| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly purified acetonitrile applicable to chromatography in a few process and a low cost by subjecting crude acetonitrile as a by-product in producing acrylonitrile to distillation and an ion exchange resin treatment. SOLUTION: The objective compound is obtained by distilling crude CH3 CN by using three distilling columns having overhead reflux loops of respectively having a reflux ratio higher than (3:1), (3.4:1) and (6.4:1), in turn, under >=1 atm., to remove HCN and generating a bottom product containing (A) a CH3 CN/ water azeotropic mixture and water, separating the component A to (B) a CH3 CN/water azeotropic mixture having a higher CH3 CN concentration and a bottom product containing water under <=1 atm., distilling the component B under a pressure of >=1 atm., then generating a CH3 CN/water azeotropic mixture containing substantially whole amount of water derived from the component B, a bottom product containing CH3 CN and heavy organic compounds, and a side stream containing (C) a highly purified CH3 CN, thus purifying the component C by an acidic ion exchange resin. |
