A METHOD FOR THE PREPARATION OF 1,2-PROPANEDIOL

    公开(公告)号:US20230399279A1

    公开(公告)日:2023-12-14

    申请号:US18249825

    申请日:2021-10-07

    摘要: A method for preparing 1,2-propanediol involves 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. The method then involves separating the reaction mixture into an aqueous phase (Pa) containing 1,2-propanediol and formic acid and an organic phase (Po); recycling at least part of the separated organic phase (Po) to the reaction; contacting at least a part of the separated aqueous phase (Pa) with a palladium catalyst; and recovering 1,2 propanediol from the aqueous phase provided by the contacting. The contacting of at least a part of the separated aqueous phase (Pa) with the palladium catalyst reduces the content of formic acid.

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

    公开(公告)号:US20230382839A1

    公开(公告)日:2023-11-30

    申请号:US18249980

    申请日:2021-10-07

    摘要: A method can be used for preparing 1,2-propanediol, dipropylene glycol, and tripropylene glycol. The method involves reacting propene with hydrogen peroxide containing nitrate, 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. The method then involves separating the reaction mixture into an aqueous phase containing 1,2-propanediol, dipropylene glycol, tripropylene glycol, and nitrate and an organic phase. The method further involves recycling at least part of the separated organic phase to the reaction; hydrogenating the separated aqueous phase using a heterogeneous hydrogenation catalyst to provide a hydrogenated aqueous phase with a reduced nitrate content; and recovering 1,2-propanediol, dipropylene glycol, and tripropylene glycol from the hydrogenated aqueous phase by a sequential multiple-step distillation.