A process for preparing a compound of the formula ##STR1## wherein m represents zero or 1, which comprises reacting azobenzene with nitric acid in the presence of sulfuric acid in two steps, wherein (1) the first-step reaction is carried out under the following conditions 0<x.ltoreq.80, 0<y.ltoreq.11, and -0.3x+12.ltoreq.y.ltoreq.-0.22x+22 wherein x is the reaction temperature in .degree.C., and y is the weight ratio of sulfuric acid to water and fed into the reaction system, and (2) the second-step reaction is carried out under the following conditions 0.ltoreq.x, and -(1.7/100)x+1.7.ltoreq.y.ltoreq.-(3.9/88)x+3.9.
制备化合物的过程的方程式如下:其中m表示零或1,包括在
硫酸的存在下用两步反应
偶氮苯与
硝酸反应,其中(1)第一步反应在以下条件下进行:0
水的重量比,输入反应系统,以及(2)第二步反应在以下条件下进行:0≤x,-(1.7/100)x+1.7≤y≤-(3.9/88)x+3.9。