Sodium hypochlorite manufacture

Oxidation of Aromatic Amines. The technically important dye Direct Yellow 28 (23) [10114-47-3] (Cl 19555) for cotton usage is manufactured by oxidation of dehydrothio- i ra-toluidinesulfonic acid sodium salt with sodium hypochlorite ia aqueous alkaline solutioa. 

Economic Aspects. Sodium hypochlorite—trisodium phosphate complex was commercialized in 1930. Chlorinated TSP is manufactured by Stauffer (a subsidiary of Rhc ne-Poulenc, Inc.). The consumption, steadily decreasing since 1980, dropped sharply in 1985 because of reduced use in dishwasher detergents. The estimated demand in 1987 was 37,360 t (220). In 1988 it sold for 0.32/lb ( 0.70/kg) for tmddoad quantities of 660 kg (300-lb) dmms. 

Other industries of interest are (1) the manufacturing of spices and flavorings, which may use activated carbon filters to remove odors from their exhaust stream (2) the tanning industry, which uses afterburners or activated carbon for odor removal and wet scrubbers for dust removal and (3) glue and rendering plants, which utilize sodium hypochlorite scrubbers or afterburners to control odorous emissions. 

Saponification to the sulphonic acid yields the product marketed as Nafion. This material is said to be permselective in that it passes cations but not anions. It is used as a membrane material in electrochemical processes, in for example the manufacture of sodium hypochlorite. 

The reduction in the numbers of incinerators and the limitations of autoclaves have created the need for alternative medical waste treatment systems. Currently, there are over 40 such technologies available from greater than 70 manufacturers within the United States, Europe, the Middle East, and Australia. While these systems vary in their treatment capacity, the extent of automation, and overall volume reduction, all alternative technologies utilize one or more of the following methods (1) heating the waste to a minimum of 90 to 95°C by means of microwaves, radio waves, hot oil, hot water, steam, or superheated gases (2) exposing the waste to chemicals such as sodium hypochlorite (household bleach) or... 

At one time, sodium hypochlorite was manufactured electrochemically on a substantial scale. Now it is regarded as a by-product of the chlor-alkali industry [10]. On the other hand, there are many situations where low volumes of hypochlorite may be required or the requirement is irregular. Aqueous solutions of hypochlorite are much safer than chlorine gas but contain < 15wt% of active chlorine. Hence, storage and transportation costs are relatively high. Often the most convenient and cost-effective solution is to eleetrolytically generate OC1- in situ [10]. 

The existing mercury cell plant in Melbourne (ICI Mark 1 cells) is 14 000 tonnes per annum capacity whereas the market demand in Victoria, South Australia and Tasmania is 30 000 tonnes per annum. Owing to the age, condition and location of this plant (adjacent to residential areas and 5 km from the centre of Melbourne), it was decided to close this site and construct a new Greenfield plant in Laverton North, approximately 10 km away. The new plant includes chlor-alkali manufacture, sodium hypochlorite, hydrochloric acid, liquid chlorine storage and packing and chlor-paraffin manufacture. 

The Sydney plant is a combination of older mercury cell technology (updated ICI Mark 1 cells) and modern derivative plants (hydrochloric acid, sodium hypochlorite and ferric chloride) combined with liquid chlorine packing. The mercury cells had originally been in excess of 80 000 tonnes per annum capacity and cells had been progressively taken off-line following closure of chlorinated solvents (CTC/PCE) and EDC/VCM manufacture over a period of 10 years. This had left an asset significantly oversized compared with the present market demands. 

Nickel(lll) oxide, prepared from a nickel(ii) salt and sodium hypochlorite, is used for the oxidation of alkanols in aqueous alkali [46]. Residual nickel(Ii) oxide can be re-activated by reaction with sodium hypochlorite. Nickel oxides have also long been used in the manufacture of the positive pole in the Edison nickel-iron rechargeable battery, now largely superseded by die lead-acid accumulator, and in the Jungner nickel-cadmium batteries used as button cells for calculators [47]. Here, prepared nickel oxide is pressed into a holding plate of perforated nickel. Such prepared plates of nickel(lli) oxide have been proposed as reagent for the oxidation, in alkaline solution, of secondary alcohols to ketones and primary alcohols to carboxylic acids [48]. Used plates can be regenerated by anodic oxidation. 

This is a preservative-free formula shelf-life stability is achieved by maintaining pH of the suspension above 9.00 through the addition of magnesium hydroxide. Absence of preservatives makes it a more palatable formula but requires extra care in the manufacturing process. Rigidly control the microbial specification of all ingredients. Thoroughly clean all equipment and rinse with 1% sodium hypochlorite solution before use. Finally, rinse with purified water. 

Bleaching. Crude wood cellulose is bleached by means of calcium or sodium hypochlorite in large tanks, bleachers , equipped with stirrers. Bleaching cellulose is of great importance for nitrocellulose manufacture, particularly in the case of nitrocellulose intended for the production of smokeless powder. It is essential that the powder should be pale in colour, as a change in the colour of the powder often indicates decomposition. Similarly, cellulose destined for manufacturing collodion cotton, for varnishes, celluloid and film, should be carefully stripped of colour so that the final products are colourless. 

Apart from sodium hypochlorite and sodium bromide solutions, almost all other liquid biocides (or biocide intermediates) are nonoxidizer types. Most nonoxidizers are manufactured by specialist chemical companies, who sell these branded products for scores of different sanitizing or disinfection applications, of which cooling water system treatment is only one. These chemicals may be merely renamed (according to subregistration permits) or they may be blended with other biocides or inhibitors to form new and different products with accordingly modified properties. Some biocides may only be available from the primary manufacturer, often as extremely concentrated and hazardous materials. These chemicals will then usually require some form of dilution, stabilization, and quality verification before being incorporated into a service company s product line. 

The most important (and also the most expensive) grapefruit aroma compound is the bicyclic terpene nootkatone. It is manufactured by oxidation of valencene, which is extracted from Valencia oranges. Figure 1.23 shows two routes for this oxidation, a stoichiometric reaction using chromium trioxide, and a catalytic alternative using sodium hypochlorite (bleach) in the presence of 1 mol% osmium tetraoxide catalyst. 

The most common method for manufacturing sodium hypochlorite is by the treatment of sodium hydroxide solution with gaseous chlorine. 

Sodium hydroxide has many different uses in the chemical industry. Considerable amounts are used in the manufacture of paper and to make sodium hypochlorite for use in disinfectants and bleaches. Chlorine is also used to produce vinyl chloride, the starting material for the manufacture of polyvinyl chloride (PVC), and in water purification. Hydrochloric acid may be prepared by the direct reaction of chlorine and hydrogen gas or by the reaction of sodium chloride and sulfuric acid. It is used as a chlorinating agent for metals and organic compounds. 

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