Hypochlorite preparation

Starch oxidation was investigated as early as 1829 by Liebig. The objective, as with other modifications, was to obtain a modified granular starch. The oxidant commonly employed is sodium hypochlorite, prepared from chlorine and aqueous sodium hydroxide. This reaction is exothermic and external cooling must be provided during preparation of the oxidant. 

In some small-scale preparations of this type in the checkers laboratory, commercial household bleach (Chlorox , 5.25% NaOCl) has been used and the course of the reaction has been followed by thin layer chromatography. The yields appear to be somewhat lower than those obtained with sodium hypochlorite prepared as described above. The obvious attractive alternative, preparation of potassium hypochlorite as described elsewhere in this series, apparently has not been tried. 

Unlike most known fluoroalkylhypohalites, which have low thermal stability, a,a-dihydropolyfluoroalkyl hypochlorites prepared by the reaction of C10S02F with the corresponding alcohols are stable at ambient temperature and can even be distilled at reduced pressure [101] ... 

Wear goggles and protective gloves and clothing. To each 10 mL of solution containing 500 mg of fluorouracil, add 40 mL of an aqueous solution of calcium hypochlorite (prepared by stirring 10 g of calcium hypochlorite in 100 mL of water for 2 hours, and then removing the undissolved material by filtration). Stir the solution at room temperature for 5 hours, remove the precipitated calcium fluoride by filtration, and discard as normal refuse. Wash the filtrate into the drain with water.3... 

No iron salts (or salts of other heavy metals) should be allowed to come into contact with the product either during the operation or when storing, as they cause it to decompose with the liberation of oxygen [see equation (XIII-22)]. For this reason it is better to use steam condensate for the preparation of the caustic solution instead of river water. Sodium hypochlorite prepared in this way is a solution which contains 150 grams of active chlorine per litre as well as 140 g of NaCl, 3 to 5 g of NaOH, 5 to 8 g of Na COg and maximum of 0.01 g Fe. 

Hypochlorites are very good oxidizers of alcohols and are frequently selective enough to oxidize secondary alcohols in preference to primary alcohols see equations 288-291). Solutions of sodium hypochlorite in acetic acid react exothermically with secondary alcohols within minutes [693]. Calcium hypochlorite in the presence of an ion exchanger (IRA 900) oxidizes secondary alcohols at room temperature in yields of 60-98% [76 5]. Tetrabutylammonium hypochlorite, prepared in situ from 10% aqueous sodium hypochlorite and a 5% dichloromethane solution of tetrabutylammonium bisulfate, oxidizes 9-fluorenol to fluorenone in 92% yield and benzhydrol to benzophenone in 82% yield at room temperature in 35 and 150 min, respectively [692]. Cyclohexanol is oxidized to cyclohexanone by teit-butyl hypochlorite in carbon tetrachloride in the presence of pyridine. The exothermic reaction must be carried out with due precautions [709]. 

Figure 5.3 illustrates a process to manufacture acetylene from calcium carbide. The carbide is introduced by a screw conveyor into a perforated horizontal cylinder housed in a concentric envelope. Water is sprayed inside the internal shell. The acetylene formed passes upstream through the screw conveyor to a scrubbing tower, where, a new water spray carries off most, of the solids conveyed by the gas. The residual lime and carbide impurities are removed by a screw conveyor to a sludge receiver. The acetylene is cooled to — 10°C to condense most of the water. It is then purified by contact with dilute sulfuric acid in a liquid liquid absorber, and then with sodium hypochlorite prepared by the action of chlorine on caustic soda, to. remove impurities. The acetylene is then cooled to 0°C for the more complete separation of moisture. The final product nevertheless still contains 0.4 per cent by weight of water, which is suitable for most uses. More intensive dehydratation can be achieved by passage over silicagel. 

There are various methods of chlorinating water, for example with gaseous chlorine or with such hypochlorite preparations as sodium hypochlorite, calcium hypochlorite or chlorinated lime, but also using other chlorine compounds such as chlorine dioxide. 

How is sodium hypochlorite prepared Give the balanced chemical equation. 

