The Research On Improved Technology For Synthesis Of 6-Nitro-1, 2-Diazoxynaphthalene-4-Sulfonic Acid

6-Nitro-1,2-diazoxynaphthalene-4-sulfonic acid is mainly synthesized from base-dissolving method in dyestuff industry whose total product yield is 58~60%.There has been plenty of wastewater during the production process, and the waste water has the characteristic of dark color, high organic matter concentration, strong acidity and hardly in biodegradation. The thesis is to begin with the change in synthetic technology conditions, through changing the condition of nitration reaction to improve the yield and try to reduce the discharge of waste water at the same time.Forβ-naphthol is insoluble in water and soluble in organic soluent such as ethanol,ether,chloroform,glycerol etc .We plan to use water-ethanol binary mixtures to take place of the liquid alkali to dissolveβ-naphthol for nitration reaction. The main factors influencing the total product yield in nitration are the selection of organic soluent, reaction temperature, sulfuric acid concentration, the speed of acidification etc. Measures such as filtration,washing and air drying should be taken to materials after nitration. It is showed that the optimal experimental conditions for nitration reaction are determined by the following points: reaction temperature(0~3℃) , reaction time(4 hours), nitration reaction with a mixture of 30gβ-naphthol and 22ml sulfuric acid whose concentration is 500g.l-1 in 100ml ethanol medium. When the diluent water consumption is 100ml, namely the sulfuric acid concentration is 9%, heart-preservation time of the nitration reaction is 1 hour, then it has a filtration, washing and six-hour air drying after reaction. Wastewater from the nitration reaction is desalted by electrodialysis. The effects that Voltage and outlet flow rate have on the desalination by electrodialysis technology are discussed in this thesis. And conditions of the desalination by electrodialysis are concluded: Voltage 40V, fresh waster flow rate of desalination 24L/h, desalination rate of the freshwater reaches 94.89% which can be totally recycled. The residual wastewater is only 1/5 from the base-dissolving method. As ethanol has been distillated after the nitration reaction, so ethanol is not contained in the next addition reaction and sulfonation reaction. A series of comparison experiments are done according to a lot of factors that effect addition reaction and sulfonation reaction. Such as material amount,reaction time,catalyst amount,reaction temperature, etc. And best experiment conditions are concluded: take the amount of sodium bisulfite 2.5 times that ofβ-naphthol for addition reaction in 1.5h , choose CuSO4 as catalyst and translocate for 6h when the temperature reaches 55~60℃.The production technology process has obvious improvement on material consumption, product yield, wastewater amount of product and economic benefit after modification. Ethanol-solution method needs less materials than that of base-dissolving method, and the yield of 1-amino-2-naphthol-4-sulfonic acid(1,2,4-acid for short) has improved from 68～70% to 74.5%, wastewater of nitration reaction has reduced to 1/5 of the original process, thus it will save production cost for about 3290.4 yuan for synthesize every 1000kg 1,2,4-acid .So it is a economical and feasible process , good for industrial production.