Process for preparing propylene oxide

The present invention is related to a process for preparing propylene oxide, comprising (i) providing a stream comprising propene, hydrogen peroxide or a source of hydrogen peroxide, water, and an organic solvent; (ii) passing the liquid feed stream provided in (i) into an epoxidation zone comprising an epoxidation catalyst comprising a titanium zeolite, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propene, propylene oxide, water, and the organic solvent; (iii) removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, water, organic solvent, and propene; (iv) separating propene from the effluent stream by distillation, comprising (iv.1) subjecting the effluent stream to distillation conditions in a distillation unit, obtaining a gaseous top stream S0 enriched in propene compared to the effluent stream subjected to distillation conditions, and a liquid bottoms stream S01 enriched in propylene oxide, water and organic solvent compared to the effluent stream subjected to distillation conditions; (iv.2) returning a condensed portion of the stream S0 to an upper part of the distillation unit.