Heterogeneously catalyzed epoxidation of vegetable oils by hydrogen peroxide represents a greener route for the production of epoxides and a thermally safer reaction route compared to the classical Prileschajew epoxidation approach. The epoxidation kinetics of the heterogeneous system formed by aluminium oxide catalyst, hydrogen peroxide and methyl oleate as a model compound was studied with semibatch experiments in laboratory scale. It was found that semibatch operation improved the performance significantly compared to classical batch operation, a low and constant volumetric flowrate of hydrogen peroxide increased the final oxirane yield considerably. A semibatch reactor model and a kinetic model were developed, featuring the reaction temperature, the reactant molar ratio, the catalyst loading and the mass flow rate as the most significant experimental parameters. The mathematical model was able to well describe the experimental data. The approach can be applied to other liquid–solid catalyst systems in future in order to optimize the semibatch operation policy for complex reaction systems.