Cerium(IV) impregnated TiZrO4/SO42− for selective glycerol valorization into diacetin
摘要
The Ce/TiZrO4@SO42− synthesised using the co-precipitation method has been used similarly to a heterogeneous acid catalyst in the esterification of glycerol with acetic acid to formulate diacetin as an exclusive product. The results of XRD and FTIR support the sulphate group anchoring over TiZrO4 matrix, which creates both Lewis and Brønsted acidic sites, onto the catalyst surface. The FE-SEM and TEM images of the catalyst show that the crystallite size is ~ 15 nm to indicate that the particles of the catalyst have a nanostructure. The total acid sites of the catalyst have been estimated by the temperature programmed desorption (TPD) analysis and found to be 8.15 mmol g−1. The XPS study confirms the presence of Ce4+, Ti4+ and Zr4+ coordinated with the sulphate group on the surface of the catalyst. The Ce/TiZrO4@SO42− catalyst yielded diacetin (96% selectivity) within 60 min by employing acetic acid to glycerol in 6:1 ratio (mol/mol) at 120 °C. The recovered catalyst has been successfully reused five times while retaining ~ 36% activity in the last run.