Properties
The boiling point of has been extrapolated as being , approximately higher than water. In practice, hydrogen peroxide will undergo potentially explosiveStructure
Hydrogen peroxide () is a nonplanar molecule with (twisted) C2Aqueous solutions
InDiscovery
Production
Today, hydrogen peroxide is manufactured almost exclusively by the 
Other sources
Small, but detectable, amounts of hydrogen peroxide can be formed by several methods. Small amounts are formed by electrolysis of dilute acid around the cathode where hydrogen evolves if oxygen is bubbled around it. It is also produced by exposing water to Ultraviolet, ultraviolet rays from a Mercury Lamp, mercury lamp, or an electric arc while confining it in a UV transparent vessel (e.g. quartz). It is detectable in ice water after burning a hydrogen gas stream aimed towards it and is also detectable on floating ice. Rapidly cooling humid air blown through an approximately 2,000 °C spark gap results in detectable amounts. A commercially viable process to produce hydrogen peroxide directly from the environment has been of interest for many years. Efficient direct synthesis is difficult to achieve, as the reaction of hydrogen with oxygen thermodynamically favours production of water. Systems for direct synthesis have been developed, most of which employ finely dispersed metal catalysts similar to those used for hydrogenation of organic substrates. None of these has yet reached a point where they can be used for industrial-scale synthesis.Availability
Hydrogen peroxide is most commonly available as a solution in water. For consumers, it is usually available from pharmacies at 3 and 6 wt% concentrations. The concentrations are sometimes described in terms of the volume of oxygen gas generated; one milliliter of a 20-volume solution generates twenty milliliters of oxygen gas when completely decomposed. For laboratory use, 30 wt% solutions are most common. Commercial grades from 70% to 98% are also available, but due to the potential of solutions of more than 68% hydrogen peroxide to be converted entirely to steam and oxygen (with the temperature of the steam increasing as the concentration increases above 68%) these grades are potentially far more hazardous and require special care in dedicated storage areas. Buyers must typically allow inspection by commercial manufacturers. In 1994, world production of was around 1.9 million tonnes and grew to 2.2 million in 2006, most of which was at a concentration of 70% or less. In that year, bulk 30% sold for around 0.54 USD/Kilogram, kg, equivalent to US$1.50/kg (US$0.68/pound (mass), lb) on a "100% basis". Hydrogen peroxide occurs in surface water, groundwater and in the atmosphere. It forms upon illumination or natural catalyst, catalytic action by substances contained in water. Sea water contains 0.5 to 14 μg/L of hydrogen peroxide, freshwater 1 to 30 μg/L and air 0.1 to 1 parts per billion.Reactions
Decomposition
Hydrogen peroxide decomposes to form water and oxygen with a Standard enthalpy change of reaction, Δ''H''Redox reactions
The redox properties of hydrogen peroxide depend on pH. In acidic solutions, is a powerful oxidizer, stronger than chlorine, chlorine dioxide, and potassium permanganate. When used for cleaning laboratory glassware, a solution of hydrogen peroxide and sulfuric acid is referred to as Piranha solution. is a source of hydroxyl radicals (·OH), which are highly reactive. is used in the Briggs–Rauscher reaction, Briggs–Rauscher and Bray–Liebhafsky reaction, Bray–Liebhafsky oscillating reactions. In acidic solutions is oxidized to (hydrogen peroxide acting as an oxidizing agent): :2 (aq) + + 2 (aq) → 2 (aq) + 2 (l) and sulfite () is oxidized to sulfate (). However, potassium permanganate is reduced to by acidic . Under alkaline conditions, however, some of these reactions reverse; for example, is oxidized to (as ). In basic solution, hydrogen peroxide can reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen gas is also produced. For example, hydrogen peroxide will reduce sodium hypochlorite and potassium permanganate, which is a convenient method for preparing oxygen in the laboratory: :NaOCl + → + NaCl + :2 + 3 → 2 + 2 KOH + 2 + 3Organic reactions
Hydrogen peroxide is frequently used as an Redox, oxidizing agent. Illustrative is oxidation of thioethers to sulfoxides: :Ph + → Ph + Alkaline hydrogen peroxide is used for epoxidation of electron-deficient alkenes such as acrylic acid derivatives, and for the oxidation of alkylboranes to ethanol, alcohols, the second step of hydroboration-oxidation. It is also the principal reagent in the Dakin oxidation process.Precursor to other peroxide compounds
Hydrogen peroxide is a weak acid, forming hydroperoxide orBiological function
Hydrogen peroxide is formed in humans and other animals as a short-lived product in biochemical processes and is Toxicity, toxic to Cell (biology), cells. The toxicity is due to oxidation of proteins, membrane lipids and DNA by the peroxide ions. The class of biological enzymes called superoxide dismutase (SOD) is developed in nearly all living cells as an important antioxidant agent. They promote the disproportionation of superoxide into oxygen and hydrogen peroxide, which is then rapidly decomposed by the enzyme catalase to oxygen and water.
