Ube Industries, Inc.

Jun Haruta

Yasushi Yamamoto

Tetsuro Tsuji

Kikuo Ataka

Noboru Kakeya

A method for producing biphenyl and its derivative comprising oxidatively coupling a benzene aromatic compound in the presence of a catalyst comprising a palladium salt, a copper salt, and a bidentate ligand compound capable of forming a complex with the palladium salt via the nitrogen atom and the oxygen atom in the molecule thereof in an atmosphere containing molecular oxygen. In particular, an improved method for selectively producing an asymmetrically substituted biphenyl derivative, such as a 2,3,3',4&#x2032;-biphenyltetracarboxylic acid tetraester, which comprises oxidatively coupling a substituted aromatic compound, such as a phthalic diester, in the presence of the catalyst in an atmosphere containing molecular oxygen without replenishing with a ligand.

Method for producing biphenyl and its derivatives

A production process, especially a continuous production process, for a biphenyltetracarboxylic acid tetraester characterized by carrying out, in parallel, a step of preliminarily mixing a phthalic acid diester and a palladium compound-containing catalyst to prepare a starting mixture, a step of continuously or intermittently supplying the starting mixture to a reactor, a step of conducting oxidative dimerization reaction of the phthalic acid diester in a temperature range of from 140&#xb0; C. and lower than 250&#xb0; C. while supplying molecular oxygen to the reactor to form a reaction mixture in the reactor, and a step of continuously or intermittently removing a portion of the reaction mixture from the reactor. Preferably, the palladium compound-containing catalyst in the starting mixture is dissolved in the phthalic acid diester, the palladium compound-containing catalyst comprises a palladium compound, a bidentate ligand and a copper compound, the reactor consists of a plurality of serially connected reactors and a carboxylic acid is also continuously or intermittently supplied to the reactor.

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Yamaguchi, Japan

Jun Haruta