Synthesis of diazo dyes using the cellulose sulfuric acid at room temperature



This article, describes a new method for synthesis of diazo dyes. In this protocol, cellulose sulfuric acid has been used as a proton source for producing diazonium salts. The resulting anion, in the presence of diazonium salt (ArN2+-O3SO-Cellulose), causes high stability of this salt at room temperature, and also results avoidance the use of harmful acids. This procedure for the preparation of diazonium salt was carried out under solvent free condition. The mixtur of amine, sodium nitrite and cellulose sulfuric acid, was grinded in a mortar and by grinding futher, coupling reaction was carried out. So by using cellulose sulfuric acid, diazo dyes with different derivatives were prepared in good to excellent yields and short reaction time, in one pot under ambient condition.