Graphite Oxide-Catalyzed Esterification and Transesterification

Graphite oxide (GO) was involved in the esterification of carboxylic acids with alcohols or phenols and the transesterification of esters with alcohols. Three types of GO prepared by different methods were screened and GO by modified Hummers method was found superior to the others. The esterification of primary and secondary alcohols afforded the corresponding esters in moderate to excellent yields under mild conditions. GO-catalyzed esterification of tertiary alcohols and phenols took place hardly. Moreover, GO showed highly catalytic activity for the transesterification. As a weakly acidic solid catalyst, GO is easily available, cheap, environmentally benign, and well tolerant to various functional groups. Only catalyzed by GO, the esterification of long-chain carboxylic acids and the transesterification of the glycerol ester of long-chain carboxylic acids underwent steadily. As such, GO-catalyzed esterification and transesterification could be used in the biodiesel preparation potentially.