| 摘要 |
977,984. Separating methyl acetate from methanol by distillation. BORDEN CO. Nov. 6, 1961, No. 39673/61. Heading BIB. In a process for separating methyl acetate from a methanol/methyl acetate mixture, the mixture is distilled in fractionating column 16, and water is introduced into the column at a level where the concentration of methyl acetate in the mixture is at-least 70%, the proportion of water added being 100-600 parts by weight per 100 parts by weight of methanol in the vapours in the column at the level of the waterinlet. The azeotrope of methyl acetate and water distils over into condenser 24 and the condensate flows into receiver 32, where part of it is returned to column 16 as reflux and the remainder is passed into column 22, wherein the methyl acetate/water azeotrope is contacted with n-pentane vapour, and the water is entrained by the pentane. The pentane/water vapour is condensed in condenser 30 and the condensate flows into a gravity separator 38. The pentane recovered from separator 38 passes back into column 22 and the water is rejected as effluent. Dehydrated methyl acetate is withdrawn continuously from the base of column 22. A dilute mixture of methanol in water, plus traces of methyl acetate, passes from the reboiler 40 of column 16 into column 18, where it is fractionated to remove the remaining methyl acetate. The distillate comprises a ternary azeotrope of methyl acetate, methanol and water, and is recirculated into the feed to column 16. A mixture of methanol and water passes from the reboiler 42 of column 18 into column 20, where it is fractionated to produce methanol as the overhead distillate, the water plus traces of methanol being discharged as effluent from reboiler 44. Instead of pentane, the following liquids may be employed for dehydrating methyl acetate: hexane, cyclopentane, methylene chloride, and mono-bromoethane. |
