Preparation Of Sodium Dichloroisocyanurate

Sodium dichloroisocyanurate(DCCNa)is a new type of internal absorption fungicide.It has wide application range,high efficiency and good biocidal effect.After decades of development,the production technology of DCCNa has been popularized,the products produced by sodium hypochlorite method and the double decomposition of trichloroisocyanuric acid method are of high quality.In this paper,the effects of reaction temperature,pH and material ratio on the the double decomposition of trichloroisocyanuric acid method were studied systematically.Then this paper studied the sodium hypochlorite method,including the effects of reaction temperature,pH,the material ratio and the difference between low concentration sodium hypochlorite method and high concentration sodium hypochlorite method.It was found that pH and material ratio are important factors influencing the the double decomposition of trichloroisocyanuric acid method,while temperature has little effect on the reaction.According to the experimental results,the mole ratio of trichloroisocyanuric acid and trisodium cyanurate was 1:2.1,and trisodium cyanurate solution was chlorinated to pH=5,after 10 minutes of reaction,the relative optimal results could be obtained,the available chlorine content of DCCNa product was 57.88%and the yield was 69.73%.It was found that the reaction temperature,material ratio and the concentration of sodium hypochlorite solution had a great influence on the reaction results of the sodium hypochlorite method,and supplying chlorine in the reaction could increase the product quality.The final solution is to use high-concentration sodium hypochlorite and supply chlorine,the reaction temperature is 10?,the mole ratio of sodium hypochlorite to cyanuric acid is equal to 3.5:1,the reaction time is 20 minutes,the highest available chlorine content reached 62.03%,while product yield is 57.88%.The production of DCCNa using sodium hypochlorite produces a large amount of mother liquor,which contains many unreacted chlorine,cyanuric acid and sodium hydroxide.In this paper,mother liquid circulation method is used.The experiment shows that incorporation of 30%mother liquor in the reaction solution can make the available chlorine content of the DCCNa product reach 59.12%,while the DCCNa product yield can be increased to 66.30%.At last,this paper compared the difference between sodium hypochlorite method and double decomposition of trichloroisocyanuric acid method and used sodium hypochlorite method to design a process of producing 2,000 tons of DCCNa per year.The material and heat balance were calculated.