDMH après reaction selective de l'hydrazine avec la salicylaldéhyde. Pour des mélanges ternaires trois parties aliquotes sont nécessaires: le total des hydrazines est déterminé par iodate de potassium; la somme MMH +UDMH est obtenue après reaction selective de l'hydrazine avec salicylaldéhyde; enf in la teneur en UDMH est mesurée par titrage en milieu non aqueux après reaction de l'hydrazine et de MMH avec anhydride acétique dans le dioxane.
ZUSAMMENFASSUNG
Mischungen von Hydrazin und Monomethyihydrazin (MMH) und von Hydra-zin mit i,i-Dimethylhydrazin(UDMH) konnen massanalytisch bestimmt werden. Dabei werden zwei aliquote Teile mit Kaliumjodat titriert und zwar wird zunächst die Summe der vorhandenen Hydrazine bestimmt und dann das MMH oder UDMH nach selektiver Reaktion des Hydrazins mit Salizylaldehyd. Bei ternären Mischungen wird zunächst die Summer der Hydrazine mit Kaliumjodat bestimmt, dann MMH und UDMH nach Reaktion des Hydrazins mit Salizyaldehyd und schliesslich der 1.JDMH-Gehalt durch Titration in nichtwassrigem Losungsmittel nach Reakt ion sowohl von Hydrazin als auch MMH mit Essigsaureanhydrid in Dioxan.
REFERENCES
i J. D. CLARK AND J. R. SMITH, Anal. Chem., 33 (1961) 1186. 2 H. E. MALONE, Anal. Chem,, 33 (1961) 575.
H. E. MALONE AND R. BARRON, Anal. Chem., 37 (1965) 548. H. E. MALONE AND R. BARRON, SSO-TRD 62-41, AFRPL, Edwards, Calif. H. H. MALONE AND R. BIGGERS, Anal. Chem., 36 (1964) 1037.
6 H. E. MALONE AND D. M. W. ANDERSON, Anal. Chim. Acta, 47 (1969) 363. N. SEREECHA, J. G. HANNA AND E. KIJCHAR, Anal. Chem., 37 (1965) 1116.
8 R. M. JONES, Anal. Chem., 38 (1966) 338.
9 L. A. DEE AND A. K. WEBB, Anal. Chem. , 39 (1967) 1165. io G. S. JAMIESON, Am. J. Sci., 33 (1912) 352. ii W. R. MCBRIDE AND H. W. KRUSE, Navord Project 5263 (NOTS 1475-1956).
Anal. Chins. Acta, 48 (1969) 87-91
Anal ylica Chimica Ada 363 Elsevier Publishing Company, Amsterdam Printed in The Netherlands
An acid-base-isocyanate method for the analysis of admixtures of hydrazi ne with 1,1 -di methyl hyd razine, and monomethyl hyd razine with 1,1-dimethylhydrazine
Hydrazine and its derivatives are now used extensively as rocket fuels, in fuel cells, and in a wide variety of industrial processes. A gas-evolution method for the determination of milligram amounts of hydrazines has recently been described', together with a brief review of the other methods of analysis available.
Mixtures of hydrazine with its methyl derivatives are, however, now commonly used; chemical and instrumental methods of analysis for such mixtures have been described27, including a differential reaction-rate acetylation method 8 and, most recently, a proton magnetic resonance method 9 . Rapid, chemical methods offer many advantages, however, e.g. for field investigations, and this communication describes a useful differential reaction-rate method in which either phenylisocyanate or naphthylisocyanate can be used.
In alcoholic solution, with ethanolic hydrochloric acid as titrant, hydrazine (N2H4), monomethylhydrazine (MMH), and I,i-dimethylhydrazine (UDMH) all react with isocyanates at about the same rate to form semicarbazides. In anhydrous acetic acid, however, N21 14 and MMH react rapidly (MMH slightly slower than N2H 4) with isocyanates, but UDMH does not react appreciably in less than 2 h at room temperature.
Reactions The experimental procedure is based on the reaction of N2114, MMH, and
UDMH with either phenylisocyanate or naphthylisocyana,te (R.NCO) to give the
Anal. Chisn. Ada, 47 (1969) 363-366
364 SHORT COMMUNICATIONS
semicarbazjdes NHI .NH.CO.NH.R, CHrNHNHCONH•R, and (CH3)2•N•NH.00.- NH•R respectively. In acetic acid, the rate of formation of the latter is very slow.
Preparation of sample By pipette, add the mixture of hydrazines (0.4 ml) to a tared volumetric flask
(50 ml) containing about 30 ml of anhydrous acetic acid; obtain the sample weight by difference. Make up to the mark with the acetic acid and mix carefully.
