Synthesis of MCM-36 Molecular Seive and Studies on Catalytic Performance of MCM-36 on Benzene Alkylation with Propylene

Pillared layered MCM-36 zeolites were prepared from MCM-22 and MCM-49 precursors with polymeric silica as the pillaring agent, respectively. The structure and acid properties of samples were studied by means of N2 adsorption, XRD, and FTIR. A higher BET specific surface area and a significant mesopore volume is obtained for MCM-36(A). The amount of Brnsted and Lewis acid sites in MCM-36(A) decreases obviously compared to MCM-22 resulting from the same precursor. For MCM-36(B) synthesized from MCM-49 precursor, the intensity of low angle XRD peak is lower than that of MCM-36(A), and the amount of acid sites decreases moderately compared to MCM-49. Under our operation conditions, the MCM-36(A) zeolite shows a higher activity and selectivity to cumene than MCM-22 zeolite. MCM-36(B) exhibits a higher activity but lower selectivity to cumene compared to MCM-36(A). Combined with the characterization results of acidic properties and textural parameters, we suppose that the increase of the selectivity to cumene in MCM-36 should be mainly due to the decrease of the density of Brnsted acidity, while the improvement of the catalytic activity of MCM-36 can be mainly assigned to the presence of a larger amount of structurally accessible acid sites in this material.