Microwave-assisted and conventional polycondensation reaction of optically active N,N′-(4,4′-sulphonediphthaloyl)-bis-L-leucine diacid chloride with aromatic diamines

3,3',4,4'-Diphenylsulfonetetracarboxylic dianhydride (1) was reacted with L-leucine (2) in acetic acid and the resulting imide-acid (3) was obtained in high yield. The diacid chloride (4) was prepared from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines such as 4,4'-sulfonyldianiline (5a), 4,4'-diaminodiphenyl methane (5b), 4,4'-diaminodiphenylether (5c), p-phenylenediamine (5d), m-phenylenediamine (5e), 2,4-diaminotoluene (5f), and 1,5-diaminonaphthalene (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o-cresol. The polymerization reactions were also performed under two conventional methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and a short period reflux conditions. A series of optically active poly(amide-imide)s with inherent viscosity of 0.25-0.42 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly (amide-imide) s are reported. (C) 2004 Wiley Periodicals, Inc.