Alkylation of isobutane with light olefins using mesoporous superacidic catalysts

A new type of solid catalyst for use in alkylation of isobutene has been developed using a mesoporous support, MCM-41 loaded with an organic superacid, trifluoro methanesulfonic acid (triflic acid). The state of the acid in the pores, catalytic activity and characterization has been studied for this catalytic system. The organic acid has been found to exist in an adsorbed state within the support as well as in a "free" form without a significant association with the surface. The activity of the catalyst during alkylation reactions has been found to be much improved over traditional solid acid zeolite catalysts. The mechanism by which the reaction proceeds is consistent with liquid phase reactions invoking carbocation based mechanisms and a relatively new type of reaction, self alkylation, appears to be occurring in the reactions. Isobutene delivers much higher conversion levels compared to the linear butenes due to carbocation stability considerations. 1-butene however yields higher than expected selectivites for octanes compared to 2-butene. This phenomenon has been related to the self alkylation regime. The catalyst possesses very high surface areas but exhibits some structural collapse as a result of the acid loading. Thermal analysis data has also shown that significant coke deposits begin at reaction temperatures above 200C̕