| 摘要 |
PROBLEM TO BE SOLVED: To obtain high-purity 4,4'-biphenyldicarboxylic acid useful as a resin raw material in a high oxidation yield. SOLUTION: In this method for producing 4,4'-biphenyldicarboxylic acid by oxidizing a raw material such as a 4,4'-dialkylbiphenyl, etc. with molecular oxygen in the presence of a catalyst, a solid material consisting essentially of 4,4'-biphenyldicarboxylic acid is separated from the obtained oxidation reaction mixture and then the solid material is washed by using an organic solvent selected from alcohols, aliphatic carboxylic acids, pyrrolidones, formamides and dialkylalkyl sulfoxides having 50-200 deg.C boiling point in an amount of 0.5 to 10 times as much as the solid material.
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