Polyamide synthesis by ester aminolysis. I. A new route for nylon-6,6 synthesis

Abstract

A new route for nylon-6,6 synthesis has been studied. The process is grounded on the synthesis of an α-amino ω-ester monoamide precursor (AME-6,6) easily available in reacting in the bulk hexamethylene diamine and dimethyl adipate at a low temperature (T ≈ 50°C) preferably in the presence of a phenol derivative. In such conditions AME-6,6 precipitates with a very good yield (90-95%). One of the greatest advantages of AME-6,6 is to keep the stoichiometric balance for further polyamidation; that is not the case in other processes. Moreover AME-6,6 is very stable, e.g., even stored at room temperature under air during 50 days. Polyamides-6,6 have been obtained from AME-6,6 (used freshly prepared or after storage) in glass laboratory reactors by direct heating under vacuum (T = 270°C) with number-average molecular weights of roughly 20,000. © 1996 John Wiley & Sons, Inc.