| 摘要 |
The invention relates to a process for purifying a mixture containing benzophenone 4,41-dicarboxylic acid or terephthalic acid, or for separating benzophenone 4,41-dicarboxylic acid from a mixture containing the same and benzophenone 2,41-dicarboxylic acid, or for separating terephthalic acid from a mixture containing the same and impurities admixed therewith by treating the mixture with a diether defined by the following formula <FORM:1093996/C2/1> wherein R1 is an alkyl group having from one to five carbon atoms and R11 and R111 are hydrogen or alkyl groups having from one to four carbon atoms. Examples of the diethers are dimethoxymethane, 1,1-dipropoxybutane, 1,1-di(tert.-butoxy) methane, 2,2-dimethoxypropane, 2,2-diethoxybutane, 2,2-dipropoxy - 4 - methylpentane, 3,3 - dipentoxypentane, diethoxymethane; 1,1 - dimethoxyethane; 1,1-diethoxyethane and preferably 2,2 - dimethoxypropane. Instead of the diether there may be used a mixture of an alcohol R1OH in which R1 is an alkyl group of 1 to 5 carbon atoms and a carbonyl-containing compound of the formula <FORM:1093996/C2/2> in which R11 and R111 are the same or different and are hydrogen or alkyl groups having 1 to 4 carbon atoms, preferably a mixture containing methanol and acetone. Examples are given on the separation of benzophenone 4,41-dicarboxylic acid from the 2,41 acid and of the purification of terephthalic acid. |
