摘要 |
Polyamides are produced by reacting aminocarboxylic acid compounds of the general formula Iwhere R1 is OH, O-C1-12-alkyl or NR2R3, where R2 and R3 are independently hydrogen, C1-12-alkyl or C5-8-cycloalkyl, and m is an integer from 3 to 12,optionally in a mixture with aminonitriles and their hydrolysis products and optionally in the presence of water,in a liquid phase at elevated pressure and elevated temperature in the presence of metal oxides as heterogeneous catalysts, the metal oxides being used in a form which permits mechanical removal from the reaction mixture and being removed from the reaction mixture during or after the polymerization. |