processo para preparar um poliéster à base de 1,3-propanodiol
A process for preparing polytrimethylene terephthalate in which a carbonyl-containing 1,3-propanediol stream is purified for reuse of the 1,3-propanediol. The process involves reacting, under condensation polymerization conditions, terephthalic acid and a molar excess of 1,3-propanediol, with vacuum...
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Zusammenfassung: | A process for preparing polytrimethylene terephthalate in which a carbonyl-containing 1,3-propanediol stream is purified for reuse of the 1,3-propanediol. The process involves reacting, under condensation polymerization conditions, terephthalic acid and a molar excess of 1,3-propanediol, with vacuum distillation and condensation of a major portion of the unreacted 1,3-propanediol. To this condensed stream is added a sufficient amount of base to raise the pH to a value greater than 7, and from this base-containing condensate the 1,3-propanediol is distilled and recycled to the polymerization reaction. |
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