Patent ID: 8168819

Claim:
A process for producing 5-phenylisophthalic acid represented by formula (1): characterized in that the process comprises the following steps (A) to (C): (A) reacting m-xylene with cyclohexene in the presence of hydrogen fluoride and boron trifluoride, to thereby produce 1-cyclohexyl-3,5-dimethylbenzene; (B) dehydrogenating the 1-cyclohexyl-3,5-dimethylbenzene produced in step (A) in the presence of a dehydrogenation catalyst, to thereby produce 3,5-dimethylbiphenyl; and (C) dissolving the 3,5-dimethylbiphenyl produced in step (B) in a solvent and oxidizing the 3,5-dimethylbiphenyl in the co-presence of an oxidation catalyst, to thereby produce 5-phenylisophthalic acid wherein, in step (A), m-xylene is alkylated with cyclohexene in the presence of hydrogen fluoride, and, subsequently, isomerization/transalkylation is performed in the presence of hydrogen fluoride and boron trifluoride; wherein the dehydrogenation catalyst employed in step (B) is a catalyst containing platinum and/or palladium, supported on a carrier; and wherein, in step (C), the solvent is acetic acid containing 3 to 15 mass % of water, the oxidation catalyst is a catalyst containing a cobalt atom, a manganese atom, and a bromine atom, and oxidation is performed by an oxygen-containing gas.