Commercial preparations, bleached

The reaction of S03 with 1-alkenes is strongly exothermic and control of the reaction is difficult. In the past it was practice to bleach commercially prepared AOS to obtain acceptable Klett color. Chlorosultones, such as the 2-chloro-y derivative may be formed after addition of hypochlorite to the AOS. 

In some small-scale preparations of this type in the checkers laboratory, commercial household bleach (Chlorox , 5.25% NaOCl) has been used and the course of the reaction has been followed by thin layer chromatography. The yields appear to be somewhat lower than those obtained with sodium hypochlorite prepared as described above. The obvious attractive alternative, preparation of potassium hypochlorite as described elsewhere in this series, apparently has not been tried. 

However carefully prepared, bleaching powder always contains an excess of lime at any rate, a deposit of slaked lime is always found as a residue when bleaching powder is extracted with water. Since the available chlorine in commercial bleaching powder usually ranges between 36 and 38 per cent., and under the very best conditions a maximum of about 43 5 per cent, of available chlorine is taken up, it is inferred that the calcium hydroxide, Ca(0H)2, is not completely sat. with chlorine, and that calcium hydroxide is present—either free or combined. 

Small Quantities. Wear eye protection, laboratory coat, and butyl rubber gloves. Work in the fume hood. Prepare a dilute aqueous (5%) solution of phenylhydrazine (phenylhydrazine-HCl add 3 mL of 10% NaOH for each 1 g of the hydrochloride) by adding slowly to the appropriate volume of water. For each 1 g of phenylhydrazine or phenylhydrazine-HCl, place 18 mL (about 25% excess) of commercial laundry bleach (containing about 5.25% sodium hypochlorite) into a three-necked, round-bottom flask equipped with a stirrer, thermometer, and dropping funnel. Add the aqueous phenylhydrazine to the stirred hypochlorite solution, monitoring the rate of addition by rise in temperature. The temperature is maintained at 45-50°C, and addition takes about 1 hour. Stirring is continued for 2 hours until the temperature gradually falls to room temperature. The cooled reaction mixture can be flushed down the drain with at least 50 times its volume of water.6... 

Most of the commercially prepared SO2 is converted to SO3, which is subsequently used to manufacture sulfuric acid, H2SO4. Other uses of SO2, albeit on a much-smaller scale, include its application as a refrigerant, food preservative, and bleaching agent. 

A compound typical of lichens, for example, genus Cladonia and Usnea. It occurs in two enantiomeric forms, which are effective CH3 against a large variety of Gram-positive bacterial strains. The (-l-)-enantiomer is selective against Streptococcus mutans and is included in some oral-care commercial preparations. (-)-Usnic acid, as opposed to (-l-)-form, is a selective herbicide, which irreversibly inhibits one of the important plant enzymes involved in carotenoid synthesis and bleaching — 4-hydroxyphenylpyruvate dioxygenase [68-71],... 

Chloric(III) acid is a fairly weak acid, and is an oxidising agent, for example it oxidises aqueous iodide ion to iodine. Sodium chlorate(III) (prepared as above) is used commercially as a mild bleaching agent it bleaches many natural and synthetic fibres without degrading them, and will also bleach, for example, oils, varnishes and beeswax. 

Titanium Trichloride Hexahydrate. Titanium trichloride hexahydrate [19114-57-9] can be prepared by dissolving anhydrous titanium trichloride ia water or by reduciag a solutioa of titanium tetrachloride. Evaporation and crystallisation of the solution yield violet crystals of the hexahydrate. The hydrated salt has had some commercial appHcation as a stripping or bleaching agent ia the dyeiag iadustry, particularly where chlorine must be avoided. 

Sodium Tetrahydroborate, Na[BH ]. This air-stable white powder, commonly referred to as sodium borohydride, is the most widely commercialized boron hydride material. It is used in a variety of industrial processes including bleaching of paper pulp and clays, preparation and purification of organic chemicals and pharmaceuticals, textile dye reduction, recovery of valuable metals, wastewater treatment, and production of dithionite compounds. Sodium borohydride is produced in the United States by Morton International, Inc., the Alfa Division of Johnson Matthey, Inc., and Covan Limited, with Morton International supplying about 75% of market. More than six million pounds of this material suppHed as powder, pellets, and aqueous solution, were produced in 1990. 

Chlorine dioxide, discovered in 1811 by Davy, was prepared from the reaction of potassium chlorate with hydrochloric acid. Early experimentation showed that chlorine dioxide exhibited strong oxidizing and bleaching properties. In the 1930s, the Mathieson Alkali Works developed the first commercial process for preparing chlorine dioxide from sodium chlorate. By 1939, sodium chlorite was established as a commercial product for the generation of chlorine dioxide. 

Commercial heparin preparations are also frequently bleached with oxidants (for example, KMn04 and H202),32 a treatment that must lead to some modification of their original structure and biological properties. 

An overly efficient student simultaneously prepared two titration mixtures, consisting of diluted bleaching solution, KI solution, and HC1 solution. The student found that data from the two titrations yielded significantly different percents NaOCl in the commercial bleaching solution. Which determination would give the higher % NaOCl Briefly explain. 

Figure 2.2 Light photomicrographs of fibre preparations illustrating the morphological differences between softwood and hardwood commercial pulps (a) bleached sulfate pine (softwood), (b) bleached sulfate eucalyptus (hardwood). Scale bar = 200 /an.

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