An Introduction Of Sodium Dichloroisocyanurate(SDIC,DCCNa)
1. What’s the Sodium Dichloroisocyanurate ?
Sodium dichloroisocyanurate (DCCNa) is an organic compound with a molecular formula of C3Cl2N3NaO3. It is a white powdery crystal or granule at room temperature with a chlorine odor.Sodium dichloroisocyanurate is a commonly used disinfectant with strong oxidizing properties and has a strong biocidal effect on various pathogenic microorganisms such as viruses, bacterial spores, fungi, etc. Efficient fungicide.
– Chinese name : 二氯异氰尿酸钠 – Melting point: 225 ℃
– Foreign name : sodium dichloroisocyanurate – Boiling point: 306.7 ℃
– Chemical formula : C3Cl2N3NaO3 – Flash point: 139.3 ℃
– Molecular weight : 219.946 – Solubility: Easily soluble in water, insoluble in organic solvents
– Exterior : White powder crystals or granules – security description: S8；S26；S41；S60；S61
– CAS code : 2893-78-9 – Hazard Symbols: Xn
– EINECS code : 220-767-7 – Hazard description: R8；R22；R31；R36/37；R50/53
– Density : 2.06 g/cm³ – UN Dangerous Goods Number: 2465
2. DCCNa Features
(1) Strong sterilization and disinfection ability. The effective chlorine content of pure DCCNa is 64.5%, and the effective chlorine content of high-quality products is more than 60%, which has a strong disinfection and sterilization effect. At 20ppm, the sterilization rate reaches 99%. It has a strong killing effect on various bacteria, algae, fungi and germs.
(2) Its toxicity is very low, the median lethal dose (LD50) is as high as 1.67g/kg (the median lethal dose of trichloroisocyanuric acid is only 0.72~0.78g/kg). It has been approved at home and abroad to use DCCNa in the process of disinfection and sterilization of food and drinking water.
(3) Wide range of applications, this product can not only be used in food and beverage processing industry and drinking water disinfection, cleaning and disinfection of public places, but also widely used in industrial circulating water treatment, civil household sanitation and disinfection, and aquaculture disinfection. .
(4) The utilization rate of available chlorine is high, and the solubility of DCCNa in water is very high. At 25°C, 30g of sodium dichloroisocyanurate can be dissolved per 100mL of water. Even in an aqueous solution with a water temperature as low as 4°C, SDIC can quickly release all the available chlorine contained in it, so that its disinfection and sterilization effect can be fully utilized. Other solid chlorine-containing products (except chlorinated isocyanuric acid) have a much lower chlorine value than SDIC due to low solubility or slow release of chlorine.
(5) Good stability, because the triazine ring in the molecule of chlorinated isocyanuric acid products has high stability, so the properties of DCCNa are very stable. It is determined that the loss of available chlorine is less than 1% after 1 year of storage of the dried SDIC in the warehouse.
(6) The product is solid and can be made into white powder or granules or tablets, which is convenient for packaging and transportation, and is also convenient for users to choose and use.
3. DCCNa Applications
DCCNa is an efficient disinfectant with high solubility in water, long-lasting anti-virus ability and low toxicity, so it is widely used as a drinking water disinfectant and a household disinfectant. It can hydrolyze hypochlorous acid in water and can replace hypochlorous acid in some occasions, so it can be used as a bleaching agent. And because it can be industrially produced on a large scale and has a low price, it is widely used in many industries.
- Anti-shrinkage treatment agent for wool:
- DCCNa can release hypochlorous acid evenly in the aqueous solution, interact with the protein molecules in the wool scale layer, break some bonds in the protein molecules, and change its molecular structure to prevent wool from shrinking. In addition, it can also be added to detergents such as washing powder, so that when washing wool products, it can effectively prevent the occurrence of wool adhesion and pilling. Wool fabrics treated with SDIC have bright color, good hand feel, and basically do not shrink; adding 2% to 3% SDIC solution to wool or wool blended fibers and fabric impregnation treatment aids can effectively prevent wool and its Product pilling, felt shrinkage and other phenomena occur.
