The chlorine dioxide It is an inorganic compound formed by the element chlorine (Cl) and oxygen (O). Its chemical formula is ClOtwo. It is a greenish-yellow to reddish gas. It is not found naturally in the environment.
It is extremely reactive, so it is common for it to be prepared where it is to be used. One of its most important uses is as a microbicide, antiseptic and deodorizer because it eliminates bacteria, viruses and fungi very easily and in very low concentrations..
Allows you to disinfect foods such as vegetables, fruits, meat, poultry and seafood. It is used to sanitize surfaces, floors, bathrooms, ventilation systems, swimming pools, laboratory equipment, dental equipment, etc..
For this reason it is used in food processing, in hospitals and clinics, in industries and shops. It is used to purify drinking water and municipal wastewater.
It is very effective as an oxidizing agent, which is why it is used to bleach paper pulp, oils, flour, leather, textile fibers, among others..
When it is in the form of a gas, it is very dangerous, as it is highly explosive, and is used mainly in aqueous solutions. It is toxic if inhaled.
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Chlorine dioxide is formed by the union of a chlorine atom (Cl) with two oxygen atoms (O). The bonds of chlorine with each oxygen are covalent and double. Chlorine in this compound has a valence of +4.
It has a symmetric and angled structure, as it has free electrons. That is, they do not form a bond with any other atom.
- Chlorine dioxide
- Chlorine oxide (iv)
Greenish-yellow to reddish-yellow gas.
67.45 g / mol.
-59 ºC.
11 ºC.
Liquid at 0 ° C = 1,642 g / cm3
Gas = 2.33 (relative density to air, air = 1).
Soluble in water: 2000 cm3 of the ClOtwo gas in 100 cm3 of cold water or 0.8 g / 100 mL of water at 20 ° C. Soluble in alkaline solution and in sulfuric acid solution HtwoSW4.
The ClOtwo it is extremely reactive and can explode violently. It is a very effective oxidizing agent.
The ClOtwo it decomposes violently if it comes into contact with organic materials. If it is in air at a concentration greater than 10%, it can explode due to the effect of sunlight or heat.
It can also detonate in the presence of mercury (Hg) or carbon monoxide (CO).
Under the action of ultraviolet (UV) light or ozone, ClOtwo becomes chlorine hexoxide CltwoOR6, very unstable compound.
Its aqueous solutions are yellow or reddish yellow. They are stable if kept cool, well sealed and protected from sunlight. In the presence of light these solutions slowly decompose to give hydrochloric acid HCl and chloric acid HClO.3.
In alkaline solutions, ClOtwo decomposes into chlorite ions ClOtwo- and Chlorate ClO3-. Chlorous acid HClO is formed in acid solutionstwo and then this decomposes to hydrochloric acid HCl and chloric acid HClO3.
The concentrated vapors of ClOtwo they are potentially explosive, so it has not been possible to compress it alone or mixed with other gases. For this reason, it is preferred to prepare it on the site where it will be used..
When it is at very low temperatures in its hydrated form, which is the way it is sometimes transferred, it is a block-shaped solid similar to ice and orange in color..
It has an odor similar to chlorine. It is toxic by inhalation.
It can be obtained in several ways. For example, in some cases ClO solutionstwo are prepared by passing a mixture of chlorine gas (Cltwo) and air (or chlorine gas and nitrogen Ntwo) through a column containing sodium chlorite granules (NaClOtwo).
2 NaClOtwo + Cltwo → 2 NaCl + 2 ClOtwo
The generated product contains approximately 90% ClOtwo, among other chlorine compounds.
It is also obtained from potassium chlorate (KClO3) and sulfuric acid (HtwoSW4) in the presence of oxalic acid as a reducing agent. In this case, carbon dioxide (COtwo) used to dilute the ClOtwo.
It can be prepared at the site of use starting from sodium chlorate (NaClO3), sulfuric acid (HtwoSW4) and methanol (CH3OH).
In industry it is obtained by sodium chlorate (NaClO3) and sulfur dioxide (SOtwo) in the presence of sulfuric acid.
2 NaClO3 + SWtwo + HtwoSW4 → 2 ClOtwo + 2 NaHSO4
It can be used as a powerful antimicrobial agent. It has been found to be highly effective against various microorganisms, such as the Escherichia coli and the Staphylococcus aureus.
With the latter, a concentration of only 5 ppm of ClO suffices.two to eliminate 100% of them. It is bactericidal, antiseptic and deodorizing. It is effective over a wide pH range.
It is used as an antimicrobial agent in water to fumigate fruits and vegetables, in the processing of poultry, red meat, both pieces of meat and organs, and marine products such as shellfish..
Chlorine dioxide solutions should be used at a concentration not exceeding 3 ppm (parts per million) of ClOtwo residual, so that it does not have an effect on food.
After treatment with ClOtwo all food must be thoroughly rinsed with potable water, or intended for blanching, cooking or canning.
In the case of marine products, the ClO solutiontwo It should be used in water and ice used in rinsing, washing, thawing, transportation, or storage. Raw shellfish should then be thoroughly washed with potable water before consumption..
ClO solutionstwo are used to eliminate slime-causing microorganisms (such as algae, bacteria and fungi) in the process water used in the manufacture of paper and cardboard that will come into contact with food.
It is used to purify water and make it drinkable (safe to drink). It is used in the pretreatment of water that will later be bottled for drinking or water that will be used as an ingredient in the manufacture of beverages or soft drinks..
It is used in the instruments used by the dentist or dentist to disinfect them and destroy pathogenic organisms in them.
Aqueous solutions of ClOtwo have been used to treat oral yeast infections (infection in the mouth). Candidiasis is an infection caused by the fungus Candida albicans.
Chlorine dioxide kills mouth fungus and significantly improves the appearance of oral tissues without side effects.
Some medical researchers indicate that ClO solutionstwo applied to wounds from surgical operations can reduce or suppress adhesion formation without affecting its healing, with the additional advantage of its antiseptic properties.
Due to its oxidizing and microbicidal properties, ClOtwo is used for:
- Whiten pulp from wood in pulp and paper manufacturing, providing a stable shine.
- Bleaching fats and oils, leather, bleaching flour and textiles.
- Agricultural applications such as disinfecting hard surfaces, equipment, water systems, and mushroom greenhouses.
- Applications in industries, shops and hospitals such as disinfecting hard surfaces (walls, floors, bathrooms), ventilation systems, laboratory equipment.
- Disinfect floors and bathrooms of homes, air conditioning systems, pool water circulation systems.
- Municipal and industrial wastewater treatment.
- Oil Field Pollution Cleanup.
- Manufacture of chloride salts (Cl-).
- The concentrated vapors of ClOtwo are potentially explosive.
- It is toxic by inhalation and ingestion. It is irritating to the eyes, nose and throat, can cause pulmonary edema and chronic bronchitis.
- According to the sources consulted, the ClOtwo does not cause DNA mutations or cause cancer in humans.
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