"Ab initio" synthesis of zeolites for preestablished catalytic reactions

Abstract

Unlike homogeneous catalysts that are often designed for particular reactions, zeolites are heterogeneous catalysts that are explored and optimized in a heuristic fashion. We present a methodology for synthesizing active and selective zeolites by using organic structure-directing agents that mimic the transition state (TS) of preestablished reactions to be catalyzed. In these zeolites, the pores and cavities could be generated approaching a molecular-recognition pattern. For disproportionation of toluene and isomerization of ethylbenzene into xylenes, the TSs are larger than the reaction products. Zeolite ITQ-27 showed high disproportionation activity, and ITQ-64 showed high selectivity for the desired para and ortho isomers. For the case of a product and TS of similar size, we synthesized a catalyst, MIT-1, for the isomerization of endo-dicyclopentane into adamantane. ; This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the " Severo Ochoa Program " (grant SEV 2012-0267). The Electron Microscopy Service of the Universitat Politècnica de València (UPV) is acknowledged for help with sample characterization. The Red Española de Supercomputación (RES) and Centre de Càlcul de la Universitat de València are gratefully acknowledged for computational facilities and technical assistance. E.M.G. acknowledges " La Caixa – Severo Ochoa " International Ph.D. Fellowship (call 2015). We thank I. Millet for technical assistance and V. J. Margarit and Á. Cantín for helpful discussions.