Selective monoesterification of dicarboxylic acids catalysed by ion-exchange resins
Symmetrical dicarboxylic acids with 4–14 carbon atoms gave selectively the corresponding monoesters in high yields in the transesterification catalysed by strongly acidic ion-exchange resins in ester–hydrocarbon mixtures. It was found that the rate of the esterification of the dicarboxylic acids is much higher than that of the monocarboxylic acids formed. This result can explain the high selectivity for the monoester formation and can also be explained by the existence of an aqueous layer on the surface of the resins. This method of selective esterification is quite simple and practical.