Acidic properties of propyl sulfonic acid functionalized SBA-15 catalysts for acetylation of glycerol

Abstract

Glycerol, a by-product of biodiesel production through transesterification, presents an opportunity for biodiesel industries to transform surplus glycerol into high-value chemical products. This study focuses on the development of a series of propyl sulfonic acid functionalized (PrSO3H) SBA-15 catalysts, synthesized by direct synthesis of 3-mercaptopropyltrimethoxysilane (MPTMS) and tetraethoxysilane (TEOS) in an acidic medium. The catalysts were evaluated for acetylation of glycerol with acetic acid under conditions optimized through response surface methodology. Among the catalysts tested, the direct-synthesized PrSO3H-SBA-15 catalyst with a 20 % MPTMS/(MPTMS + TEOS) ratio exhibited the highest amount Brønsted acid sites, resulting in a complete glycerol conversion level and 30.1 % triacetin selectivity. Notably, the catalysts maintained its conversion over three consecutive reaction runs without a significant reduction in glycerol conversion level.