Chlorate solutions

Sulfuric acid is an economical alternative source of acid and many commercial generators substitute concentrated sulfuric acid for HCl. Furthermore, the requited chloride ion needed as the reductant is already present or added as NaCl in the chlorate solution or crystal obtained from the chlorate manufacturer. This process, popular in the 1960s and 1970s, produces substantial amounts of Hquid effluent containing 20—35% sulfuric acid, 20—25% sodium sulfate, and minor amounts of sodium chloride and unreacted chlorate that must be neutralized with alkaH. 

The electrical conductivity of a pure aqueous sodium chlorate solution is given in Table 2. Additional data are given (27). Table 3 summarizes the solubiHty data for two aqueous chlorate—chloride systems (28—30). 

Table 2. Electrical Conductivity of Aqueous Sodium Chlorate Solutions (ohm m—1...

Chromium Removal System. Chlorate manufacturers must remove chromium from the chlorate solution as a result of environmental regulations. During crystallization of sodium chlorate, essentially all of the sodium dichromate is recycled back to the electrolyzer. Alternatively, hexavalent chromium, Cr, can be reduced and coprecipitated in an agitated reactor using a choice of reducing agents, eg, sodium sulfide, sulfite, thiosulfate, hydrosulfite, hydrazine, etc. The product is chromium(III) oxide [1333-82-0] (98—106). Ion exchange and solvent extraction techniques have also... 

Lithium chlorate [13453-71 -9] LiClO, has rhombic needles mp 124—129°C decomposes on heating to 270°C. It is one of the most soluble salts known and it is very hygroscopic. LiClO is prepared by adding lithium chloride [7447-41-8] to sodium chlorate solution. Sodium chloride precipitates, the hquor is concentrated, and the lithium chlorate is filtered and dried. It has limited use in pyrotechnics. 

When potassium chlorate solution, KClOi, is added to hydrochloric acid, chlorine gas is evolved. Although we can find the half-reaction, 2C1- = Ck(g) + 2e, in Appendix 3, we find no equation with CIQT ion involved. We can surmise that CIO3" is accepting electrons and changing into chlorine. Let us write a partial half-reaction in which we indicate an unknown number of electrons and in which we have conserved only chlorine atoms ... 

Procedure. To obtain experience in the method, the purity of analytical-grade potassium chlorate may be determined. Prepare a 0.02M potassium chlorate solution. Into a 250 mL conical flask, place 25.0 mL of the potassium chlorate solution, 25.0mL of 0.2M ammonium iron(II) sulphate solution in 2M sulphuric acid and add cautiously 12 mL concentrated sulphuric acid. Heat the mixture to boiling (in order to ensure completion of the reduction), and cool to room temperature by placing the flask in running tap water. Add 20 mL 1 1 water/phosphoric(V) acid, followed by 0.5 mL sodium diphenyl-amine-sulphonate indicator. Titrate the excess Fe2+ ion with standard 0.02M potassium dichromate to a first tinge of purple coloration which remains on stirring. 

Standardise the ammonium iron(II) sulphate solution by repeating the procedure but using 25 mL distilled water in place of the chlorate solution. The difference in titres is equivalent to the amount of potassium chlorate added. 

Procedure, (a) Place 25 mL of the chlorate solution (approx. 0.02M) in a glass-stoppered conical flask and add 3 mL of concentrated hydrochloric acid followed by two portions of about 0.3 g each of pure sodium hydrogencarbonate to remove air. Add immediately about 1.0 g of iodate-free potassium iodide and 22 mL of concentrated hydrochloric acid. Stopper the flask, shake the contents, and allow it to stand for 5-10 minutes. Titrate the solution with standard 0.1M sodium thiosulphate in the usual manner. 

Procedure. The chlorate solution should have a volume of about 100 mL, and contain about 0.2 g C103. Add 50 mL of a 10 per cent solution of crystallised iron(II) sulphate, heat with constant stirring to the boiling point, and boil for 15 minutes. Allow to cool, add nitric acid until the precipitated basic iron(III) salt is dissolved, precipitate the chloride by means of silver nitrate solution, and collect and weigh as AgCl after the usual treatment (Section 11.57). 

Alternatively, treat the chlorate solution with excess of sulphur dioxide, boil the solution to remove the excess of the gas, render slightly acid with nitric acid, and precipitate the silver chloride as above. 

