Air Water Inc.

Sumikin Chemical Co., Ltd.

Hebei Sinochem Fuheng Co., Ltd.

Takeshi Namekata

Ikuo Ito

Toshio Sato

Keiichi Yokota

Kazuhiko Maeda

Tetsuo Murata

Koichi Fukui

Akihiko Nemoto

The present invention provides a method, as a means for industrially producing a refined 6-bromo-2-naphthalenecarboxylic acid product from a crude 6-bromo-2-naphthalenecarboxylic acid product, comprising: causing the above crude product to react with sodium hydroxide in water to precipitate a sodium salt of 6-bromo-2-naphthalenecarboxylic acid; performing recrystallization treatment for the obtained precipitate; causing the obtained crystal to react with acid in water to precipitate 6-bromo-2-naphthalenecarboxylic acid; and recovering the obtained precipitate.

Production method for refined 6-bromo-2-naphthalenecarboxylic acid product

Provided is a process for producing a high-purity pyridine compound from a crude pyridine compound that contains a diazine compound as an impurity, the method including a reaction step of reacting the crude pyridine compound with an aluminum hydride compound, and a distillation step of distilling the product obtained from the reaction step. The aluminum hydride compound preferably contains one or more compounds selected from lithium aluminum hydride and sodium aluminum hydride.

Process for producing pyridine compound, and pyridine compound

A process for producing 2,2'-bis (trifluoromethyl)-4,4&#x2032;-diaminobiphenyl which is useful as a raw material for polyimide resin, etc. In benzidine rearrangement of 3,3&#x2032;-bis(trifluoromethyl) hydrazobenzene in the presence of an inorganic acid such as sulfuric acid aqueous solution or concentrated hydrochloric acid, use of a water-immiscible organic solvent such as toluene as reaction solvent can increase the yield of the product. 3,3&#x2032;-bis(trifluoromethyl) hydrazobenzene can be synthesized by reduction of m-nitrobenzotrifluoride.

Process for producing 2,2'-bis(trifluoromethyl)-4,4&#x2032;-diaminobiphenyl

Highly pure 2,3-pyridinedicarboxylic acid is produced by a process suitable for application in commercial production with a high yield and with recirculation of waste liquor. The process comprises the steps of: (a) oxidizing quinoline or 8-hydroxyquinoline in a solvent in the presence of copper (II) ions to precipitate copper (II) salt of 2,3-pyridinedicarboxylic acid and then separate the precipitates, (b) reacting the separated copper (II) salt with an alkali in a solvent to obtain a solution of an alkali metal salt of 2,3-pyridinedicarboxylic acid, and (c) reacting the solution of the alkali metal salt with a mineral acid to precipitate 2,3-pyridinedicarboxylic acid and then separate the precipitates, and is characterized in that (A) part or all of the solution obtained after the precipitated 2,3-pyridinedicarboxylic acid is separated in step (c) is used as at least part of the solvent in step (a) or (b), or (B) copper or a copper compound is added to the solution obtained after the precipitated 2,3-pyridine-dicarboxylic acid is separated in step (c) to recover the 2,3-pyridinedicarboxylic acid remaining in the solution as its copper (II) salt.

Process for producing 2,3-pyridinedicarboxylic acid

Alkoxynaphthalenecarboxylic acid is produced by a process comprising the addition of 1,3-butadiene to alkoxyalkylbenzene to yield an adduct. The adduct is cyclized in the presence of an acid catalyst to alkoxyalkyltetralin. The tetralin derivative is then dehydrogenated to produce aloxyalkylnaphthalene, which is oxidized to alkoxynaphthalenecarboxylic acid.

Production method for alkoxynaphthalenecarboxylic acid

An improved process for manufacturing 5-hydroxyisophthalic acid by means of oxidizing 5-acyloxy-m-xylene or its oxidation intermediate with molecular oxygen in a solvent consisting of lower aliphatic carboxylic acid and acetic anhydride in the presence of catalyst consisting of heavy metal comprising cobalt as the main component, and a bromine compound, and hydrolyzing the product thereby obtained. The improvement is characterized in that the oxidation is carried out under a pressure of 2-15/cm.sup.2 gauge in the presence of an alkali metal compound corresponding to 0.1-1.1 gram atom in terms of alkali metal atom based upon 1 gram atom of the heavy metal used for the catalyst. The present invention produces a high-quality 5-hydroxyisophthalic acid having excellent color from 5-acyloxy-m-xylene.

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Kashima, Japan

Takeshi Namekata