Trichloroisocyanuric acid, chemical formula CthreeClthreeNthreeOthree, with a molecular weight of 232.41, is aOrganic compound, white crystalline powder or granular solid, with strongchlorineIrritating taste.[7]
Trichloroisocyanuric acid is a strong oxidant and chlorination agent, which is mixed with ammonium salt, ammonia and urea to form explosiveNitrogen trichlorideIt also emits nitrogen trichloride in case of moisture and heat, and is flammable in case of organic matter.Trichloroisocyanuric acid has almost no corrosion effect on stainless steel, and the corrosion of brass is stronger than that of carbon steel.[1]
White crystalline powder or granular solid with strongchlorineIrritating taste, containing more than 90% effective chlorine, the solubility in water at 25 ℃ is 1.2g, and it is easy to decompose in case of acid or alkali[4]。
Trichloroisocyanuric acid is a kind of chloroisocyanuric acid compound, which is an important bleaching agent, chlorinating agent and disinfectant.Compared with traditional chlorinators (such as liquid chlorine, bleaching powder and bleaching powder concentrate), it has the characteristics of high effective chlorine content, stable storage and transportation, convenient molding and use, high sterilization and bleaching power, long time to release effective chlorine in water, safety and non-toxic, etc. Therefore, its development and research have attracted the attention of all countries.Trichloroisocyanuric acid is widely used as a bactericide for industrial water, swimming pool water, hospital, tableware, etc. It has a broad prospect of development and utilization.Trichloroisocyanuric acid has been widely used in industrial circulating water.[5]
Trichloroisocyanuric acid is one of the series products of chloroisocyanuric acid, called TCCA for short. The pure product is white powder crystal, slightly soluble in water, easily soluble in organic solvents;[2]The content of active chlorine is 2-3 times higher than that of bleaching powder.Trichloroisocyanuric acid is a new generation product of bleaching powder and bleach. The three wastes are greatly reduced compared with bleach. It can be used as a substitute in advanced countriesBleachTrend.[3]
Historical development
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The main consumption and production of trichloroisocyanuric acid abroad are in the United States, Japan and Western Europe, and the domestic demand is about 6kt. With the continuous expansion of the application scope of this product, the demand is on the rise.In China, research began in the 1960s. In the 1970s, pilot production and small batch production began. In the 1980s, there were more than 20 trial production or trial production of such products, and 30 manufacturers.
Product use
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Sterilization
Trichloroisocyanuric acid is an effective disinfectionbleaching agentsIt is stable in storage, convenient and safe in use. It is widely used in food processing, drinking water disinfection, sericulture and rice seed disinfection. It has a killing effect on almost all fungi, bacteria, and virus spores, has a special effect on killing hepatitis A and hepatitis B viruses, and has a good disinfection effect on sex viruses and HIV. It is safe and convenient to use.Now it has been used in industrial water, swimming pool waterCleaning agent, hospitals, tableware, etc. used as disinfectant: used as disinfectant in sericulture and other aquaculture.Trichloroisocyanuric acid is not only widely used as disinfectant and bactericide, but also widely used in industrial production.
Application in printing and dyeing industry
Trichloroisocyanuric acid contains up to 90% active chlorine. It is used as a bleaching agent in the printing and dyeing industry and is suitable for bleaching cotton, linen, wool, synthetic fibers and blended fibers.It not only does not damage the fiber, but also has better performance than sodium hypochlorite and bleach. It can also replace imported sodium hypochlorite.
Application in food industry
Instead of chloramine T for food disinfection, its effective chlorine content is three times that of chloramine T.It can also be used as decolorizing and deodorizing agent of dextrin.
Application in wool textile industry
It is used as wool shrink proof agent in wool textile industry instead of potassium bromate.
Application in rubber industry
It is used as chlorination agent in rubber industry.
