Preparation,characterization and copolymerization of the 12‐membered cyclic diamide 1,6‐diazacyclododecane‐2,5‐dione

A 12‐membered cyclic diamide monomer for nylon 64 was successfully synthesized in fairly high yield (～45%). The synthesis conditions were varied to see the effect of the diamine and succinyl chloride reactants on yield. Threefold excess of 1,6‐hexamethylenediamine (HDA) gave the highest yield, while further increasing the amount of HDA decreased the yield. Using N,N‐diisopropylethylamine as acid scavenger resulted in the formation of two different cyclic amides, which were fully analyzed by ¹H and ¹³C solution nuclear magnetic resonance spectrometry and mass spectrometry. Copolymerization of cyclic amides with ε‐caprolactam via an anionic route gave a block copolyamide with a two distinct endotherms in the differential scanning calorimetry analysis. However, copolymerization by the hydrolytic route gave only nylon 6 with terminal 64 units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 96–103