Mixed titanium/silicon oxides modified by organosilicon groups, useful as catalysts in the preparation of epoxides from alkenes

摘要

Mixed oxide of titanium and silicon of a mesoporous structure, with attached halogen atoms and alkoxide groups. Mixed oxide of titanium and silicon of a mesoporous structure, with attached halogen atoms and alkoxide groups. The mixed oxides are represented by the formula (I). Halogen atoms, X, and alkoxide groups OR' are fixed at the surface by M-X and M-OR' bonds, where M is Si or Ti and R' is alkyl or aryl. The porous vol, V p is 0.2- 3 cm 3>/g, and surface area, SBET is 100- 1500 m 2>/g. The product is homogeneous on the micronic scale and contains Si-O-Si bonds. (TiO 2)(SiO 2) x(R uSiO 2-(u/2)) y (I) x : greater than 2 and less than 100; u : 0-4; x+y : greater than 3; y : greater than 0.1 and less than 100; R : alkyl, aryl or a divalent arylene or alkylene group joining 2 Si atoms Independent claims are also included for: (1) preparation of the oxides; and (2) epoxidation of olefins.