Sodium hypochlorite, formation solution

The pH of the chlorine dioxide reaction mixture must be maintained in the 2.8—3.2 pH range, otherwise decreased conversion yields of chlorite to chlorine dioxide are obtained with by-product formation of chlorate. Generator efficiencies of 93% and higher have been demonstrated. A disadvantage of this system is the limited storage life of the sodium hypochlorite oxidant solution. 

Sodium hydride, 5 10 dispersions of, 6 13 Sodium hypochlorite, formation of, in preparation of chlorine(I) oxide, 6 159re. solution of, 1 90... 

Several chlorinating agents have been used for SBR soles bonding. Acidified sodium hypochlorite aqueous solutions have been used successfully (O Table 51.1) and the mechanism of chlorination has been established (Vukov 1984), which consists in the formation of H2CIO which produces chlorine chlorine is added to double C=C bond in the rubber producing chlorinated hydrocarbon moieties and some cross-linking. 

Anhydrous zinc chloride can be made from the reaction of the metal with chlorine or hydrogen chloride. It is usually made commercially by the reaction of aqueous hydrochloric acid with scrap zinc materials or roasted ore, ie, cmde zinc oxide. The solution is purified in various ways depending upon the impurities present. For example, iron and manganese precipitate after partial neutralization with zinc oxide or other alkah and oxidation with chlorine or sodium hypochlorite. Heavy metals are removed with zinc powder. The solution is concentrated by boiling, and hydrochloric acid is added to prevent the formation of basic chlorides. Zinc chloride is usually sold as a 47.4 wt % (sp gr 1.53) solution, but is also produced in soHd form by further evaporation until, upon cooling, an almost anhydrous salt crystallizes. The soHd is sometimes sold in fused form. 

Use of sodium hypochlorite solution to destroy acidifed benzyl cyanide residues caused a violent explosion, thought to have been due to formation of nitrogen trichloride. 

Liquid household bleach is generally a 5% solution of sodium hypochlorite (NaOCl). Ammonia cleansers—including general household cleansers, wax removers, glass and window cleaners, and oven cleaners — are aqueous solutions of 5-10% ammonia, NH3. Mixing bleach with cleansers containing ammonia leads to the formation of a family of potentially toxic compounds known as chloramines. These toxic gases have acrid fumes that can bum mucous membranes. Scented bleaches can mask one s natural ability to detect these harmful fumes. 

The sample is acidified with sulfuric acid. The bromide content is then determined by the volumetric procedure described by Kolthoff and Yutzy [21 ]. In this procedure the buffered sample is treated with excess sodium hypochlorite to oxidise bromide to bromate. Excess hypochlorite is then destroyed by addition of sodium formate. Acidification of the test solution with sulfuric acid followed by addition of excess potassium iodide liberates an amount of iodine equivalent to the bromate (i.e., the original bromide) content of the sample. The liberated iodine is titrated with standard sodium thiosulfate. 

Thermal. Heating the solution to 60-80°C decomposes the sodium hypochlorite, albeit slowly. If the temperature is too high then this leads to the formation of chlorates via Equation 26.2. Therefore, care is required not to overheat the solution. The consequent requirement for large holding tanks and process safety issues mean that this approach is generally not favoured. 

A normal solution of sodium hypochlorite is prepared as follows in a 5-I. round-bottom flask are placed 1800 g. of sodium hydroxide solution (300 g. of sodium hydroxide to 1500 g. of water) and 1500 g. of ice. Chlorine gas is then passed into the solution until it has gained in weight approximately 213 g. During this addition, the solution must be kept thoroughly cooled with ice, in order that chlorates will not be formed. After all the chlorine has been passed in, it is necessary to be certain that the mixture is slightly alkaline, since any excess of free chlorine in the solution prevents the formation of hydrazine. 

ELECTROPHILIC ADDITIONS TO CARBON-CARBON MULTIPLE BONDS A. Chlorinating agents Sodium hypochlorite solution 7V-Chloro succi n i m i de Antimony pentachloride Formation of chlorohydrins from alkenes Chlorination with solvent participation and cyclization Controlled chlorination of acetylenes... 

The para-diamines cannot be estimated by means of the diazo reaction. The following estimation is based on the formation of benzoquinone dichloro-imide when p-phenylenediamine in hydrochloric acid solution is added to a solution containing excess of sodium hypochlorite and sodium carbonate. 

The paper pulp should be basic. Sodium hypochlorite (NaCIO) is a salt prepared from a strong base (NaOH) and a weak acid (HCIO). Salts of strong bases and weak acids are basic. The solution is basic because the hypochlorous ion (CIO1) bonds with hydrogen ions (H+) from water leaving an excess of hydroxide ions (OH1-). The following equations describe the salt formation and the hydroxide ion formation ... 

Add 20 mL of 3.5% (m/v) calcium hypochlorite solution followed by 1 mL of 1 4 HC1 solution. Add 0.2 to 0.3 g powdered CaC03. Heat the solution to boiling. Add 4 mL sodium formate solution (50% w/w) slowly. Heat to boiling for 10 min, occasionally washing down the sides with distilled water. 

Both hypochlorous acid and the hypochlorites are relatively unstable and decompose readily with liberation of oxygen and the formation of chlorides. In fact, the acid is known only in solution. These compounds are excellent oxidizing agents they are used as bleaching agents, as antiseptics, as disinfectants, and in the production of ethylene glycol. The commercial production of sodium hypochlorite by electrolysis has been described previously. 

In Eq. (18.1), sodium hypochlorite is produced by feeding chlorine into a 30% aqueous caustic solution in a circulating reactor/cooler system. To avoid sodium chlorate formation, the reaction temperature is kept below 30°C and NaOH concentration is kept below 1 g/liter. Typical reaction temperature is 5 °C132. 

Oxidation of internal perfluoroolefins by alkaline solutions of hydrogen peroxide and alkaline and alkaline-earth hypohalides leads to the formation of olefin oxides, the yield of the target product being 40-50%. The reaction with sodium hypochlorite in an alkali in the presence of acetonitrile is an example of epoxidation performed by the nucleophilic attack of the OC1-anion of the multiple bond with further elimination of the chloride anion by the intermediate carbanion (79IZY2509, 79IZV2812, 79RP666176,... 

Thomsen 6 gives for the heat of formation of sodium hypochlorite in aqueous solution from its elements the value 83 36 Cal., Berthelot7 84 7 Cal. For the molecular depression of the freezing-point in aqueous solution Kaoult 8 found the value 3 38° C. 

By electrolysis of a solution of sodium chloride the chlorine and sodium hydroxide can be formed in situ. I hey will then react immediately forming sodium hypochlorite solution. The first stage is the formation of Na+ ions at the cathode and Cl ions at the anode. The sodium immediately reacts with water forming sodium hydroxide and, if the anode and cathode are sufficiently close to each other, the chlorine will react with the sodium hydroxide and the result will be a sodium hypochlorite solution. The available chlorine, however, in sodium hypochlorite solutions prepared in this manner is considerably less than that obtained by the process previously described. 

---