Dilute bleach

Chiral irara-cyclohexane- 1,2-diamine was used as the bridging diamine and this led to a successful catalyst [14], often referred to as Jacobsen s catalyst (Figure 14.12). The oxidising agent is household bleach ( ) diluted and buffered... 

Toned prints should be dried face up on clean drying racks, as many toners will transfer to the screen when placed face down. One exception is properly washed selenium toned prints, which may be safely dried face down. Drying racks should be cleaned with a solution of household bleach diluted 1 4 with water (wear gloves and use proper ventilation when using bleach). 

Be certain there are no residual chemicals on the drying rack. The best way to clean residual fixer from a washer, print drying racks, trays, sink, and other surfaces is with a solution of common household bleach diluted 1 4 with water (200.0 ml of bleach with 800.0 ml of water). Sponge the bleach solution on and wash it off with fresh water. 

In the section entitled Cleaning Up at the end of each experiment the goal is to reduce the volume of hazardous waste, to convert hazardous waste to less hazardous waste, or to convert it to nonhazardous waste. The simplest example is concentrated sulfuric acid. As a by-product from a reaction, it is obviously hazardous. But after careful dilution with water and neutralization with sodium carbonate, the sulfuric acid becomes a dilute solution of sodium sulfate, which in almost every locale can be flushed down the drain with a large excess of water. Anything flushed down the drain must be accompanied by a large excess of water. Similarly, concentrated base can be neutralized, oxidants such as Cr " can be reduced, and reductants such as hydrosulfite can be oxidized (by hypochlorite— household bleach). Dilute solutions of heavy metal ions can be precipitated as their insoluble sulfides or hydroxides. The precipitate may still be a hazardous waste, but it will have a much smaller volume. 

A US Environmental Protection Agency (EPA) registered hospital disinfectant or a 1 100 dilution of household bleach (1/4 cup per gallon of water) is effective as a disinfectant. However, for grossly soiled surfaces, such as those contaminated with vomitus or stool, staff should use a 1 10 bleach dilution. 

Chlorine is used to prepare bleach—dilute solutions of sodium hypochlorite from the reaction with sodium hydroxide and chlorine. Chlorine forms explosive mixtures with ammonia due to the formation of nitrogen trichloride. ... 

Phenylhydrazine is toxic avoid contact with it. If you spill some on your skin, rinse it off thoroughly with household bleach, dilute acetic acid, and then water. 

Heating with soda-dime. See Section 3, p. 327, Condense the aniline which distils over in a test-tube, dilute with water and add bleaching powder (or NaClO) solution. Note the iolet coloration. 

A 25.00-mL sample of a liquid bleach was diluted to 1000 mb in a volumetric flask. A 25-mL portion of the diluted sample was transferred by pipet into an Erlenmeyer flask and treated with excess KI, oxidizing the OCh to Ch, and producing The liberated was determined by titrating with 0.09892 M NaySyOy, requiting 8.96 mb to reach the starch indicator end point. Report the %w/v NaOCl in the sample of bleach. 

The process operated by ACl is outlined in Figure 7. Bales of cotton linter are opened, cooked in dilute caustic soda, and bleached with sodium hypochlorite. The resulting highly purified ceUulose is mixed with pre-precipitated basic copper sulfate in the dissolver, and 24—28% ammonium hydroxide cooled to below 20°C is added. The mixture is agitated until dissolution is complete. If necessary, air is introduced to aUow oxidative depolymerization and hence a lowering of the dope viscosity. 

A number of perhalides aie known, and one of the most stable is ammonium tetiachloioiodide [19702 3-3] NH IQ. Ammonia reacts with chlorine in dilute solution to give chloramines, a reaction important in water purification (see Cm,ORAMINES AND BROMAMINEs). Depending upon the pH of the water, either monochloramine [10599-90-3] NH2CI, or dichloramine [3400-09-7] NHCI2, is formed. In the dilutions encountered in waterworks practice, monochloramine is neady always found, except in the case of very acidic water (see Bleaching AGENTS Water). 

