Phase-switching Homogeneous Catalysis for Clean Production of Biodiesel and Glycerol from Soybean and Microbial Lipids

With the increasing concerns into the utilization of lipids as renewable resources for production of biofuels, chemicals, and materials, the efficient extraction and conversion of lipid is one of most important issues for the foundation of cost competitive lipid-economy. In this study, we found that by using a range of switchable solvents from 1,8-diazabicyclo[5.4.0]undec-7-ene to methanol, CO2, a recognized greenhouse gas, can be used as a trigger to catalyze the methanolysis of soybean and microbial lipids, and facilitate the separation of fatty acid methyl esters (FAMEs) and glycerol. It was found that the FAMEs can be decanted from the system in a 95.2?% conversion efficiency. The produced glycerol can be extracted from the FAMEs completely by the switchable solvents, and can be separated with high purity after recycling the DBU by an easy extraction process. Our primary investigation of the in situ extraction and conversion of microbial lipids from oleaginous yeast (Rhodosporidium toruloides Y4) shows that, although a 95.4?% extraction yield was achieved, the methanolysis efficiency was only 21.9?%. Our study presents an efficient and facile process for the integrated clean production of biodiesel and glycerol from soybean and microbial lipids, and the catalyst DBU can be recycled by an easy extraction process.