GB924453A - Improved lactam polymerisation process - Google Patents

Abstract

In the alkaline polymerization of at least one monomeric lactam having at least six carbon atoms in the ring, the lactam is maintained above its melting point and a compound of the formula <FORM:0924453/IV(a)/1> or a salt thereof is added to the lactam, either as such or dissolved in a suitable solvent, R and R1 being alkyl, alkenyl, aryl, alkaryl, aralkyl or cycloalkyl groups, R and R1 being linked together, if desired, to form a ring with C, Y and X, and Z is either an -NH- radical in which case X and Y can each be O, S or -NH-, or, alternatively, Z is O or S, in which case X can be O or S or -NH- and Y can be O or S. Specified lactams are e -caprolactam, enantholactam, capryllactam, dodecanolactam, a -methyl caprolactam, b -d -dimethyl caprolactam and b -phenyl caprolactam. The reaction is effected in the presence of conventional alkali catalysts. Many co-catalysts of the above formula are specified. In the examples, e -caprolactam is polymerized in the presence of:-(1) sodium methoxide and dimethyl carbonate; (2) sodium methoxide and N-methyl-(ethyl carbamate); (3) sodium methoxide and dimethyl guanidine; (4) potassium t-butoxide and diethyl carbonate; (5) potassium t-butoxide and methyl octyl carbonate; (6) lithium hydride and N-ethyl(ethyl carbamate); (7) sodium hydride and N-octyl-(ethyl carbamate); (8) potassium hydroxide and N-phenyl-(ethyl carbamate); (9) ethanolic sodium ethoxide and N-dodecyl-(ethyl carbamate); (10) sodium hydroxide and N-phenyl-(cyclohexyl carbamate); (11) sodium hydroxide and N-phenyl-(allyl carbamate); (12) lithium and diphenyl guanidine and (13) sodium and di-t-butyl carbonate.