Synthesis of polyesters by direct polycondensation with picryl chloride

Abstract

The polycondensation reaction of various dicarboxylic acids and diols such as terephthalic acid and ethylene glycol occurred at room temperature in pyridine in the presence of picryl chloride to give polyesters in high yield. Reaction conditions, basic solvents, temperatures, concentrations of monomer, and amount of picryl chloride were investigated. A combination of picryl chloride and pyridine was found to be satisfactory for the polyester synthesis. The polycondensation reaction possibly proceeds through the formation of an active ester from picrylic acid and carboxylic acid, followed by esterification with hydroxyl group. Yields of polyester from 2, 5-pyridinedicarboxylic acid and 1, 10-decanediol by this direct polycondensation reached up to 89%, and the solution viscosity of the polyester was approximately 1.0 under optimum reaction conditions. The polyester obtained from terephthalic acid and 1, 5-pentanediol had a higher solution viscosity than those from various combinations of dicarboxylic acids and diols. Aliphatic dicarboxylic acid such as adipic acid yielded polyester having a lower solution viscosity than aromatic dicarboxylic acid. © 1982 The Society of Polymer Science, Japan.