THE EFFECT OF ACIDITY OF AL AND FE SILICATES WITH MFI STRUCTURE ON BENZENE AND TOLUENE ALKYLATION WITH ISOPROPYL-ALCOHOL

Kinetic study of toluene and benzene alkylation with isopropyl alcohol on alumo- and ferrisilicates of MFI structure has shown that the alky lation activity does not follow the acidity (both the number and stren gth of bridging OH groups) of these molecular sieves. The rate of the overall reaction is controlled by the desorption/transport rate of bul ky, strongly adsorbed cymenes and cumene. A higher concentration of n- propyltoluenes compared to n-propylbenzene, both undesired reaction pr oducts, formed via a bimolecular isomerization of isopropyl aromate wi th benzene or toluene, was due to the higher reactivity of isopropylto luene with toluene in comparison with that of cumene with benzene. It is concluded that ferrisilicates of MFI structure possessing low stren gth acid sites appear to be promising catalysts for achieving both a h igh isopropyl- and para-selectivity in toluene alkylation to p-cymene.