Alternating poly(ester amide)s from succinic anhydride and α,ω‐amino alcohols: synthesis and thermal characterization

Abstract

AbstractAlternating poly(ester amide)s 6a–e from succinic anhydride and α,ω‐amino alcohols H2N—(CH2)x—OH (x = 2–6) 2a–e were obtained in two steps: α‐carboxyl‐ω‐hydroxy amides 3a–e were prepared from the starting materials in a highly selective reaction, followed by a polycondensation reaction. 1H and 13C NMR analyses of the poly(ester amide)s clearly reveal the alternating microstructure. The poly(ester amide)s with homologous α,ω‐amino alcohols H2N—(CH2)x—OH (x = 2–6) are semi‐crystalline materials, their melting points show the odd/even effect observed for [n]‐polyamides and [n]‐polyurethanes. Heating the poly(ester amide)s 6a–e yields the corresponding N‐(hydroxyalkyl) imides 4a–e with no trace of cyclic ester amides. Theoretical calculations revealed that the cyclic ester amides 5a–e are clearly richer in energy than the isomeric N‐(hydroxyalkyl) imides. These results show that cyclic ester amides can not be prepared from N‐(hydroxyalkyl) imides by ring‐enlargement reactions. Copyright © 2003 Society of Chemical Industry