COMPUTER-ASSISTED SCREENING OF ZEOLITE CATALYSTS FOR THE SELECTIVE ISOPROPYLATION OF NAPHTHALENE

Molecular graphics screening of potential zeolite catalysts for the se lective synthesis of 2,6-diisopropylnaphthalene indicated that mordeni te was a promising candidate. Molecular mechanics calculations of the minimum energy pathway for diffusion of the diisopropylnaphthalene iso mers in mordenite showed that significant energy barriers exist for th e 2,7 isomer, while the diffusion of the 2,6 isomer is unimpeded. In t he case of zeolite L, no significant energy barrier was found for eith er isomer. In an experimental study of naphthalene isopropylation in a batch autoclave reactor, mordenite produced a 2,6/2,7 ratio of 2.5, w hile zeolite L was essentially nonselective. The combination of molecu lar graphics and molecular mechanics appears to be a powerful and reli able method for the screening of zeolites for selective catalysis. (C) 1994 Academic Press, Inc.