Patent ID: 6222033
Filing Date: 2001-04-24
Classification: C07D

Abstract:
A process for preparing cyclic lactams of the formula I: ##STR4##whereR.sup.1 is hydrogen, alkyl, cycloalkyl or aryl, andA is C.sub.3 -C.sub.12 -alkylene, unsubstituted or substituted by 1, 2, 3, 4, 5 or 6 substituents selected independently of one another from the group consisting of alkyl, cycloalkyl and aryl,by conversion of an .omega.-aminocarbonitrile of the formula II:HR.sup.1 N--A--CN (II)where R.sup.1 and A are each as defined above, in the presence of a homogeneous catalyst K1, which comprises a phosphorous compound, wherein K1 is selected from the group consisting of phosphoric acid, diphosphoric acid, metaphosphoric acid, polyphosphoric acid, the salts and esters of phosphorous acid, phosphonic acid, the salts, esters and organic derivatives of phosphonic acid, the esters and salts of organic derivatives of phosphonic acid, the esters and salts of phosphonous acid, phosphinic acid, the esters and salts of phosphinic acid, and mixtures thereof, the process comprises:a) converting said nitrile II into an oligomer mixture, wherein step a) is effected in the presence of water and optionally in the presence of the catalyst K1 orwherein step a) is effected in an inert solvent and optionally in the presence of a heterogeneous catalyst K2 different from K1, wherein K2 is selected from the group consisting of oxides, sulfides, selenides and/or tellurides of elements of the 2.sup.nd, 3.sup.rd or 4.sup.th main group, of the 2.sup.nd, 3.sup.rd, 4.sup.th, 5.sup.th or 6.sup.th transition group, of the lanthanides, of the actinides, a zeolite, a phosphate, a heteropolyacid, an ion exchanger and mixtures thereof, and wherein said catalyst K2 is removed after converting said nitrile II into said oligomer mixture,b) adding a catalyst K1 unless already present from step a), and treating said K1-comprising oligomer mixture with superheated steam.