Mechanism study of aromatics production from furans with methanol over zeolite catalysts

摘要

In this paper, we study the production of aromatic hydrocarbons by co-feeding furans and methanol in a continuous flow fixed-bed reactor over HZSM-5 at 400-600 degrees C. The effects of reaction temperature, weight hourly space velocity (WHSV), furan to methanol molar ratio and time on stream on the product distribution were investigated. Maximum aromatics yield of 42.0% was obtained over HZSM-5 (Si/Al = 25) with 2-methylfuran (MF) to methanol molar ratio of 1:5 at 500 degrees C. With the methanol to MF molar ratio increasing from 0 to 5, the conversion of MF increased from 64.7% to 100.0% and the yield of coke decreased from 22.3% to 11.4%. In this process, dimethyl ether derived from methanol dehydration could promote the conversion of MF to aromatic hydrocarbons via Diels-Alder reaction. HZSM-5 with Si/Al ratio of 25 exhibited superior catalytic activity, indicating that strong acidity was necessary for the coupling conversion of MF and methanol. Additionally, the coupling conversions of 2,5-dimethylfuran (DMF), furfural (FF) and furfuryl alcohol (FA) and methanol were investigated. Functional groups of furan rings did not change the formation pathway of aromatic hydrocarbons but they have different constraints on the Diels-Alder reaction of furan ring with olefins.