Novel catalysts based on zirconium(IV) for the synthesis of poly(ethylene terephthalate-co-isophthalate) copolyesters

In this Letter, we report the employment of zirconium–aminoethanol as a novel catalyst for the synthesis of copolyesters. The Zr(IV) complex (Cl)2Zr(OCH2CH2NR1R2)2 was prepared by the direct reaction of ZrCl4 with aminoethanol in CH2Cl2. The zirconium catalysts 1a–c were produced in high yields from aminoethanol by using a one-step procedure. The efficiency of zirconium catalyst can be harnessed for the large scale synthesis of poly(ethylene terephthalate-co-isophthalate) copolyesters in a 20L pilot plant. From this study, catalyst 1a was shown to be the most effective catalyst for the polycondensation. When this catalyst was used in the subsequent steps, copolyesters with the excellent intrinsic viscosity and physical properties were received.