- Textile Industry Bleaching:
- SDIC is also widely used in bleaching agents for natural and synthetic fibers in the textile industry. The principle of bleaching is to destroy the pigments in natural fibers and synthetic fibers.
- It can release hypochlorous acid uniformly in aqueous solution, and hypochlorous acid can react with some chromophoric groups in the fiber through addition reaction with its conjugated bond, destroy the original pigment in the fiber, and make the fiber absorb the wavelength of light change, so as to achieve the purpose of bleaching.
- Compared with the use of bleaching agents in the traditional sense, SDIC has great advantages. Traditional bleaching agents can only be used at lower temperatures, because the speed of traditional bleaching agents destroying the molecular structure of fibers under high temperature conditions will be reduced. Accelerate, the strength of the fiber will drop rapidly under its influence.
- However, it can still achieve good bleaching effect even at lower temperature; in addition, the use of SDIC to destroy the molecular structure of natural fibers and synthetic fibers is slow, the bleaching effect is good, and the strength of the fibers will not be greatly affected. In addition, adding SDIC to the bleaching agent can also improve the hydrophilicity of clothing, remove cotton pulp from clothing, reduce the degradation rate of cellulose, and improve the flexibility and ductility of clothing.
- Sterilization and disinfection in aquaculture:
- (1) Sterilization and disinfection of silkworm breeding If there is some negligence in silkworm breeding, bacteria, diseases and insect pests will damage the silkworm, and even cause the silkworm body to die. Using sodium dichloroisocyanurate as the main component, adding an appropriate amount of stabilizer and accelerator, the three are evenly mixed to form a disinfectant aqueous solution, and the silkworm body and the living environment where the silkworm body is located can be disinfected and sterilized, which can quickly kill viruses that affect silkworms, Fungi and bacteria.
- The SDIC aqueous solution can be sprayed on the silkworm, silkworm gear and silkworm body, which can prevent and control silkworm disease and kill gastrointestinal type pus polyhedrosis, gastrointestinal type pus disease virus, and blood type thick disease polyhedron. Compared with the traditional disinfectant for silkworms, the disinfectant with DCCNa as the main component has higher solubility, more stability and longer duration of efficacy. As an excellent disinfectant for the development of sericulture, It has little effect on the growth and development of silkworms and silkworm quality.
- (2) Sterilization and disinfection of aquaculture In the prevention and control of fish diseases, sodium dichloroisocyanurate also has a good performance. It can quickly kill bacteria, fungi and other microorganisms in the water body, and can also prevent viral diseases of fish.
- Therefore, it is often used for water disinfection of fish, shrimp, crab, frog and other aquatic products. It also has certain applications in the disinfection of fish fingerlings and fish utensils. The disinfection effect of sodium dichloroisocyanurate on drinking water: after the drinking water is disinfected, the survival rate of chickens is about 97%, while the average survival rate of chickens without drinking water disinfection is 90.07%, an increase of nearly 7 percentage points. The water sterilized by sodium cyanurate is given to chickens to drink, which is of great benefit to the health of chickens, greatly improves the survival rate of chickens, and naturally improves economic benefits.
- Civil Sanitation and Disinfection:
- 1) Additives for detergents Adding an appropriate amount of sodium dichloroisocyanurate to household dishwashing liquids and other detergents can increase the function of the detergent, so that it can play the role of anti-virus and sterilization, and the effect is very significant when cleaning stains containing protein and juice.
- 600mg of DCCNa can be weighed and added to 1L of water, and the tableware can be soaked in water for 2 minutes to kill 100% of Escherichia coli. After 8 minutes of immersion and disinfection, the survival rate of Bacillus is reduced to only 2%. After 15 minutes of immersion and disinfection, hepatitis B virus can be destroyed. Total kill. In addition, SDIC is also widely used in the disinfection of fruits, vegetables, eggs and other agricultural products, and is a common additive for refrigerator disinfectants and toilet disinfection and deodorants.