Bleach (50% Clorox final concentration 2.5% hypochlorite), prepare fresh each day Halocarbon oil 700, to keep the embryos moist and oxygenated (Sigma H 8898)... 

Methyl and ethyl hypochlorites, the first alkyl hypohalites known, were prepared by Sandmeyer in 1885. Chattaway and Backeberg of Oxford subsequently reported the preparation of alkyl hypochlorites such as propyl, isopropyl, and f-butyl hypochlorites in 1923 and observed that although the primary and secondary hypochlorites are very unstable and decompose rapidly at room temperature, the tertiary hypochlorites, such as f-butyl hypochlorite, prepared by the reaction of chlorine, sodium hydroxide, and... 

Mills, J.S. and Petrow, V., The rearrangement of steroid hypochlorites Preparation of 6-methylan-drost-5-ene-3P,17P,19-triol, Chem. Ind. (London), 946, 1961. 

It is prepared by the action of sodium hydroxide and sodium hypochlorite on phthalimide (Hofmann reaction). When heated with soda lime it gives aniline. 

Place 0 5 ml. of acetone, 20 ml. of 10% aqueous potassium iodide solution and 8 ml. of 10% aqueous sodium hydroxide solution in a 50 ml. conical flask, and then add 20 ml. of a freshly prepared molar solution of sodium hypochlorite. Well mix the contents of the flask, when the yellow iodoform will begin to separate almost immediately allow the mixture to stand at room temperature for 10 minutes, and then filter at the pump, wash with cold w ater, and drain thoroughly. Yield of Crude material, 1 4 g. Recrystallise the crude iodoform from methylated spirit. For this purpose, place the crude material in a 50 ml. round-bottomed flask fitted with a reflux water-condenser, add a small quantity of methylated spirit, and heat to boiling on a water-bath then add more methylated spirit cautiously down the condenser until all the iodoform has dissolved. Filter the hot solution through a fluted filter-paper directly into a small beaker or conical flask, and then cool in ice-water. The iodoform rapidly crystallises. Filter at the pump, drain thoroughly and dry. 

Dichloramine-T. Dilute 80 ml, of freshly prepared 2N sodium hypochlorite soluticMi (preparation, p. 525) with 80 ml. of w ter, and then add with stirring 5 g. of finely powdered toluene-p-sulphonamide, a clear solution being rapidly obtained. Cool in ice-water, and then add about 50 ml. of a mixture of equal volumes of glacial acetic acid and water slowly with stirring until precipitation is complete the dichloro-amide separates at first as a fine emulsion, which rapidly forms brittle colourless crystals. Filter off the latter at the pump, wash well with... 

Iodoform reaction. To i ml. of the aldehyde solution, add 3 ml. of 10% KI solution and 10 ml. of freshly prepared sodium hypochlorite solution. Yellow crystals of iodoform, CHI3, soon separate. 

Lead dioxide. A convenient method of preparation is to oxidi.se a plumbous salt in an alkaline medium with a hypochlorite solution ... 

Anthranilic acid. This substance, the ortho amino derivative of benzoic acid, may be conveniently prepared by the action of sodium hypobromite (or sodium hypochlorite) solution upon phthalimide in alkaline solution at 80°. The ring in phthalimide is opened by hydrolysis to phthalamidic acid and the latter undergoes the Hofmann reaction (compare Section 111,116) ... 

Prepare a solution containing about 100 g, of potassium hypochlorite from commercial calcium hypochlorite ( H.T.H. ) as detailed under -Dimethylacrylic Acid, Section 111,142, Note 1, and place it in a 1500 ml. three-necked flask provided with a thermometer, a mechanical stirrer and a reflux condenser. Warm the solution to 55° and add through the condenser 85 g, of p-acetonaphthalene (methyl p-naphthyl ketone) (1). Stir the mixture vigorously and, after the exothermic reaction commences, maintain the temperature at 60-70° by frequent cooling in an ice bath until the temperature no longer tends to rise (ca. 30 minutes). Stir the mixture for a further 30 minutes, and destroy the excess of hypochlorite completely by adding a solution of 25 g. of sodium bisulphite in 100 ml. of water make sure that no hypochlorite remains by testing the solution with acidified potassium iodide solution. Cool the solution, transfer the reaction mixture to a 2-litre beaker and cautiously acidify with 100 ml. of concentrated hydrochloric acid. Filter the crude acid at the pump. 

