On the Color-reactions of the Condensed Polycyclic Aromatic Hydrocarbons and their Related Quinones in the Solutions of the Concentrated Sulfuric Acid

The basicity of the condensed polynuclear aromatic hydrocarbons and their related quinones with higher molecular weight have been measured after the method of L. P. Hammett and J. Dyrup, and it is approximately estimated in terms of pKB. In dibenzopyrene molecule two values of pKB have been found. The larger seems to correspond to that of the smaller molecules such as hexamethylbenzene, tetracene. The smaller one seems to be equivalent to that of ovalene, anthanthrene etc. approximately, with which molecules the larger pKB value seems to be unable to be found, owing to the unstability or the low-solubility of them in the sulfuric acid in the present method of measurement. The relatively large difference of pKB between monoketones and quinones seems to be explained on the same considerations as above. The relatively small difference of pKBseems to be dependent on the molecular structure as in the case of azaaromatic hydrocarbons such as pyridine, quinoline and acridine. From the results of such series of molecules as violanthrene, mesonaphhtodianthrene, zethrene, compared with the series of circulartype of molecules such as ovalene, anthanthrene, it is suggested that the proton is more easily attached to the molecule which seems to have localized π-electron in some sense.