| 摘要 |
A continuous process for the preparation of propylene oxide, comprising (a) reacting propene with hydrogen peroxide in a reaction apparatus in the presence of acetonitrile as solvent, obtaining a stream SO containing propylene oxide, acetonitrile, water, at least one further component B wherein the normal boiling point of the at least one component B is higher than the normal boiling point of acetonitrile; (b) separating propylene oxide from SO, obtaining a stream SI containing acetonitrile, water and the at least one further component B; (c) dividing S1 into two streams S2 and S3; (d) subjecting S3 to a vapor-liquid fractionation in a first fractionation unit, obtaining a vapor fraction stream S4 a being depleted, relative to S3, of at least one of the at least one component B and obtaining a liquid bottoms stream S4b, and subjecting at least part of the vapor fraction stream S4 a to a vapor-liquid fractionation in a second fractionation unit, obtaining a vapor fraction stream S4c and a liquid bottoms stream S4 being depleted, relative to S4a, of at least one of the at least one component B; (e) recycling at least a portion of S4, optionally after work-up, to (a). |
