Patent ID: 7135428

Claim:
Catalyst solution for the anionic polymerization of lactones and/or lactams, comprising a salt of at least one compound of the general formula I wherein R 1 is H or an aliphatic, cycloaliphatic or aromatic radical with 1 to 12 C atoms, the radical R 2 , which is the same or different, is H, halogen, C1–C5-alkyl, ethoxy or methoxy, and n=1, 2 or 3, and wherein the salt is dissolved in an aprotic solvation agent S, wherein said solvation agent S comprises N-methylpyrrolidone, N-octylpyrrolidone, N-cvclohexylpyrrolidone, N-octylcaprolactam, tetrabutyl urea or mixtures thereof.