The partial oxidation of benzene in a reaction-extraction system was studied. The system consisted of a reactor, an extractor and a regenerator. The reactor contained both a benzene phase and an aqueous phase. Benzene was partially oxidized to phenol in the aqueous phase and then extracted to benzene phase. Phenol was finally extracted from benzene in the extractor. The regenerator reduced the oxidation catalyst. The phenol production rate increased when oxidation catalyst concentration, regenerator temperature, circulation rate between the reactor and the regenerator were increased. Thus, the regenerator played an important role in this system.