Process for the epoxidation of olefins

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
• 3 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.