Epoxidation of olefines with PDMS membranes containing zeolite occluded manganese diimine complexes |
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Authors: | P. P. Knops-Gerrits, I. F. J. Vankelecom, E. B atse,P. A. Jacobs |
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Affiliation: | Centrum voor Oppervlaktechemie en Katalyse, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, B-3001, Heverlee, Belgium |
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Abstract: | A new composite catalyst for selective epoxidation of olefins with tert-butyl hydroperoxide (tBHP) is reported. The catalyst contains manganese diimine complexes (cis-Mn bis-2,2′-Bipyridyl), occluded within a NaY zeolite, in turn incorporated in a polydimethylsiloxane membrane (cis-[Mn(bpy)2]2+-NaY-PDMS). The three-step synthesis consists of a Mn2+exchange of NaY, ligand sorption to form cis-[Mn(bpy)2]2+-NaY and incorporation of the latter in a PDMS membrane. The major differences between [Mn(bpy)2]2+-NaY as such and occluded in PDMS are observed in the sorption and catalytic characteristics. With the membrane system, the use of a solvent becomes obsolete. Whereas optimal cyclohexene oxidation with [Mn(bpy)2]2+-NaY occurs with hydrogen peroxide in acetone, tBuOOH proves to be a better oxidant for [Mn(bpy)2]2+-NaY-PDMS. The reactions in batch and fed-batch reactors are discussed. A simple regeneration procedure, monitored by FT-IR spectroscopy is proposed. |
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Keywords: | Oxidation catalysis Manganese complex PDMS Zeolites Peroxides Cyclohexene Styrene |
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