Nippon Steel Corporation

Nippon Steel Chemical Co., Ltd.

Yoshimi Kata

Shuichi Mitamura

Yasuhisa Tsutsumi

Atsushi Kawada

Koichi Fujishiro

Naoya Okabayashi

The process of this invention for preparing 2,6-naphthalene-dicarboxylic acid comprises a reaction step (Step A) wherein 2,6-naphthalene-dicarboxylic acid potassium salts consisting of 2,6-naphthalene-dicarboxylic acid dipotassium salt and/or 2,6-naphthalene-dicarboxylic acid monopotassium salt are allowed to react with benzene-carboxylic acids in the presence of water to yield 2,6-naphthalene-dicarboxylic acid and benzene-carboxylic acid potassium salts and a separation step (Step B) wherein the crystallized 2,6-naphthalene-dicarboxylic acid is separated from the benzene-carboxylic acid potassium salts dissolved in the aqueous solution and provides 2,6-naphthalene-dicarboxylic acid, useful as raw material for polymers, at low cost on a commerical scale with recycle of potassium.

Process for preparing 2,6-naphthalene-dicarboxylic acid

A process for the preparation of aromatic carboxylic acids or their salts comprises heating carboxyl-free aromatic compounds and aromatic carboxylic acid salts whose basic structures differ from those of the aromatic compounds, or heating polycyclic aromatic compounds with three or more rings and monocyclic or bicyclic aromatic carboxylic acid salts, under carbon dioxide pressure in the presence of one or more metal compounds selected from group (a) of compounds of zinc, cadmium, and thallium and one or more compounds selected from group (b) of compounds of cesium, Group II metals, And Group IIIa metals to effect the intermolecular transfer of the carboxyl groups.

Process for the preparation of aromatic carboxylic acids

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Kawasaki, Japan

Yoshimi Kata