Synthesis of novel optically active poly(ester-imide)s with benzophenone linkages by microwave-assisted polycondensation

Abstract

A new simple and rapid polycondensation reaction of 4,4′-carbonyl-bis(phthaloyl-L-alanine)diacid chloride [N,N ′-(4,4′-carbonyldiphthaloyl)]bisalanine diacid chloride with several diphenols, such as bisphenol-A, phenolphthalein, 1,8-dihydroxyanthraquinone, 4,4′-dihydroxybiphenyl, 1,5-dihydroxynaphthalene and hydroquinone, in the presence of a small amount of a polar organic medium such as o-cresol was performed using a domestic microwave oven. The polycondensation reaction proceeded rapidly and was almost complete within 12 min to give a series of poly(ester-imide)s with inherent viscosities of about 0.35–0.58 dl g−1. The resulting poly(ester-imide)s were obtained in high yield and are optically active and thermally stable. All the above compounds have been fully characterized by IR spectroscopy, elemental analysis, inherent viscosity (ηinh), solubility test and specific rotation. Thermal properties of the poly(ester-imide)s have been investigated using thermal gravimetric analysis (TGA). © 2000 Society of Chemical Industry