12-Tungstophosphoric acid supported on MCM-41 for esterification of fatty acid under solvent-free condition

The potential of supported 12-tungstophosphoric acid (HPW) is of great importance as acid catalyst. Therefore, a series solid acid catalysts, comprised of 10–50 wt.% HPW supported on MCM-41 were synthesized and characterized using XRD, FT-IR, BET and TEM. The catalytic activities of these catalysts were tested for esterification of lauric acid with butanol using Dean-Strak apparatus, under solvent-free conditions. The host material suffers severe structural distortions at higher loading, which lead to a considerable loss of long-range orders. Based on these experimental findings, the optimal conversion of lauric acid with loading of 30 wt.% HPW was found to be higher than other loading and bulk HPW. The reaction was also studied over commercially available liquid acid, such as sulfuric acid and p -toluene sulfonic acid. It is assumed that the reaction mainly occurs inside the mesopores of the partially distorted MCM-41 because HPW loaded on an as-synthesized catalyst shows lower conversion than that of calcined material.