To provide a system for heating a cumene hydroperoxide-containing solution having excellent characteristics that since the heating temperature of equipment to heat the cumene hydroperoxide-containing solution is set low and a coefficient of heat transfer is enlarged, the equipment is miniaturized and since the retention time of the cumene hydroperoxide-containing solution liable to be thermally decomposed is short, formation of undesirable by-products is minimized.

The system for heating the cumene hydroperoxide-containing solution comprises using a falling film heater. The system concretely comprises an oxidation process for oxidizing cumene to give the cumene hydroperoxide- containing solution, a concentration process for concentrating a reaction solution after the oxidation process and an epoxidation process for reacting cumene hydroperoxide in the reaction solution after the concentration process with propylene to give propylene oxide and cumyl alcohol.