キノン系分子化合物とその赤外部吸収スペクトル (第3報)

2-メチル-1,4-ナフトキノンの複合物と2-メチル-1,4-ナフトキノン酸性亜硫酸ナトリウムの着色について

抄録

2-Methyl-1, 4-naphthoquinone-sodium hydrogensulfite adduct (menadione sodium bisulfite) is used as the vitamin K₃ preparation. This compound, in solid state, undergoes coloration with passage of time, from yellow to red, and the most marked colors reddish violet. The cause of this coloration was proved to be the formation of a solid complex between 2-methyl-1, 4-naphthoquinone, produced by liberation of sulfurous acid from the above compound, and its reduction product, 2-methyl-1, 4-naphthohydroquinone. Infrared absorption spectra were measured of a mixture of these two components in various ratios and the displacement of absorption bands of ν_O-H, ν_C=O, and δ′_C-H was examined. It was thereby learned that the complex responsible for the coloration is composed of 1 mole of 2-methyl-1, 4-naphthoquinone and 2 moles of 2-methyl-1, 4-naphthohydroquinone, and that the complex dissociated in nonpolar solvents into the two components.