Abstract: A process for recovering ammonium sulphate from an aqueous ammonium sulphate solution containing organic contaminants is disclosed. The aqueous solution is contacted with an organic substance which is water soluble and which is capable, in combination with a saturated ammonium sulphate solution, of forming a two-layer system. The organic substance is selected from the group consisting of lactames of 4 to 20 carbon atoms, and mixtures thereof. The resultant two layers may be separated into an aqueous phase containing the ammonium sulphate, and an organic phase containing the organic substance and the organic contaminants. Typical organic contaminants include acrylonitrile prepared from propylene, methyl methacrylate prepared from acetone cyandihydrin, and methyl methacrylate prepared from acrylonitrile. The ammonium sulphate is readily crystallized from the aqueous phase.

Abstract: A process is disclosed in which the heat generated, during neutralization, y ammonium sulfate of a solution of .xi.-caprolactam in sulfuric acid, is used to effect evaporation of water present, and the temperature is kept at about 40.degree.C to 50.degree.C, under subatmospheric pressure, so that substantial hydrolysis of the caprolactam is avoided while a substantial portion of the water present in the neutralization mixture is evaporated at the subatmospheric pressure, and the ammonium sulfate is crystallized substantially free from entrained caprolactam. The caprolactam is then separated from the aqueous phase.