The kinetics of the heterogeneous catalytic epoxidation of propene to propene oxide with hydrogen peroxide and titanium silicalite (TS-1) as the catalyst was studied under mild conditions in an autoclave reactor using methanol/water mixtures as the solvent. The effects of reactant concentration, solvent composition, catalyst loading, stirring speed, and reaction temperature on the propene oxidation were investigated. The initial rates increased almost linearly with catalyst loading. The apparent orders of reaction with respect to hydrogen peroxide and propene were found to be 0.67 (0.17-0.70 wt %) and 0.63 (0.3-0.8 bar), respectively. The apparent activation energy was found to be 25.8 kJ mol(-1). Methanol content in the solvent was shown to have a dual influence on the reaction rate, enhancing the solubility of propene and inhibiting the epoxidation reaction by competitive adsorption.