Hydrogen Peroxide Essay, Research Paper
(H2O2), a colourless liquid usually produced as aqueous solutions of various strengths, used principally for bleaching cotton and other textiles and wood pulp, in the manufacture of other chemicals, as a rocket propellant, and for cosmetic and medicinal purposes. Solutions containing more than about 8 percent hydrogen peroxide are corrosive to the skin.
First recognized as a chemical compound in 1818, hydrogen peroxide is the simplest member of the class of s. Of the several processes of manufacture, the principal ones involve reactions of oxygen from the air with certain organic compounds, especially anthraquinone or isopropyl alcohol. Major commercial grades are aqueous solutions containing 35, 50, 70, or 90 percent hydrogen peroxide and small amounts of stabilizers (often tin salts and phosphates) to suppress decomposition.
Hydrogen peroxide decomposes into water and oxygen upon heating or in the presence of numerous substances, particularly salts of such metals as iron, copper, manganese, nickel, or chromium. It combines with many compounds to form crystalline solids useful as mild oxidizing agents; the best-known of these is sodium perborate (NaBO2H2O23H2O or NaBO34H2O). With certain organic compounds, hydrogen peroxide reacts to form hydroperoxides or peroxides, several of which are used to initiate polymerization reactions. In most of its reactions, hydrogen peroxide oxidizes other substances, although it is itself oxidized by a few compounds, such as potassium permanganate.
Pure hydrogen peroxide freezes at -0.43? C (+31.3? F) and boils at 150.2? C (302? F); it is denser than water and is soluble in it in all proportions.
The most important covalent peroxide is hydrogen peroxide, H2O2. When pure, this syrupy, viscous liquid has a pale blue colour, although it appears almost colourless. Many of its physical properties resemble those of water. It has a larger liquid range than water, melting at -0.43? C and boiling at 150.2? C, and it has a higher density (1.44 gr
2H2O + O2 —> 2H2O2
In the absence of catalysts, minimal decomposition occurs. In the presence of even trace amounts of many metal ions or metal surfaces, however, explosive decomposition can occur. Traces of alkali metal ions dissolved from glass can cause this decomposition, and, for this reason, pure H2O2 (or a concentrated solution) is normally stored in wax-coated or plastic bottles. Hydrogen peroxide is a strong oxidizing agent in either acidic or basic solutions and will also act as a reducing agent toward very strong oxidizing agents, such as the permanganate ion, MnO4-. The largest industrial use of hydrogen peroxide is as a bleach for such materials as textiles, paper pulp, and leather. It is used in dilute solution as a mild antiseptic and disinfectant and is employed in the production of organic stabilizers, polymerization initiators, curing agents, and pharmaceuticals.