Determination of total hydrazines Add an aliquot (5.00 ml) of the mixture of hydrazines to a 50-ml beaker
containing 20 ml of a mixture of acetic acid and dioxan (i : i). Add 4 drops of quinaldine red indicator, 0.2% in acetonitrile. Titrate to a colourless end-point with o.I N perchloric acid in dioxan to obtain titre "A". Titrate a blank for the reagents and indicator to obtain titre "a".
Determination of i,I-dimethylhydrcizine Add an aliquot (5.00 ml) of the mixture of hydrazines to a 50-ml beaker
containing 20 ml of the acetic acid—dioxan mixture and i ml of either naphthyliso-cyanate or phenylisocyanate. (Use 2 ml for MMH/UDMH mixtures.) Set aside for 30 mm (a white precipitate forms). Add 4 drops of the quinaldine red indicator, and titrate to a colourless end-point to obtain titre "B". By titrating a blank similarly, obtain titre "b".
Calculations
%N2114 (or MMH) = (A—a)—(B—b)NHC1O4•3.2o (or 4.60)
to (sample weight)
%UDMH = (B - b) N HCI04 6.oi
io (sample weight)
Results and discussion The effect of time and of the isocyanate concentration on the reactions is
TABLE I
EFFECT OF TIME ON THE REACTION OF VARIOUS HYORAZINES WITH pHENYLIs0cYANATE (1.0 nil) AT 19 °
Time (min) ml HC104 (o.i N) used
For N2H4 For MMH For UDMH
7.90° 5.00° 7.10°
5 0.26 1.90 7.10 15 0.19 1.19 7.08 30 0.15 1.05 7.09
45 o.16 0.77 7.10 6o 0.18 0.70 7.08
75 0.17 0.30 7.05
a Without phenylisoCyanate.
Anal. Chim. Ac/a, 47 (1969) 363-366
SHORT COMMUNICATIONS 365
shown in Tables I and II. At least 0.4 ml of phenylisocyanate and a reaction time Of 15 min must be used for the effective 0.04 ml of hydrazine used here. For MMH, however, 2 nil of the isocyanate and 30 min reaction time is required; UDMH gives no significant reaction under these conditions. After 3 h at 19° , however, white crystals of i,i-dimethylphenylsemicarbazide begin to form, but the reaction solutions are still basic after 18 h.
TABLE II
EFFECT OF VARIOUS CONCENTRATIONS OF PHENYLISOCYANATE
Plienyliso- cyanate (ml)
ml HC104 (o.i N) used
For N2H4 For MMH For UDMH
0.0 8.2o 5.06 7.05 0.2 3.00 2.05 7.05 0.4 0.17 1.25 7.05 o.6 o.18 0.75 7.05 0.8 0.14 o.8o 7.03 1.0 0.21 0.55 7.00 2.0 - 0.10 7.00 3.0 - o.o6 -
a 20-40 min allowed for the reactions at 19 °
Water affects the analysis of hydrazines with isocyanates by causing the end-point of quinaldine red (red to colourless) to revert to red. The reason for this is shown in the equations below; hydrolysis of the isocyanate gives the amine which eventually reacts with sufficient isocyanate to give a substituted urea derivative.
R•NCO+H20 - R•NH CO2 H ---> R•NH2+CO2 (i)
R•NH2+R•NCO - R•NHCO•NHR (2)
The water content of the acetic acid can be reduced satisfactorily by the molecular-sieve technique 3 . Acetic anhydride cannot be used since it reacts 9 with N2H4 and MMH; it can, however, be added as required during the titration of UDMH. Potas-sium cyanate, potassium cyanide, lead thiocyanate, phenyl and methyl isothiocya-nates give no reaction with N 2H4 , MMH, or UDMH in acetic acid media.
TABLE III
ANALYSIS OF N1H4/UDMH ADMIXTURES
Experimental (%)
N2H4 UDMH
Theoretical (%)
N1H4 UDMH
Variation (%)
N2H4 UDMH
82.4 13.9 82.6 14.0 +0.2 +0.1
74.0 23.6 73.4 23.5 -o.6 -o.i 64.7 32.6 65.1 32.2 +04 +04 60.1 37.6 59.6 37.9 -0.5 +0.3 54.1 44.0 53.6 44.3 -0.5 +0.3 48.9 49.4 48.4 49.6 -0.5 +0.2 42.5 55.8 42.2 56.0 -0.3 +0.2 32.7 66.o 32.0 66.7 -0.7 +07 20.2 78.5 19.5 79.0 -0.7 +0.5
Anal. Chim. Ada, 47 (1969) 363-366
366 SHORT COMMUNICATIONS
TABLE IV
ANALYSIS OF MMH/UDMH ADMIXTURES
Experimental (%) Theoretical (%) Variation (%)
MMH UDMH MMH UDMH MMH UDMH
76.1 23.7 76.8 23.2 +0.7 -0.5 85.6 13.6 85.8 14.2 +0.2 +0.6 11.2 88.7 ,o.8 89.2 -0.4 +0.5 25.5 74.0 25.8 74.2 +0.3 +0.2 47.0 52.4 47.5 52.4 +0.5 0.0 51.4 47.5 51.8 471 +0.4 -0.4
A series of mixtures of N 2H4/UDMH and MMH/UDMH were prepared for test analyses; the results are shown in Tables III and IV.
