Patent ID: 7223830

Claim:
A process for the continuous production of polytrimethylene terephthalate, in which pure terephthalic acid is esterified with 1,3-propanediol, thereafter prepolycondensated and subsequently polycondensated, the vapors formed thereby are rectified to form a liquid phase and a vapor phase, and the liquid phase, consisting of 1,3-propanediol, is recirculated to the production process and the vapor phase, containing the lower-boiling components water, acrolein, allyl alcohol, 1-butanol, 1-propanol, hydroxypropanol and acetic acid is condensed and supplied to a stripping column wherein the condensate is stripped with air, a portion of the stripped condensate is circulated back to the stripping column as reflux, a portion is recirculated to the rectification, and a portion of the stripped condensate is discharged.