Epoxidation of cyclohexene on Ti/SiO2 catalysts prepared by chemical grafting TiCl4 on deboronated silica xerogel

Ti/SiO2 (or Ti/de[B]SiO2) catalysts were prepared by grafting deboronated s ilica xerogel with gaseous TiCl4. Using TBHP as oxidant, the Ti/de[B]SiO2 c atalyst shows both catalytic activity and selectivity in epoxidation of cyc lohexene better than 80%, and the activity can be comparable with that of T i-beta. The catalytic activity of Ti/de[B]SiO2 strongly depends on the cont ent of B of support precursor, and the pretreatment temperature of the supp ort. IR studies show that the sites in the deboronated silica xerogel to re act with TiCl4 are not only the silanol nests, but also the defect sites pr oduced during the deboronation. (C) 2001 Elsevier Science B.V. All rights r eserved.