| 摘要 |
1,244,859. Polycondensation of bisglycol esters. IMPERIAL CHEMICAL INDUSTRIES Ltd. 13 Nov., 1969 [3 Dec., 1968], No. 57270/68. Heading C3R. [Also in Division C2] Compounds of the Formula (I) (Division C2 where both M's are the same and are phosphorus or arsenic atoms, each R is hydrocarbyl or hydrocarbyloxy, R 1 is a direct link or a divalent hydrocarbon group and X is ananionic ligand or an alkyl group, are used as catalysts in the polycondensation of bisglycol esters of aromatic dicarboxylic acids. The ester may be obtained from dimethyl terephthalate and ethylene glycol, and the condensation may be carried out in the presence of TiO 2 . Reference has been directed by the Comptroller to Specification 1,197,717. |
