| 摘要 |
PURPOSE:A reaction mixture resulting from the oxidation of 2-methyl-naphthalene is treated with a specific solvent and an aqueous bisulfite solution to separate the titled compound with which can be used as a vitamin K3 in high yield and purity advantaneously from the view point of pollution. CONSTITUTION:2-Methylnaphthalene is oxidized in a solvent such as aliphatic hydrocarbon and/or alicyclic hydrocarbon using aqueous ceric salt solution and the resultant mixed solution containing 2-methyl-1,4-naphthoquinone and 6-methyl-1,4-naphthoquinone is cooled down to precipitate crystals containing 2-methyl-1,4-naphthoquinone (the first crystals), which are separated. Then, the filtrate is treated with an aqueous bisulfite salt to form an adduct thereof to 6-methyl-1,4-naphthoquinone and the adduct is extracted in the form of aqueous solution. Then, the oil phase containing 2-methyl-1,4-naphthoquinone is concentrated, cooled down, then the first crystals are dissolved in the resultant oil phase to effect recrystallization to separate the crystals. The filtrate is recycled.
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