Maximum synergistic effect in the coupling conversion of bio-derived furans and methanol over ZSM-5 for enhancing aromatic production

Abstract

We firstly propose the coupling conversion of bio-derived furans and methanol over ZSM-5 for enhancing aromatic production. The coupling conversion of bio-derived furans and methanol was conducted in a continuous fixed bed reactor. 2-Methylfuran (MF) was used as a probe molecule to identify the possible reaction pathways. The effects of the methanol to MF molar ratio, reaction temperature and weight hourly space velocity (WHSV) on the product distribution from the coupling conversion of MF and methanol were investigated. The experimental results showed that the aromatic yield from the coupling conversion of MF and methanol is about 5.2 times higher than that of the catalytic fast pyrolysis of only MF. In addition, it can also enhance the yield of olefins, the selectivity of xylenes and reduce coke formation. These results indicate that there is a significant synergistic effect between MF and methanol. The synergistic effect could be attributed to the methanol-to-olefins reactions, the Diels–Alder reactions of furans with olefins, and the alkylation reaction of benzene/toluene with methanol occurring during the coupling conversion of MF and methanol. The reaction conditions for maximizing the synergistic effect were a methanol to MF molar ratio of 2 at 550 °C. Moreover, the comparative study of the coupling conversion of different bio-derived furans (MF, 2,5-dimethylfuran (DMF), furfural (FF) and furfuryl alcohol (FA)) and methanol were also considered in this study. The coupling conversion of DMF and methanol exhibited maximum yields of aromatics, olefins and a minimum yield of coke, suggesting that DMF is the best candidate of bio-derived furans for aromatic production in the coupling conversion of bio-derived furans and methanol.