Patent RU-2766954-C2 (RU)
Title: Extraction of propene by cleaning in scrubber with solvent/water mixture
Inventor: WOERZ NICOLAI TONIO
IPC: C07D301/12
Filed: 2018-04-13
Granted: 2022-03-16
Abstract: FIELD: chemistry. 
     SUBSTANCE: present invention relates to a method for producing propylene oxide, including (i) providing a flow containing propene, propane, hydrogen peroxide or a source of hydrogen peroxide, water and an organic solvent; (ii) passing the liquid flow of incoming material provided at the stage (i) into the epoxidation zone containing an epoxidation catalyst containing titanium-based zeolite, and subjecting the liquid flow of incoming material to conditions of the epoxidation reaction in the epoxidation zone, obtaining a reaction mixture containing propene, propane, propylene oxide, water and an organic solvent; (iii) removing the outflow from the epoxidation zone, wherein the outflow contains propene, propane, propylene oxide, water and an organic solvent; (iv) separating propene and propane from the outflow by distillation, including subjecting the outflow to distillation conditions in a distillation unit, obtaining a gaseous stream S1, which is enriched with propene and propane, compared with the outflow subjected to distillation conditions, and a cubic liquid flow S2, which is enriched with propylene oxide, water and an organic solvent, compared with the outflow subjected to distillation conditions; (v) separating propane from stream S1 in the separation zone, including subjecting stream S1 to washing conditions in a scrubber, where a solvent mixture containing an organic solvent and water is added as a capturing agent, obtaining a cubic flow S3, which contains an organic solvent, water and at least 70 wt.% of propene contained in S1; and a gaseous upper stream S4, which contains at least 5 wt.% of propane contained in stream S1, where the solvent mixture containing an organic solvent and water added as a capturing agent at the stage (v) has a KAP capacity relatively to propene at 25°C in the range from 0.01 to 0.2, wherein the KAP capacity is a value of the inversion of the limiting coefficient of propene activity in the solvent mixture (g∞ (propene)): KAP=1/g∞(propene); and/or where the solvent mixture containing an organic solvent and water added as a capturing agent in the stage (v) has a weight-based KAPm capacity relatively to propene at 25°C in the range from 4.4 to 10, wherein the weight-based KAPm capacity is calculated as KAP=1/g∞(propene)/MW(solvent mixture)·1000; where g∞(propene) is the limiting coefficient of propene activity in the solvent mixture, and MW(solvent mixture) is the molar weight of the solvent mixture; and/or where the solvent mixture containing an organic solvent and water added as a capturing agent at the stage (v) has a selectivity S relatively to propene at 25°C in the range from 1.3 to 3.5, wherein the selectivity S is the ratio of limiting coefficients of activity of propane g∞(propane) and propene g∞(propene) at infinite dilution: S=g∞(propane)/g∞(propene). The method does not require additional separation stages. 
     EFFECT: obtaining a method for producing propylene oxide. 
     15 cl, 5 dwg, 12 tbl, 5 ex