Bleaching properties

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. 

Sulphurous acid gas is absorhed by water and hence, in order to examine its properties in that state, it must he collected over moreury. It is colorless and transparent, having a peculiar irritating odor, and cannot be respired. It is neither combustible, nor a supporter of combustion. It possesses bleaching properties, owing to wliich it is used in the arts to whiten straw bonnets, com, silk, sponges, and other substances if a red rose be expesed to the flame of burning sulphur, it becomes completely white. 

I. Janicot, A. Bouchu, G. Descotes, and E. Wong, Correlation structure-activity in the bleaching properties of peracetylated carbohydrates, Tenside Surfactants Deterg., 33 (1996) 290-296. 

Perborate of sodium, NaBOg,4H20, is similarly prepared, or it may be produced by cooling a solution of borax to which some caustic soda and hydrogen peroxide have been added. It, too, is a sparingly soluble salt, possessing bleaching properties. 

Sodium perborate has been for some time in use mixed with soap, borax, alkali, etc., and is sold for laundry work under such names as Persil, Glarax, and Ozonite. It possesses detergent and bleaching properties. Since 1914 the salt NaBOj, 4H20 has been produced by electrolysis, and many recent patents deal with this process. Formerly, the only means available for preparation was that of mixing borax with hydrogen peroxide. 

Since the fledgling days of industrial chemical practice, the bleaching properties of chlorine have been in demand. Rampant spread of the great killer diseases such as cholera and typhoid was eliminated by the treatment of wastewater and drinking water with small amounts of bleach. Textile manufacturers and the paper industry had established the value of bleach in their operations early on. 

Spirooxazines (NISO) have UV activation properties and thermal bleaching properties that are convenient for eyewear applications. A plastic photochromic lens must have several features, such as (1) ultraviolet energy protection, (2) comfortably lightweight, and (3) tint from a fashionably light tint to a functionally darker tinted sun lens. 45... 

Aliphatic diol 4,5-disulfonate-based resist adjustment for generation of square-wave relief pattern, 127 application, 127 bleaching properties, 126/ development rate function, 130/ print quality, 127/ spectra of unexposed and bleached materials, 126/... 

The Swedish chemist Carl Scheele first isolated chlorine in 1774 and the bleaching properties of its aqueous solutions were discovered soon afterwards. Various preparations were marketed for this purpose, but its medical use was not explored until 1825 when the Parisian apothecary Labarraque... 

The presence of impurities or foreign ions in KC1 has a marked effect on the coagulation of F-eentres. Watson and Scott83 have shown that the introduction of alkaline earth ions into additively coloured KC1 enhances the stability of F-centres. Markham and Hersh84 have found that the optical and thermal bleaching properties of potassium halides are radically affected by doping with thallium ions. 

Scheele discovered chlorine when he treated black manganese with hydrochloric acid and isolated a suffocating, greenish-yellow gas. The bleaching properties of chlorine were readily apparent. Scheele s discovery that plumbago (graphite) burned completely to yield fixed air allowed him to conclude that black lead was, in reality, pure carbon, just like diamond. ... 

Water absorbs about 50 times its volume of this gas, forming liquid sulphurous acid, as it is called, properly an aqueous solution of the acid. This solution has the suffocating smell, peculiar taste, and bleaching properties of the gas. If exposed to the air, it gradually absorbs oxygen, and passes into sulphuric acid. Nitnc acid also converts sulphurous acid into sulphuric acid. 

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