BigPatents India

Disclosed is a process for the purification of a polyester precursor wherein a polyester oligomer derived from terephthalic acid and one or more glycols or diols is purified or decolorized by hydrogenating the oligomer to convert colored impurities to colorless compounds and the thereby improve the color of the oligomer. The colored impurities are present in the terephthalic acid used to prepare the oligomers and are formed during the manufacture of terephtalic acid. The purified/decolorized oligomer obtained from the disclosed process may be used to prepare high molecular weight polyesters. Drawing Sheets. NIL Total Pages: 21 (FIG.-NIL)