Calcium bleaching with

If to a solution of chloroxide of calcium—bleaching powder—anilin be added, a desp violet color is obtained, which in the presence of acids becomes red. By these reactions, anilin is distinguished from the other bases which have the same constitution. With the acids, anilin forms ciystallizable inodorous Balts, which are soluble in water and in alcohol, and which in the moist j... 

The ash of true leather tanned with tannin consists essentially of calcium carbonate with traces of iron and of phosphates. Coloured leathers may contain metals from the mordants used (tin, copper, iron, chromium, aluminium) tin may also be introduced as stannous chloride used for bleaching. Small quantities of silicates (talc, kaolin) may be employed in the treatment of the leather. Finally, other mineral matters (barium, magnesium and lead salts and sodium chloride) may have been added as filling to increase the weight. Complete quantitative analysis of the ash is rarely necessary, but determination of its calcium content is sometimes required, this being made by the ordinary methods. 

Wear breathing apparatus, eye protection, laboratory coat, and butyl rubber gloves. Cover spill with 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand.8 For each 1 mL of iron pentacarbonyl, place 45-50 mL of household bleach (about 5% sodium hypochlorite solution) in a plastic bucket equipped with a stirrer and located in a fume hood. Dilute the bleach with three times its volume of water and, to this solution, slowly add the contaminated spill mix while stirring. Continue the stirring for a period of 48 hours, and then filter the slurry using vacuum filtration. The... 

The hypohalite ions, OCl, OBr, and OI, are formed (along with equivalent quantities of the corresponding halide ions) when the elemental halogens are hydrolyzed in basic solution. Two solid hypobromites and several solid hypochlorites have been isolated. The so-called bleaching powder or chloride of lime, prepared by treatment of calcium hydroxide with chlorine, is often described as a mixed salt Ca(OCl)Cl (however,... 

Before the pulp can be made into paper, it is necessary to mechanically beat or refine it. It is also usually bleached with chlorine and calcium hypochlorite. Unbleached kraft pulp is used for grocery bags and heavy wrapping paper. Other materials may also be added to the pulp depending on the type of paper to be made. For book paper, fillers such as white clay and titanium oxide may be added to provide opaqueness and extra whiteness. Size may be added for stiffness and smoothness. Dyes are added for tinted papers. The specific combination of pulp and additives used to produce a particular type of paper is called the furnish for that paper. With better grades of paper, care is taken to produce a furnish that is chemically neutral (pH 7 on the acid-base scale). For a paper to have long life, it must be acid-free. 

Bleaching powder (chloride of lime) was first used industrially at the beginning of the nineteenth century and for over a century was the only transportable form of chlorine, since chlorine could be made available by acidification with hydrochloric acid. It contains ca. 36% of available chlorine. Since transportation of liquid chlorine became technically feasible at the beginning of the twentieth century, the manufacture of bleaching powder has steadily declined in importance. It is manufactured by reacting moist calcium hydroxide with chlorine, this reaction being fairly slow. 

A normal liquor made up with bleaching powder will have an initial pH of 11-05, and when sodium hypochlorite is used it will be 11-55. In each case the pH falls during j, ing and with subsequent bleaches when standing baths are used. 1. unospheric carbon dioxide forms insoluble calcium carbonate with bleaching powder and soluble alkaline sodium carbonate with sodium hypochlorite. The risk that the pH may fall below the... 

Chitin is isolated by dissolving away the calcium carbonate with 5% cold hydrochloric acid. After filtering and washing, the proteins are removed either with boiling 4% caustic soda or with proteolytic enzymes. The chitin recovered after bleaching is insoluble in water, dilute acids and bases, as well as in organic solvents. It dissolves with hydrolysis in formic acid and in concentrated mineral acids. 

Oven-dried cotton contains about 90% cellulose whilst cotton linters contain 80-85%. In the preparation of chemical cellulose, cotton linters are processed in the following manner. Firstly, the linters are heated at 130-180°C under pressure with 2-5% aqueous sodium hydroxide for 2-6 hours this treatment solubilizes particles of seed-hull and other contaminants present in the linters. The liquor is drained off. The residual linters are washed with water, bleached with gaseous chlorine or calcium hypochlorite, re-washed and dried at about 70°C. The final product has a cellulose content of about 99%. 

Dichloranrine-T (p-toluenesulphondichloramide). Prepare about 200 ml. of a saturated solution of calcium hjrpochlorite by grinding a fresh sample of bleaching powder with water and filtering with shght suction. Dissolve 5 g. of p-toluenesulphonamide in as small a volume of the calcium hypochlorite solution as possible (about 150 ml.) and filter the solution if necessary. Cool in ice, and add about 50 ml. of a mixture of equal volumes of glacial acetic acid and water slowly and with stirring until precipitation is complete. The dichloramine T separates out first as a fine emulsion, which rapidly forms colourless crystals. Filter the latter... 

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