Inactivation of acid sites on external surface of zeolites with methoxytripropylsilane

The modification of HZSM-5 and H-mordenite zeolites was carried out by a chemical vapor deposition method of silicon alkoxides, e.g. , SiOCH 3 (C 3 H 7 ) 3 and Si(OCH 3 ) 4 . The parent and modified zeolites were characterized by 1,3,5-triisopropylbenzene cracking reaction, IR spectroscopy and o-xylene adsorption measurement. The silanation with SiOCH 3 (C 3 H 7 ) 3 was effective in the selective inactivation of the acid sites on the external surfaces of zeolite. On the other hand, the Si(OCH 3 ) 4 is effective for the controlling of the pore-opening size of zeolite.