4-(Phenylamino)benzenediazonium

Method 1: Using p-nitrochlorobenzene and aniline as raw materials, firstly condense the two in the presence of a copper catalyst, then reduce by sodium sulfide to obtain 4-aminodiphenylamine, and obtain the product by diazotization. . Method 2: Using diphenylamine as raw material, through nitrosation, 4-aminodiphenylamine is obtained by reduction, and the product is obtained by diazotization. . Add 640L of chloroform and 270kg of diphenylamine (100% in flakes) to the nitrosation kettle, stir to dissolve, then add 470kg of 29% sulfuric acid, and slowly add 220L of 40% sodium nitrite solution at 25-28°C in 2.5-3h. After the addition, let it stand for 24 hours to obtain a chloroform solution of N-nitroso diphenylamine. Transfer it to a lead-lined transposition kettle, and at the same time add 88kg of methanol, and pass in 75kg of hydrogen chloride gas at 25-30°C within 5.5-6h to obtain a p-nitrosodiphenylamine slurry. Transfer it to the extraction pot pre-added with 4000L water, 700L 33% sodium hydroxide solution and 1000kg ice. The temperature rises from 0℃ to 4-5℃. After vigorous stirring, let it stand for 24h to separate the p-nitrosodiphenylamine. Aqueous solution. Then add 30kg silica gel and mix with it, blow with air for 5 hours to remove residual chloroform, filter to remove silica gel, and put the filtrate into the reduction pot. After the separated chloroform layer is washed with water and dilute lye, it is separated from the lye layer and can be reused. The alkaline water layer can also be used in the extraction pot. Put the p-nitrosodiphenylamine aqueous solution and 400kg sodium polysulfide solution into the reduction pot, and the temperature will rise from 30-40℃ to 80℃ within 3-4h, and keep it for 1h. 4-aminodiphenylamine precipitates out in granular form. Cool to 30°C and filter. The filter cake is washed 5 times with a total of 5000L of water, and the product is about 270kg. After diazotization, salt formation, filtration and drying, the finished product is obtained.

Blue salt VRT is mainly used for dyeing cotton, but also for dyeing viscose fiber and printing cotton cloth. Coupling with Naphthol AS, Naphthol AS-D to dye red light blue; Coupling with Naphthol AS-RL, Naphthol AS-BS to dye blue. The coupling ability is weak and the coupling speed is medium. It is widely used for printing drawings, and its 4-aminodiphenylamine is an important fine chemical intermediate for the production of antioxidants and dyes.