Kinetics simulation of propylene epoxidation over different Ti species in TS‐1

Abstract

AbstractA thorough experimental investigation on the kinetic behavior of liquid‐phase propylene epoxidation over TS‐1 and tetrapropylammonium hydroxide (TPAOH) treated TS‐1 catalysts was conducted in a fixed‐bed reactor. The amounts of different coordinated Ti species in the catalysts were quantified by spectroscopies, and their catalytic performances of the epoxidation and alcoholysis of propylene oxide were measured by kinetic modeling. The study shows that the TPAOH treatment converted some of the tetrahedrally coordinated Ti to octahedrally coordinated Ti, and both species were active for the epoxidation and alcoholysis. The superior catalytic performance observed over the TPAOH treated TS‐1 is due to two factors, the increased percentage of active sites, and reduced energy barrier for epoxidation on the octahedrally coordinated Ti. In addition, as the H2O2 conversion increases, the adsorption equilibrium constant of propylene oxide plays a more decisive role than the activation energy for the selectivity of propylene glycol monomethyl ethers.