A METHOD FOR INCREASING PROPYLENE OXIDE OUTPUT OF AN INTEGRATED PROCESS FOR MAKING PROPYLENE OXIDE AND PROPYLENE GLYCOL

摘要

The propylene oxide output of an integrated process for making propylene oxide and propylene glycol, which comprises a step a) of reacting propene with an oxidant to provide propylene oxide, a step b) of reacting a fraction of the propylene oxide provided in step a) with water to provide an aqueous glycol solution comprising monopropylene glycol and dipropylene glycol and a step c) of separating monopropylene glycol and dipropylene glycol from said aqueous glycol solution by a multi-step distillation, can be increased without increasing the capacity of the unit for reacting propene to propylene oxide in step a) by adding a step d) of reacting propene and hydrogen peroxide in the presence of a catalyst mixture comprising a phase transfer catalyst and a heteropolytungstate in a liquid reaction mixture which comprises an aqueous phase with a maximum apparent pH of 6 and an organic phase, and a step e) of separating the liquid reaction mixture provided by step d) into an organic phase, which is recycled to step d), and an aqueous phase comprising monopropylene glycol and dipropylene glycol, which is passed to step c) replacing aqueous glycol solution provided by step b).