Abstract: Butene-2 oligomerization was performed in a continuous flow fixed-bed reactor. Several zeolite catalysts with different acidity and textural properties were investigated in order to show the effects of acidity and pore size on the catalyst activity and selectivity for butene-2 oligomerization. A solid phosphorous acid catalyst was included as comparison. The acidity and pore size of various zeolites are important factors that influence the catalyst activity and selectivity for higher olefins in oligomerization. The zeolite with an 8-membered ring system shows low activity because of the strong diffusion resistance to butene-2. The zeolite with an 12-membered ring system lessens the diffusion limitation and results in a higher activity at lower temperature. As for the zeolites with a 10-membered ring system, the pore size and strong acidity improve the catalyst activity and selectivity for higher olefins further. Compared with the solid phosphorous acid catalyst with C=9+selectivity of less than 30%, the zeolite catalysts, such as ZSM-5, ZSM-22, and β with 10- and 12-membered ring systems and with strong acid sites, show C=9+selectivity of more than 50%, which indicates the better catalytic performance of the zeolite catalysts.

Key words: zeolite catalyst, pore size, acidity, butene, oligomerization, higher olefin