Hierarchically Ordered Porous Solid Acid: Preparation and Application as a Biodiesel Catalyst

Abstract

Acid‐catalyzed esterification of high fatty acid content feedstocks with methanol is an efficient way to prepare biodiesel. In this work, using the dual template method combining the colloidal crystal template and the porogen, a series of hierarchical ordered porous weak cross‐linked polystyrene solid acid catalysts with high mass transfer efficiency and high acid density were successfully prepared. This catalyst displayed stronger acid strength and better swelling properties. The specific surface area of the obtained catalyst is 32 m2 ⋅ g−1, and its acid value reaches 4.11 mmol ⋅ g−1. The effect of the hierarchical porous structure and swelling on the access to the catalytic sites were illuminated. Acid‐catalyzed reactions showed that hierarchically ordered porous cross‐linked polystyrene solid acid catalyst was more active (the efficiency of the esterification of oleic acid and methanol was up to 93.67 %) than Amberlyst‐15 catalyst.

In situ impregnation of cobalt‐doped tungstophosphoric acid on MOF‐801 toward enhanced catalytic activity for esterification

“…As could be seen, the LA conversion was enhanced from 76.5% to 86.3% as the substrate molar ratio of methanol/LA increased from 10:1 to 20:1. As the molar ratio further increased to 30:1, the conversion of LA seemed to be slightly decreased, which is possibly caused by the dilution effect of excessive methanol, which led to reducing the frequency of collisions 48 . Therefore, by carefully inspecting the substrate molar ratio, 20:1 was selected as the optimal the molar ratio of methanol/LA in the present study.…”

“…As the molar ratio further increased to 30:1, the conversion of LA seemed to be slightly decreased, which is possibly caused by the dilution effect of excessive methanol, which led to reducing the frequency of collisions. 48 Therefore, by carefully inspecting the substrate molar ratio, 20:1 was selected as the optimal the molar ratio of methanol/LA in the present study. Therefore, the optimized esterification reaction conditions performed by a single-variable experiment are catalyst amount of 0.15 g, methanol/LA molar ratio of 20:1, time of 4 h, and temperature of 100 C affording 86.3% LA conversion to methyl laurate.…”