Esters - Structure and Nomenclature

In this article we will discuss about Structure and Nomenclature of Esters. They are important functional group compounds in organic chemistry. 

Esters are chemical compounds in organic chemistry. They are derived from carboxylic acid compounds. Here we will learn Common Nomenclature and IUPAC Nomenclature of ester compounds.

Key words: Esters, Common Nomenclature, IUPAC Nomenclature, Carboxylic acids. 

Introduction

The esters are organic compounds which consist of an alkyl / aryl group and one alkoxy group bonded to a carbonyl group. The esters are the derivatives of carboxylic acids and has general formula R-COOR’; where R and R’ = alkyl / aryl group.

Common Nomenclature

The ester compounds are named by writing two words; first is alkyl / aryl group and second is the carboxylic acid from which the ester compound formed. Also “-ic acid” form the carboxylic acid is replaced by suffix “ate”.

For example:

Compound 1 is derived from the carboxylic acid known as acetic acid and there is ethyl group bonded to oxygen. Therefore common name of the ester is ethyl acetate.

Common names of some ester compounds are shown in Table 1

Structure	Name of carboxylic acid	Alkyl / aryl group	Name of ester
	Propionic acid	methyl	Methyl propionate
	Propionic acid	ethyl	Ethyl propionate
	Butyric acid	phenyl	Phenyl butyrate
	Benzoic acid	ethyl	ethyl benzoate
	Cyclohexayl carboxylic acid	propyl	propyl cyclohexylcarboxylate
	Butyric acid	cyclohexyl	Cyclohexyl butyrate

Table 1

IUPAC Nomenclature

In similar way to common nomenclature system; IUPAC names of carboxylic ester compounds are assigned from the name of carboxylic acids. Let’s consider compound 1 again it is made up of acetic acid. The IUPAC name of acetic acid is ethanoic acid, therefore name of ester compound 1 is ethyl ethanoate.

Common names of some ester compounds are shown in Table 2

Structure	Name of carboxylic acid	Alkyl / aryl group	Name of ester
	Ethanoic acid	butyl	butyl ethanoate
	Pentanoic acid	methyl	methyl pentanoate
	Benzene carboxylic acid	propyl	Propyl benzene carboxylate
	Butanoic acid	benzyl	Benzyl butanoate
	Cyclopropane carboxylic acid	ethyl	ethyl cyclopropane carboxylate
	Pentanoic acid	cyclopentyl	cyclopentyl pentanoate

Table 2

Examples for practice:

That's all for this topic. If you have any questions please feel free to ask me in the comment box. Thank you..!