Method for the continuous purification by distillation of the solvent methanol, used in the synthesis of propylene oxide
AssigneeBASF SE
InventorsPeter Bassler, Hans-Georg Goebbel, Joaquim Henrique Teles, Peter Rudolf
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Abstract
Process for the continuously operated purification by distillation of the methanol used as solvent in the synthesis of propylene oxide by reaction of a hydroperoxide with propylene, with the methoxypropanols being separated off simultaneously, wherein the solvent mixture obtained in the synthesis is separated in a dividing wall column into a low-boiling fraction including methanol, an intermediate-boiling fraction containing the methoxypropanols as azeotrope with water and a high-boiling fraction including water and propylene glycol.
Claims9
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.
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 dividing wall column comprises and is configured as two thermally coupled columns,
- wherein the solvent mixture is separated into the low-boiling, intermediate-boiling and high-boiling fractions in a column downstream of a feed column, or
- the low-boiling and high-boiling fractions are taken off from the solvent mixture in the feed column and the intermediate-boiling fractions is taken off in the downstream column, or
- the high-boiling fraction is taken off from the solvent mixture in the feed column and the low-boiling and the intermediate-boiling fractions are taken off in downstream column, or
- the low-boiling fraction is taken off from the solvent mixture in the feed column and the intermediate-boiling and high-boiling fractions are taken off in the downstream column.
Dependencies are inferred from the claim text.