Kinetics of 2-Methylfuran Acylation with Fatty Acid Anhydrides for Biorenewable Surfactants

Abstract

Friedel-Crafts acylation using long-chain fatty acid derivatives and biomass-derived furans is the key reaction to produce alkyl furan ketones, an important precursor for biorenewable oleo-furan surfactants. In this work, the steady-state acylation kinetics and reaction mechanism were investigated using a model system of 2-methylfuran and n-octanoic anhydride in a fixed-bed tubular reactor using Al-MCM-41, a mesoporous aluminosilicate. An apparent activation energy (15.5 +or- 1.4 kcal mol- 1) was obtained for the formation of the acylated product, 2-octanoyl-5-methylfuran (2O5MF), for a temperature range of 348-408 K. The apparent reaction rate orders were ~0.6 and ~0.5 in the 2-methylfuran and anhydride concentrations, respectively, while near-zero apparent rate orders were measured in the product concentrations, indicating negligible product inhibition. An Eley-Rideal catalytic acylation mechanism was proposed to explain the experimentally observed apparent rate orders.