Synthesis, Characterization and Catalytic Activity of a New Chromium Catalyst Supported on Nanoporous MCM-41 for Oxidation of Olefins and Alkyl Aromatics

The mesoporous molecular sieve MCM-41 was covalently grafted with 3-chloropropyl trimethoxylsilane and then was reacted with [Cr(salpr)(H2O)]Cl, (salpr = N,N'-bis(3-salicylidenaminopropyl)amine) to afford MCM-41 containing Cr(salpr) moiety, Cr(salpr)MCM-41. Powder X-ray diffraction and nitrogen adsorption-desorption analyses revealed that not only the textural characteristics of the support were preserved during the grafting experiments but also the channels remained accessible despite sequential reduction in surface area, pore volume and pore size. The chromium content of the prepared catalyst was 0.57 mmol.g-1. The chromium-containing MCM-41 was shown to successfully catalyze the epoxidation of 1-hexene, 1-octene, cyclohexene, cyclooctene, trans-stilbene and norbornene and also benzylic oxidation of toluene and ethyl benzene with tert-butylhydroperoxide (TBHP).