Process for production of biphenyltetracarboxylic acid tetraesters

Abstract

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° C. and lower than 250° 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.