: 2 + 2 → +
: 2 H2O2 → O2 + 2 H2O
Peroxisomes are organelles found in virtually all eukaryotic cells. They are involved in the catabolism of very long chain fatty acids, Branched-chain-fatty-acid kinase, branched chain fatty acids, D-amino acid, D-amino acids, polyamines, and biosynthesis of plasmalogens, ether phospholipids critical for the normal function of mammalian brains and lungs. Upon oxidation, they produce hydrogen peroxide in the following process catalyzed by flavin adenine dinucleotide (FAD):
: 
The degradation of guanosine monophosphate yields xanthine as an intermediate product which is then converted in the same way to uric acid with the formation of hydrogen peroxide.
Eggs of sea urchin, shortly after fertilization by a sperm, produce hydrogen peroxide. It is then quickly dissociated to OH· radical (chemistry), radicals. The radicals serve as initiator of radical polymerization, which surrounds the eggs with a protective layer of polymer.
The bombardier beetle has a device which allows it to shoot corrosive and foul-smelling bubbles at its enemies. The beetle produces and stores hydroquinone and hydrogen peroxide, in two separate reservoirs in the rear tip of its abdomen. When threatened, the beetle contracts muscles that force the two reactants through valved tubes into a mixing chamber containing water and a mixture of catalytic enzymes. When combined, the reactants undergo a violent exothermic chemical reaction, raising the temperature to near the boiling point of water. The boiling, foul-smelling liquid partially becomes a gas (flash evaporation) and is expelled through an outlet valve with a loud popping sound.
Hydrogen peroxide is a signaling molecule of Plant pathology, plant defense against pathogens.
Hydrogen peroxide has roles as a signalling molecule in the regulation of a wide variety of biological processes. The compound is a major factor implicated in the free-radical theory of aging, based on how readily hydrogen peroxide can decompose into a hydroxyl radical and how superoxide radical byproducts of cellular respiration, cellular metabolism can react with ambient water to form hydrogen peroxide. These hydroxyl radicals in turn readily react with and damage vital cellular components, especially those of the mitochondria. At least one study has also tried to link hydrogen peroxide production to cancer. These studies have frequently been quoted in fraudulent treatment claims.
The amount of hydrogen peroxide in biological systems can be assayed using a Enzyme assay, fluorometric assay.
Uses
Bleaching
About 60% of the world's production of hydrogen peroxide is used for bleaching of wood pulp, pulp- and paper-bleaching. The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. Sodium percarbonate, which is an adduct of sodium carbonate and hydrogen peroxide, is the active ingredient in such laundry products as OxiClean and Tide (detergent), Tide laundry detergent. When dissolved in water, it releases hydrogen peroxide and sodium carbonate, By themselves these bleaching agents are only effective at wash temperatures of or above and so, often are used in conjunction with bleach activators, which facilitate cleaning at lower temperatures.Production of organic compounds
It is used in the production of various organic peroxides with dibenzoyl peroxide being a high volume example. It is used in Radical polymerization, polymerisations, as a flour bleaching agent, and as a treatment for acne. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid also are produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide.Disinfectant
Hydrogen peroxide is used in certain waste-water treatment processes to remove organic impurities. In advanced oxidation processing, the Fenton reaction gives the highly reactive hydroxyl radical (·OH). This degrades organic compounds, including those that are ordinarily robust, such as Aromatic hydrocarbon, aromatic or halogenated compounds. It can also oxidize sulfur based compounds present in the waste; which is beneficial as it generally reduces their odour.
Hydrogen peroxide may be used for the sterilization of various surfaces, including surgical tools, and may be deployed as a vapour (Vaporized hydrogen peroxide, VHP) for room sterilization. H2O2 demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. In general, greater activity is seen against Gram-positive than Gram-negative bacteria; however, the presence of catalase or other peroxidases in these organisms may increase tolerance in the presence of lower concentrations. Lower levels of concentration (3%) will work against most spores; higher concentrations (7 to 30%) and longer contact times will improve sporicidal activity.
Hydrogen peroxide is seen as an environmentally safe alternative to chlorine-based bleaches, as it degrades to form oxygen and water and it is generally recognized as safe as an antimicrobial agent by the U.S. Food and Drug Administration (FDA).
Hydrogen peroxide may be used to treat Acne vulgaris, acne, although benzoyl peroxide is a more common treatment.
Niche uses
Hydrogen peroxide has various domestic uses, primarily as a cleaning and disinfecting agent.
;Hair bleaching
Diluted (between 1.9% and 12%) mixed with aqueous ammonia has been used to bleach human hair. The chemical's bleaching property lends its name to the phrase "peroxide blonde".
Hydrogen peroxide is also used for tooth whitening. It may be found in most whitening toothpastes. Hydrogen peroxide has shown positive results involving teeth lightness and chroma shade parameters. It works by oxidizing colored pigments onto the Tooth enamel, enamel where the shade of the tooth may become lighter. Hydrogen peroxide may be mixed with baking soda and salt to make a homemade toothpaste.
