Diels-Alder cycloaddition of biomass-derived 2-methylfuran and ethylene provides a thermochemical pathway to renewable toluene. In this work, the kinetics and reaction pathways of toluene formation have been evaluated with H-BEA and Sn-BEA catalysts. Kinetic analysis of the main reaction chemistries reveals the existence of two rate-controlling reactions: (i) Diels-Alder cycloaddition of 2-methylfuran and ethylene where the production rate is independent of the Brønsted acid site concentration, and (ii) dehydration of the Diels-Alder cycloadduct where the production rate is dependent on the Brønsted acid site concentration. Application of a reduced kinetic model supports the interplay of these two regimes with the highest concentration of toluene measured at a catalyst loading equal to the transition region between the two kinetic regimes. Selectivity to toluene never exceeded 46%, as 2-methylfuran was consumed by several newly identified reactions to side products, including dimerization of 2-methylfuran, the formation of a trimer following hydrolysis and ring-opening of 2-methylfuran, and the incomplete dehydration of the Diels-Alder cycloadduct of 2-methylfuran and ethylene.
Bibliographical noteFunding Information:
Financial support was provided from the Catalysis Center for Energy Innovation , a U.S. Department of Energy – Energy Frontiers Research Center (www.efrc.udel.edu) under Award DE-SC0001004 . This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 .