Oligomerization of Hex-1-ene over Acidic Aluminosilicate Zeolites, MCM-41, and Silica-Alumian Co-gel Catalysts: A Comparative Study

摘要

Hex-1-ene in octane solvent was oligoemrized in a down-flow tubular reactor holding a fixed catalyst bed at temperatures of 80-300deg C and a pressure of 5 MPa. Ultrastable Y (US-Y), hydrogen beta, and MCM-22 zeolites, MCM-41, silica-alumina and silicamagnesia co-gels, and #gamma#-alumina were evaluated as catalysts. The reaction products obtained are composed of hexene dimers and trimers, cracked products, C_6 alkanes, and isohexenes. The catalytic activity of the mesoporous silica-alumina co-gles an MCM-41 is very similar to that of beta, MCM-22, and US-Y zeolites. Teh oligomerizaiton process occurs in the mesoplores and on the exterior surfaces of hte zeolite crystals. In the micropores of zeolite beta and US-Y, the hexenes undergo dimerizaiton-cracking reactions generating siohexenes and cracked products. In MCM-22, having narower micropores, these creacking reactions are suppressed. MCM-22, MCM-41, and silica-alumina co-gels lacking microporosity are the most selective hexene dimerizaiton catalysts.