LAUSR

ABSTRACT A multi-step catalyst-free synthesis of azo compounds by using n-butyl nitrite as a diazotization reagent and p-toluene sulfonic acid as a mild acidic agent in ethanol/water mixed solvent was investigated. In the combined one-pot synthesis process, no nitrous acid was produced during the diazotization. By controlling the conditions in a continuous process, a 62–88% yield was obtained. The current method has the following advantages: reduce waste by avoiding solvent for the purification of products in the diazotization step; save energy, time, and cost; work under environmentally benign conditions, and produce a good amount of products with potential use as azo-dyes, pigments, and therapeutic agents.