Equilibrium data for some o—o′-dihydroxyazo dyes. Part 1.—Acid ionization constants

Abstract

Acid ionization constants for the two hydroxy groups in each of several o—o′-dihydroxyazo dyes have been determined spectrophotometrically at 25°C. Where self-association of the dyes in aqueous solutions interfered with the measurements, the self-association could be eliminated in dioxan + water mixtures, and the acid ionization constants in a series of solvent mixtures could be extrapolated to give the required values for pure water.