Abstract: Amphiphilic TMS-Hβ, TMS-HY, and TMS-HZSM-5 zeolite samples were prepared by modification of the surface of their parent zeolites with trimethylchlorosilane (TMS). X-ray diffraction, infrared spectroscopy, water adsorption, and titration experiments were used to characterize the surface properties of these modified samples. The modification results by TMS were different on these three zeolites. TMS molecules only covered the external surface of the HZSM-5 zeolite, while part of TMS entered the channels of the Hβ and HY zeolites and even partly destroyed the framework of HY. The amphiphilic TMS-HZSM-5 and TMS-Hβ zeolites exhibited catalytic activity for hydrolysis of isoamyl acetate obviously superior to their parent zeolites. The stability of the alkylsilane on the zeolite surface had an effect on the phase-boundary catalytic performance of the amphiphilic zeolites. TMS molecules covered on TMS-Hβ were more stable than that covered on TMS-HZSM-5. Thus, the TMS-Hβ zeolite maintained its amphiphilic properties at a higher reaction temperature and exhibited a higher phase-boundary catalytic activity than the TMS-HZSM-5 zeolite.

Key words: H&beta, zeolite, HY zeolite, HZSM-5 zeolite, amphiphilic zeolite, trimethylchlorosilane, phase-boundary catalysis, isoamyl acetate, hydrolysis, 3-methyl-1