For industrial-grade hydrazines, greater accuracy can be obtained if the "contaminant titration values" for each of the hydrazines is known. MALONE AND
BIGGERS 9 reported contaminant titration values of 0.20, 0.12, and 0.04 ml for N2 114 ,
MMH, and UDMH respectively; these are corrections for any impurities in N 2H4 and MMH which behave similarly to another hydrazine (UDMH) and vice-versa.
We thank the Olin Corporation, New Haven, Conn., and the Food Machinery Chemical Corporation, Princeton, N.J., for providing hydrazine, monomethyl-hydrazine, and i,i-dimethylhydrazine. We acknowledge the award of an Air Force Systems Command Study Fellowship (to H. E. M.).
Department of Chemistry, H. E. MALONE*
The University, D. M. W. ANDERSON
Edinburgh EH9 3JJ (Scotland)
i C. P. LLOYD AND W. F. PIcKERING, Talanta, 16 (1969) 532. 2 H. E. MALONE, Anal. Chem., 33 (1961) 575. 3 E. BURNS AND E. LAWLER, Anal. Chem., 35 (1963) 802.
N. SERENCHA, J. G. HANNA AND E. KUCHAR, Anal. Chem., 37 (1965) 1116 . 5 H. M. JONES, Anal. Chem., 38 (1966) 338. 6 L. A. DEE AND A. K. WEBB, Anal. Chem., 39 (1967)1165. 7 A. F. WEED, J. E. ZAREMBO AND L. H. DIAMOND, Analytical Me/hod CA-io6, Food Machinery
and Chem. Corpn., May 1960. 8 J. C. MACDONALD, Anal. Chim. Ac/a, 44 (1969) 391. 9 H. E. MALONE AND R. A. BIGGERS, Anal. Chem., 36 (1964) 1037.
(Received May 20th, 1969)
* Permanent address: Air Force Rocket Propulsion Laboratory, Edwards, Calif. (U.S.A.)
Anal. Chim. Ac/a, 47 (1969) 363-366
ABSTRACT OF THESIS
Name of of Cadjdate ........ H EcPiiard .a1 one .
Address ....... 41 LancasterCa..forn.a4 ....U.SA.
Degree...................................................................................................Date ary74
Title of Thesis ... !°!... y H..y...d..r..a...z..i..n..e... ..C..o...m..p...o..u..n...d..s.. ...a..n..d... ..T.....e.. Use of Hydrazine as an Analytical Reagent
The versatility of using 1H4 as an analytical reagent haó been demonstrated. High purity NA is simple to use. Although hygroscopic and highly reactive with strong oxidizers, It can be safely used and Is a powerful tool as a reducing agent and as a basic agent.
Complete references for the analysis of bydrazino compounds by oxidation methods and acid-base methods are presented,
Viethods for determination of 2H4/U1U and 2t4/ 1}/UTh have been presented. The method used potassium iodate as a titrant to determine the total hydrazine content before and after salicylaldehyde was used to selectively precipitate hydrazine from the mixtures. For all three hydrazines, the above lodate-aldehyde method was incorporated with a non-aqueous titration method.
Ron-aqueous titration methods for determination of 2ILDI and /Ui are presented. The methods are based on the selective reaction of 2H4 and with phenylisocyanate and naphthyl$socyanato; UDH did not react appreciably in less than 2 h. at room temperature.
51; 1gn.-aqueous titration methods for determination of various a1dehyde, an Isocyanates and isothiocyanatos are presented. An excess of N H 4 is allowed to react with the functional group and the unreacted H 4 reagent is titrated with perchloric acid.
Pon-aquous titration methods for determination of phenylisocyanate and phenylisothiocyanate are presented. The method is based on the reaction of 024 with phenylisocyanato and phenylisothiocyanato in alcoholic cedium using alcoholic HC1 as a titrant; UPH4 is essentially unreactive with phenylisothlo- cyanate in dioxana medium using perchloric acid. By Incorporating two titratlons, two solvents and two titrants, methods for the mixtures were developed.
New ideas are presented for analyzing hydrazines and for using hydrazine to determine other compounds. Aldehydes are reacted with hydrazine to produce precipitates. Based on this reaction, methods for hydrazinos and aldehydes could be developed.
L Hydrazines, amines, dlainines, triamines and tetranines reacted with dinitro, trinitro and dinitro compounds containing chlorine and fluorine groups to produce highly colored compounds. Proper selection of the dinitro compounds would allow detection procedures for hydrazines and amines to be developed. Further work In this area could result in air pollution detection methods for hydrazines and amines.
Use other side if necessary.