Patent ID: 7527712

Claim:
A process for the continuously operated distillation purification of methanol, wherein the methanol is used as a solvent in a synthesis of propylene oxide by reaction of a hydroperoxide with propylene, wherein methoxypropanols formed as by-products from the reaction of the propylene oxide with the methanol are separated off simultaneously, wherein the solvent mixture obtained in the synthesis of the propylene oxide is separated in a dividing wall column into a low-boiling fraction comprising methanol, an intermediate-boiling fraction comprising the methoxypropanols as an azeotrope with water and a high-boiling fraction comprising water and propylene glycol, and wherein the propylene oxide is prepared by a process comprising at least (i) to (iii) (i) reacting the hydroperoxide with propylene to form a mixture, (ii) separating the unreacted hydroperoxide from the mixture resulting from (i), (iii) reacting the hydroperoxide which has been separated off in (ii) with propylene, wherein an isothermal fixed-bed reactor is used in (i), an adiabatic fixed-bed reactor is used in (iii), and a separation apparatus is used in (ii) and wherein hydrogen peroxide is used as hydroperoxide, and wherein the hydroperoxide and the propylene are reacted in the presence of a heterogeneous catalyst.