Hexanitrostilbene may be prepared by a dding a solution of TNT ia tetrahydrofuran and methanol at 5°C to aqueous sodium hypochlorite. To this mixture a 20% solution of trimethyl amine hydrochloride is added at 5—15°C. Hexanitrostilbene precipitates, and is filtered and washed with methanol and... 

The tetramethylol derivative of DABT, prepared by reaction of DABT with alkaline aqueous formaldehyde, polymerized readily on cotton. It imparted excellent flame retardancy, very durable to laundering with carbonate- or phosphate-based detergents as well as to hypochlorite bleach. This was accomphshed at low add-on without use of phosphoms compounds or antimony(III) oxide (75—77). 

Bis(azol-2-5l)stilbenes (2(i]ll such as (4) have been prepared. 4,4 -Dihydrazinostilbene-2,2 -disulfonic acid, obtained from the diamino compound, on treatment with 2 moles of oximinoacetophenone and subsequent ring closure, leads to the formation of (4) [23743-28 ]. Such compounds are used chiefly as washing powder additives for the brightening of cotton fabrics, and exhibit excellent light- and hypochlorite-stabiUty. 

Reaction of perfluoroaLkenes and hypochlorites has been shown to be a general synthesis of perfluoroepoxides (32) (eq. 7). This appears to be the method of choice for the preparation of epoxides from internal fluoroalkenes (38). Excellent yields of HFPO from hexafluoropropylene and sodium hypochlorite using phase-transfer conditions are claimed (34). 

Hydrazine [302-01-2] (diamide), N2H4, a colorless liquid having an ammoniacal odor, is the simplest diamine and unique in its class because of the N—N bond. It was first prepared in 1887 by Curtius as the sulfate salt from diazoacetic ester. Thiele (1893) suggested that the oxidation of ammonia (qv) with hypochlorite should yield hydrazine and in 1906 Raschig demonstrated this process, variations of which constitute the chief commercial methods of manufacture in the 1990s. 

The best known oxoanion of iron is the ferrate(VI) prepared by oxidizing a suspension of hydrous iron(III) oxide in concentrated alkah with potassium hypochlorite or by anodic oxidation of iron in concentrated alkah. Crystals of potassium ferrate [13718-66-6], K FeO, are deep purple, orthorhombic, and contain discrete tetrahedral [FeOJ anions. Barium ferrate [13773-23A] can be precipitated from solutions of soluble ferrate salts. 

Lithium Hypochlorite. Lithium hypochlorite [13840-33-0], LiOCl, is obtained from reaction of chlorine and an aqueous solution of lithium hydroxide. The soHd is usually obtained as a dry stable product containing other alkaH haHdes and sulfates (64). A product containing 35% available chlorine is used for sanitizing appHcations in swimming pools and in food preparation areas where its rapid and complete dissolution is important. The salt can also be obtained in higher purity by reaction of lithium hydroxide and hypochlorous acid (65). 

HCIO4, one of the strongest of the mineral acids. The perchlorates are more stable than the other chlorine oxyanions, ie, chlorates, CIO chlorites, CIO or hypochlorites, OCf (3) (see Chlorine oxygen acids and salts). Essentially, all of the commercial perchlorate compounds are prepared either direcdy or indirectly by electrochemical oxidation of chlorine compounds (4—8) (see Alkali and chlorine products Electrochemical processing). 

Since 1980, mthenium tetroxide, RuO, has been used for staining a number of heterophase polymers for tern (221) it seems to be a more versatile staining agent than OsO. For instance, in SAN modified with acrylate mbber, where the mbber phase is fully saturated, an excellent contrast between the mbber and the matrix has been achieved (222). Crystalline polymers have been stained with RuO (223), and excellent cra2e stmctures have been revealed (221). The stain may be prepared by dissolving RuCl - 3H2O in aqueous sodium hypochlorite for immediate use (224). 

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