1958 年 78 巻 4 号 p. 410-414
The oxidation reaction reported in Parts IX and X of this series is a reaction in weak acidity of pH 4.2-4.5. In the present series of experiments, the effect of pH on the oxidation of aniline with periodic acid was examined in detail.
1) Reaction in strong acidity (pH 1.0): In the initial stage of the reaction, precipitate of emeraldine is formed but if the mixture is allowed to stand until consumption of IO4- becomes constant, then a black powder is obtained. This powder, as well as the substance obtained by its treatment with ammonia, forms a precipitate insoluble in 80% acetic acid and other common solvents. In this case, IO3- formed from IO4- also takes part in this reaction.
2) Reaction in strong alkalinity (pH 12.0): Reaction does not occur at all.
3) Reaction in weak alkalinity (pH 9.0-9.4): The reaction is very slow and it requires about 120 hours until consumption of IO4- becomes constant. The chief component of the oxidation products is dianilino-p-benzoquinone. In addition, bibliographically unknown two substances, reddish brown needles of m.p. 151° (decomp.) and yellow plates of m.p. 174°, were obtained as the oxidation products of aniline.