Method for producing propylene oxide

A process for producing purified propylene oxide comprising:

• first to sixth steps below, and
• using heat of reaction generated in the first and/or second steps as a heat source for rectification in the fifth step and/or a heat source for rectification in the sixth step:
• first step:
• a step of obtaining cumene hydroperoxide through oxidation of cumene at a temperature of from 50 to 200° C.,
• second step:
• a step of obtaining propylene oxide and cumyl alcohol by reacting cumene hydroperoxide with propylene at a temperature of from 0 to 200° C. in the presence of an epoxidation catalyst,
• third step:
• a step of separating into a fraction (2) containing crude propylene oxide and a fraction (3) containing crude propylene by subjecting an outlet liquid (1) of the second step to rectification,
• fourth step:
• a step of obtaining a fraction (4) containing crude propylene oxide and a fraction (6) containing cumyl alcohol by subjecting the fraction (2) to rectification,
• fifth step:
• a step of obtaining a fraction (7) containing purified propylene oxide by subjecting the fraction (4) to rectification, and
• sixth step:
• a step of obtaining a fraction (5) containing purified propylene by subjecting the fraction (3) to rectification,
• wherein the reaction temperature in the first and/or second steps is higher by 10° C. or more than the temperature of a heat source for rectification in the fifth and/or sixth steps.