Arsenic acid Manufacture

Sulfuric acid manufacture released both sulfur oxides and arsenic into the environment. 

Chemically, arsenic is complex in that it can exist in a variety of forms including trivalent and pentavalent or as arsenic trioxide (computer chip manufacture) and arsenic acid. Arsenic is excreted in skin cells, sweat, hair, and fingernails, which can be seen as white transverse bands. Acute exposure to arsenic results in gastrointestinal pain, sensory loss, cardiovascular failure, and death. Chronic exposure or survival of acute exposure can cause loss of peripheral sensory function and loss of central nervous system function. Chronic arsenic exposure can also cause cancer of the lung and skin (see the chapter on arsenic). 

Commercial lead arsenate usually consists mainly of the monohydrogen arsenate, but may also contain the normal arsenate. It is in great demand as an insecticide (see p. 301). Many methods of manufacture are described in the patent literature,14 some of the more recent being as follows (1) Metallic lead and arsenious oxide are added to a concentrated solution of arsenic acid containing nitric acid 15 lead arsenate is precipitated, the concentration of the arsenic acid remaining constant. At intervals the precipitate is removed and the arsenic acid solution again treated. (2) A solution of a soluble arsenate is treated... 

Arsenic Pentoxide—Hydrates of Arsenic Pentoxide—Manufacture of Arsenic Acid—Properties of Arsenic Acid Solutions—The Arsenates—Perarsenates. 

Refined arsenic trioxide is used both as a fining and decolorizing agent in glass, As Og and arsenic acid are used in the manufacture of chroma ted copper arsenate, which is used extensively as a wood preservative. 

Before 1914, the US imported most metallic arsenic from Germany (e.g., Smith, 1945). From 1914 to about 1930, the bulk of the arsenic production in the US (marketed for commercial applications as As203, arsenic trioxide, or white arsenic) was derived as a metallurgical by-product of the smelting of copper, lead, and gold. Arsenic trioxide was used in the production of fertilizers, herbicides, and insecticides (Kirk-Othmer, 1992 Ullman s Encyclopedia, 1998), or if transformed to arsenic acid, used in the manufacture of CCA, a preservative of wood products (Mineral Commodity Summaries, 2004). Arsenic metal is also used for solders, ammunition, anti-friction additive to bearings, and in the computer and electronics industry for semiconductors (Mineral Commodity Summaries, 2004). 

The chrysanilines are formed in small quantities as bye-products in the manufacture of magenta, both by the arsenic acid and the... 

Manufacture of the aniline red with arsenic acid underwent extensive improvement at Roberts, Dale Co. in the hands of the German chemist and colorist August Leonhardt, who developed a process for recovery and reuse of the arsenic acid. This overcame the... 

Rosaniline is the color-base of magenta. The hydrochloride of the base is generally called magenta or fuchsine, although the acetate is also used under these names. Rosaniline is manufactured by ojddizing a mixture of aniline, o-toluidine, and p-toluidine, with arsenic acid, mercuric nitrate, or nitrobenzene. The reaction is analogous to that which takes place in the preparation of pararosaniline, of which rosaniline is a methyl derivative with the structure indicated by the following formula —... 

Antimonic acid, HSbOg -1- 2H2O, has replaced arsenic acid in the manufacture of aniline yellow and aniline red. 

The sources of dyes used by man include animal, vegetable, and mineral. Sir William Henry Perkins, in 1856, synthesized the first aniline dye. In 1860, a triphenylmethane dye, fuch-sine, was used by the French to color wine. On August 2, 1886, the U.S. Congress authorized the addition of color to butter. On June 6, 1896, Congress approved colorants in cheese, and by 1900 colorants were added to catsup, jellies, cordials, candies, sausage and noodles. However, there were some concerns by the public. For example, chrome yellow, martius yellow and quicksilver Vermillion were added to foods to hide poor quality or to increase weight. There was no control over the purity of colorants used. For example, it has been noted that rejected textile dyes were sometimes added to foods. Use of arsenic acid and mercury in the manufacture of colorants also created some concerns. 

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