Preparation of tetraester of 3, 3′, 4, 4′, - biphenyltetracarboxylic acid
AssigneeUbe Industries, Ltd.
InventorsAkira Ishikawa, Hiroto Mitsui, Kiyotaka Akao, Norihisa Komoda
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Abstract
A tetraester of 3,3′,4,4′-biphenyltetracarboxylic acid is advantageously prepared by a process composed of a step of dimerizing an o-phthalic diester in the presence of a catalyst comprising a powdery palladium salt having a specific surface area of at least 0.5 m2/g and a basic bidentate ligand compound and one or more steps of continuing the dimerization after supplemental addition of at least one of the powdery palladium salt and the basic bidentate ligand compound.
Claims9
A process for the preparation of a tetraester of 3,3′,4,4′-biphenyltetracarboxylic acid which comprises a step of dimerizing an o-phthalic diester in the presence of a catalyst composition comprising a powdery palladium salt having a specific surface area of at least 0.5 m2/g and a basic bidentate ligand compound and one or more steps of continuing the dimerization after supplemental addition of at least one of the powdery palladium salt and the basic bidentate ligand compound.
Dependencies are inferred from the claim text.