| 摘要 |
There is provided a process for producing 3,3',4,4'-tetramethyldiphenylmethane which comprises subjecting tetramethyldiphenylmethane containing at least one of 2,3,3',4'-tetramethyldiphenylmethane and 2,2',3,3'-tetramethyldiphenylmethane to isomerization reaction in the presence of a catalyst to convert into 3,3',4,4'-tetramethyldiphenylmethane. According to the process of the present invention, the objective 3,3',4,4'-tetramethyldiphenylmethane is efficiently obtained from tetramethyldiphenylmethane obtainable in particular by the reaction of o-xylene with formaldehyde. The 3,3',4,4'-tetramethyldiphenylmethane thus obtained can be converted by oxidation into 3,4,3',4'-benzophenonetetracarboxylic acid dianhydride which is important as a raw material for heat-resistant high molecular compounds. |
