Comparison of protonated zeolites with various dimensionalities for the liquid phase alkylation of i-butane with 2-butene

Abstract

This study focused on the effects of structure on the catalytic performance of various three-, two-, and one-dimensional zeolites. The alkylation of isobutane with 2-butene was carried out under both mild and severe conditions with respect to the feed flow rate. It was observed that zeolite beta outperformed the other zeolites, exhibiting high olefin conversion and alkylate selectivity. For the olefin WHSV used in this work, LTL and USY deactivated rapidly. It is proposed that their fast deactivation was a result of the periodic expansions of their respective pore structures. In contrast to the behavior of other zeolites, the C-8 selectivities almost remained high and constant over LTL. The one-dimensional ZSM-12 was found to outperform in terms of activity many of the samples in this study because of its unique pore structure. A study of the carbonaceous material formed inside the zeolites pores discovered that their composition also depended on the zeolite pore structure. The results of this study indicate that the ability of certain zeolites to inhibit the formation of coke precursors because of their particular pore structures is an important parameter.