Application of pervaporation in the bio-production of glycerol carbonate

Glycerol carbonate is a platform molecule with a large range of applications. It can be synthesized from glycerol by transesterification with dimethyl carbonate, which is considered a bio-based path of synthesis since glycerol is originated during the production of biodiesel. The purification of the reaction products is quite challenging and costly using conventional separation technology, since methanol (by-product) and dimethyl carbonate (in excess) form an azeotropic mixture. In this work, pervaporation is presented as a technological alternative to separate the multicomponent mixture composed of methanol, glycerol, dimethyl carbonate and glycerol carbonate, i.e reactants and products of the reaction of synthesis of glycerol carbonate. The separation performance of four commercial membranes namely PERVAP 1255-30, PERVAP 4155-40, PERVAP 1255-50, PERVAP 4155-80 from Sulzer Chemtech, Switzerland, was evaluated. The effect of temperature (30 °C, 45 °C, and 60 °C ± 2 °C) on the separation performance was also studied in terms of transmembrane flux, separation factor, permeance and selectivity. Results show that the membranes reject glycerol and glycerol carbonate completely (not detected in the permeate), and permeate methanol and dimethyl carbonate, with higher selectivity for methanol. In addition, the performance of pervaporation separation was compared with that obtained by distillation via the McCabe-Thiele diagram, showing the technical advantage of pervaporation.