Production of targeted aromatics by using Diels–Alder classes of reactions with furans and olefins over ZSM-5

Abstract

In this paper we study the co-feeding of olefins (ethylene and propylene) with a series of furanic compounds (furan, 2-methylfuran, furfural, and furfuryl alcohol) over ZSM-5 catalyst in a continuous flow fixed-bed reactor at a temperature range of 450–600 °C. We show the importance of Diels–Alder cycloaddition reactions when olefins are co-fed with furanics over ZSM-5. Co-feeding propylene with furan (C₄ diene) increased the toluene aromatic selectivity from 22% to 59%. Similarly, co-feeding propylene with 2-methylfuran (C₅ diene) increased the xylenes aromatic selectivity from 9% to 27%. Co-feeding of ethylene with furans did not change the aromatics selectivity. The increase of toluene selectivity was also observed in the co-feeding of propylene with furfural and fufuryl alcohol. Furfural and furfuryl alcohol both underwent decarbonylation reactions to produce CO and furan. The reaction conditions that maximize Diels–Alder products were a propylene to 2MF molar ratio of 1 at 450 °C. Increasing the temperature to 600 °C increased the selectivity of benzene, toluene and CO. Decreasing the temperature to 300 °C increased the coke yield and decreased the xylene yield. The xylene selectivity went through a maximum at a propylene to 2-methylfuran molar ratio of 1 : 1.