ZEOLITIC CATALYST FOR THE SELECTIVE CONVERSION OF HYDROCARBONS AND PROCESS FOR PREPARING THE SAME

摘要

The invention relates to a zeolitic catalyst having a ZSM-5 type structure, for the selective conversion of hydrocarbons, comprising zeolite, zinc or zinc and cobalt on a silica carrier with a content of modified zeolite ranging from 0.1 to 4 %, preferably 0.5 to 2 %. The catalyst is prepared by adding a solution of sodium silicate at a temperature ranging from 45 to 50 degree C onto a sulphuric acid solution of a concentration ranging from 20 to 25 %. The resulting silica hydrosol is ripened for 2.3 to 3 h. and then the silica hydrogel is settled with an ammonia solution of a concentration ranging from 12.5 to 25 %. The silica powder resulting by atomization is homogenized at the room temperature, with the ZSM-type zeolite modified with zinc or cobalt to a zeolite-silica ratio value ranging from 1 to 4.