Sodium iodate preparation

A solution of sodium iodate, prepared from lOg of iodine according to (I), is diluted to 120ml with water and 4g of sodium hydroxide are added. Twenty-two grams of potassium persulfate are used as m (II) and then a second portion of 17g sodium hydroxide is added. The mixture is boiled for 15 minutes longer, then cooled to 40° C, and the liquid is decanted. The solid is broix it on to the filter with about 25ml of ice water, pressed dry, and then heated at 110°C for one or two hours. 

Stock solution. The concentration of the stock solution was determined by the sodium iodate-thiosulfate titration method. For each determination, a 100.0-ml solution was prepared and placed in a vessel connected to a manometer for measuring the pressure. The vessel was sealed after insertion of a measured piece of catalase-immobilized CoFoam. The reaction of catalase with peroxide produces O2, and an increase in pressure indicates a degradation of the peroxide. Thus, a change in pressure in the vessel is a measure of the reaction rate. Since it is sufficient to show differences in test samples, the ideal gas law was used to convert the pressure into mass. The barometer was calibrated with a gauge traceable to National Institutes of Standards and Technology (NIST) standards. 

Sodium Iodate. This compound, from which all of the following are prepared, may be readily obtained by oxida-... 

Crystalline paraperiodic acid, H5I06, which is hygroscopic and readily soluble in water, is commercially available. Most of the salts of periodic acid are characterized by their slight solubility in water. For oxidation experiments sodium metaperiodate, NaIC>4, is the most suitable salt because of its solubility in water (9.3% at 20° and 12.6% at 25°).99 Sodium metaperiodate is commercially available and also can be obtained readily from the slightly soluble trisodium paraperiodate, Na3H2I06, by crystallization from nitric acid in the ratio of 150 cc. of water and 45 cc. of concentrated nitric add to 100 g. of salt.9 Trisodium paraperiodate is formed in 90% yield by the reaction of bromine and sodium iodide in aqueous sodium hydroxide solution at 80°.100 It is also produced in 80% yield by the oxidation of sodium iodate with chlorine in aqueous sodium hydroxide solution.99 In connection with this preparation of trisodium paraperiodate from sodium iodate, it should be noted that in the usual periodate oxidation reactions the periodate is converted quantitatively into iodate. Paraperiodic acid has been prepared in about 93% yield from trisodium paraperiodate " 1 it has been prepared also by the electrolytic oxidation 191 >192 of iodic add. 

Sodium iodate, NaI03.—The iodate is a constituent of Chile saltpetre or sodium nitrate, and remains in the mother-liquor after crystallization of the nitrate. It is an important source of iodine. The salt can be prepared by oxidizing sodium iodide with sodium peroxide6 or by the electrolytic method,7 and also by the interaction of sodium iodide and periodate.8 It forms white crystals. 

Disodium periodate, Na2HgI06, can be prepared by the action of chlorine on a mixture of sodium iodate and hydroxide,16 or by the oxidation of iodine with sodium peroxide.17 It is soluble with difficulty in both cold and hot water. The table gives determinations of solubility made by Rosenheim and Loewenthal 18... 

Ferric iodate, Fe203.I205, is obtained as a brown precipitate5 on mixing hot solutions of an alkali iodate and a ferric salt. Small crystals may be prepared by addition of an acid solution of iron in nitric acid to sodium iodate. The precipitate first formed readily dissolves, and upon concentration of the solution the salt crystallises out. It is stable in air at ordinary temperatures, but decomposes when heated,... 

Silver oxide and sodium sulfate are frequently used to oxidize 1,2-dihydroxy aromatic compounds to orf/io-quinones. Phenanthrene furnishes, after being shaken for 15 s with the mixture in ether at room temperature, a 65% yield of 3,4-phenanthrenequinone [171]. Another oxidant used to prepare orfho-quinones is sodium iodate (equation 321) [754],... 

Solution B is prepared by placing 29 g of potassium iodate (KIO3) (26 g of NalOs can be substituted) and about 400 mL of distilled water in a 1-L beaker. Add 8.6 mL of 6.0 M H2SO4. (To prepare a stock solution of 6.0 M sulfuric acid, carefully pour 330 mL of concentrated [18 M] sulfuric acid into 500 mL of distilled water and dilute to 1.0 L.) Stir the solution until the iodate dissolves (this may require some heating—sodium iodate will dissolve more readily). 

Certain food additives contain iodine. For example, potassium iodate and calcium iodate are components of preparations for stabilising dough. The synthetic red food colouring erythrosine contains 58% iodine (fouriodineatomsinthemolecule).Therefore, foods coloured using this pigment have a higher iodine content, but the bioavailability of erythrosine iodine is low (2-5%). The content of iodine in foods and meals may also increase with the use of table salt fortified with iodine (as sodium iodide or sodium iodate). The iodine concentration in table salt is 20-50 mg/kg. 

In the second method a solution of the approximate strength required is prepared, and this is standardised against some standard alkaline substance, such as sodium tetraborate or anhydrous sodium carbonate standard potassium iodate or pure silver may also be used (see Section 10.84). If a solution of an exact strength is required, a solution of an approximate strength somewhat greater than that desired is first prepared this is suitably diluted with water after standardisation (for a typical calculation, see Appendix 17). 

For the preparation of standard iodine solutions, resublimed iodine and iodate-free potassium iodide should be employed. The solution may be standardised against pure arsenic(III) oxide or with a sodium thiosulphate solution which has been recently standardised against potassium iodate. 

MRH Barium chlorate 5.06/83, calcium chlorate 5.61/77, potassium chlorate 6.07/76, sodium bromate 4.98/80, sodium chlorate 7.32/75, zinc chlorate 6.11/76 Dry finely divided mixtures of red (or white) phosphorus with chlorates, bromates or iodates of barium, calcium, magnesium, potassium, sodium or zinc will readily explode on initiation by friction, impact or heat. Fires have been caused by accidental contact in the pocket between the red phosphorus in the friction strip on safety-match boxes and potassium chlorate tablets. Addition of a little water to a mixture of white or red phosphorus and potassium iodate causes a violent or explosive reaction. Addition of a little of a solution of phosphorus in carbon disulfide to potassium chlorate causes an explosion when the solvent evaporates. The extreme danger of mixtures of red phosphorus (or sulfur) with chlorates was recognised in the UK some 50 years ago when unlicenced preparation of such mixtures was prohibited by Orders in Council. 

The sal natron liquor, prepared by heating crude nitrate from the aqua vicja tanks with 15 per cent, of coal dust, is made into a cone 5 ft. high with a kind of moat dug round the base of the cone. The cone is sat. with water and ignited. The crude sodium carbonate formed fuses and runs into the pit. The product dissolved in water forms the sal natron liquor. The sodium bisulphate soln. is made by passing the fumes of burning sulphur into the sal natron liquor. The liquid acid is then acid enough to liberate iodic acid from iodates. 

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