Journal of Catalysis, Vol.285, No.1, 168-176, 2012
Epoxidation catalysts derived from introduction of titanium centers onto the surface of mesoporous aluminophosphate: Comparisons with analogous catalysts based on mesoporous silica
Titanium/AlPO materials were prepared by grafting a titanium alkoxide (titanium isopropoxide) onto a mesoporous aluminophosphate. The structures of the surface-bound titanium species were investigated by UV-vis, FTIR, MAS NMR, and XANES/EXAFS spectroscopies. The titanium anchoring occurs by reaction between the alkoxide precursor and surface Al-OH and P-OH groups of the AlPO support. The titanium species exist in isolated tetrahedral coordination environments, and as oligomerized species. The catalysts prepared are selective and active for the liquid-phase epoxidation of cyclohexene in the presence of TBHP. The observed activities and selectivities were comparable with those obtained for similarly prepared titanium/SBA-15 samples of similar Ti content (but higher BET surface area). Published by Elsevier Inc.
Keywords:Mesoporous aluminophosphates;Titanium isopropoxide;Ti-grafted aluminophosphates;Ti-grafted SBA-15;Cyclohexene catalytic oxidation