Environmentally friendly efficient synthesis and mechanism of Triazenes derived from cyclic amines on Clays and Zeolites

The formation of diazotizing reagent starts with protonation of nitrous acid under strongly acidic conditions, and azo coupling carried out at low temperature in the presence of nucleophilic coupling components [1]. These conventional acid–base catalyzed processes are effective for the near quantitative formation of the desired products. But the main limitation of such synthetic processes is their environmental incompatibility. The acidic and basic effluents from the laboratory and industry produce permanent damage to the environment and disturb the ecological balance [2]. Clays have long been used as acidic catalysts and existence of both Lewis and Bronsted acid sites [3]. Montmorillonite clay, enable to function as an effcient solid acid catalyst in organic transformations with excellent product, regio- and stereo-selectivity [4]. Nowadays more and more heterogeneous Bronsted acids, e.g. zeolites are utilized, the excellent catalytic abilities are due to the presence of Bronsted and Lewis acid centers in the zeolite structure [5]. Because of its high protonic acidity and unique shape-selective behavior,