| 摘要 |
An improved process for the polymerization of polytrimethylene terephthalate by esterification of terephthalic acid or dimethylterephthalate with 1,3 propanedio (PDO), precondensation of the esterification product to produce a precondensation product, and polycondensation of the precondensation product to produce polytrimethylene terephthalate wherein excess PDO is removed from the esterification and/or polycondensation stages and PDO vapor is separated from the high boiling fraction (solid byproduct). The improvement comprises: a) heating the solid byproduct in the presence of 5 ppm to 5000 ppm, based on metal, of a metal catalyst selected from the group consisting of one or more 3rd, 4th, or 5th row metal compounds from Groups 3 - 12 and Groups 14 - 15 of the Periodic Table (IUPAC 1989) at a temperature of from 100 °C to 240 °C for from 5 minutes to 24 hours, optionally in the presence of a diluent, and b) optionally, recycling the reaction product into the polymerization process.
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