Adsorption and oxidation of dimethylaniline by Laponite

Abstract

Coloration of synthetic Laponite by dimethylaniline was studied in relation to the adsorption data, and to different reaction conditions including the nature of the exchangeable cations, the pH and the concentration.

Using visible and i.r. spectra, together with X-ray patterns, the colour reaction mechanism was investigated. The coloration could be ascribed to the following stages: (1) sorption of dimethyl-aniline, (2) oxidation by atmospheric oxygen into N,N-dimethyl-N′-methylbenzidine and bis-p(N,N-dimethylaminophenyl)-p(N′-methylaminophenyl)methane and (3) further oxidation to a blue quinoid cation or its protonated yellow component and to methyl violet, respectively.