| abstract |
The invention relates to a method for preparing a lactam in a continuous process, comprising forming the lactam and ammonium sulphate by contacting a lactam sulphate contained in an acidic liquid with ammonia, during which forming of lactam heat of reaction is generated, which heat is partially or fully recovered, wherein ammonia is brought into contact with the acidic liquid as part of a liquid aqueous ammonia solution, and wherein the contacting takes place at a temperature of at least 120 DEG C, and wherein the average residence time at a temperature of at least 120 DEG C is at most 15 minutes, and wherein the ammonium sulphate remains dissolved in a liquid phase during said residence time. |