Alkaline depolymerization of poly(trimethylene terephthalate)

The purpose of this study was to investigate the effects of reaction media, composition, and temperature on the rate of the alkaline depolymerization of poly(trimethylene terephthalate) (PTT). The alkaline depolymerization of PTT was carried out at 160-190 degreesC in ethylene glycol (EG), diethylen e glycol (DEG), triethylene glycol (TEG), ethylene glycol monobutyl ether ( EGMBE), diethylene glycol monoethyl ether (DEGMEE), and a mixture of these solvents. During the reaction, PTT was quantitatively converted to disodium terephthalate and 1,3-propanediol. The alkaline depolymerization reaction rate constants were calculated based on the concentration of sodium carboxy late, which was equivalent to the molar amount of sodium hydroxide. The dep olymerization rate of PTT was increased by increasing the reaction temperat ure and by adding ethereal solvents. Moreover, the depolymerization rate wa s significantly accelerated in the order of EG < DEG < TEG < EGMBE < DEGMEE . (C) 2001 John Wiley & Sons, Inc.