Chlorate sodium

Sodium chlorate is used in papermaking, where demand for it is increasing, in the textile industry and as a cheap, if unselective, weedkiller. There are many electrolytic plants for its production, usually on the 1000—10000 ton yr scale, and because of the proximity of both wood and hydroelectric power it is common in Scandinavia, USA, Japan and Canada for the plant to be close to the paper mill. 

The electrolytic formation of chlorate is dependent on complex chemistry coupled to a simple electron transfer process, i.e. 

There is a second route to the formation of chlorate which involves the direct anodic oxidation of hypochlorite. This has the stoichiometry 

Other alkali-metal chlorates are produced by analogous technology while sodium and potassium bromate are produced electrolytically starting both from bromide ion and bromine solutions. The production of bromate is, however, a very small-scale process and the cells have not been optimized to any extent for example while cells with lead dioxide and platinized titanium have been described, some plants still use solid platinum electrodes The mechanism of bromate formation is identical to that described for chlorate by reactions (5.10)—(5.13) the kinetics are, however, different. The hydrolysis of bromine is slower than chlorine but the disproportionation step is much faster (by a factor of 100) and it is therefore advisable to use a more alkaline electrolyte, about pH 11. 

The International Agency for Research on Cancer (1991) concluded that sodium chlorite was not classifiable as to its carcinogenicity to humans (Group 3). 

Groups of 50 male and 50 female B6C3F1 mice were dosed with sodium chlorite (purity 82-87%) in the drinking-water at concentrations of 0,250 or 500 mg/ I for 80 weeks followed by distilled water alone for 5 weeks. Total sodium chlorite intakes over the 80 weeks calculated from mean water consumption data indicated average sodium chlorite doses of 33 and 53 mg/kg bw per day for females (25 and 

Because a NOAEL was not identified in this study, the Committee decided to apply a benchmark dose (BMD) approach to derive a point of departure on the dose-response curve (see Annex 3 of reference 176 m Annex 1). A summary of the key neoplastic and non-neoplastic findings is shown in Table 4. 

The United States Environmental Protection Agency (USEPA) BMD software version 1.4.1 (United States Environmental Protection Agency, 2007) was used for modelling the data on rat thyroid gland follicular cell hypertrophy, which was the effect observed at the lowest dose levels. A range of models were applied in order to derive the BMD for a 10% increase in follicular cell hypertrophy (BMDio) and the corresponding 95% lower confidence limit (BMDUo), as shown in 

Sodium chlorate concentration in drinking-water (mg/l) Approximate dose of sodium chlorate (mg/kg bw per day) Survival Thyroid gland follicular cell hypertrophy incidence Follicular cell adenoma and carcinoma (combined) incidence 

Electrochemical oxidation of one gram-ion Cl- to ClOj requires 6 26.82 — = 160.9 A-hr. The theoretical quantity of electricity needed to produce 1 kg of potassium chlorate is 1313 A-hr. The production of 1 kg of sodium chlorate requires 1512 A-hr. 

The theoretical voltage needed for electrochemical decomposition of chloride under the simultaneous formation of chlorate is calculated in the same way as has been used for hypochlorites. In a neutral solution (a0u- = 10 7) at a hydrogen pressure of pH, = 1 atm., the reduction potential at the cathode where reaction (XVII-10) occurs, will equal 

During the electrochemical oxidation of chloride, chlorate is formed in accordance with the equation  

The standard potential of this reaction equals ept ci-, 0107 = — 0.62 V. If we assume that the solution is neutral, and the activity a of both chloride and chlorate ions is unity, the following equation is valid at 25 °C according to Nernst s law  

By adding the values (XVII-16 and XVII-18), the resulting theoretical decomposition voltage can be ascertained  

EXPLOSIVE WHEN MIXED WITH COMBUSTIBLE MATERIAL 

Freely soluble in water slightly soluble in cold alcohol soluble in boiling alcohol and glycerol.1 

Mixtures of sodium chlorate and combustible materials are readily ignited mixtures with finely divided combustible materials can react explosively. Extinguish fire with water spray.2 

Alkenes and Potassium Osmate. Sodium chlorate should not be used in the hydroxylation of alkenes to diols in the presence of potassium osmate if the diol is to be distilled from the reaction mixture explosive oxidation may occur.3 

Ammonium Salts, Metals, or Nonmetals, or Sulfides. Mixtures with ammonium salts, powdered metals, phosphorus, silicon, sulfur, or sulfides are readily ignited and potentially explosive.4 

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CH3C(0)CH2Br. Colourless liquid which rapidly becomes violet in colour it is a powerful lachrymator b.p. 1367725 mm. Manufactured by treating aqueous propanone with bromine at 30-40 C it is usual to add sodium chlorate(V) to convert the hydro-bromic acid formed by the reaction back to bromine. It is not very stable and decomposes on standing. 

