Hierarchically structured monolithic silicalite-1 consisting of crystallized nanoparticles and its performance in the Beckmann rearrangement of cyclohexanone oxime.

Wen-Cui Li, An-Hui Lu, Regina Palkovits, Wolfgang Schmidt, Bernd Spliethoff, Ferdi Schüth

Index: J. Am. Chem. Soc. 127(36) , 12595-600, (2005)

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Abstract

In this study, we present a synthetic pathway for the fabrication of self-supporting zeolite monoliths consisting of crystallized nanoparticles. A resorcinol-formaldehyde-based organic aerogel is used as a template, and silicalite-1 is used as the zeolite example. The silicalite-1 monoliths obtained consist of individual well-defined zeolite nanocrystals with sizes of 30-40 nm. The monoliths exhibit a high mechanical stability and have hierarchical porosity, with micropores within the zeolite particles, a mesopore system formed by the packing of the nanoparticles, and a macropore system on the monolith level. Such monolithic zeolites show high selectivity typically above 80% to epsilon-caprolactam combined with a high rate of reaction of 0.46 g(caprolactame)/(g(catalyst).h) in the Beckmann rearrangement of cyclohexanone oxime.