TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Fire may produce irritating and/or toxic gases. Toxic fumes or dust may accumulate in confined areas (basement, tanks, hopper/tank cars, etc.). Runoff from fire control or dilution water may cause pollution.
May explode from friction, heat or contamination. These substances will accelerate burning when involved in a fire. May ignite combustibles (wood, paper, oil, clothing, etc.). Some will react explosively with hydrocarbons (fuels). Containers may explode when heated. Runoff may create fire or explosion hazard.
Hydrogen peroxide is an oxidizing agent used as a topi-
cal antiseptic, and as part of permanent hair-dyes and
color-removing preparations, and as a neutralizing agent
in permanent waving. The concentration of the hydrogen
peroxyde solution is expressed in volume or percentage:
Ten volumes correspond to 3%. It is an irritant.
The 30% material has been steam distilled using distilled water. Gross and Taylor [J Am Chem Soc 72 2075 1950] made 90% H2O2 approximately 0.001M in NaOH and then distilled it under its own vapour pressure, keeping the temperature below 40o, the receiver being cooled with a Dry-ice/isopropyl alcohol slush. The 98% material has been rendered anhydrous by repeated fractional crystallisation in all-quartz vessels. EXPLOSIVE IN CONTACT WITH ORGANIC MATERIAL.
Hydrogen peroxide is a strong oxidizing agent. Concentrated solutions, even a 30% aqueous solution, should be handled carefully. The compound decomposes violently in the presence of trace impurities. Inhibitors are, therefore, added at trace levels to prevent decomposition. Explosion can occur when concentrated solutions are heated or brought in contact with a number of organic substances that are readily oxidizable or that form organic peroxides, such as alcohols, aldehydes, ketones, anhydrides, and carboxylic acids (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd ed. New York: John Wiley & Sons). Also, reactions with metals, metal alloys, a number of metal salts and oxides, and concentrated mineral acids can proceed to explosive violence.
ChEBI: An inorganic peroxide consisting of two hydroxy groups joined by a covalent oxygen-oxygen single bond.
A colorless liquid dissolved in water. Vapors may irritate the eyes and mucous membranes. May violently decompose on contact with most common metals and their compounds. Contact with combustible material may result in spontaneous ignition. Corrosive to tissue. Under exposure to fire or heat containers may violently rupture due to decomposition. Used to bleach textiles and wood pulp, in chemical manufacturing, food processing, and in water purification.
The hazards associated with the use of HYDROGEN PEROXIDE(especially highly concentrated solutions) are well documented. There is a release of enough energy during the catalytic decomposition of 65% peroxide to evaporate all water and ignite nearby combustible materials. Most cellulose materials contain enough catalyst to cause spontaneous ignition with 90% peroxide. Contamination of concentrated peroxide causes the possibility of explosion. Readily oxidizable materials, or alkaline substances containing heavy metals may react violently. Solvents(acetone, ethanol, glycerol) will detonate on mixture with peroxide of over 30% concentration, the violence increasing with concentration. Concentrated peroxide may decompose violently in contact with iron, copper, chromium, and most other metals or their salts, and dust(which frequently contain rust). During concentration under vacuum of aqueous or of aqueous-alcoholic solutions of hydrogen peroxide, violent explosions occurred when the concentration was sufficiently high(>90%), [Bretherick 2nd ed., 1979]. Hydrogen selenide and hydrogen peroxide undergo a very rapid decomposition, [Mellor 1:941(1946-1947)].
Colorless liquid; pure compound or 90% solution unstable; bitter taste; density 1.463 g/mL; boils at 150.2°C; freezes at –0.43°C; vapor pressure 9.9 torr
at 50°C and 121.5 torr at 100°C; viscosity 1.245 centipoise at 20°C; surface
tension 80.4 dyn/cm at 20°C; miscible with water in all proportions; soluble in
ether; densities of 30%, 70%, and 90% H2O2 solutions are 1.1081, 1.2839 and
1.3867 g/mL, respectively, at 25°C; freezing points at these concentrations are
–25.7°C, –40.3°C and –11.5°C, respectively; and their boiling points are
106.2°C, 125.5°C and 141.3°C, respectively; decomposed by many organic solvents; pKa at 25°C is 11.62.
Hydrogen peroxide was prepared first by Thenard in 1818. It has many industrial applications. Aqueous solutions at varying concentrations are used for bleaching fabrics, silks, furs, feathers and hair; as a dough conditioner; and a bleaching and oxidizing agent in foods; for cleaning metals; as a laboratory reagent for oxidation; as an antiseptic; in sewage and wastewater treatment; and in preparation of inorganic and organic peroxides. An 80% concentrated solution is used in rocket propulsion.
Hydrogen peroxide is commercially produced by autooxidation of ethyl anthraquinol in a solvent such as toluene or ethylbenzene. The product ethyl anthraquinone is reduced by hydrogen over supported nickel or platinum catalyst to regenerate back the starting material, ethyl anthraquinol for a continuous production of H2O2. The reaction steps are:
Hydrogen peroxide may also be made by heating 2-propanol with oxygen at 100°C under 10 to 20 atm pressure:
C(OH)OOH → CH3
Vapor phase partial oxidation of hydrocarbons also yield H2
. However, several by-products are generated, the separations of which make the process difficult and uneconomical.
Hydrogen peroxide may also be prepared by treating barium peroxide with dilute sulfuric acid:
Another preparative method involves electrolytic conversion of aqueous sulfuric acid to peroxydisulfate followed by hydrolysis to H2
(Weissenstein process). The reaction steps are as follows:
2H2SO4 → H2
O → H2
O → H2
An earlier method, which currently is no longer practiced commercially, involved oxidation of phenyl hydrazine:
Hydrogen peroxide obtained this way may contain many impurities, depending on the process used. Such impurities are removed by ion exchange, solvent extraction, and distillation. Dilute solutions of H2
may be purified
and concentrated by fractional distillation at reduced pressures.
Air & Water Reactions