DESIGNING ZEOLITE CATALYSTS FOR SIZE AND SHAPE-SELECTIVE REACTIONS

Highly selective catalysts are demanded by both nature and industry. I n nature, catalytic sites which are normally non-selective are made se lective by placing them within a relatively inert protein structure. E mploying silicon-based zeolite frameworks as direct replacements for t his selectivity-directing protein structure, zeolite mimics of natural enzymes can be prepared. In this article, we review some of our work at DuPont on the preparation of hemoglobin, cytochrome P450, and iron- sulfur protein analogues. In addition, the use of this strategy for th e rational design of catalysts for reactions of industrial importance, including selective hydrogenations and aminations, is described.