- (2) Swimming pool water body disinfection, swimming pool water is very suitable for the reproduction of microorganisms such as germs. Without frequent disinfection, algae and other microorganisms can quickly grow, causing the water to smell disgusting and cling to the walls of the pool in a slippery, dirty layer. Encountering these dirt while swimming can make the swimmer feel disgusted, and also infect the swimmer’s skin, and even the swimmer’s eyes, respiratory tract and respiratory organs. An appropriate amount of SDIC disinfection tablets can be added to the swimming pool water, which can not only keep the water body clear and bright, but also keep the pool wall clean, remove the adherents, and make the swimmers happy. The SDIC disinfectant tablet has a good sterilization effect under the use concentration, and basically does not harm the human body.
- (3) Disinfection of drinking water, adding an appropriate amount of SDIC to drinking water can quickly kill microorganisms such as various germs and viruses. Not only that, but DCCNa can also destroy pollutant molecules such as hydrogen sulfide in water, eliminating its color and its odor. It has a significant killing effect on serotonin virus and coliform bacteria. Adding 10 mg sodium dichloroisocyanurate per liter of water, the survival rate of Escherichia coli in water is 0.01%.
- Industrial circulating water treatment:
- Many thermal power plants, petroleum refineries, and chemical plants generate a lot of heat during the production process. This heat requires a lot of cooling water to handle. Typically, these industries use heat exchange equipment such as heat exchangers, condensers, circulation pipes, cooling towers, pump systems, etc. But the algae in these heat exchangers are very easy to multiply and breed a lot of fouling. The algae in the cooling water can be treated very effectively by using the fungicide treatment, among which DCCNa is a commonly used cooling water fungicide. sodium dichloroisocyanurate can effectively inhibit the reproduction of algal microorganisms in cooling water, and has little erosion to industrial equipment, and can keep the water quality in the circulating water system in good condition for a long time. Therefore, SDIC is an important part of industrial cooling water treatment agent.
- Food industry, cleaning and disinfection of public places:
- Food processing industries such as dairy processing plants, breweries and other beverage factories have also begun to use SDIC in large quantities for cleaning and disinfection. It is mainly used for disinfection and sterilization of processing equipment such as containers, pipes, tools and sites. There are also some catering industries such as cold drink shops, teahouses, restaurants, etc., which often use SDIC to sanitize dishes such as trays, bowls, tablecloths, and hand towels. The use of DCCNa can maintain the hygiene of tableware and food processing equipment and eliminate stains, mildew spots, odors, etc. caused by proteins, maintain the luster of tableware, and prevent the spread of diseases.
4. DCCNa Preparation
DCCNa has three main synthesis methods, namely dichloroisocyanuric acid method, trichloroisocyanuric acid metathesis method and sodium hypochlorite method, each method has different characteristics, which are briefly described as follows:
Sodium hypochlorite method
This method can be divided into a low-concentration sodium hypochlorite method and a high-concentration sodium hypochlorite method according to the concentration of the sodium hypochlorite solution used. In the low-concentration sodium hypochlorite method, the chlorine gas is first introduced into the sodium hydroxide solution to generate a sodium hypochlorite solution with an effective chlorine mass fraction of 10% to 11%. The wet product is obtained by filtration, and chlorine gas can be supplemented in the reaction of cyanuric acid and sodium hypochlorite solution to further increase the effective chlorine content of the product, and simultaneously suppress the generation of nitrogen trichloride.
