Effect of Temperature, Isotopic Composition of Water and Ethanol on the Tautomeric Equilibrium of Sulphonated Phenylazonaphtholes

The effect of temperature, isotopic composition of water and ethanol on the tautomeric equilib- rium of two phenylazonaphtholes that differ by sulphonic group in benzene ring was investigated spectrophotometrically. It was established that enhancement of water structure under decrease of temperature or change of common water to heavy one shifts the azoquinonhydrazone tautomeric equilibrium to more polar hydrazone tautomer. The destruction of water structure and decrease of solvent polarity at ethanol addition, on the contrary, increases the concentration of azotautomer.

Synthesis and Spectroscopic Study of Some Phenylazonaphthols

Synthesis of eight phenylazonaphthols containing hydroxyl-, carboxy-, sulpho- and aldehyde groups was described. The data concerning elemental, thermogravimetric analysis, NMR-spectra and electronic absorption spectra in ethanol were described.