ZSM-5 zeolite prodn. from sources of silica, alumina and alkali metal - ethanol, water and ZSM-5 crystal seed, avoiding organic base

摘要

A zeolite of the ZSM-5 type is prepd. from a reaction mixt. contg. a source of SiO2, a source of Al2O3, a source of alkali metal ethanol, water, and previously synthesised ZSM-5 zeolite crystals, by (a) dispersing a precise amt. of 0.002-0.03% of ZSM-5 seed, based on the total wt. of SiO2 to be used, in deionised water, and dividing the suspension into two almost equal portions, (b) adding about half of the seed suspension from step (a) to an Al salt, e.g. Al2(SO4)3 or Na aluminate, (c) adding the other half of the seed suspension to a source of SiO2, e.g. Na silicate, (d) combining the suspensions from (b) and (c), (e) adding ethanol and 98%H2SO4, in predetermined amts., to form a gel, (f) homogenising the gel by mechanical stirring for 20 mins., (g) subjecting the gel to hydrothermal conversion in an autoclave, at 135-180 deg. C, under autogenous pressure, for 1-5 days, and (h) recovering the ZSM-5 zeolite.