Neutralization with sulfuric and hydrochloric acid can also be used to lower the pH of the mother liquor. The advantage of the low-concentration sodium hypochlorite method is that the operation is simple, but the utilization rate of the raw material sodium hypochlorite is low. In the chlorination section of this method, a large amount of inorganic salts will be generated, and it is necessary to repeatedly wash off the salts with a saturated aqueous solution of sodium dichloroisocyanurate, so the production process is complicated, and the available chlorine content of the product dichloroisocyanuric acid is low. This method is only suitable for chlor-alkali plants with a large by-product of sodium hypochlorite.
The first step of the high-concentration sodium hypochlorite method is to synthesize sodium hypochlorite with an effective chlorine content of more than 20% (generally 23% to 25%), and then perform a chlorination reaction with cyanuric acid to generate DCCNa. The mass fraction of available chlorine in the product of this method largely depends on the concentration of sodium hypochlorite solution. The product synthesized by using high concentration sodium hypochlorite has a high content of available chlorine, and the mother liquor produced in the production can be used to co-produce trichloroisocyanuric acid to Improve the utilization rate of raw materials.
Dichloroisocyanuric acid method
The first step of this method is to synthesize dichloroisocyanuric acid, and then react it with caustic soda to prepare DCCNa. First, mix cyanuric acid and sodium hydroxide solution in a molar ratio of 1:2 to generate a neutralization reaction to generate disodium cyanurate; After centrifugal filtration, wet dichloroisocyanuric acid slurry is obtained and put into DCCNa mother liquor, and caustic soda is added in a molar ratio of 1:1 to carry out neutralization reaction, and wet DCCNa is obtained after cooling, crystallization and filtration. After drying, powdery DCCNa or its dihydrate is obtained. The method can co-produce dichloroisocyanuric acid, which is also a chlorinated isocyanuric acid disinfectant product.
The solubility of dichloroisocyanuric acid is very low, and the filter cake can be fully washed to remove salts, so the product has high purity and low salt content. The disadvantage of this method is that dichloroisocyanuric acid is highly corrosive, and it is necessary to use titanium material with strong corrosion resistance or a reaction kettle and centrifuge lined with polytetrafluoroethylene, which leads to an increase in equipment costs; because dichloroisocyanuric acid The crystals are small and difficult to separate, so the requirements for separation technology are relatively high; more caustic soda solution is required to absorb the tail gas of the chlorination section.
Trichloroisocyanuric acid metathesis method
This method is also called neutralization. Firstly, cyanuric acid and sodium hydroxide solution are mixed in a molar ratio of 1:3 to make a neutralization reaction to generate trisodium cyanurate. Then at a suitable temperature, chlorine gas is introduced to chlorinate trisodium cyanurate into trichloroisocyanuric acid and centrifugal filtration to obtain trichloroisocyanuric acid slurry. Finally, trichloroisocyanuric acid slurry is prepared in a molar ratio of 2:1. The material is poured into the trisodium cyanurate solution, and it undergoes a metathesis reaction at an appropriate temperature to generate DCCNa. Finally, DCCNa is obtained by cooling, crystallization, filtration and drying of the mother liquor.
The advantage of this method is that trichloroisocyanuric acid can be co-produced at the same time, and trichloroisocyanuric acid is also an important chlorinated isocyanuric acid disinfectant product, and the output of the two products can be adjusted according to changes in market conditions; The concentration of sodium hydroxide solution used is very high, and the mother liquor obtained after separation can be reused.
The amount of inorganic salts produced in the production process of this method is very small, and repeated washing is not required; the content of inorganic salts in the product is small, and the mass fraction of available chlorine is high ; Continuous chlorination can be used in the reaction of trisodium cyanurate and chlorine, with large output and high safety.
Disadvantages of this method: the trichloroisocyanuric acid produced by chlorination is difficult to separate, so the requirements for separation technology and equipment are high, and the investment is large; in the production of trichloroisocyanuric acid, the utilization rate of chlorine gas in the chlorination section is not high , requires more caustic soda solution to absorb the tail gas of the chlorination section.
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