Mitsubishi Gas Chemical Company, Inc.

Hiroshi Watanabe

Tatsuya Hasegawa

Fumiya Zaima

Masato Inari

Kazuhiko Amakawa

Hiroshi Machida

Emiko Yokose

Kuniaki Muneyasu

Yasuaki Kambe

Kohei Uchida

Daigo Hirakawa

Synthesizing methanol from a synthesis gas and separating an unreacted gas from a reaction mixture obtained by passing through the synthesis step, the method including a synthesis loop having at least two synthesis steps and at least two separation steps; obtaining a first mixed gas by increasing through a circulator a pressure of a residual gas, obtained by removing a purge gas from the final unreacted gas separated from the final reaction mixture subsequent to the final synthesis step, and by mixing the residual gas with a fraction of a make-up gas; synthesizing methanol; separating a first unreacted gas from the first reaction mixture obtained in the synthesizing step; obtaining a second mixed gas by mixing the first unreacted gas and a fraction of the make-up gas; finally synthesizing methanol; and separating the final unreacted gas from the final reaction mixture obtained in the final synthesis step.

Method for producing methanol and apparatus for producing methanol

A crude liquid containing 1,3-bis(aminomethyl)cyclohexane and a high-boiling component having a boiling point higher than that of 1,3-bis(aminomethyl)cyclohexane is distilled. By controlling the distillation conditions, the high-boiling component is prevented from entering into a distilled 1,3-bis(aminomethyl)cyclohexane and the content of a low-boiling component in the distilled 1,3-bis(aminomethyl)cyclohexane is minimized.

Purification of 1,3-bis(aminomethyl)cyclohexane by distillation

Dialkylnaphthalene is oxidized to naphthalenedicarboxylic acid in a lower aliphatic carboxylic acid solvent in the presence of a catalyst comprising a cobalt compound, a manganese compound and a bromine compound having an atomic ratio of manganese to cobalt of 0.03 to 0.5. The catalyst is supplied to the oxidation reaction zone so that the total amount of cobalt and manganese is 0.025 to 0.1 gram atom based on 1 gram mol of the dialkylnaphthalene. An oxidation product slurry is subjected to solid-liquid separation when the concentration of the naphthalenedicarboxylic acid in the slurry is 8 to 30% by weight. The process prevents the by-production of benzotricarboxylic acid such as trimellitic acid, thereby drastically reducing the incorporation of heavy metal complexes with trimellitic acid into naphthalenedicarboxylic acid crystals. The process optionally includes the addition of a polymer flocculant, this forming crystal aggregates with a large particle size and facilitating the separation of the crystals from the mother liquor.

Method of producing naphthalenedicarboxylic acid

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Niigata, Japan

Hiroshi Watanabe