Preparation of Polyarylates from Dihydroxyaceto-phenones by the Solution Polycondensation with TsCl/DMF/Py as a Condensing Agent

The polyesterification of a mixture of equal parts of isophthalic and terephthalic acids with 2,4-dihydroxybenzophenone (2,4-DHBP) and several dihydroxyacetophenones (DHAPs), from which polyesters of high molecular weight have not been prepared, was studied. Based on favorable results of two-stage copolycondensation with bisphenols first and then with 2,4-DHBP, factors such as dropwise addition of DHAPs, mol-% of them used in the initial stage, and the temperature in the subsequent stage were examined in a two-stage polycondensation. Favorable results were obtained by longer period of addition, initial reaction of 50–70 mol-%, and lowering the temperature to 60°C. The relationship between the temperature and the distribution of resulting oligomers determined by GPC was also examined. The copolymers obtained exhibited the glass transition temperatures and polymer melting points in the ranges of 165–183°C and of 280–310°C, respectively. Most of them were soluble in DMF, chloroform, cyclohexanone, and THF.