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Sodium chlorate: NAClO3
CAS NO: 7775-09-9
EC NUMBER: 231-887-4
Sodium chlorate (chemical formula: NAClO3) is an inorganic compound, appearing as white crystalline powder.
Sodium chlorate has an annual yield of several hundred million tons around the world.
Sodium chlorate has many applications.
Sodium chlorate's major commercial application is for the manufacture of chlorine dioxide which is used in bleaching of pulp.
Sodium chlorate can also be used for the industrial manufacture of perchlorate compounds through electrolysis.
Sodium chlorate can also be used as a non-selective herbicide to control many kinds of plants such as morning glory, Canada thistle, Johnson grass and bamboo.
In addition, it can also be used as a defoliant and desiccant.
Sodium chlorate is also used for the generation of chemical oxygen which is important for emergency oxygen generation in commercial aircraft.
In industry, sodium chlorate is manufactured by the electrolysis of a hot sodium chloride solution.
Sodium chlorate is also useful for making inks, cosmetics, paper and leather.
Sodium chlorate is a colourless, odourless and crystalline solid.
Sodium chlorate is also known as chlorate of soda.
Sodium chlorate is a white crystalline powder that is readily soluble in water.
Sodium chlorate is hygroscopic. Sodium chlorate decomposes above 300 °C to release oxygen and leaves sodium chloride.
Several hundred million tons are produced annually, mainly for applications in bleaching pulp to produce high brightness paper.
Synthesis
Industrially, sodium chlorate is produced by the electrolysis of a hot sodium chloride solution:
NaCl + 3 H2O → NaClO3 + 3 H2
This reaction progresses in heat (at least 70 °C), and controlled pH.
In lower temperature or with high pH another reaction progresses:
2 NaCl + H2O → NaClO + NaCl + H2
The sodium chlorate process is not to be confused with the Chloralkali process, which is an industrial process for the electrolytic production of sodium hydroxide and chlorine gas.
Uses
The main commercial use for sodium chlorate is for making chlorine dioxide (ClO2).
The largest application of ClO2, which accounts for about 95% of the use of chlorate, is in bleaching of pulp.
All perchlorate compounds are produced industrially by the oxidation of solutions of sodium chlorate by electrolysis.
Herbicides
Sodium chlorate is used as a non-selective herbicide.
Sodium chlorate is considered phytotoxic to all green plant parts.
Sodium chlorate can also kill through root absorption.
Sodium chlorate may be used to control a variety of plants including morning glory, canada thistle, johnson grass, bamboo, Ragwort, and St John's wort.
The herbicide is mainly used on non-crop land for spot treatment and for total vegetation control on areas including roadsides, fenceways, and ditches.
Sodium chlorate is also used as a defoliant and desiccant for:
-Corn
-Cotton
-Dry beans
-Flax
-Grain sorghum
-Peppers
-Rice
-Safflower
-Southern peas
-Soybeans
-Sunflowers
If used in combination with atrazine, it increases the persistence of the effect.
If used in combination with 2,4-D, performance is improved.
Sodium chlorate has a soil sterilant effect.
Mixing with other herbicides in aqueous solution is possible to some extent, so long as they are not susceptible to oxidation.
Chemical oxygen generation
Chemical oxygen generators, such as those in commercial aircraft, provide emergency oxygen to passengers to protect them from drops in cabin pressure.
Oxygen is generated by high-temperature decomposition of sodium chlorate:
2 NaClO3 → 2 NaCl + 3 O2
Heat required to initiate this reaction is generated by oxidation of a small amount of iron powder mixed with the sodium chlorate, and the reaction consumes less oxygen than is produced.
Barium peroxide (BaO2) is used to absorb the chlorine that is a minor product in the decomposition.
An ignitor charge is activated by pulling on the emergency mask. Similarly, the Solidox welding system used pellets of sodium chlorate mixed with combustible fibers to generate oxygen.
Oxygenless combustion
Sodium chlorate can be mixed with sucrose sugar to make a highly explosive fuel, similar to that of gunpowder, that burns in airtight spaces.
This is the reaction:
8 NaClO3 + C12H22O11 → 8 NaCl + 12 CO2 + 11 H2O
However, this sodium chlorate is mostly replaced by potassium chlorate.
Trade names
Sodium chlorate is the active ingredient in a variety of commercial herbicides.
Some trade names for products containing sodium chlorate include Atlacide, Defol, De-Fol-Ate, Drop-Leaf, Fall, Harvest-Aid, Kusatol, Leafex, and Tumbleaf.
The compound may be used in combination with other herbicides such as atrazine, 2,4-D, bromacil, diuron, and sodium metaborate.
