Process for the epoxidation of olefins
AssigneesDegussa AG, Uhde GmbH
InventorsWilli Hofen, Georg Thiele, Alexander Möller
Life of this patent
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Abstract
The present invention relates to a process for the working up of a product stream from the epoxidation of olefins that contains olefin, olefin oxide, water-miscible organic solvent and water, by separating this product stream into an overhead product containing olefin, olefin oxide and organic solvent, and into a bottom product containing organic solvent and water, wherein the separation takes place in a pre-evaporator with at most 5 theoretical separation stages, and 20 to 60% of the total amount of organic solvent introduced with the product stream is removed with the overhead product and the residue remains in the bottom product, as well as a process for the epoxidation of olefins that includes this working up stage.
Claims12
Process for the working up of a product stream from the epoxidation of olefins that contains olefin, olefin oxide, water-miscible organic solvent and water, by separating this product stream into an overhead product containing olefin, olefin oxide and organic solvent, and into a bottom product containing organic solvent and water, characterised in that the separation is carried out in a pre-evaporator with at most 5 theoretical separation stages and 20 to 60% of the total amount of organic solvent introduced with the product stream is removed with the overhead product and the residue remains in the bottom product.
Process for the catalytic epoxidation of propene, in which
- a) in a reaction step the propene is reacted with aqueous hydrogen peroxide in methanol in the presence of a titanium silicalite catalyst,
- b) the product stream from the reaction step is optionally passed to a pressure release step, and
- c) the product stream is then separated, without prior distillative separation, in a pre-evaporator having at most 5 theoretical separation steps into an overhead product containing propene, propene oxide and methanol, and into a bottom product containing methanol and water, 20 to 60% of the total amount of methanol introduced with the product stream being removed with the overhead product and the residue remaining in the bottom product,
- d) the overhead product from step c) is at least partially condensed, the condensate containing, optionally after stripping out propene and any propane present
- 0-12 wt. % propene, 0-5 wt. % propane, 15-75 wt. % propene oxide, 25-85 wt. % methanol and 0-3 wt. % water, and
- e) the condensate from step d) is subjected to an extractive distillation, wherein
- e1) the condensate is added to a middle section of an extractive distillation column,
- e2) a polar solvent with hydroxyl functionality and having a boiling point that is higher than that of methanol is added to the extractive distillation column at a point above the point at which the condensate enters,
- e3) propene oxide is distilled off at the head of the column, and
- e4) a bottom product containing methanol and the polar solvent is removed.
Dependencies are inferred from the claim text.