carboxylic acids and their derivatives by: dr. shatha alaqeel
TRANSCRIPT
Carboxylic Acids and Their Derivatives
By:
Dr. Shatha Alaqeel
2
Structure Of Carboxylic AcidsStructure Of Carboxylic Acids
Carboxylic acids are organic acids contain one or more carboxyl group
A carboxyl group is made up of a carbonyl (C=O) group and a hydroxyl (O-H) group
It is often written in condensed form as –CO2H or –COOH
The general formula of a carboxylic acid is R-COOH or Ar-COOH
Nomenclature of Carboxylic Acid
General formula: R-COOH or Ar-COOH
In the IUPAC: Find the longest continuous carbon chain contains the COOH group to Find the longest continuous carbon chain contains the COOH group to get the root name of the parent hydrocarbon, then replace the ending get the root name of the parent hydrocarbon, then replace the ending -e-e by the suffix by the suffix –oic –oic acidacid..
Number the chain starting with the carbon of COOH group as C-1Number the chain starting with the carbon of COOH group as C-1
If there are substituents identify their names, positions and list them as prefixes in If there are substituents identify their names, positions and list them as prefixes in alphabetical orderalphabetical order..
common Formic acid Acetic acid Propionic acid Butyric acid Valeric acid
IUPAC Methanoic acid Ethanoic acid Propanoic acid Butanoic acid Pentanoic acid
C
O
H OH CH3 C
O
OH C2H5 C
O
OH C3H7 C
O
OH C4H9 C
O
OH
In common : the position of the carbons present on the acid chain, are located by the Greek letters αα indicating the carbon indicating the carbon
atom next to COOH group (C2), atom next to COOH group (C2), ββ (C3), (C3), γγ (C4), (C4), δδ (C5), etc (C5), etc. .
In IUPAC: The carboxylic carbon is numbered 1.
common: -- Dimethyl butyric acid
IUPAC: 2,3-Dimethyl butanoic acid
CH3
COOH
CH3
CH3
5
Cyclic compounds containing one or more COOH groups attached to the ring are Cyclic compounds containing one or more COOH groups attached to the ring are named by identifying the name of the ring followed by the word carboxylic acid or named by identifying the name of the ring followed by the word carboxylic acid or dicarboxylic aciddicarboxylic acidss etc. The etc. The carbon atom bearing the carboxylic group is numbered 1carbon atom bearing the carboxylic group is numbered 1 and the substituents are numbered relative to itand the substituents are numbered relative to it..
COOH
HOOC
COOH
HOOC
Cyclopropane Cyclobutane Cyclopentane Cyclohexane Carboxylic acid Carboxylic acid Carboxylic acid Carboxylic acid
COOHCOOH
COOHCOOH
NH2Cl
2-Isopropyl-cyclobutanecarboxylic acid
3-Amino-cyclohexanecarboxylic acid
Br
2-Bromo-4-chloro-cyclopentanecarboxylic acid
Cyclopropanecarboxylic acidCH(CH3)2
commoncommon Benzoic acid Salicylic acid
IUPACIUPAC Benzene carboxylic acid 2-Hydroxybenzenecarboxylic acid
commoncommon Phethalic acid Terephtalic acid
IUPACIUPAC Benzene-1,2-dicarboxylic acid Benzene-1,4-dicarboxylic acid
COOH COOH
OH
COOH
COOH
COOH
COOH
Some aromatic compounds have common names accepted by the Some aromatic compounds have common names accepted by the IUPACIUPAC also they also they Can be named aCan be named as benzene carboxylic acidss benzene carboxylic acids
Physical Properties OF Carboxylic Acids
SolubilitySolubility
Carboxylic acids are Carboxylic acids are polar, polar, they can form hydrogen bonds with water moleculesthey can form hydrogen bonds with water molecules
Smaller carboxylic acids (1 to 4 carbons) are soluble in waterSmaller carboxylic acids (1 to 4 carbons) are soluble in water
Whereas the solubility of bigger carboxylic acids decrease with sizeWhereas the solubility of bigger carboxylic acids decrease with size
Aromatic acids are insoluble in waterAromatic acids are insoluble in water
RC
O
O
H
O
H
H
H
O
H
H-Bonds
The boiling points of carboxylic acids indicate a greater degree than alcohols
This is due to carboxylic acids usually exist as dimeric pairs by forming two This is due to carboxylic acids usually exist as dimeric pairs by forming two intramolecular hydrogen bonds in nonpolar media intramolecular hydrogen bonds in nonpolar media
Boiling Boiling PointsPoints
H3C CO
O H O
H OC CH3
Hydrogen bond
Carboxylic acids are the most acidic simple organic compounds (they are Carboxylic acids are the most acidic simple organic compounds (they are stronger acids by over ten powers of ten compared to alcohols of comparable stronger acids by over ten powers of ten compared to alcohols of comparable weights); also they are more acidic than phenols weights); also they are more acidic than phenols
However, they are weak acids compared to inorganic acids (HCl or HHowever, they are weak acids compared to inorganic acids (HCl or H22SOSO44))
Adjacent Adjacent electron withdrawing electron withdrawing substituents substituents nearnear the carboxyl group the carboxyl group increase increase the the acidity acidity
Whereas Whereas electron donating electron donating substituents substituents decrease decrease the aciditythe acidity. .