Sodium chlorate was an extensively used weed killer within the EU, until 2009 when it was withdrawn after a decision made under terms of EU Regulations.
Its use as a herbicide outside the EU remains unaffected, as does its use in other non-herbicidal applications, such as in the production of chlorine dioxide biocides and for pulp and paper bleaching.
Formulations
Sodium chlorate comes in dust, spray and granule formulations. Mixtures of chlorates and organic compounds pose a severe risk of explosions
Marketed formulations contain a fire retardant.
Most commercially available chlorate weedkillers contain approximately 53% sodium chlorate with the balance being a fire depressant such as sodium metaborate or ammonium phosphates.
Sodium chlorate appears as an odourless pale yellow to white crystalline solid.
It is appreciably soluble in water and heavier, so maybe expected to sink and dissolve at a rapid rate.
Although it is not itself flammable, the solid product and even 30% solutions in water are powerful oxidizing agents.
Contact with wood, organic matter, ammonium salts, sulfur, sulfuric acid, various metals, and other chemicals may result in fires or explosions, particularly if any solid materials are finely divided.
Excessive heat, as in fires, may cause the evolution of oxygen gas that may increase the intensity of fires and may also result in explosions.
Mixtures with combustible materials are very flammable and may be ignited by friction.
It is used for making herbicides, explosives, dyes, matches, inks, cosmetics, pharmaceuticals, defoliants, paper, and leather.
Sodium chlorate in a water solution is a clear colourless liquid.
It is noncombustible but it can accelerate the burning of surrounding combustible materials.
This can easily occur if the material should dry out.
Contact with strong sulfuric acid may cause fires or explosions.
USE AREAS
Industry Uses
Consumer Uses
Methods of Manufacturing
Production of sodium chlorate is by electrolysis of an acidified sodium chloride solution.
Purified brine is acidified with hydrochloric acid and sodium dichromate is added to improve cell efficiency and reduce electrode corrosion.
The acidified brine is fed to a bank of electrolytic cells.
Chlorate ions form at the anode while hydrogen gas leaves the cell at the cathode.
Cell liquor, the solution exiting the electrolytic cells, contains a fairly high concentration of chlorate ions and by-products.
Subsequent processing removes the sodium chlorate crystals from the solution.
The remaining liquor containing chlorate, chloride ions and sodium dichromate returns to cells for further reaction.
The sodium chlorate crystals are washed and dried.
General Manufacturing Information
Industry Processing Sectors
Sodium chlorate in a water solution is a clear colourless liquid.
Sodium chlorate is noncombustible but Sodium chlorate can accelerate the burning of surrounding combustible materials.
This can easily occur if the material should dry out. Contact with strong sulfuric acid may cause fires or explosions.
Agriculturally, Sodium chlorate is primarily used on cotton; however, Sodium chlorate is also applied to a wide variety of other crops including, but not limited to, rice, corn, soybeans, dry beans, potatoes, sunflowers, flax, safflower, chilli peppers (for processing only), grain sorghum, and wheat.
Sodium chlorate is used on nonagricultural (residential and industrial) areas such as rights-of-ways, building perimeters, ditch banks, bleachers, airport runways, vacant lots, fire hydrants, or as a pre-paving treatment.
Sodium chlorate is also used by a small percentage of water treatment facilities for the generation of chlorine dioxide.
Sodium chlorate as a defoliant/desiccant in agricultural settings is applied using aerial and ground boom equipment.
As a herbicide in nonagricultural settings, Sodium chlorate is applied using handheld equipment such as low-pressure hand wands or sprinkling cans;
Sodium chlorate is also applied via a ground boom or handgun sprayer application methods for larger commercial scenarios.
Granular formulations can be applied using belly grinders, push-type spreaders, tractor-drawn spreaders, or by hand.
Application Rates: In agriculture, rates range from 6 pounds active ingredient per acre (6 lb ai/A) to 12.5 lbs ai/A.
Industrial and other noncrop site rates range from 132 to 1032 lbs ai/A, based on current labels. Sodium chlorate can be applied multiple times per year.
Application Timing: Sodium chlorate is applied post-emergence.
Uses at industrial sites
Sodium chlorate is used in the following products: paper chemicals and dyes.
Sodium chlorate is used in the following areas: scientific research and development.
Sodium chlorate is used for the manufacture of pulp, paper and paper products, chemicals and wood and wood products.
Release to the environment of Sodium chlorate can occur from industrial use: as an intermediate step in further manufacturing of another substance (use of intermediates) and as a processing aid.
