A METHOD FOR THE PREPARATION OF 1,2-PROPANEDIOL AND DIPROPYLENE GLYCOL

A method for preparing 1,2-propanediol and dipropylene glycol involves continuously reacting propene with hydrogen peroxide in the presence of a catalyst mixture, containing a phase transfer catalyst and a heteropolytungstate, in a liquid reaction mixture containing an aqueous phase with a maximum apparent pH of 6 and an organic phase, to obtain 1,2-propanediol and dipropylene glycol. The method then involves separating the reaction mixture into an aqueous phase (Pa) containing 1,2-propanediol and dipropylene glycol and an organic phase (Po); recycling at least part of the separated organic phase (Po) to the reaction; and recovering 1,2-propanediol and dipropylene glycol from the separated aqueous phase (Pa), The reaction heat generated is at least partially removed, and the ratio of 1,2 propanediol to dipropylene glycol is controlled by adjusting the weight ratio of hydrogen peroxide to water fed to the reaction.