| 摘要 |
PURPOSE:To precipitate crystal of an organic acid, by bringing a solution comprising an organic acid containing plural acidic groups into contact with a basic ion exchange resin to adsorb the organic acid, eluting the adsorbed organic acid by using an eluent at high temperature and then treating the eluate containing the organic acid at low temperature. CONSTITUTION:A solution comprising an organic acid containing plural acidic groups in the molecule is brought into contact with a basic ion exchange resin (ion exchange resin containing preferably polyalkylene polyamino group) to adsorb the organic acid, which is eluted by using an eluent (e.g. aqueous solution of mineral acid) at 40-90 deg.C, the eluate containing the organic acid is treated at 0-30 deg.C to crystallize crystal of the organic acid. The solution after removal of the crystal of the organic acid is partially or wholly reused as the eluent. Adipic acid contained in water prepared as by-product in the process of production of cyclohexanone by oxidation of cyclohexane may be cited as the organic acid. This method required only a short time by simple facilities and method and is economic. |
