Integration of reaction and separation in pervaporation for enzymatic glycerol carbonate production.

In recent years, green chemistry has been a niche study area in the development of industrial-scale biochemical synthesis and process intensification1. Glycerol carbonate is a non-toxic organic compound that serves as an intermediary in the manufacturing of batteries, surfactants, detergents, and medicinal products2. The process of producing glycerol carbonate, which includes transesterification of glycerol and dimethyl carbonate (DMC), has been chosen as a feasible conversion pathway since it principally produces methanol as a coproduct, which can be selectively separated from the mixture using pervaporation2. However, glycerol carbonate synthesis is not as environmentally safe as we think. There are two processes: the high-temperature reaction (70 – 80o C) is followed by a purification step, which compromises the process's greener character in terms of energy consumption, as an azeotrope methanol/DMC (approximately 30 wt% methanol azeotrope) is produced, resulting in an extremely energy intensive separation3. The separation portion, which involves pervaporation, has already been investigated with the construction of selective membranes using ZIF-8 fillers in chitosan polymer3. The ZIF-8/Chitosan membrane showed selectivity to methanol with a high separation factor and flux for separation of methanol from DMC. But the ZIF-8 is a zinc-centric MOF that forms a weak link with the carboxylic ligands often causing the crystals to disorient making the MOFs unstable4. Therefore, a different set of MOFs, which is zirconium-centric will be analyzed for methanol/DMC separation. The drop in temperature in the process can be addressed by adding enzymes that work at low temperatures (30 – 40o C)5. The goal is to integrate enzymes with methanol-selective membranes in a reactive pervaporation unit. This development will enable more efficient and regulated reactions, boosting the total production of glycerol carbonate and decreasing energy consumption.