GB873257A - Improvements in the production of omega-aminododecane acidlactam, and a new intermediate compound therein - Google Patents

Abstract

o -Aminododecane acid lactam is obtained by treating cyclododecane in dissolved form at a temperature of -30 to +40 DEG C. under the action of light with hydrogen chloride and a nitrosating agent, separating the resulting cyclododecanone oxime hydrochloride, treating it at 80-150 DEG C. with an acid or acid chloride known for the Beckmann rearrangement and separating the o -aminododecane acid lactam by introducing the resulting rearrangement mixture into water. Cyclododecanone oxime hydrochloride is claimed per se; it may be obtained in solid or liquid forms. Specified nitrosating agents are nitrosyl chloride, which may be prepared in situ, e.g. from an alkyl nitrite and hydrogen chloride, and a mixture of chlorine and nitrogen monoxide. The initial cyclododecane solution preferably contains 0.5 to 5% by weight of by-products formed by the nitrosation of cyclododecane. Specified Beckmann rearrangement agents are sulphuric acid, oleum, chlorsulphonic acid, phosphorus pentachloride and benzene-sulphonyl chloride. o -aminododecane acid lactam, e.g. 1-10% based on sulphuric acid, is preferably added to the mixture to be subjected to rearrangement. The cyclododecanone oxime hydrochloride may be converted to the free oxime by digestion with water or by precipitation from an alcoholic solution of the hydrochloride by means of water. o -aminododecane acid lactam may be used in polyamide preparation; it may be converted to o -aminododecane carboxylic acid or its hydrochlorides by boiling with concentrated HCI.