| 摘要 |
1,145,678. Poly (alkylene terephthalates). FMC CORP. 5 Oct., 1967 [28 Feb., 1967], No. 45445/67. Heading C3R. In the manufacture of polyalkylene terephthalates by effecting an ester-interchange reaction between a dialkyl terephthalate and an alkylene glycol and thereafter polycondensing the resulting product, there is used as a polycondensation catalyst a salt of ethylene diamine tetracetic acid and an alkali metal, Fe, Zn, Cd, Hg, Ge, Sn, or Pb. Specified salts are dilithium ethylene diamine tetracetate, disodium lead ethylene diamine tetracetate, disodium zinc ethylene diamine tetracetate and mono-ferrous ethylene diamine tetracetate. Suitable esterinterchange catalysts are lithium hydride and zinc acetate. Examples describe the preparation of polyethylene terephthalate by reacting dimethyl terephthalate and ethylene glycol. |
