Process for the preparation of a polyamide

摘要

The invention relates to a process for the preparation of a polyamide comprising at least a step in which a composition that comprises at least (a) a primary aminocarbonamide and (b) an aminocarboxylic acid and/or a lactam is polymerised, said composition comprising at least (a) 10-90 wt. % primary aminocarbonamide; (b) 10-90 wt. % aminocarboxylic acid and/or lactam; (c) 0-4 wt. % water; the amounts being relative to the sum of the compounds (a+b+c). Preferably the sum of the compounds (a+b+c) is at least 75 wt. % of the total composition, more preferably 85 wt. %, most preferably 90 wt. %. The polyamide obtained with the process has a etarel of more than 2.2. The process is eminently suitable for the preparation of polyamide-6 (polycapronamide) from a composition comprising 6-aminocapronamide, 6-aminocaproic acid and/or epsi-caprolactam. This composition is preferably obtained via the reductive amination of a 5-formylyalerate ester, preferably 5-formylmethylvalerate in water. The 5-formylvalerate ester can for example be obtained from butadiene via (a) a carbonylation and (b) a hydroformylation reaction.