(473d) Reaction Kinetics of the Diels-Alder Cycloaddition of Dimethylfuran and Ethylene for Renewable p-Xylene

Diels-Alder cycloaddition of dimethylfuran (DMF) and ethylene to produce p-xylene is a promising method of sustainably producing valuble plastic precursors [1,2].  This step completes the entire process of (a) glucose dehydration to hydroxymethylfurfural (HMF), (b) reduction of HMF to dimethylfuran, and (c) cycloaddition/dehydration of DMF to p-xylene. The DMF/ethylene reaction proceeds via two steps: a symmetry-allowed [4+2] Diels-Alder cycloaddition of DMF and ethylene to produce an oxa-norborene cycloadduct intermediate, and subsequent dehydration of the intermediate to form p-xylene.  In this work, the kinetics of the combined cycloaddition/dehydration chemistry was experimentally evaluated, and the rate-limiting phenomena were identified. The apparent activation energy for the formation of Diels-Alder products from DMF and ethylene was experimentally measured as 17±3 kcal/mole using DMF in heptane with an H-Y catalyst in the temperature range of 200-250^oC.  Research also focused on characterizing the effects of catalyst loading and determining reaction orders with respect to DMF, ethylene and p-xylene.

References

[1]  Williams, C. L.; Chang, C.-chih; Do, P.; Nikbin, N.; Caratzoulas, S.; Vlachos, D. G.; Lobo, R. F.; Fan, W.; Dauenhauer, P. J. ACS Catalysis 2012, 2, 935-939

[2] N. Nikbin, P.T. Do, S. Caratzoulas, R.F. Lobo, P.J. Dauenhauer, D.G. Vlachos, "A DFT study of the acid-catalyzed conversion of 2,5-dimethylfuran and ethylene to p-xylene," Journal of Catalysis, 2013, 297, 35-43