Used as industrial oxidant
The oxidation reduction electrode potential of trichloroisocyanuric acid is equivalent to hypochlorite, which can replace hypochlorite as a high-quality oxidant.
other aspects
It is used as a raw material in the organic synthesis industry, and can synthesize a variety of organic substances such as tri (2-hydroxyethyl) isocyanurate.Products after decomposition of trichloroisocyanuric acidCyanuric acidNot only non-toxic, but also has a variety of uses, such as the production of a series of resins, coatings, adhesives, plastics.
synthetic method
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The main synthesis methods of trichloroisocyanuric acid include chlorine method, liquid chlorination agent method, solvent method and sodium dichloroisocyanurate (sDc) deep chlorination method.
Chlorine method
Step 1: Cyanuric acid (CA) is mainly produced by urea hot cracking ammonia release method.The reaction formula is:
Ammonia removal by urea hot cracking
Step 2: alkali dissolution
Step 3: Chlorination
Alkali dissolution
This process is simple, but because in the process of preparing TCCA by chlorination of CA, CA contains more by-products of biuret, triuret, cyanuric amide and unreacted raw urea, which react with chlorine to generate NCl3. CA is easy to generate NCl3 in alkaline solution. TCCA products can also be decomposed to generate NCl3 under heating or alkaline conditions, while chlorination reaction is carried out in closed containers. As we all know, NCl3,Accumulation is extremely explosive.
Liquid chlorinator method
Cyanuric acid is prepared into slurry and chlorinated at a certain pH with prefabricated chlorinating agents (such as Cl20, HOCl, Na0Cl, etc.).The reaction formula is:
Similarly, in order to avoid NCl3, on the one hand, the CA intermediate is refined to reduce the impurity content to below 3%; on the other hand, the process conditions are strictly controlled to control the pH between 3 and 4 and the chlorination temperature between 20 and 25 ℃.This method is a liquid-liquid phase reaction. When a certain amount of air is introduced into the inlet, the chlorination reactor is equipped with an exhaust system to discharge the generated trace NCl3 in time.This method is quick and does not pollute the environment.The disadvantage is that hypochlorite is unstable, which leads to a decrease in product yield.
Liquid chlorinator method
In addition, after CA reacts with prefabricated Cl20 below 200 ℃, NCl3 free dry products can be produced without separation and drying.
Solvent method
Using inert solvents that are not miscible with water, have no reactivity, and can dissolve TcCA, such as methane chloride, this method has the advantages of continuity, automation, large scale, and low pollution. It is also used in large-scale production in developed countries.
Sodium dichloroisocyanurate (SDC) deep chlorination method
Sodium dichloroisocyanurateIt is one of the series products of chloroisocyanuric acid. In the joint production of SDC and TAAC, cyanuric acid andsodium hypochloriteReaction of solution at 20~25 ℃SDCAnd then deeply chlorinate it to generate TCCA.The reaction formula is:
Deep chlorination
Trichloroisocyanuric acid (TCCA) is one of the important varieties of chloroisocyanuric acid products. It is a new generation of efficient bleaching agent, chlorination agent and disinfectant, and has the characteristics of high sterilization and bleaching power, stable storage and transportation, making tablets safe and releasing effective chlorine in water for a long time[6]。
Market consumption
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Foreign market
The United States is the largest consumer of trichloroisocyanuric acid, with an annual consumption of more than 80000 tons, followed by Japan, with an annual consumption of about 30000 tons.The consumption of trichloroisocyanuric acid abroad is mainly sanitary disinfection.
The amount of disinfection tablets in swimming pools is the largest, accounting for about 80%. Taking the United States as an example, the annual consumption of disinfection in swimming pools is about 70000 tons, followed by the sanitary disinfection of drinking water, hospitals and other public facilities.
According to the data, the consumption of foreign countries is growing at an annual rate of 14%.
domestic market
Disinfection and sterilization of sericulture and aquaculture are the main consumption areas of trichloroisocyanuric acid in China, accounting for 50%~60% of the total consumption. With the improvement of people's living standards, the increase of silk and aquatic products will certainly drive the increase of demand for trichloroisocyanuric acid.The serious pollution problem of drinking water in China has caused great concern. In order to ensure the quality of water, this product tablet will be used for disinfection of drinking water.In addition, it has good effect in sterilization and algae removal of industrial circulating water. It can not only improve the utilization rate of circulating water, purify water quality, save water consumption, but also ensure the normal, stable and safe operation of the circulating water system, greatly reducing comprehensive energy consumption.
