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 ± 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 â0.6 and â0.5 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.
Bibliographical noteFunding Information:
We acknowledge the financial support of the Catalysis Center for Energy Innovation, a U.S. Department of Energy—Energy Frontier Research Center under Grant DE-SC0001004. Parts of this work were carried out in the Characterization Facility (CharFac) at the University of Minnesota and the Minnesota NMR Center. The authors acknowledge Dr. Hanseung Lee at CharFac for performing the scanning electron microscopy experiments and Dr. Gopinath Tata at the NMR Centre for performing the solid-state NMR experiment. The authors also thank ChoongSze Lee and Dr. Matheus Dorneles De Mello for help with Ar physisorption.
© 2020 American Chemical Society.
- chemical kinetics
- oleo-furan surfactants
- reaction mechanism