METHOD FOR THE PREPARATION OF PURE LACTAM FROM ITS PRIMARY SOLUTIONS IN AN ORGANIC SOLVENT

摘要

1430949 Lactams SNIA VISCOSA SOC NAZIONALE INDUSTRIA APPLICAZIONI VISCOSA SpA 27 June 1973 [28 June 1972] 30468/73 Heading C2C A lactam, e.g. caprolactam, is removed from solution in an organic first solvent by adding to the solution a second solvent which is miscible with the first solvent but which is not a solvent for the lactam so that the lactam is displaced from solution in the first solvent. Exemplified as the first solvent is a phenol containing at least one alkyl substituent which contains 3 or more carbon atoms and has a solubility in water of less than 0À5 g. per 100 g. of water at 25‹ C. and in sulphuric acid solution containing 50 g. of sulphuric acid per 50 g. of water has a solubility of less than 0À2 g. per 100 g. of acid solution at 25‹ C, the substituent groups of the phenol not hindering the activity of the OH group of the phenol. The second solvent may be an aliphatic, aromatic or chlorinated hydrocarbon. A third solvent, e.g. water which is immiscible with both the first and second solvents but which is a solvent for the lactam may also be added to the solution so that the displaced lactam forms a solution in the third solvent.