Methylesters epoxidation catalyzed by novel niobium oxide based materials

The performances of Nb2O5-SiO2 solids, were extensively studied in epoxidation reaction of different olefins with hydrogen peroxide: it was found that the synthesis method and the distribution of surface acid sites strongly affect the catalyst efficiency, because Lewis acid sites promote the epoxidation, but strong Brønsted acid sites promote the reaction of ring epoxide opening by hydrolysis forming diols [1-4]. Epoxidized methyl esters derived by oils are important building blocks for the preparation of chemical intermediates and consumer products, such as plasticizers and stabilizers for PVC, components of lubricants etc. In this work, Nb2O5-SiO2 materials, with different niobium content, are synthesized by sol-gel methodusing niobium chloride, NbCl5 and tetraethoxysilane, Si(OC2H5)4 (TEOS) and Brij® C10 as surfactant template, in order to control the pore size and surface area. These catalysts are studied in epoxidation of methyl oleate with hydrogen peroxide, and their activity was compared with a similar set of the niobium catalysts, without template. A higher activity was found for the catalysts synthesized with the addition of the surfactant, as a consequence of more suitablemorphological properties.