Aldehydes, Ketones and Carboxylic Acids
Carbonyl Group – Nomenclature and Structure
Nomenclature
In the IUPAC system, aliphatic carboxylic acids are named as follows:
-
By replacing the ending ‘− e’ in the name of the corresponding alkane with ‘− oic acid’
-
Carboxylic carbon is numbered one.
-
If more than one carboxyl groups are present, then the ending ‘− e’ of the alkane is retained.
-
The number of carboxyl groups is indicated by adding prefix, di, tri, etc. to the term ‘oic’.
The given table lists the common and IUPAC names and structures of some carboxylic acids.
Names and Structures of Some Carboxylic Acids
-
Structure
Common name
IUPAC name
HCOOH
Formic acid
Methanoic acid
CH3COOH
Acetic acid
Ethanoic acid
CH3CH2COOH
Propionic acid
Propanoic acid
CH3CH2CH2COOH
Butyric acid
Butanoic acid
(CH3)2CHCOOH
Isobutyric acid
2-Methylpropanoic acid
HOOC-COOH
Oxalic acid
Ethanedioic acid
HOOC −CH2-COOH
Malonic acid
Propanedioic acid
HOOC -(CH2)2-COOH
Succinic acid
Butanedioic acid
HOOC -(CH2)3-COOH
Glutaric acid
Pentanedioic acid
HOOC -(CH2)4-COOH
Adipic acid
Hexanedioic acid
HOOC -CH2-CH(COOH)-CH2-COOH
−
Propane-1, 2, 3-
tricarboxylic acid
Benzoic acid
Benzenecarboxylic acid
(Benzoic acid)
Phenylacetic acid
2-Phenylethanoic acid
Phthalic acid
Benzene-1, 2-dicarboxylic
acid
Structure of Carboxyl Group
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Carboxyl carbon is less electrophilic than carbonyl carbon because of resonance.
-
Bonds to the carboxyl carbon lie in one plane and are separated by about 120°.
Methods of Preparation of Carboxylic Acid
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From primary alcohols
-
From aldehydes
Oxidising agents − HNO3, KMnO4, K2Cr2O7 and mild oxidising agents as well like Tollen’s reagent and Fehling’s reagent.
-
From alkyl benzenes
-
1° and 2° alkyl benzene are oxidised in this manner.
-
Tertiary group is not affected.
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From nitriles and amides
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From Grignard reagents
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From acyl halides
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From acid anhydrides
-
From esters
-
Ester Carboxylic acid + Alcohol
Example:
Examples:
Nomenclature
In the IUPAC system, aliphatic carboxylic acids are named as follows:
-
By replacing the ending ‘− e’ in the name of the corresponding alkane with ‘− oic acid’
-
Carboxylic carbon is numbered one.
-
If more than one carboxyl groups are present, then the ending ‘− e’ of the alkane is retained.
-
The number of carboxyl groups is indicated by adding prefix, di, tri, etc. to the term ‘oic’.
The given table lists the common and IUPAC names and structures of some carboxylic acids.
Names and Structures of Some Carboxylic Acids
-
Structure
Common name
IUPAC name
HCOOH
Formic acid
Methanoic acid
CH3COOH
Acetic acid
Ethanoic acid
CH3CH2COOH
Propionic acid
Propanoic acid
CH3CH2CH2COOH
Butyric acid
Butanoic acid
(CH3)2CHCOOH
Isobutyric acid
2-Methylpropanoi…
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