关键词: 甲醇, 丙烯, 乙烯, MTP, 副产物

Abstract: Abstract: The yields of aromatics, C1-C4 paraffins and ethylene at varying space time and at methanol partial pressure of 20 kPa in co-reaction of methanol and butene, pentene or hexene were investigated over H-ZSM-5 catalyst in an isotherm fixed-bed reactor at 460℃. For each feed, the CH2 mass ratio of alkenes to methanol was 4. It was found that each yield of aromatics and individual C2-C4 paraffins showed liner dependence on space time while ethylene yield increased slowly with space time up to thermodynamic equilibrium. It was also found that at constant space time each yield of aromatics, individual C2-C4 paraffins and ethylene did not rely on the feed composition. Only slight dependence of mass fraction on the feed composition was observed for propylene, C4, C5 and C6, respectively. These results indicate that in co-reaction of methanol and butene, pentene or hexene, a mixture of C3=-C6= with relatively steady distribution is first formed through the methylation of C4=-C6= followed by the cracking of C6= and C7=. Ethylene is formed subsequently through oligomerization and cracking of the C3=-C6= mixture to reach thermodynamic equilibrium composition. Aromatic products, mainly toluene, xylenes and tri-methylbenzenes, are suggested to be formed through aromatization of C7 and C8 olefins along with the formation of paraffins through hydrogen transfer reactions.

Key words: methanol, propylene, ethylene, MTP, by-product