Propene oxide is an important chemical intermediate in the chemical industry. The propene oxide industry has employed two different types of commercial processes for several decades: the chlorohydrin process and the hydroperoxidation process. However, direct epoxidation of propene with hydrogen peroxide has recently attracted much attention as a more environmentally benign and profitable process. This thesis presents the catalytic reaction engineering of the epoxidation of propene to propene oxide using hydrogen peroxide as the oxidant and titanium silicalite (TS-1) as the catalyst under mild conditions.
The kinetics of the heterogeneous catalytic epoxidation was studied in an autoclave reactor using methanol/water mixtures as the solvent. The effects of stirring speed, catalyst loading, reactant concentration, reaction temperature, solvent composition and solvent variation on the propene oxidation are presented and discussed. The catalytic performance of TS-1 impregnated with precious metal nanoparticles such as gold and palladium for the propene epoxidation was also investigated. The influences of the kind of precious metal and treatment process adopted in the catalyst preparation on the propene epoxidation and the hydrogen peroxide decomposition were explored.
One of the key objectives of this research was to evaluate a new continuous reactor concept for propene epoxidation and other liquid-phase selective oxidation reactions. A conventional monolith and a confined Taylor flow (CTF) reactor were studied for the propene epoxidation. The influences of gas and liquid flow rates on the hydrodynamics of the structured reactors were investigated under Taylor flow regime at atmospheric pressure. It was found that the variation of hydrodynamics had a significant impact on the production of propene oxide. The effect of operating pressure on the propene oxide production was studied in a pressurised system. In addition, the performances of various structures of reactor column were examined to compare.