Preparation and Characterization of Supported Molybdenum and Tungsten Schiff Base Complexes on MCM-41 as Nanocatalysts for the Epoxidation of Olefins

Abstract

Two new heterogenized epoxidation nanocatalysts based on molybdenum and tungsten compounds were prepared withcovalent grafting of MCM-41 with 3-aminoropropyl trimethoxysilane and subsequent reaction with diphenylphosphinobenzaldehyde and complexation with M (Mo, W)O2(acac)2. X-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properties of the support as well as accessibility of the channel system despite sequential reduction in surface area, pore volume and pore size. Elemental analyses showed the presence of 0.15 mmol molybdenum and 0.09 mmol tungsten per gram of the catalyst, respectively. Epoxidation of olefins in the presence of M (Mo,W)O2dppb@AmpMCM-41 with tert-butyl hydroperoxide (TBHP) and hydrogen peroxide were examined.