Preparation of β-zeolite mixed catalysts using alumina and titania matrices modified by silication of gel skeletal reinforcement and their reactivity for catalytic cracking of n-dodecane

Novel alumina and titania modified by silica in surface were prepared by applying the gel skeletal reinforcement (GSR) method using hexamethyldisiloxane-acetic anhydride system to alumina-gel and titania-gel formed by the sol-gel method. When NH3-TPD of silica-modified alumina was measured, it was confirmed that new acid sites were observed in the high temperature range from 400 degrees C to 600 degrees C. Regarding silica-modified titania, the thermal stability of the anatase phase was observed in the calcination at 600 degrees C for 3 h, and the complex oxides with different physical properties were prepared. The mixed catalysts with these silica-modified alumina and titania and beta-zeolite were prepared, and their reactivity in catalytic cracking of n-dodecane was investigated using a fixed bed reactor at 500 degrees C. beta-zeolite-GSR-silica-modified alumina mixed catalysts was found to have higher conversion and improved gasoline fraction selectivity compared to the cases with the use of beta-zeolite single and alumina without GSR modification.