Industrially an aqueous solution of chlorine dioxide can be prepared by passing nitrogen dioxide up a packed tower down which sodium chlorate(V) flows ... 

The aqueous solution of sodium chlorate(I) is an important liquid bleach and disinfectant. It is produced commercially by the electrolysis of cold aqueous sodium chloride, the anode and cathode products being mixed. The sodium chloride remaining in the solution does not usually matter. There is evidence to suggest that iodic(I) acid has some basic character... 

Only chloric(III) acid, HCIO2, is definitely known to exist. It is formed as one of the products of the reaction of water with chlorine dioxide (see above). Its salts, for example NaClOj, are formed together with chlorates)V) by the action of chlorine dioxide on alkalis. Sodium chlorate(III) alone may be obtained by mixing aqueous solutions of sodium peroxide and chlorine dioxide ... 

Chloric(III) acid is a fairly weak acid, and is an oxidising agent, for example it oxidises aqueous iodide ion to iodine. Sodium chlorate(III) (prepared as above) is used commercially as a mild bleaching agent it bleaches many natural and synthetic fibres without degrading them, and will also bleach, for example, oils, varnishes and beeswax. 

Fumaric acid is conveniently prepared by the oxidation of the inexpensive furfural with sodium chlorate in the presence of a vanadium pentoxide catalyst ... 

C. Fumaric acid from furfural. Place in a 1-litre three-necked flask, fitted with a reflux condenser, a mechanical stirrer and a thermometer, 112 5 g. of sodium chlorate, 250 ml. of water and 0 -5 g. of vanadium pentoxide catalyst (1), Set the stirrer in motion, heat the flask on an asbestos-centred wire gauze to 70-75°, and add 4 ml. of 50 g. (43 ml.) of technical furfural. As soon as the vigorous reaction commences (2) bvi not before, add the remainder of the furfural through a dropping funnel, inserted into the top of the condenser by means of a grooved cork, at such a rate that the vigorous reaction is maintained (25-30 minutes). Then heat the reaction mixture at 70-75° for 5-6 hours (3) and allow to stand overnight at the laboratory temperature. Filter the crystalline fumaric acid with suction, and wash it with a little cold water (4). Recrystallise the crude fumaric acid from about 300 ml. of iif-hydrochloric acid, and dry the crystals (26 g.) at 100°. The m.p. in a sealed capillary tube is 282-284°. A further recrystaUisation raises the m.p. to 286-287°. 

Benzoquinone ( quinone ) is obtained as the end product of the oxidation of aniline by acid dichromate solution. Industrially, the crude product is reduced with sulphur dioxide to hydroquinone, and the latter is oxidised either with dichromate mixture or in very dilute sulphuric acid solution with sodium chlorate in the presence of a little vanadium pentoxide as catalyst. For the preparation in the laboratory, it is best to oxidise the inexpensive hydroquinone with chromic acid or with sodium chlorate in the presence of vanadium pent-oxide. Naphthalene may be converted into 1 4-naphthoquinone by oxidation with chromic acid. 

Oxalic acid Furfuryl alcohol, silver, mercury, sodium chlorate, sodium chlorite, sodium hypochlorite... 

Sodium chlorite [sodium chlorate (IV)] Sodium peroxide ... 

Three forms of caustic soda are produced to meet customer needs purified diaphragm caustic (50% Rayon grade), 73% caustic, and anhydrous caustic. Regular 50% caustic from the diaphragm cell process is suitable for most appHcations and accounts for about 85% of the NaOH consumed in the United States. However, it caimot be used in operations such as the manufacture of rayon, the synthesis of alkyl aryl sulfonates, or the production of anhydrous caustic because of the presence of salt, sodium chlorate, and heavy metals. Membrane and mercury cell caustic, on the other hand, is of superior quaUty and... 

Caustic Soda. Diaphragm cell caustic is commercially purified by the DH process or the ammonia extraction method offered by PPG and OxyTech (see Fig. 38), essentially involving Hquid—Hquid extraction to reduce the salt and sodium chlorate content (86). Thus 50% caustic comes in contact with ammonia in a countercurrent fashion at 60°C and up to 2500 kPa (25 atm) pressure, the Hquid NH absorbing salt, chlorate, carbonate, water, and some caustic. The overflow from the reactor is stripped of NH, which is then concentrated and returned to the extraction process. The product, about 62% NaOH and devoid of impurities, is stripped free of NH, which is concentrated and recirculated. MetaUic impurities can be reduced to low concentrations by electrolysis employing porous cathodes. The caustic is then freed of Fe, Ni, Pb, and Cu ions, which are deposited on the cathode. 

