| Popis: |
The influence of various binders such as silica, alumina and mixture thereof on the physico-chemical properties and catalytic performance in isopropylation of benzene reaction over protonic forms of zeolite beta has been investigated. The physicochemical characteristics of the materials have been determined by powder X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and chemical analyses. The catalyst composite materials with 60 % H/beta and 40 % silica formulated in different shapes such as pressed pellets, cylindrical extrudates and granules (105–150 micron size, obtained by spray drying technique) were examined for their catalytic activity. It has been shown that, H/beta catalyst prepared using amorphous silica as a binder and in the form of pellatized /10–20 mesh crushed granules and spray dried granules were observed to be more active and stable. One important finding of the present study is that, the amorphous silica alumina present in less crystalline beta zeolite obtained during synthesis leads to much faster deactivation and lower cumene selectivity as compared to that of catalyst prepared by embedding fully crystalline H/beta in a comparable quantity of matrix prepared by physically mixing of silica and alumina binders. |
