Tungstophosphoric acid-based mesoporous materials anchored to MCM-41: characterization and catalytic performance in esterification of levulinic acid with ethanol

Abstract

MCM-41 was synthesized with a non-hydrothermal procedure and then used to assemble a series of supported H3PW12O40 (HPW) mesoporous catalysts. The optimization of the reaction conditions for LA esterification with ethanol, such as the reaction temperature, reaction time, the reactant molar ratio and the catalyst dosages was performed to maximize the conversion of LA over 25 wt% HPW/MCM-41 catalysts. The catalytic performance of the resultant HPW/MCM-41 catalysts was investigated. The results show that these catalysts retain the hexagonal phase of MCM-41 and the Keggin characteristic of HPW. Although their textural parameters decrease with increasing HPW loading, these catalysts still exhibit much higher specific surface area and pore volume (SBET ≥ 446 m2 g−1, VP ≥ 0.345 cm3 g−1) than that of HPW (SBET = 5 m2 g−1, VP = 0.010 cm3 g−1). LA conversion increases with increasing HPW loading and the value may reach up to 83.7 % over 45 wt% HPW/MCM-41 under the present conditions. The resultant ethyl levulinate is promising in reducing the consumption of petroleum-derived fossil fuels.