Hypochlorite compounds

SYN LITHIUM HYPOCHLORITE COMPOUND, dt)-, containing more than 39% available chlorine (DOT)... 

Hypochlorites are usually made by the same reaction that was used in 1785 to make the first hypochlorite compound. Chlorine gas was bubbled into an aqueous solution of caustic potash (potassium hydroxide) to make potassium hypochlorite, KOCl. Sodium hypochlorite, NaOCl, was not made until 1820 when caustic soda (sodium hydroxide) was used instead of caustic potash. Today, sodium hypochlorite is the major hypochlorite compound produced, and it is the hypochlorite compound that is most often used for cleaning. Potassium hypochlorite is only a minor product that is used in a limited number of cleaning products to avoid the precipitation of certain components. These compounds are almost always made and used as aqueous solutions that are called bleach. Usually the solution contains 5-6% or 12-15% sodium hypochlorite, an equal molar amount of sodium chloride, and 0.01-1% sodium hydroxide. 

Available chlorine is the amount of chlorine needed to make the hypochlorite in a solution or a solid. It is the amount of hypochlorite compound multiplied by the number of hypochlorite groups per molecule divided by its molecular weight times the molecular weight of chlorine. The last three terms are combined to derive the theoretical available chlorine factors as shown in Table 24.1. These factors multiplied by the amount of hypochlorite compound equals available chlorine. Available chlorine is usually measured by iodometric titration. It is a convenient way of expressing the total activity of mixtures without knowing the concentrations of the components. 

Low-salt sodium hypochlorite can also be made by chlorinating a slurry of calcium hydroxide. The precipitated calcium hypochlorite compounds are ranoved by filtration and mixed with a solution of sodium hydroxide. The solids are removed by filtration. The resulting solution contains -15% sodium hypochlorite and 1.3% sodium chloride. ... 

The solubility of the carbonate in water containing carbon dioxide causes the formation of caves with stalagtites and stalagmites and is responsible for hardness in water. Other important compounds are the carbide, chloride, cyanamide, hypochlorite, nitrate, and sulfide. 

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. 

A further group of whiteners was found in the acylamino (R,R ) derivatives (16) of 3,7-diaminodibenzothiophene-2,8-disulfonic acid-5,5-dioxide. The preferred acyl groups are aLkoxybenzoyls (72—74). These compounds give a greenish fluorescence and are relatively weak in comparison with stilbene derivatives on cotton however, they show good stabiUty to hypochlorite. 

Ha.logena.tlon, 3-Chloroindole can be obtained by chlorination with either hypochlorite ion or with sulfuryl chloride. In the former case the reaction proceeds through a 1-chloroindole intermediate (13). 3-Chloroindole [16863-96-0] is quite unstable to acidic aqueous solution, in which it is hydroly2ed to oxindole. 3-Bromoindole [1484-27-1] has been obtained from indole using pytidinium tribromide as the source of electrophilic bromine. Indole reacts with iodine to give 3-iodoindole [26340-47-6]. Both the 3-bromo and 3-iodo compounds are susceptible to hydrolysis in acid but are relatively stable in base. 

Chlorine and Bromine Oxidizing Compounds. The organo chlorine compounds shown in Table 6 share chemistry with inorganic compounds, such as chlorine/77< 2-3 (9-j5y and sodium hypochlorite/7 )< /-j5 2-5 7. The fundamental action of chlorine compounds involves hydrolysis to hypochlorous acid (see Cm ORiNE oxygen acids and salts). 

Other Reactions. Dry hydrated lime adsorbs halogen gases, eg, CI2 and F2, to form hypochlorites and fluorides. It reacts with hydrogen peroxide to form calcium peroxide, a rather unstable compound. At sintering temperatures, quicklime combines with iron to form dicalcium ferrite. 

When the mercury present in the atmosphere is primarily in the form of an organic mercury compound, it may be preferable to utilise an aqueous scmbber. This method is particularly useful for control of emissions from reactors and from dryers. For efficient and economical operation, an aqueous solution of caustic soda, sodium hypochlorite, or sodium sulfide is reckculated through the scmbber until the solution is saturated with the mercury compound. 

