Method for producing biphenyltetracarboxylic acid tetraester

A method for producing a biphenyltetracarboxylic acid tetraester comprising oxidatively coupling a phthalic acid diester with a catalyst comprising at least a palladium salt, a copper salt and a β-dicarbonyl compound in the presence of molecular oxygen, wherein

• the β-dicarbonyl compound is supplied into a reaction mixture liquid intermittently or continuously at a temperature of the reaction mixture liquid not lower than 130° C.

A method for producing a biphenyltetracarboxylic acid tetraester comprising oxidatively coupling a phthalic acid diester with a comprising at least a palladium salt, a copper salt and a β-dicarbonyl compound in the presence of molecular oxygen, wherein

• the β-dicarbonyl compound is a compound denoted by a chemical formula (1), and in which a proportion of an enol form is higher than 80% at 26° C. in a solution state at a concentration of 0.1 mol/L in dimethyl phthalate ester,
• wherein Ra, Rb are each independently an alkyl group wherein the β-dicarbonyl compound is supplied into a reaction mixture liquid intermittently or continuously at a temperature of the reaction mixture liquid not lower than 130° C.