Chemical Properties
Sodium chlorate, NaCI03, is colourless, odourless crystal with a cooling, saline taste, is soluble in water and alcohol, but must not be triturated with any combustible substance.
Derived by heating and electrolyzing a concentrated acid solution of sodium chloride so that the chlorate is crystallized out.
Used as an oxidizing agent and bleach (especially to make chlorine dioxide)for paper pulps, ore processing, herbicide and defoliant, substitute for potassium chlorate (sodium chlorate is more soluble in water), matches, explosives, flares, and pyrotechnics, in the recovery of bromine from natural brines, leather tanning and finishing, textile mordant, and to make perchlorates.
Sodium chlorate (NaClO3) is a powerful oxidizing agent available in both the crystal and solution forms manufactured and supplied by Nouryon.
When handled correctly, associated risks are minimal.
Sodium chlorate has a high oxidizing potential and functions as a powerful oxidizing agent.
An example of this type of reaction would be the production of chlorine dioxide.
In 2012, more than 90% of all sodium chlorate produced worldwide was consumed by the pulp industry where it is used for the generation of chlorine dioxide.
Chlorine dioxide is a key bleaching agent and is used in the production of Elemental Chlorine-Free (ECF) bleached wood pulp all over the world.
Presented in the table below are examples of today's technologies for producing a chlorine-free chlorine dioxide solution for ECF bleaching.
The major use of sodium chlorate remains in the pulp and paper industry, Sodium chlorateit is also the preferred intermediate for sodium perchlorate and sodium chlorite manufacture.
Some common industrial applications for sodium chlorate include the surface treatment of metals and cupric chloride etch regeneration in the electronics and automotive industries.
Additional uses of sodium chlorate are as an oxidant in chemical synthesis, in the mining industry for the extraction of uranium and vanadium, in the production of oxygen candles utilized on aircraft and submarines and by manufacturers of breathing apparatus for firefighters and mine rescue crews.
Sodium chlorate is a white to off-white crystalline material.
Crystals are similar in appearance to table salt. Sodium chlorate is odourless and very soluble in water.
In its crystal form, sodium chlorate is stable at temperatures up to 250°C.
Above this temperature, chlorate decomposes slowly and steadily forming salt (sodium chloride) and oxygen.
Sodium chlorate in its pure form is not flammable but due to the fact it releases oxygen during decomposition, it will act as an extreme combustion accelerant in the presence of flammable materials.
In liquid form, extra caution should be taken.
Sodium chlorate solution is a clear odourless liquid and becomes virtually invisible (salt-like residue is often apparent) when it dries on any organic material like cloth, leather, paper or wood.
All that is then required is a spark, minor friction or heat to ignite. Sodium chlorate itself does not burn but as previously stated acts as
an extreme combustion accelerant by emitting oxygen.
Consequently, fires involving sodium chlorate spread very rapidly and explosively and cannot be extinguished by smothering.
Other substances which cause a fire in mixtures containing sodium chlorate are phosphorus, sulfur, sulfides, metallic powder and ammonium salts.
When sodium chlorate is mixed with strong acids, chlorine dioxide and or chlorine gases are formed, both are toxic and when chlorine dioxide is present may become explosive.
Consequently, due to this reaction potential, it is recommended to store acids and sodium chlorate crystals and/or solutions separately.
Chemical formula: NaClO3
Molecular weight: 106.4 g/mole
Appearance: white to off-white crystalline material, odourless
Melting point: 248–250 °C
Boiling point: none, is decomposed at temperatures higher than 250–300°C into sodium chloride and oxygen gas
Bulk density: approximate 1500 kg/m3
Solubility: soluble in water, refer to the diagram on the following page
pH: neutral, assume the pH of the solvent
Sodium chlorate is a white crystalline inorganic compound produced from salt (sodium chloride) and water in a reaction with electricity.
Although not combustible, it decomposes to release oxygen (enhancing the combustion of other substances) and toxic fumes (chlorine).
The largest use for sodium chlorate is for the generation of chlorine dioxide, which is used for bleaching chemical pulp.
In 2020, this application represented over 90% of total global consumption.
Without mainland China, the share of pulp bleaching in the total consumption of sodium chlorate is even higher at about 96%.
Manufacturing:
Sodium chlorate is produced from two commonly found raw materials: salt (NaCl, sodium chloride) and water (H2O) along with the use of large amounts of electrical energy.
The manufacturing process involves the electrolysis of an acidified sodium chloride solution in a specially designed electrochemical cell.
First, raw brine is treated to remove impurities such as calcium and magnesium.
Next, hydrochloric acid (HCl) is added to control the pH and improve efficiency. Sodium dichromate is used as a catalyst, to inhibit electrochemical side reactions and as a pH buffer.
