Synthesis of polyester by means of polycondensation of diol ester and dicarboxylic acid ester through ester–ester exchange reaction
Takayoshi Katoh, Yukiko Ogawa, Yoshihiro Ohta, Tsutomu Yokozawa
Abstract
Abstract Based on our finding that the ester‐ester exchange reaction between butyl benzoate and ethyl 4‐phenylbenzoate in the presence of a metal alkoxide is faster than the ester‐alcohol exchange reaction of butyl benzoate and ethanol, we investigated the synthesis of polyester through ester‐ester exchange reaction under various conditions. The polycondensation of diol formate and methyl dicarboxylate in the presence of a catalytic amount of potassium tert ‐butoxide ( t BuOK) in diglyme at 120 °C under reduced pressure (90–100 Torr) afforded high‐molecular‐weight polyesters. Methyl dicarboxylate containing an amino group could be used for this polycondensation, although the corresponding diacid chloride containing an amino group was not isolable. The ester‐ester exchange reaction could proceed even at the polyester backbone, and the reaction of poly(1,12‐dodecamethylene isophthalate) ( PEs 1 ) with poly(ε‐caprolactone) (PCL) in the presence of t BuOK at 140 °C afforded a copolymer PEs 1 ‐ stat ‐PCL, the structure of which was confirmed by 13 C NMR spectroscopy and DSC thermal analysis. A similar copolymer was also obtained by the polycondensation of dodecane‐1,12‐diol formate and dimethyl isophthalate in the presence of PCL and t BuOK at 120 °C under reduced pressure.