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HCOOHHCOOH >> CHCH33COOHCOOH >> CHCH33CHCH22COOHCOOH >> CHCH33CHCH22CHCH22CHCH22COOHCOOH ( size of R ( size of R
group)group)
Cl3CCOOH > Cl2CHCOOH > ClCH2COOH > CH3COOH > (OCH3)CH2COOH
) )number of e.w.g. and e.d. gnumber of e.w.g. and e.d. g(.(.
CH3CH2CH2CH(Cl)COOH > CH3CH2CH(Cl)CH2COOH > CH3CH(Cl)CH2CH2COOH > CH2(Cl)CH2CH2CH2COOH ( position of e.w.g. ( position of e.w.g.
relative to COOH group)relative to COOH group)> > > >
COOH
NO2O2N
COOH
NO2
COOH COOH COOH
Acidity And Acid Strength
11 - -Oxidation Of Primary AlcoholsOxidation Of Primary Alcohols
22 - -Oxidation Of Alkyl BenzenesOxidation Of Alkyl Benzenes
Preparation Of Carboxylic acids
33 - -Carbonation Of Grignard ReagentsCarbonation Of Grignard Reagents
44 - -Hydrolysis Of NitrilesHydrolysis Of Nitriles
H2O
H2O
Reactions of Carboxylic Acids1- Salts Formation
RCOOH
KOH or NaOHRCOO
-K
+ or Na
+ + H2O
NaHCO3 RCOO-Na
+
+ CO2 H2O+
NH3 RCOO-NH4
+
COOH
OH
+
+
NaHCO3
NaHCO3
COO-Na
+
N . R
Sodium Benzoate
2- Substitution of hydroxyl group
RCOOH
R'OH / H+
NH3
SOCl2
1) PCl52) R''COO
-Na
+
RCOOR'
RCONH2
RCOCl
RCOOCOR"
Ester
Amide
Acid Chloride
Anhydride
Carboxylic Acid Derivatives
R C
O
Cl
R C
O
OR'
R C
O
N
R C
O
O C
O
R'
Acid Chloride Ester Amide acid anhydride
1-Nomenclature of acid chloride�ٌ Replacing the –ic acid ending of the parent acid by –yl chloride:
Ethanoyl chloride Benzoyl chloride Acetyl chloride
CH3 C
O
Cl
C
O
Cl
2- Nomenclature of esters
The alkyl group (R’) is named first followed by the name of the parent acid with the ending –ate in place –ic acid:
Ethyl ethanoate Methyl benzoate Ethyl acetate
CH3 C
O
OC2H5
C
O
OCH3
3- Nomenclature of amide
Replacing the ending oic acid of the parent acid’s by amide
Ethanamide Benzamide
Acetamide
N,N-Dimethylmethamide N-Ethyl-N-methylbenzamide
N,N-Dimethylformamide
CH3 C
O
NH2
C
O
NH2
H C
O
NCH3
CH3
C
O
NCH3
CH3
4- Nomenclature of anhydride
An anhydride is named by replacing the word acid by anhydride.
Ethanoic anhydride Benzoic anhydide Succinic anhydride
CH3 C
O
O C
O
CH3C
O
O C
O
O OO
Reaction of Esters
R C
O
OR'
+ OH2 R C
O
OH
+ R'OHH
+
R C
O
OR'
+ R''OH R C
O
OR"
+ R'OHH
+
R C
O
OR'
+ NH3 R C
O
NH2
+ R'OHH
+
R C
O
OR'
R CH2 OH + R'OH1) LiAlH4
2) H3O+
R C
O
OR'
R C OH
R"
R"
+ R'OH1) Dry ether
2) H3O++ 2 R"MgX
Acid Chlorides: Reactions
R C
O
Cl+
OH2 R C
O
OH
+ ClH
R'OH R C
O
OR'+ ClH
NH3 R C
O
NH2
+ ClH
NH2R' R C
O
NHR'
+ ClH
R C
O
1) LiAlH4
2) H3O+ R CH2OH
AlCl3 + ClH
Acid anhydride: Reactions
+
OH2 R C
O
OH
+ R'COOH
R'OH R C
O
OR'+ R'COOH
NH3 R C
O
NH2
+ R'COOH
NH2R' R C
O
NHR'
+ R'COOH
R C
O
1) LiAlH4
2) H3O+ R CH2OH
AlCl3 + R'COOH
R C
O
O C
O
R'
+ R'CH2OH
Reactions of Amides
R C
O
NH2
H3O+
R C
O
OH+ NH3
R C
O
NH2
NaOH/ heatR C
O
ONa+ NH3
R C
O
NH2
1) LiAlH4R CH2 NH2
2) H3O+
R C
O
NHR'
1) LiAlH4R CH2 NHR'
2) H3O+
R C
O
NH2
P2O5R C N
- H2O
R C
O
NH2
Br2 / NaOHR NH2
or NaOBr