By fai the largest (ca 85% of the total) volume chemical blowing agent is azodicaibonamide (44), made by the oxidation of hydiazodicaiboxamide [110-21 -4] (51) using chlorine or sodium chlorate. The hydrazo precursor is made by refluxing an aqueous solution of urea and hydrazine (172) ... 

Chlorine dioxide has substantial reactivity, which precludes its shipment ia bulk. New technology that allows on-site generation of CIO2 from sodium chlorate [7775-09-9] rather than from chlorine is expected to result ia its more frequent use ia appHcations where capital investment and operators are warranted (24). 

Success in the chlorine industry led to the incorporation of DSA in sodium chlorate [7775-09-9] NaClO, manufacture. The unique stmctural characteristics of the anode allowed for innovative designs in ceU hardware, which in turn contributed to the extensive worldwide expansion of the sodium chlorate industry in the 1980s. 

An expandable anode involves compression of the anode stmcture using cHps during cell assembly so as not to damage the diaphragm already deposited on the cathode (Eig. 3a). When the cathode is in position on the anode base, 3-mm diameter spacers are placed over the cathode and the cHps removed from the anode. The spring-actuated anode surfaces then move outward to bear on the spacers, creating a controlled 3-mm gap between anode and cathode (Eig. 3b). This design has also been appHed to cells for the production of sodium chlorate (22). 

NaClO sodium hypochlorite NaC102 sodium chlorite NaClO sodium chlorate NaClO sodium perchlorate... 

Basic oxides of metals such as Co, Mn, Fe, and Cu catalyze the decomposition of chlorate by lowering the decomposition temperature. Consequendy, less fuel is needed and the reaction continues at a lower temperature. Cobalt metal, which forms the basic oxide in situ, lowers the decomposition of pure sodium chlorate from 478 to 280°C while serving as fuel (6,7). Composition of a cobalt-fueled system, compared with an iron-fueled system, is 90 wt % NaClO, 4 wt % Co, and 6 wt % glass fiber vs 86% NaClO, 4% Fe, 6% glass fiber, and 4% BaO. Initiation of the former is at 270°C, compared to 370°C for the iron-fueled candle. Cobalt hydroxide produces a more pronounced lowering of the decomposition temperature than the metal alone, although the water produced by decomposition of the hydroxide to form the oxide is thought to increase chlorine contaminate levels. Alkaline earths and transition-metal ferrates also have catalytic activity and improve chlorine retention (8). 

W. J. O ReiUy and co-workers. Development of Sodium Chlorate Candles for the Storage and Supply of Oxygen for Space Exploration Applications, Rept. No. 69-4695, Air Research Corp., Los Angeles, Calif., July 1969. 

Perchlorates. Historically, perchlorates have been produced by a three-step process (/) electrochemical production of sodium chlorate (2) electrochemical oxidation of sodium chlorate to sodium perchlorate and (4) metathesis of sodium perchlorate to other metal perchlorates. The advent of commercially produced pure perchloric acid directly from hypochlorous acid means that several metal perchlorates can be prepared by the reaction of perchloric acid and a corresponding metal oxide, hydroxide, or carbonate. 

Sodium Perchlorate. The electrochemical oxidation of sodium chlorate is carried out at the anode ia an undivided cell according to the following reaction ... 

Plants can also be pests that need to be controlled, particulady noxious weeds infesting food crops. Prior to 1900, inorganic compounds such as sulfuric acid, copper nitrate, sodium nitrate, ammonium sulfate, and potassium salts were used to selectively control mustards and other broadleaved weeds in cereal grains. By the early 1900s, Kainite and calcium cyanamid were also used in monocotyledenous crops, as well as iron sulfate, copper sulfate, and sodium arsenate. Prom 1915 to 1925, acid arsenical sprays, carbon bisulfate, sodium chlorate, and others were introduced for weed control use. Total or nonselective herbicides kill all vegetation, whereas selective compounds control weeds without adversely affecting the growth of the crop (see Herbicides). 

PoUowing further development (38), a two-cycle process has been adopted by industry. In the first concentration cycle, the clarified feed acid containing 100—200 mg/L U Og [1334-59-8] is oxidized, for example, with hydrogen peroxide or sodium chlorate [7775-09-9] to ensure that uranium is in its 6+ valence state is not extracted. Uranium is extracted with a solvent composed of 0.5 Af D2EHPA and 0.125 Af TOPO dissolved in an aUphatic hydrocarbon diluent. 

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