A New Polycondensation Involving Dicarboxylic Acids with Differently Activated Carboxyl Groups by TsCl/DMF/Py

Abstract

Aromatic dicarboxylic acids, such as terephthalic (TPA) and isophthalic (IPA) acids having different structures of the activated carboxyl groups were prepared in situ by the reaction of the diacids with TsCl/DMF/Py containing various amounts of DMF. The polycondensation involved by these carboxyl groups using 0.3 equivalents of DMF relative to dicarboxylic acids and by dropwise addition of bisphenols significantly improved the ηinh values of the IPA/TPA(50/50)-2,2-bis(4-hydroxyphenyl)propane (BPA) and IPA/TPA (50/50)-methylhydroquinone polymers. It was also the case for the polycondensations of BPA and various combinations of aromatic dicarboxylic acids other than IPA/TPA. It is likely that various structures of the aggregates between the activated IPA and TPA are involved in a mixture of them, and evaluated by melting points of mixtures of their dimethyl esters prepared by quenching the aggregates with methanol. Effect of the amounts of DMF and the dropwise addition of BPA upon the distribution of oligomers formed at an earlier stage was also examined.