According to statistics, the actual consumption of trichloroisocyanuric acid in China in 2002 was about 30000 tons. The disinfection consumption of silkworm breeding and aquaculture accounted for 50% of the total consumption, the disinfection consumption of medical catering industry was 15%, the daily disinfection was 10%, and the domestic watercirculating waterTreatment consumption accounted for 8%.The consumption of agriculture, fishery, textile, paper making and swimming pool will increase in the future.
Because the cost of producing trichloroisocyanuric acid abroad is relatively high, and there are certain restrictions on the production of chlorinated products abroad, some small and medium-sized enterprises abroad have stopped producing trichloroisocyanuric acid, and then imported it from developing countries to produce its compound preparations, forming the final product.Therefore, China's export volume of this product has been on the rise in recent years[6]。
Storage and transportation matters
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(1) Product storage: the product should be stored in a cool, dry and well ventilated warehouse. It should be moisture-proof, waterproof, waterproof, fireproof, and isolated from fire and heat sources. It is prohibited to mix it with flammable, explosive, spontaneous combustion and explosion and other substances. It should not be mixed with oxidants, reducing agents, chlorinated and oxidized substances. It is absolutely prohibited to mix it with liquid ammonia, ammonia, ammonium carbonate, ammonium sulfateAmmonium chloride, urea and other inorganic salts and organics containing ammonia, ammonium and amine shall be mixed and placed together, otherwise explosion or combustion may occur, and they shall not be mixed withNonionic surfactantContact, otherwise it is easy to burn.
(2) Product transportation: The product can be transported by train, car, ship and other means of transportation. During shipment, the package shall be protected from breakage, fire, water and moisture. It shall not be mixed with ammonia, ammonia water, ammonium salt, amide, urea, oxidant, non-ionic surfactant, flammable, explosive and other dangerous goods.
(3) Fire fighting: trichloroisocyanuric acid is non self combustible and non flammable. When it is mixed with ammonium, ammonia and amine, it is prone to combustion and explosion. At the same time, this substance will decompose and release harmful gas due to the impact of the fire. Therefore, in case of fire, firefighters must wear gas masks, work clothes and put out the fire in the windhead, because it will generate a large amount of harmful gas when encountering water,Fire sand is generally used for fire fighting.
usage method
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1. Disinfection of drinking water: add 0.4g per 100kg of water, mix well and let stand for a period of time.
2. Swimming pool disinfection: put 3-5 grams per cubic meter into the swimming pool every day.
3. IndustryCirculating cooling waterTreatment: add 0.5g per 1m3 of water, the free chlorine concentration in cooling water is generally controlled between 0.25 and 0.5ppm, and the pH value is 7 to 8.
4. Others:
(1) Disinfection of tableware.Add 0.25g per 5kg of water and soak the washed tableware for 5min.
(2) Sewage and feces treatment.Add 5g of sewage or feces per cubic meter to eliminate odor.
(3) Sterilization and disinfection of seeds.Using TCCA as seed disinfection can break the dormancy period of seeds, improve the germination rate of seeds, and inhibit the occurrence of diseases. It is also important that it does not have environmental pollution problems and is harmless to humans and animals.The method is to immerse the seeds in 0.2% TCCA aqueous solution for 12 hours.
(4) Sterilization in breeding industry.
(5) It is used for disinfection of hospital sewage, diapers, urinals, medicine bowls and instruments.And commonly usedBromogeramineCompared with carbolic acid, chlorhexidine and chloramine T, for the same disinfection object, the amount of TCCA is only 1/10-1/100 of the above conventional disinfectants, and the sterilization speed is fast and the effect is good.
(6) It is used as a disinfectant and deodorant for household and public garbage.The formula is TCCA 25%, decontamination powder 25~65%, and p-dichlorobenzene 10~15%, which is suitable for disinfection and deodorization of toilet and garbage as well as sewer.
