Process for regenerating heterogeneous epoxidation catalysts and their use to catalyze epoxidation reactions

A process for regenerating a heterogeneous titanium-containing silicon oxide catalyst comprising the steps of contacting the heterogeneous titanium-containing silicon oxide catalyst to be regenerated with with a solvent which is inert with the catalyst active sites, washing with an acid aqueous solution, impregnating the washed catalyst thus obtained with a titanium-containing impregnating agent, and calcinating the impregnated catalyst; as well as a process for the preparation of an alkylene oxide comprising carrying out the previous regeneration process, followed by reacting an olefin with an organic hydroperoxide in the presence of the regenerated heterogeneous titanium-containing silicon oxide catalyst.