Ha.logen Compounds. Fluorine is unreactive toward ozone at ordinary temperatures. Chlorine is oxidized to Cl20 and Cl20y, bromine to Br Og, and iodine to I2O2 and I4O2. Oxidation of haUde ions by ozone increases with the atomic number of haUde. Fluoride is unreactive chloride reacts slowly, ultimately forming chlorate and bromide is readily oxidized to hypobromite (38). Oxidation of iodide is extremely rapid, initially yielding hypoiodite the estimated rate constant is 2 x 10 (39). HypohaUte ions are oxidized to haUtes hypobromite reacts faster than hypochlorite (40). 

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). 

Trisodium phosphate is strongly alkaline many of its appHcations depend on this property. For example, many heavy-duty cleaning compositions contain trisodium phosphate as a primary alkalinity source. The crystalline dodecahydrate itself is marketed as a cleaning compound and paint remover. Traditionally, trisodium phosphate has been used in water softening to remove polyvalent metal ions by precipitation as insoluble phosphates. Because the hypochlorite complex of trisodium phosphate provides solutions that are strongly alkaline and contain active chlorine, it is used in disinfectant cleaners, scouring powders, and automatic dishwashing formulations. 

Chlorine Vehicle ndStabilizer. Sulfamic acid reacts with hypochlorous acid to produce /V-ch1orosu1famic acids, compounds in which the chlorine is stiU active but more stable than in hypochlorite form. The commercial interest in this area is for chlorinated water systems in paper mills, ie, for slimicides, cooling towers, and similar appHcations (54) (see INDUSTRIALANTIMICROBIALAGENTS). 

Chemical Treatment. Some organic compounds are attacked by chemical reagents such as potassium permanganate, sodium hydroxide, calcium hypochlorite, and o2one (29,30). 

For hypochlorite saniti2ers 100—120 ppm for acidic saniti2ers, chlorine, Dichlor, Trichlor, and bromine compounds. 

The first three classes are called available chlorine compounds and are related to chlorine by the equilibria in equations 1—4. These equilibria are rapidly established in aqueous solution (6), but the dissolution of some hypochlorite salts and A/-chloro compounds can be quite slow. 

In solutions, the concentration of available chlorine in the form of hypochlorite or hypochlorous acid is called free-available chlorine. The available chlorine in the form of undissociated A/-chloro compounds is called combined-available chlorine. Several analytical methods can be used to distinguish between free- and combined-available chlorine (8). Bleaches that do not form hypochlorite in solution like chlorine dioxide and nonchlorine bleaches can be characterized by thek equivalent available chlorine content. This can be calculated from equation 5 by substituting the number of electrons accepted divided by two for the number of active chlorine atoms. It can also be measured by iodomettic titration. 

Even very small amounts of transition-metal ions like cobalt, nickel, and copper cause rapid decomposition. They form reactive intermediates that can decrease the stabiUty of oxidizable compounds in the bleach solution and increase the damage to substrates. Hypochlorite is also decomposed by uv light (24,25). Acidic solutions also lose available chlorine by the reverse of equations 1 and 2. 

Chlorine dioxide is usually used in aqueous solution. It is a weaker oxidant than hypochlorite. Unlike chlorine it does not react with water to form hypochlorite or with amines to form A/-chloro compounds. Thus chlorine dioxide is easily removed from solutions by passing air through the solution or its headspace. Chlorine dioxide solutions decompose by equation 12 ... 

A study of the North American bleaching agent market was completed in June 1988 and includes consumption quantities for the year 1986 (156). Chlorine consumption for 1986 was 1.86 x 10 t. The North American consumption volume of other chlorine-containing bleaching compounds including sodium and calcium hypochlorite, chlorinated isocyanurates, and hydantoins was 286,000 t. The 1986 North American consumption of sodium chlorate was estimated at 5.5 x 10 t. 

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