Simultaneous recrystallization and post-synthesis of MCM-49 zeolite by TEAOH/piperidine: Implication on the acidity and catalytic alkylation performance

Abstract

Incompletely crystallized MCM-49 was recrystallized and post-synthesized in tetraethylammonium hydroxide solution with piperidine as a protective and structure-directing agent. The morphology of post-synthesized MCM-49 has been tailored from rose-like shape to small MWW sheets packed disorderly. The surface areas have been improved from 387 m2 g−1 (parent MCM-49) to 475 m2 g−1 (TPMP-16) and 492 m2 g−1 (TPMC-16). The number of total acid sites determined by Py-FTIR has been enhanced significantly from 464 μmol g−1 (parent MCM-49) to 873 μmol g−1 (H-TPMP-16) and 780 μmol g−1 (H-TPMC-16). Importantly, post-synthesized catalysts showed superior ethylene conversion and ethylbenzene selectivity during liquid-phase alkylation of benzene with ethylene.