| 摘要 |
1,164,240. Glycol esters of aromatic dicarboxylic acids. FARBENFABRIKEN BAYER A.G. 7 Sept., 1967 [9 Sept., 1966], No. 40966/67. Heading C2C. [Also in Division C3] In the manufacture of esters by reacting an aromatic dicarboxylic acid with a cyclic glycol carbonate, there is used as a catalyst an organic compound containing a five-membered heterocyclic aromatic ring in which there are two, three or four heterocyclic nitrogen atoms, such as imidazole, a dialkyl imidazole, benzimidazole, a 2-alkylbenzimidazole, a 2-allylbenzimidazole, pyrazole, benzpyrazole, triazoles, e.g. 3,5-dimethyl-1,2,4-triazole and tetrazoles, e.g. 5- phenyltetrazole. As additional catalysts there may be used oxides of metals of the 4th, 5th or 6th Group of the Periodic System (e.g. Ti, Ge, Sn, Pb, Sb, Bi, Ta, Th or U). Specified dicarboxylic acids are o-, iso- and tere-phthalic acids and their alkyl- and hydroxy-substitution products and naphthalene dicarboxylic acids. Specified carbonates are those of ethylene and 1: 2-propylene glycol. Examples describe reacting terephthalic acid with the cyclic carbonate of ethylene or 1: 2-propylene glycol and ophthalic acid with the cyclic carbonate of ethylene glycol. |
