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Natriumchlorat is an inorganic compound with the chemical formula NaClO3.
Natriumchlorat is a white crystalline powder that is readily soluble in water.
Natriumchlorat is hygroscopic.
CAS No: 7775-09-9
Chemical Name:Sodium chlorate
Molecular Formula:ClNaO3
Synonyma
CHLORATE;natriumchlorat;SODIUM CHLORATE, REAGENT (ACS)SODIUM CHLORATE, REAGENT (ACS)SODIUM CHLORATE, REAGENT (ACS);asex;fall;defol;dervan;hibarc;oxycil;travex
Natriumchlorat 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.
Natriumchlorat is an inorganic compound, appearing as white crystalline powder.
Natriumchlorat has an annual yield of several hundred million tons around the world.
Natriumchlorat has many applications.
Natriumchlorat'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.
Natriumchlorat 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, Natriumchlorat can also be used as a defoliant and desiccant.
Natriumchlorat is also used for the generation of chemical oxygen which is important for emergency oxygen generation in commercial aircraft.
In industry, Natriumchlorat is manufactured by the electrolysis of a hot sodium chloride solution.
Natriumchlorat is also useful for making inks, cosmetics, paper and leather.
Natriumchloratis an inorganic sodium salt that has chlorate as the counter-ion.
An oxidising agent, Natriumchlorat is used for bleaching paper and as a herbicide.
Natriumchlorat is also used in the manufacture of dyes, explosives and matches.
Natriumchlorat has a role as a herbicide.
Natriumchlorat is an inorganic sodium salt and a chlorate salt.
Natriumchlorat in a water solution is a clear colorless liquid.
Natriumchlorat is noncombustible but Sodium chlorate can accelerate the burning of surrounding combustible materials.
This can easily occur if the material should dry out.
Natriumchlorat Properties
Melting point: 248-261 °C(lit.)
Boiling point: decomposes 300℃ [MER06]
Density: 2.49
Bulk density: 1500kg/m3
Vapor pressure: 0-0Pa at 25℃
Refractive index: 1.515
Storage temp.: room temp
Solubility water: soluble(lit.)
Form: Solid
Color: White
Specific Gravity: 2.5
PH: 5-7 (50g/l, H2O, 20℃)
Water Solubility: 1000 g/L (20 ºC)
Merck: 14,8598
Stability: Stable. Mixtures of this material with organic fibrous or absorbent material and with a variety of other materials are potentially explosive. A full MSDS sheet must be consulted before use. Incompatible with strong reducing agents, organic materials, alcohols.
LogP: -7.17--2.9 at 20℃
Toxicology and Carcinogenesis: Toxicology and Carcinogenesis Studies of Sodium Chlorate (CASRN 7775-09-9) in F344/N Rats and B6C3F1 Mice (Drinking Water Studies)
Indirect Additives used in Food Contact Substances: SODIUM CHLORATE
FDA 21 CFR: 175.105; 178.3120
CAS DataBase Reference: 7775-09-9(CAS DataBase Reference)
EWG's Food Scores: 2-3
FDA UNII: T95DR77GMR
Pesticides Freedom of Information Act (FOIA): Sodium chlorate
EPA Substance Registry System: Natriumchlorat (7775-09-9)
UNSPSC Code: 12352302
NACRES: NA.55
Natriumchlorat, NaCI03, is colorless,odorless crystals 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.
Natriumchlorat is a nonselective soil sterilant used on noncrop land or in combination with triazines, ureas, or other organic herbicides for soil sterilization.
Natriumchlorat leaches,has foliar contact activity, and in the past, was used widely along railroads.
Natriumchlorat is flammable when dried on foliage, and many railroad fires occurred when sparks from coal-fired engines landed on sprayed plants.
Natriumchlorat is an example of an herbicide that desiccates and disrupts a plant's osmotic balance.
Natriumchlorat has been used for nonselective weed control for centuries.
Synthesis
Industrially, Natriumchlorat is produced by the electrolysis of concentrated sodium chloride solutions.
All other processes are obsolete.
Natriumchlorat 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.
The overall reaction can be simplified to the equation:
NaCl + 3 H2O → NaClO3 + 3 H2
First, chloride is oxidised to form intermediate hypochlorite, ClO−, which undergoes further oxidation to chlorate along two competing reaction paths:
(1) Anodic chlorate formation at the boundary layer between the electrolyte and the anode, and (2) Autoxidation of hypochlorite in the bulk electrolyte.
Under electrolysis hydrogen and sodium hydroxide are formed at the cathode and chloride ions are discharged at the anode (mixed metal oxide electrode is often used).
The evolved chlorine does not escape as a gas but undergoes hydrolysis:
Cl2 + H2O ⇋ HClO + H+ + Cl−
The hydrolysis of chlorine is considered to be fast.
The formation of H+ ions should make the boundary layer at the anode strongly acidic and this is observed at low chloride concentrations.
However, large concentrations of chloride, as they occur in industrial chlorate cells, shift the hydrolysis equilibrium to the left.
At the boundary layer the concentration of H+ is not high enough to permit diffusion into the bulk electrolyte.
Therefore hydrogen is transported away from the anode mostly as hypochlorous acid rather than H+.
The hypochlorous acid dissociates in the bulk electrolyte where the pH is high and the hypochlorite ion diffuses back to the anode.
More than two thirds of the hypochlorite is consumed by buffering before reaching the anode. The remainder is discharged at the anode to form chlorate and oxygen:
3 ClO− + 1.5 H2O → ClO3− + 3 H+ + 2 Cl− + 0.75 O2
The autoxidation of hypochlorous acid in the bulk electrolyte proceeds according to the simplified overall equation:
3 HClO → ClO3− + 2 Cl− + 3 H+
It is preceded by the dissociation of a part of the hypochlorous acid involved:
HClO → ClO− + H+
The reaction requires a certain distance from the anode to occur to a significant degree, where the electrolyte is sufficiently buffered by the hydroxyl formed at the cathode. The hypochlorite then reacts with the rest of the acid:
2 HClO + ClO− → ClO3− + 2 Cl− + 2 H+
In addition to anode distance the autoxidation also depends on temperature and pH. A typical cell operates at temperatures between 80 °C and 90 °C and at a pH of 6.1–6.4.
Independent of the reaction route the discharge of 6 mol of chloride is required to yield 1 mol of chlorate.
However, the anodic oxidation route requires 50% additional electric energy.
Therefore, industrial cells are optimised to favour autoxidation.
Chlorate formation at the anode is treated as a loss reaction and is minimised by design.
Other loss reactions also decrease the current efficiency and must be suppressed in industrial systems.
The main loss occurs by the back reduction of hypochlorite at the cathode.
The reaction is suppressed by the addition of a small amount of dichromate (1–5 g/L) to the electrolyte.
A porous film of chromium hydroxide is formed by cathodic deposition.
The film impedes the diffusion of anions to the cathode, whereas the access of cations and their reduction is facilitated.
The film stops growing on its own after it reaches a certain thickness.
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 other, less important chlorates are derived from sodium chlorate, usually by salt metathesis with the corresponding chloride.
All perchlorate compounds are produced industrially by the oxidation of solutions of sodium chlorate by electrolysis.
Natriumchlorat is used to prepare chlorine dioxide in the pulp and paper industry.
Natriumchlorat is utilized for bleaching the wood pulp in order to make environmentally friendly and quality white paper products.
Natriumchlorat is also used to produce other perchlorate compounds in the industry.
Herbicides
Natriumchlorat is used as a non-selective herbicide.
Natriumchlorat is considered phytotoxic to all green plant parts.
Natriumchlorat can also kill through root absorption.
