Bleaching manufacture

Uses Solvent for chlorinated rubber insecticide and bleach manufacturing paint, varnish and rust remover manufacturing degreasing, cleansing, and drying of metals denaturant for ethyl alcohol preparation of 1,1-dichloroethylene extractant and solvent for oils and fats insecticides weed killer fumigant intermediate in the manufacturing of other chlorinated hydrocarbons herbicide. 

Use Soap manufacture, bleaching, manufacture of potassium carbonate and tetrapotassium pyrophosphate, electrolyte in alkaline storage batteries and some fuel cells, absorbent for carbon dioxide and hydrogen sulfide, dyestuffs, liquid fertilizers, food additive, herbicides, electroplating, mercerizing, paint removers, reagent. 

Wood-processing processes (wood delignification, bleaching, manufacture of cellulose derivatives such as carboxymethyl cellulose, CMC)... 

Sodium hypochlorite bleaches possess a specific odor generally considered as a real signal of efficacy. A sizable number of consumers perceive this odor as disagreeable. In response, bleach manufacturers have tried to formulate with fragrance systems which can at least partially cover the hypochlorite odor perceived from the product as is, firom the product diluted for use, as well as in the room where the product is used. Bleach is sold as scented solutions in which the ingredients of the composition are carefully selected in order to be stable in the presence of sodium hypochlorite. 

CH2CI-CO-CH3. Colourless lachrymatory liquid b.p. 119°C. Manufactured by treating propanone with bleaching powder or chlorine. It is used as a tear gas and is usually mixed with the more potent bromoacetone. chloro acids Complex chloroanions are formed by most elements of the periodic table by solution of oxides or chlorides in concentrated hydrochloric acid. Potassium salts are precipitated from solution when potassium chloride is added to a solution of the chloro acid, the free acids are generally unstable. 

C4H8CI2S, (CH2CICH2)2S. Colourless oily liquid with a faint garlic-like odour m.p. 13-I4 C, b.p. 215-217 C. Manufactured by treating S2CI2 with ethene at 30-35°C. Decomposed violently by bleaching powder. It is a powerful vesicant and poison, and causes... 

By far the most commercially important boron compound in terms of dollar sales is Na2B407.5H20. This pentahydrate is used in very large quantities in the manufacture of insulation fiberglass and sodium perborate bleach. 

Most of the chlorine produced is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants, and textile processing. Further use is in the manufacture of chlorates, chloroform, carbon tetrachloride, and in the extraction of bromine. 

Early demand for chlorine centered on textile bleaching, and chlorine generated through the electrolytic decomposition of salt (NaCl) sufficed. Sodium hydroxide was produced by the lime—soda reaction, using sodium carbonate readily available from the Solvay process. Increased demand for chlorine for PVC manufacture led to the production of chlorine and sodium hydroxide as coproducts. Solution mining of salt and the avadabiHty of asbestos resulted in the dominance of the diaphragm process in North America, whereas soHd salt and mercury avadabiHty led to the dominance of the mercury process in Europe. Japan imported its salt in soHd form and, until the development of the membrane process, also favored the mercury ceU for production. 

Bleaching. The largest single use for hydrogen peroxide in the United States and North America is wood pulp bleaching, but consumption for the manufacture of chemicals, environmental appHcations, and for bleaching cotton (qv), wool (qv), and other textiles (qv) is significant. 

The main industrial uses of petoxycatboxyhc acids ate in the manufacture of epoxides, synthetic glycerol (qv), and epoxy resins (qv) (165,167,168). They also have been used as disinfectants (177), fungicides, and bleaching agents and for shrink-proofing wool (34). 

Their performance falls short of most present finishes, particularly in durabiUty, resistance to chlorine-containing bleaches, and formaldehyde release, and they are not used much today. Both urea and formaldehyde are relatively inexpensive, and manufacture is simple ie, 1 —2 mol of formaldehyde as an aqueous solution reacts with 1 mol of urea under mildly alkaline conditions at slightly elevated temperatures. 

Closed-Mill Concept. The closed-mill concept, or water circuit closure, has been studied by the pulp and paper industry for many years. In some parts of the paper manufacturing process, up to 98% of the water is recycled within the process, eg, the wet end of the paper machine. However, in the pulp mill, especiaUy kraft mills, effluents are produced owing to the need to purge from the system various metals that come in with the wood, as weU as organic by-products from the pulping process, additives, and especially chloride ions that originate in the bleach plant. 

Pa.le Crepes. Sri Lanka is the largest producer of crepe mbber, as either thin pale crepe or thick pale crepe, which accounts for 35% of mbber production. Pale crepes are divided into one of three classes, depending on the manufacturing process (11,12) fractionated and bleached mbber (FB) unfractionated, but bleached mbber (UFB) or yellow fraction mbber (YF). 

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