High-performance liquid chromatography of esters of aliphatic and aromatic carboxylic acids

Abstract

Chromatographic elution data for 29 aliphatic and aromatic carboxylic acids methyl esters, dicarboxylate acids dimethyl esters and esters of acetic acid with different alcohols have been determined, using silica gel as the stationary phases. Twelve mobile phases containing n-heptane and/or diethyl ether, 2-propanol and chloroform at different concentrations were used. The analysis of methyl esters of diamantane and adamantane carboxylic acids under the same conditions is discussed and a survey is given of the chromatographic behaviour of 60 compounds. Among all the compounds tested, esters having two functional groups have a longer retention time than esters having only one COOCH 3 group. The effects of molecular structure on the chromaographic behaviour are discussed, namely the length of the alkyl chain of the acids, the length of the alkyl chain of the alcohol and the influence of unsubstituted and substituted aromatic rings. A relationship between the measured compounds and polycyclic derivatives has been established. The effects of mobile phase composition on the elution data for the compounds studied are discussed.