Interactions of chloroanilines with natural and ion exchanged montmorillonites

The interaction of 4-chloroaniline, 2,3- and 2,5-dichloroanilines with K-10 montmorillonite, and Cu2+-, Fe3+- and Al3+- ion exchanged montmorillonites have been investigated using GC/MS detection of the reaction products in n-hexane. Only 4-chloroaniline was found to react appreciably forming a condensation product, 4,4′-dichloroazobenzene over the ion exchanged montmorillonites. The efficiency of this reaction is dependent on the choice of exchangeable cation. It was found that for temperatures up to n-hexane boiling (69°C), Cu2+- montmorillonite shows greatest activity compared to K-10, Fe3+- or Al3+-montmorillonites. The reaction mechanism over the Cu2+-montmorillonite is interpreted to be a catalytic oxidative process involving the redox participation of the cation. The results suggest that the observed production of 4,4′-dichloroazobenzene in soils containing montmorillonite may have a chemical and not a biological origin as proposed previously.