For the reduction with zinc, render the chlorate solution strongly acid with acetic acid, add excess of zinc, and boil the mixture for 1 hour. Dissolve the excess of unused zinc with nitric acid, filter, and treat the filtrate with silver nitrate in the usual manner. 

Perchlorates are also produced electrochemicaUy. The oxidation of chlorate to perchlorate ions occurs at a higher positive potential (above 2.0 V vs. SHE) than chloride ion oxidation. The current yield of perchlorate is lower when chloride ions are present in the solution hence, in perchlorate production concentrated pure chlorate solutions free of chlorides are used. Materials stable in this potential range are used as the anodes primarily, these include smooth platinum, platinum on titanium, and lead dioxide. 

SRS skids have been proposed for a number of different types of sulphate removal operations, including sodium sulphate from sodium bromide solutions, sodium chlorate solutions and potassium sulphate from potassium chloride solutions. All of these different separations have been tested on a commercial spiral-wound membrane and the results have been good. 

The hydroquinone process was developed by BASF [12]. Hydroquinone-2,5-di-carboxylic acid is prepared by a modified Kolbe-Schmidt synthesis from hydroquinone and carbon dioxide. Subsequent reaction with arylamine in an aqueous-methanolic suspension in the presence of an aqueous sodium chlorate solution and a vanadium salt affords the product in good yield ... 

The Raman spectra of zinc chlorate solutions show chlorate coordination in the species [Zn(aq)C103]+. J... 

Sodium chlorate is produced by the electrolysis of a sodium chloride solution in an electrolyzer without a diaphragm, having an iron cathode and a magnetite or graphite anode. For the manufacture of potassium chlorate either the sodium chloride solution is used, or a mixed solution of both sodium and potassium chloride. The chlorate solution obtained will finally be converted with potassium chloride into potassium chlorate, which is separated by crystallisation while the mother liquor is returned to the electrolytic process. The potassium chloride solution will not be electrolyzed directly as potassium chlorate is sparingly soluble and the potassium chloride entrained in the chlorate crystals is not easy to remove. 

Indigo test A dilute solution of indigo in concentrated sulphuric acid is added to the chlorate solution until the latter has a pale-blue colour. Dilute sulphurous acid or sodium sulphite solution is then added drop by drop the blue colour is discharged. The chlorate is reduced by the sulphurous acid to chlorine or to hypochlorite, and the latter bleaches the indigo. 

The salt can also be prepared by neutralizing perchloric acid with sodium hydroxide, but it is manufactured by the electrolytic oxidation of a 25 per cent, sodium-chlorate solution at 10° C., platinum electrodes and a high anode-potential being employed.1 This process finds application in the manufacture of potassium perchlorate, this salt being obtained from the sodium compound by the action of potassium chloride. 

Ferrous chlorate, Fe(C103)2, is probably formed in solution when ferrous sulphate and barium chlorate solutions are allowed to react. It is very unstable, however.15... 

Many experimental results have been reported which show that materials other than the solute and solvent present in the solution may inhibit crystal growth and induce a greater degree of supersolubility than usual. For example, many years ago, Marc (M6) showed that the presence of even small amounts of the dye Ponceau 2R extends the supersaturation limit of potassium chlorate solution. The general effects of impurities and additives on nucleation and growth are discussed further below and in detail by Buckley (B8). 

POTASSIUM CHLORATE, solution pN 2427) pOp POTASSIUM OXYMURIATE POTCRATE SALT OF TARTAR... 

Oxidation of primary alcohols in acid media is often accompanied by esterification. By the use of the proper proportions of reactants, fair yields of esters may be obtained directly from the alcohols e.g., -butyl n>butyrate (47%) by chromic acid oxidation of n-butyl alcohol. Aqueous acid chlorate solutions in the presence of vanadium pentoxide have been used for this purpose. ... 

Why is potassium chlorate rather than sodium chloiate usually uacv in the chemical laboratory when a chlorate is needed Why is sodium chlorate solution, rather than potassium chlorate solution, used as a weed-killer ... 

Any substance or mixture which, in the 1 1 mixture, by mass, of substance (or mixture) and cellulose tested, exhibits a mean pressure rise time less than or equal to the mean pressure rise time of a 1 1 mixture, by mass, of 40% aqueous sodium chlorate solution and cellulose and the criteria for Category 1 are not met ... 

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