Production of biodiesel through transesterification of soybean oil using lithium orthosilicate solid catalyst

This study synthesized biodiesel from soybean oil using transesterification over a lithium orthosilicate (Li4SiO4) catalyst. Under the optimal reaction condition of a methanol/oil molar ratio of 18:1, a 6% (wt/wt oil) catalyst amount, and a reaction at 65 °C for 2 h, the conversion to biodiesel could achieve 98.1%. The catalyst was prepared using a solid-state reaction. Li4SiO4 can be used directly for biodiesel production without being further dried or thermal pretreated, avoiding the usual activation of solid catalysts at high temperature. The effects of the methanol/oil ratio, catalyst amounts, reaction time and reaction temperature on the conversion are also reported in this paper. The solid base catalyst was highly active, air‐insensitive and can be reused for at least ten cycles without loss of activity. The catalysts were characterized using XRD, SEM-EDS, FTIR, TGA-DTA, and the Hammett indicator method.