NaCl + 3H2O + Electricity > NaClO3 + 3H2
Salt + Water + Power > Sodium Chlorate + Hydrogen Gas
Chlorine gas (Cl2) forms at the anode while hydrogen gas (H2) forms at the cathode. Chlorine is then hydrolyzed in the cell to a hypochlorite species which then react to form sodium chlorate.
The solution that leaves the electrochemical cell is called cell liquor. This solution contains a high concentration of chlorate ions and other intermediate reaction products.
The solution is treated to remove byproducts such as hypochlorite. Sodium chlorate crystals are then removed and the remaining liquor containing salt, chloride ions and dichromate are returned to the electrochemical cells.
The crystals are washed and dried to form the final product.
For some customers, the crystals are dissolved in water and shipped as a liquid solution.
Uses:
Sodium chlorate is largely used by the pulp & paper industry to produce chlorine dioxide, which is used to bleach wood pulp for the manufacture of higher quality and environmentally friendly white paper products.
Pulp mills convert sodium chlorate into chlorine dioxide – an environmentally friendly bleaching agent.
The process of using chlorine dioxide to bleach pulp is referred to as “ECF” bleaching meaning “elemental chlorine-free”.
Sodium chlorate is a hygroscopic inorganic compound with the chemical formula NaClO3.
Sodium chlorate is available as a white crystalline powder and is readily soluble in water.
Sodium chlorate disintegrates into oxygen and sodium chloride above 300 °C (572 °F).
Sodium chlorate is corrosive to zinc and mild steel.
There is a risk of pitting and stress corrosion cracking in the presence of chlorides.
Sodium chlorate is used to manufacture herbicides, oxidizing agents, explosives, dyes, matches, inks, cosmetics, pharmaceuticals, defoliants and leather.
Sodium chlorate is odourless pale yellow to white crystalline solid.
Sodium chlorate is appreciably soluble in water and heavier, so maybe expected to sink and dissolve at a rapid rate.
Although Sodium chlorate is not itself flammable, the solid product and even 30% solutions in water are powerful oxidizing agents.
Contact with wood, organic matter, ammonium salts, sulfur, sulfuric acid, various metals, and other chemicals may result in fires or explosions, particularly if any solid materials are finely divided.
Excessive heat, as in fires, may cause the evolution of oxygen gas that may increase the intensity of fires and may also result in explosions.
Mixtures with combustible materials are very flammable and may be ignited by friction.
Sodium chlorate is used for making herbicides, explosives, dyes, matches, inks, cosmetics, pharmaceuticals, defoliants, paper, and leather.
IUPAC NAMES
Natriumchlorat
SODIUM CHLORATE
Sodium Chlorate
Sodium chlorate
sodium chlorate
Sodium Chlorate
Sodium chlorate
sodium chlorate
sodium-chlorate-
sodium;chlorate
SYNONYMS
asex
SODIUM CHLORATE, REAGENT (ACS)SODIUM CHLORATE, REAGENT (ACS)SODIUM CHLORATE, REAGENT (ACS)
atlacide
b-herbatox
chloratedesodium
chlorateofsoda
chloratesaltofsodium
Chloricacid,sodiumsalt
Chloricacidsodiumsalt
chlorsaure
defol
dervan
desolet
drexeldefol
dropleaf
evau-super
fall
grainsorghumharvest-aid
granexo
harvest-aid
hibarc
kusa-tohru
kusatol
leafex2
leafex3
natriumchloraat
natriumchlorat
ortho-c-1-defoliant
orthoc-1defoliant&weedkiller
oxycil
rasikal
shed-a-leaf
shed-a-leaf’l’
sodachlorate
sodakem
sodio(cloratodi)
sodium(chloratede)
sodium(chloratede)(french)
sodiumchlorate(naclo3)
sodiumchlorate,aqueoussolution
travex
tumbleaf
tumbleleaf
unitedchemicaldefoliantno.1
unitedchemicaldefoliantno1
val-drop
SODIUM CHLORATE
STOCK SODIUM CHLORATE, 25G/L
CHLORATE
CHLORATE IC STANDARD
CHLORATE ION
SODIUM CHLORATE ACS REAGENT
SODIUM CHLORATE 99+% A.C.S. REAGENT
SODIUM CHLORATE POWDER, PURE
SODIUM CHLORATE, REAGENTPLUS, >=99%
SODIUM CHLORATE REAGENTPLUS(TM) >=99%
SODIUM CHLORATE EXTRA PURE
Sodium chlorate ACS reagent, >=99.0%
