Abstract
Infrared absorption spectra of a mixture of 1, 4-naphthoquinone and phenol, hydroquinone, or 1, 4-naphthohydroquinone in various molar ratios were measured in Nujol and cyclohexane. The spectra of mixtures with phenol in various ratios in liquid or solid state exhibited three absorptions of νC=O, one of which agreed with that of 1, 4-naphthoquinone. This fact suggests that, differing from the mixture of p-benzoquinone and phenol, there does not seem to be complex formation and formation of a molecular compound must be assumed. The mixtures with hydroquinone or 1, 4-naphthohydroquinone gave characteristic spectra differing from the spectra of each individual component in equimolar ratios and formation of a complex was recognized from their absorptions. The complex of 1, 4-naphthohydroquinone and 1, 4-naphthoquinone colored dark violet and absorption of νC=O appeared in the lowest wave number. However, these complexes showed absorption band of 1, 4-naphthoquinone in cyclohexane, so that the complex was considered to be dissociated into their molecular compound and 1, 4-naphthoquinone. It was thereby learned that the molecular compound is far more labile than that of p-benzoquinone series.
