MgO–Li2O catalysts templated by a PDMS–PEO comb-like copolymer for transesterification of vegetable oil to biodiesel

Abstract

In this study, MgO–Li2O catalysts were developed for biodiesel synthesis using poly(dimethylsiloxane–ethyleneoxide) PDMS–PEO as a structure-directing agent. The MgO–Li2O catalysts have a three-dimensional interconnected highly porous structure with bimodal pore distribution that enhances the transesterification reaction. Moreover, Li atoms are not accommodated by alternating MgO slabs within the growth regions; thus a Li exsolution is locally generated and gives rise to a unique morphology of hybrid MgO and Mg2SiO4 crystals loaded with the surface Li2O nanoparticles. The dispersed Li2O nanoparticles results in an increases of strong basic sites. We found that the best catalyst of LM0.12-873 (Li/Mg molar ratio=0.12, calcination temperature is 873K) with the largest amount of strong basic sites has better catalytic activity and anti-leaching ability compared with other reported catalysts. The MgO–Li2O catalysts templated by a PDMS–PEO comb-like copolymer have a high potential for use in the large-scale biodiesel production.