Pollution Control in the Bleachery. The quantity of water necessary for bleaching, and consequently the volume of effluents, has been decreased significantly by various schemes for recycle of Hquors, eg, pulp washing using dilute spent Hquors and countercurrent flow. Effort is underway to close bleach plants and further reduce water consumption. 

Raw lac is first treated to remove water-soluble carbohydrates and the dye that gives lac its red color. Also removed are woody materials, insect bodies, and trash. It is further refined by either hot filtration or a solvent process. In the heat process, the dried, refined lac is filtered molten through cloth or wine screens to produce the standard grades of orange shellac. In the solvent process, lac is dissolved and refluxed in alcohol solvents, filtered to remove dirt and impurities, and concentrated by evaporation. The lac can be further decolori2ed in this process to produce very pale grades. Bleached shellac is prepared by treatment with dilute sodium hypochlorite and coalesced into slabs. 

Diacetone-L-sorbose (DAS) is oxidized at elevated temperatures in dilute sodium hydroxide in the presence of a catalyst (nickel chloride for bleach or palladium on carbon for air) or by electrolytic methods. After completion of the reaction, the mixture is worked up by acidification to 2,3 4,6-bis-0-isoptopyhdene-2-oxo-L-gulonic acid (2,3 4,6-diacetone-2-keto-L-gulonic acid) (DAG), which is isolated through filtration, washing, and drying. With sodium hypochlorite/nickel chloride, the reported DAG yields ate >90% (65). The oxidation with air has been reported, and a practical process was developed with palladium—carbon or platinum—carbon as catalyst (66,67). The electrolytic oxidation with nickel salts as the catalyst has also... 

Pulp and Paper Chemical and coatings preparation Stock dilution and consistency control Addition of bleaching chemicals... 

Ship and use the material or a substitute in diluted form e.g., aqueous ammonia instead of anhydrous ammonia, or bleach instead of chlorine. 

This reaction is the basis for the use of thiosulfates as antichlorine in the bleaching industry where they are used to destroy any excess of CI2 in the fibres. Bromine, being intermediate between iodine and chlorine, can cause 8203 to act either as a 1-electron or an 8-electron reducer according to conditions. For example, in an amusing and instmctive experiment, if concentrated aqueous solutions of 8203 and Br2 are titrated, and the titration is then repeated after having diluted both the 8203 and Br2 solutions 100-fold, then the titre will be found to have increased by a factor of exactly 8. 

To a solution of m-ethyl cinnamate (44, 352 mg, 85% pure, 1.70 mmol) and 4-phenylpyridine-A-oxide (85.5 mg, 29 mol%) in 1,2-dichloromethane (4.0 mL) was added catalyst 12 (38.0 mg, 3.5 mol%). The resulting brown solution was cooled to 4°C and then combined with 4.0 mL (8.9 mmol) of pre-cooled bleach solution. The two-phase mixture was stirred for 12 h at 4°C. The reaction mixture was diluted with methyl-t-butyl ether (40 mL) and the organic phase separated, washed with water (2 x 40 mL), brine (40 mL), and then dried over Na2S04. The drying agent was removed by filtration the mother liquors concentrated under reduce pressure. The resulting residue was purified by flash chromatography (silica gel, pet ether/ether = 87 13 v/v) to afford a fraction enriched in cis-epoxide (45, cis/trans . 96 4, 215 mg) and a fraction enriched in trans-epoxide cis/trans 13 87, 54 mg). The combined yield of pure epoxides was 83%. ee of the cis-epoxide was determined to be 92% and the trans-epoxide to be 65%. 

The available chlorine refers to the chlorine liberated by the action of dilute acids on the hypochlorite, and is expressed as the percentage by weight in the case of bleaching powder. Commercial bleaching powder contains 36-38 per cent of available chlorine. 

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