Tuesday, October 15, 2019
Hydrogen Peroxide Essay Example for Free
Hydrogen Peroxide Essay The same reaction is catalysed by theÃ enzymeÃ catalase, found in theÃ liver, whose main function in the body is the removal of toxic byproducts ofmetabolismÃ and the reduction ofÃ oxidative stress. The decomposition occurs more rapidly inÃ alkali, soÃ acidÃ is often added as a stabilizer. The liberation of oxygen and energy in the decomposition has dangerous side-effects. Spilling high concentrations of hydrogen peroxide on a flammable substance can cause an immediate fire, which is further fueled by the oxygen released by the decomposing hydrogen peroxide. High test peroxide, or HTP (also called high-strength peroxide) must be stored in a suitable, vented container to prevent the buildup of oxygen gas, which would otherwise lead to the eventual rupture of the container. In the presence of certain catalysts, such asÃ Fe2+Ã orÃ Ti3+, the decomposition may take a different path, withÃ free radicalsÃ such as HOÃ · (hydroxyl) and HOOÃ · (hydroperoxyl) being formed. A combination ofÃ H2O2Ã andÃ Fe2+Ã is known asÃ Fentons reagent. A common concentration for hydrogen peroxide isÃ 20-volume, which means that, when 1 volume of hydrogen eroxide is decomposed, it produces 20 volumes of oxygen. AÃ 20-volumeconcentration of hydrogen peroxide is equivalent to 1. 667Ã mol/dm3Ã (Molar solution) or about 6%. Redox reactions In acidic solutions,Ã H2O2Ã is one of the most powerful oxidizers knownÃ¢â¬âstronger thanÃ chlorine,Ã chlorine dioxide, andÃ potassium permanganate. Also, through catalysis,Ã H2O2Ã can be converted intohydroxyl radicalsÃ (Ã¢â¬ ¢OH), which are highly reactive. Oxidant/Reduced product| OxidationÃ potential, V| Fluorine/Hydrogen fluoride| 3. 0| Ozone/Oxygen| 2. 1| Hydrogen peroxide/Water| 1. 8| Potassium permanganate/Manganese dioxide. Chlorine dioxide/HClO| 1. 5| Chlorine/Chloride| 1. 4| In aqueous solutions, hydrogen peroxide can oxidize or reduce a variety of inorganic ions. When it acts as a reducing agent,Ã oxygenÃ gas is also produced. InÃ acidicÃ solutionsÃ Fe2+Ã is oxidized toÃ Fe3+Ã (hydrogen peroxide acting as an oxidizing agent), 2Ã Fe2+(aq) +Ã H2O2Ã + 2Ã H+(aq) ; 2Ã Fe3+(aq) + 2H2O(l) andÃ sulfiteÃ (SO2? 3) is oxidized toÃ sulfateÃ (SO2? 4). However,Ã potassium permanganateÃ is reduced toÃ Mn2+Ã by acidicÃ H2O2. UnderÃ alkalineÃ conditions, however, some of these reactions reverse; for example,Ã Mn2+Ã is oxidized toÃ Mn4+Ã (asÃ MnO2). Other examples of hydrogen peroxides action as a reducing agent are reaction withÃ sodium hypochloriteÃ orÃ potassium permanganate, which is a convenient method for preparingÃ oxygenÃ in the laboratory. NaOCl +Ã H2O2Ã Ã O2Ã + NaCl +Ã H2O 2Ã KMnO4Ã + 3Ã H2O2Ã 2Ã MnO2Ã + 2 KOH + 2Ã H2OÃ + 3Ã O2 Hydrogen peroxide is frequently used as anÃ oxidizing agentÃ in organic chemistry. One application is for the oxidation ofÃ thioethersÃ toÃ sulfoxides. For example,Ã methyl phenyl sulfidecan be readily oxidized in high yield toÃ methyl phenyl sulfoxide: Ph? S? CH3Ã +Ã H2O2Ã Ph? S(O)? CH3Ã +Ã H2O Alkaline hydrogen peroxide is used forÃ epoxidationÃ of electron-deficient alkenes such asÃ acrylic acids, and also for oxidation ofÃ alkylboranesÃ toÃ alcohols, the second step ofÃ hydroboration-oxidation. Formation of peroxide compounds Hydrogen peroxide is a weak acid, and it can formÃ hydroperoxideÃ orÃ peroxideÃ saltsÃ or derivatives of many metals. For example, on addition to an aqueous solution ofÃ chromic acidÃ (CrO3) or acidic solutions of dichromate salts, it will form an unstable blue peroxide CrO(O2)2. In aqueous solution it rapidly decomposes to form oxygen gas and chromium salts. It can also produce peroxoanions by reaction withÃ anions; for example, reaction withÃ boraxÃ leads toÃ sodium perborate, a bleach used in laundry detergents: Na2B4O7Ã + 4Ã H2O2Ã + 2 NaOH 2Ã Na2B2O4(OH)4Ã +Ã H2O H2O2Ã convertsÃ carboxylic acidsÃ (RCOOH) into peroxy acids (RCOOOH), which are themselves used as oxidizing agents. Hydrogen peroxide reacts withÃ acetoneÃ to formÃ acetone peroxide, and it interacts withÃ ozoneÃ to formÃ hydrogen trioxide, also known asÃ trioxidane. Reaction withÃ ureaÃ producesÃ carbamide peroxide, used for whitening teeth. An acid-base adduct withÃ triphenylphosphine oxideÃ is a useful carrier forÃ H2O2Ã in some reactions. Alkalinity Hydrogen peroxide can still form adducts with very strong acids. TheÃ superacidÃ HF/SbF5Ã forms unstable compounds containing theÃ [H3O2]+Ã ion. Domestic uses * DilutedÃ H2O2Ã (between 3% and 8%) is used to bleach humanÃ hairÃ when mixed withÃ ammonium hydroxide, hence the phrase peroxide blonde. * It is absorbed byÃ skinÃ upon contact and creates a local skinÃ capillaryÃ embolismÃ that appears as a temporary whitening of the skin. * It is used to whitenÃ bonesÃ that are to be put on display. 3%Ã H2O2Ã is effective at treating fresh (red) blood-stains in clothing and on other items. It must be applied to clothing before blood stains can be accidentally set with heated water. Cold water and soap are then used to remove the peroxide treatedÃ blood. Some horticulturalists and users ofÃ hydroponicsÃ advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plants root development and helps to treatÃ root rotÃ (cellular root death due to lack of oxygen) and a variety of other pests. Laboratory tests conducted by fish culturists in recent years have demonstrated that common household hydrogen peroxide can be used safely to provide oxygen for small fish. Hydrogen peroxide releases oxygen by decomposition when it is exposed toÃ catalystsÃ such asÃ manganese dioxide. * Hydrogen peroxide is a strong oxidizer effective in controlling sulfide and organic-related odors in wastewater collection and treatment systems. It is typically applied to a wastewater system where there is a retention time of 30 minutes to 5 hours before hydrogen sulfide is released.