Much experimental studies on the polyesterification reactions between dibasic acids and glycols have been reported by various authors, among them Menshyt-kind^[1], Dostal and Raff^[2], Flory^[3,4], Rafikov and Korshak^[5], Davies^[6,7], Colonge and Stuchlik^[8], and others, but quite diversed results were obtained. According to polyeaterification in the absence of a foreign acid, owing to catalytic effect of the dibasic acid molecule, is a third-order reaction^[3,4].