Chemistry Nomenclature and Structure of Carboxyl Group

Topics Covered :

● Carboxylic Acids
● Nomenclature of Carboxylic Group
● Structure of Carboxylic Group

Carboxylic Acids :

`=>` Carbon compounds containing a carboxyl functional group, `color{red}(–COOH)` are called carboxylic acids.

`=>` The carboxyl group, consists of a carbonyl group attached to a hydroxyl group, hence its name carboxyl.

`=>` Carboxylic acids may be aliphatic `color{red}((RCOOH))` or aromatic `color{red}((ArCOOH))` depending on the group, alkyl or aryl, attached to carboxylic carbon.

`=>` Large number of carboxylic acids are found in nature.

`=>` Some higher members of aliphatic carboxylic acids `color{red}((C_(12) – C_(18)))` known as fatty acids, occur in natural fats as esters of glycerol.

`=>` Carboxylic acids serve as starting material for several other important organic compounds such as anhydrides, esters, acid chlorides, amides, etc.

Nomenclature and Structure of Carboxyl Group :

Nomenclature and structure of carboxyl group is given as follow :

Nomenclature :

`=>` Since carboxylic acids are amongst the earliest organic compounds to be isolated from nature, a large number of them are known by their common names.

`color{green}(text(Common Names :))` The common names end with the suffix `color{red}(–ic)` acid and have been derived from Latin or Greek names of their natural sources.

● `color{green}(text(For example :))` Formic acid `color{red}((HCOOH))` was first obtained from red ants `color{green}(("Latin: formica means ant"))`, acetic acid `color{red}((CH_3COOH))` from vinegar `color{green}(("Latin: acetum, means vinegar"))`, butyric acid `color{red}((CH_3CH_2CH_2COOH))` from rancid butter `color{green}(("Latin: butyrum, means butter"))`.

`color{green}(text(IUPAC Name :))` In the IUPAC system, aliphatic carboxylic acids are named by replacing the ending `color{red}(–e)` in the name of the corresponding alkane with `color{red}(– oic)` acid.

● In numbering the carbon chain, the carboxylic carbon is numbered one.

● For naming compounds containing more than one carboxyl group, the ending `color{red}(–e)` of the alkane is retained.

● The number of carboxyl groups are indicated by adding the multiplicative prefix, di, tri, etc. to the term oic.

● The position of `color{red}(–COOH)` groups are indicated by the arabic numeral before the multiplicative prefix.

● Some of the carboxylic acids along with their common and IUPAC names are listed in Table 12.3.

Structure of Carboxyl Group :

`=>` In carboxylic acids, the bonds to the carboxyl carbon lie in one plane and are separated by about `color{red}(120°)`.

`=>` The carboxylic carbon is less electrophilic than carbonyl carbon because of the possible resonance structure shown in fig.