A method for continuously preparing azo dye in micro-reactors

The invention discloses a method for continuously preparing azo dye in micro-reactors in the field of dye synthesis. The azo dye is prepared by firstly subjecting a sodium nitrite solution, an aromatic primary amine and an inorganic acid to a diazotization reaction at room temperature in a first micro-reactor to generate an aromatic primary amine diazonium salt; and then subjecting the aromatic primary amine diazonium salt and a coupling component to a coupling reaction in a second micro-reactor to generate the azo dye. Continuous preparation of the azo dye is achieved by utilizing the micro-reactors, a process is simple, a reaction period is short, and a reaction process can be easily monitored and controlled. Addition of an excessive amount of the sodium nitrite and the coupling agent to increase the reaction speed is not required so that raw materials are saved and the method is environmentally friendly. Reaction liquid in the micro-reactors achieves high-speed collision mixing, a uniform reaction environment is formed immediately, the reaction efficiency is high, and the yield and quality of a reaction product are greatly improved.