Effect of reaction substrates on membrane-assisted transesterification reactions

Abstract

Zeolite membranes are promising for the assistance of transesterification reactions, but the effects of the reaction conditions have not been fully clarified. In this study, the membrane-assisted transesterification of several methyl esters and alcohols was examined to investigate the influence of the substrates on the conversion and methanol permeation. The conversion of methyl hexanoate was 55.0% without a membrane when reacted with 1-hexanol at 353 K. When the methanol byproduct was removed using an FAU-type zeolite membrane, the conversion increased to 79.6%. A large increase in conversion was also obtained using substrates with long linear alkyl chains. The highest conversion among the 18 transesterification reactions was obtained when methyl hexanoate was reacted with 1-hexanol. These results suggest that the reaction substrates influence the boiling point of the solution and the vapor-phase methanol concentration. Additionally, the effect of temperature and feed concentration on the methanol permeation performance was evaluated for the FAU-type zeolite membrane by pervaporation to discuss their influence on the conversion. Higher reaction temperatures were favorable for membrane-assisted transesterification because more methanol was removed by the membrane. This suggests that controlling the vapor-phase methanol concentration is significant for membrane-assisted transesterification reactions.