Effects of preparation conditions and reaction conditions on the epoxidation of propylene with molecular oxygen over Ag/TS-1 in the presence of hydrogen Original Research Article

The effects of preparation conditions, treatment methods of the Ag/TS-1 catalyst and the reaction conditions on propylene epoxidation using oxygen as the oxidant in a fixed-bed quartz reactor were investigated. The catalysts were characterized by XRD, UV-Vis, TEM and ESR spectra. Results show that hydrogen is essential for the epoxidation reaction. The optimum preparation conditions are as follows: Ag loading 2 wt.%, the ratio of Si/Ti in TS-1 64, and calcination temperature (in air) 450 °C. The optimum Ag/TS-1 catalyst, by passing a reactant mixture of C3H6, O2, H2 and N2 at 150 °C at a volume ratio of 1:2:3:12 with a space velocity of 4000 h−1, can exhibit the best results. At this condition, after 70 min reaction the conversion of propylene and the selectivity to propylene oxide are 1.37 and 93.51%, respectively. The results of the characterization show that the oxidized Ag species without single electrons plays an important role in the epoxidation of propylene.