The formation of indoaniline dye on silver and copper-silver hydrosol particles
The influence of the composition of copper-silver hydrosol particles on the kinetics of heterogeneous formation of indoaniline dye was studied. The rate constant for the reaction first-order in N-ethyl-N-β-hydroxyethyl-p-phenylenediamine (TsPV-2) was found to decrease as the content of Cu in sol particles increased to 12 at. %. The observed dependence of the apparent activation energy of the reaction on solution pH was explained in terms of a reaction scheme with the rate-determining step of the formation of a semi-quinone radical in the oxidation of TsPV-2. The effective electron density, the coefficient of plasma oscillations of damping, and other parameters of sol particles were determined based on a theoretical analysis of the absorption spectra of sols. Changes in these parameters during the reaction were recorded. The observed kinetic parameter variations depending on the composition of particles were explained by changes in particle electronic characteristics.