Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a flasher. A first stream of gaseous by-products is continuously vaporized and removed from the flasher, and a liquid flasher reaction product having a mole ratio of propylene groups to terephthalate groups of less than about 1.5 is continuously withdrawn from the flasher. The liquid flasher reaction product is continuously fed to a prepolymerizer where it is continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a second stream of gaseous by-products.

Abstract: A process for the continuous production of at least one of bis(3-hydroxypropyl) terephthalate and low molecular weight oligomers of 1,3-propanediol and terephthalic acid is disclosed. According to the process, preheated 1,3-propanediol (about 150° C. to about 200° C.) and preheated lower dialkyl esters of terephthalic acid (about 150° C. to about 220° C.) are combined in a mole ratio of about 1.2:1 to about 2.3:1 and fed to an ester exchange vessel where the mixture undergoes a continuous transesterification reaction. The liquid reaction mixture is continuously heated and mixed, at a temperature of about 215° C. to about 250° C., and a pressure of about 800 mm Hg to about 1,000 mm Hg. Gaseous reaction products are continuously separated from the liquid reaction mixture, and a stream of liquid reaction products containing bis(3-hydoxypropyl) terephthalate and low molecular weight oligomers of 1,3-propanediol and terephthalic acid is continuously removed from a base portion of the ester exchange vessel.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture-having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a flasher. A first stream of gaseous by-products is continuously vaporized and removed from the flasher, and a liquid flasher reaction product having a mole ratio of propylene groups to terephthalate groups of less than about 1.5 is continuously withdrawn from the flasher. The liquid flasher reaction product is continuously fed to a prepolymerizer where it is continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a second stream of gaseous by-products.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a flasher. A first stream of gaseous by-products is continuously vaporized and removed from the flasher, and a liquid flasher reaction product having a mole ratio of propylene groups to terephthalate groups of less than about 1.5 is continuously withdrawn from the flasher. The liquid flasher reaction product is continuously fed to a prepolymerizer where it is continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a second stream of gaseous by-products.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture-having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a flasher. A first stream of gaseous by-products is continuously vaporized and removed from the flasher, and a liquid flasher reaction product having a mole ratio of propylene groups to terephthalate groups of less than about 1.5 is continuously withdrawn from the flasher. The liquid flasher reaction product is continuously fed to a prepolymerizer where it is continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a second stream of gaseous by-products.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a flasher. A first stream of gaseous by-products is continuously vaporized and removed from the flasher, and a liquid flasher reaction product having a mole ratio of propylene groups to terephthalate groups of less than about 1.5 is continuously withdrawn from the flasher. The liquid flasher reaction product is continuously fed to a prepolymerizer where it is continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a second stream of gaseous by-products.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a prepolymerizer. Bis-3-hydroxypropyl terephthalate and the low molecular weight polyesters are continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a first stream of gaseous by-products. Poly(trimethylene terephthalate) prepolymer having a relative viscosity of at least about 5 is continuously withdrawn from the prepolymerizer and continuously fed to a final polymerizer, where it is continuously polymerized to form a higher molecular weight poly(trimethylene terephthalate) and a second stream of gaseous by-products.