Mitsubishi Gas Chemical Company, Inc.

Hideharu Kurashima

Masahiro Kurokawa

Yasushi Higuchi

Akio Hashimoto

Masayoshi Hayashi

Tsutomu Numoto

Ryuusuke Shigematsu

Jyunichi Hisae

A method for producing a purified naphthalenedicarboxylic acid includes steps of mixing a naphthalenedicarboxylic acid-containing material and an amine in a mixed liquid of water and an organic solvent to give a crystal of a naphthalenedicarboxylic acid amine salt; and obtaining a purified naphthalenedicarboxylic acid from the crystal of the naphthalenedicarboxylic acid amine salt, wherein (1) in the step of forming the naphthalenedicarboxylic acid amine salt by adding an amine to the slurry that contains water, an organic solvent and a naphthalenedicarboxylic acid, the amine addition rate is from 0.002 to 0.4 mol/min relative to one mol of the naphthalenedicarboxylic acid, or (2) an amine is added to the aqueous solution prepared by dissolving the naphthalenedicarboxylic acid amine salt in water, or to the liquid prepared through solid-liquid separation of the aqueous solution to insolubilize and precipitate the metal component, and the precipitated metal component is removed through solid-liquid separation.

Method for producing a purified naphthalene dicarboxylic acid

A diamine and an epihalohydrin are subjected to ring-opening addition reaction in the presence of water, to thereby produce a tetrahalohydrinamino compound (i.e., halohydrin compound). Thereafter, the halohydrin compound is reacted with an alkali metal hydroxide in the co-presence of a phase-transfer catalyst, to thereby allow cyclization reaction to proceed. An alkali metal halide by-produced during the cyclization reaction is dissolved in water and removed through phase separation. The resultant organic layer is washed with water for phase separation. Then, a crude tetraglycidylamino compound obtained by recovering unreacted epihalohydrin through evaporation is dissolved in an organic solvent and washed with water for phase separation. Subsequently, the organic solvent is recovered through evaporation under reduced pressure with heating, to thereby isolate a tetraglycidylamino compound (i.e., a product of interest). An aqueous alkali metal hydroxide solution is added to the organic solvent recovered through evaporation, followed by thermal treatment. The thus-purified organic solvent is recycled. This method can effectively produce, at low cost, a tetraglycidylamino compound (i.e., a product of interest) of reliable quality having low residual epihalohydrin and hydrolyzable halogen contents.

Process for producing tetraglycidylamino compound

A process for preparing a cyclic ester by reacting an .alpha.-hydroxycarboxylic acid or an .alpha.-hydroxycarboxyliclic acid ester with an orthoester. A process for purifying a cyclic ester by containing water and acid as impurities by adding an orthoester to a cyclic ester obtained by reaction of a reaction mixture including an .alpha.-hydrocarboxylic acid or an .alpha.-hydroxycarboxyliclic acid ester. According to the present invention, a high-purity cyclic ester containing small amounts of impurities such as water and an acid component can be provided.

Preparation process and purification process of cyclic ester

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Kurashiki, Japan

Hideharu Kurashima