Post Synthetically Functionalized SBA-15 with Organosulfonic Acid and Sulfated Zirconia for Esterification of Glycerol to Monoglyceride

The pore structural properties and catalytic activity of SBA-15 post synthetically functionalized with organo sulfonic acid and with sulfated zirconia are presented. The SBA-15 incorporated with 3-(mercaptopropyl) trimethoxysilane (MPTMS) was prepared by post synthesis-grafting. Mild oxidation was carried out to obtain an acid catalyst (HSO3SBA-15). Whilst SBA-15 immobilized with sulfated zirconia was prepared by reacting SBA-15 with solution of zirconiumoxychloride and urea at 90°C to ZrO2-SBA-15. SZSBA-15 acid catalyst was obtained by sulfation of the ZrO2-SBA-15 with H2SO4 solution at room temperature. The catalysts were characterized by surface area analysis, EDX, SEM, Fourier transform infrared (FTIR) spectroscopy and pulse chemisorptions of NH3, followed by TPD of NH3. The organo sulfonic acid functionalized SBA-15 catalysts (HSO3SBA-15) were found to be more efficient solid acid catalysts for the esterification of glycerol with lauric acid to monolaurin at 160°C for 6 h using molar ratio of fatty acid to glycerol of 1:4. Excellent lauric acid conversion (94%) with high selectivity to monolaurin (70%) can be achieved using organo sulfonic acid functionalized SBA-15 catalyst with preparation condition of 20 h reflux time and MPTMS amount of 1 mL g-1 SBA-15.