Synthesis of Al-BEC zeolite as an efficient catalyst for the alkylation of benzene with 1-dodecene

Abstract

A novel quaternary ammonium hydroxide, p-Xylylene-bis(N-methylpiperidinium hydroxide) (XBMPOH), was prepared and used as an organic structure-directing agent (OSDA) for the syntheses of BEC zeolites. Both Si,Ge-BEC and Al incorporated BEC (Al-BEC) zeolites were successfully synthesized. In comparison with commonly used OSDA (tetraethylammonium hydroxide (TEAOH)), XBMPOH was more suitable for the crystallization of BEC structure, especially in the Al containing system. Al-BEC zeolites were directly synthesized at lower germanium and OSDA content, in a wider (Si + Ge)/Al ratio range (20 to ∞ vs. 50 to ∞) and shorter time (6 h vs. 12 h). For the first time, Al-BEC zeolites were used as a solid acid to catalyze the alkylation of benzene with 1-dodecene, and showed significant catalytic performance. After an acidic treatment procedure, the catalytic performance was further improved due to the removal of non-framework Al with accompanied exposure of framework Al.