Propylene Epoxidation to Propylene Oxide Over RuO2, CuO, TeO2, and TiO2 Supported on Modified Mesoporous Silicas

Direct gas phase epoxidation of propylene to propylene oxide (PO) using O(2) is a challenging problem in catalysis research. Silica-supported ruthenium-copper-based catalysts have been recently reported to be promising for propylene epoxidation. In this work, mesoporous silica supports modified with RuO(2), CuO, and TeO(2) with and without TiO(2) were investigated for propylene epoxidation to PO. The prepared catalysts were divided into two groups. The first group consisted of mesoporous silica supports modified with RuO(2), CuO, and TeO(2), and the second group consisted of the same components as the first group but adding TiO(2). The prepared supports and catalysts were characterized using BET surface area analysis and other advanced instrument techniques. It was found that the catalyst made with RuO(2) and TeO(2) impregnated onto porous silica modified with CuO and TiO(2) (denoted as RuTe/CuTiSi) exhibited an excellent PO formation of 344 gPO h(-1) kg(-1)cat, which was superior to that of the other prepared catalysts. Moreover, the addition of TiO(2) into the catalyst greatly improved the PO formation rate and the arrangement of active components in the catalyst and strongly influenced catalytic performance.