;Removal of blood stains
Hydrogen peroxide reacts with blood as a bleaching agent, and so if a blood stain is fresh, or not too old, liberal application of hydrogen peroxide, if necessary in more than single application, will bleach the stain fully out. After about two minutes of the application, the blood should be firmly blotted out.
;Propellant
High-concentration is referred to as "high-test peroxide" (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber, where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over , which is expelled through a nozzle, generating thrust. monopropellant produces a maximal specific impulse (''I''sp) of 161 s (1.6 newton-second, kN·s/kg). Peroxide was the first major monopropellant adopted for use in rocket applications. Hydrazine eventually replaced hydrogen-peroxide monopropellant thruster applications primarily because of a 25% increase in the vacuum specific impulse. Hydrazine (toxic) and hydrogen peroxide (less-toxic [ACGIH TLV 0.01 and 1 ppm respectively]) are the only two monopropellants (other than cold gases) to have been widely adopted and utilized for propulsion and power applications. The Bell Rocket Belt, reaction control systems for Bell X-1, X-1, X-15, Centaur (rocket stage), Centaur, Project Mercury, Mercury, Little Joe (rocket), Little Joe, as well as the turbo-pump gas generators for X-1, X-15, Jupiter, Redstone and Viking used hydrogen peroxide as a monopropellant.
As a bipropellant, is decomposed to burn a fuel as an oxidizer. Specific impulses as high as 350 s (3.5 kN·s/kg) can be achieved, depending on the fuel. Peroxide used as an oxidizer gives a somewhat lower ''I''sp than liquid oxygen, but is dense, storable, non-cryogenic and can be more easily used to drive gas turbines to give high pressures using an efficient ''closed cycle''. It may also be used for regenerative cooling of rocket engines. Peroxide was used very successfully as an oxidizer in World War II German rocket motors (e.g. T-Stoff, containing oxyquinoline stabilizer, for both the Walter HWK 109-500 ''Starthilfe'' RATO externally podded monopropellant booster system, and for the Walter HWK 109-509 rocket motor series used for the Me 163B), most often used with C-Stoff in a self-igniting hypergolic combination, and for the low-cost British Black Knight (rocket), Black Knight and Black Arrow launchers.
In the 1940s and 1950s, the Hellmuth Walter Kommanditgesellschaft, Hellmuth Walter KG-conceived gas turbine, turbine used hydrogen peroxide for use in submarines while submerged; it was found to be too noisy and require too much maintenance compared to Submarine#Propulsion, diesel-electric power systems. Some torpedoes used hydrogen peroxide as oxidizer or propellant. Operator error in the use of hydrogen-peroxide torpedoes was named as possible causes for the sinking of HMS Sidon (P259), HMS ''Sidon'' and the Russian submarine Kursk, Russian submarine ''Kursk''. SAAB Underwater Systems is manufacturing the Torpedo 2000. This torpedo, used by the Swedish Navy, is powered by a piston engine propelled by HTP as an oxidizer and kerosene as a fuel in a bipropellant system.
;Glow sticks
Hydrogen peroxide reacts with certain di-esters, such as phenyl oxalate ester (cyalume), to produce chemiluminescence; this application is most commonly encountered in the form of glow sticks.
;Horticulture
Some horticulturalists and users of hydroponics advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat root rot (cellular root death due to lack of oxygen) and a variety of other pests.
;Fishkeeping
Hydrogen peroxide is used in aquaculture for controlling Fish mortality, mortality caused by various microbes. In 2019, the U.S. FDA approved it for control of ''Saprolegniasis'' in all coldwater finfish and all fingerling and adult coolwater and warmwater finfish, for control of external columnaris disease in warm-water finfish, and for control of ''Gyrodactylus'' spp. in freshwater-reared salmonids. Laboratory tests conducted by fish culturists have demonstrated that common household hydrogen peroxide may be used safely to provide oxygen for small fish. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide.
Safety
Regulations vary, but low concentrations, such as 5%, are widely available and legal to buy for medical use. Most over-the-counter peroxide solutions are not suitable for ingestion. Higher concentrations may be considered hazardous and typically are accompanied by a safety data sheet (SDS). In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a reducing agent, high concentrations of will react violently. High-concentration hydrogen peroxide streams, typically above 40%, should be considered hazardous due to concentrated hydrogen peroxide's meeting the definition of a United States Department of Transportation, DOT oxidizer according to U.S. regulations, if released into the environment. The United States Environmental Protection Agency, EPA Reportable Quantity (RQ) for D001 hazardous wastes is , or approximately , of concentrated hydrogen peroxide. Hydrogen peroxide should be stored in a cool, dry, well-ventilated area and away from any flammable or combustible substances. It should be stored in a container composed of non-reactive materials such as stainless steel or glass (other materials including some plastics and aluminium alloys may also be suitable). Because it breaks down quickly when exposed to light, it should be stored in an opaque container, and pharmaceutical formulations typically come in brown bottles that block light. Hydrogen peroxide, either in pure or diluted form, may pose several risks, the main one being that it forms explosive mixtures upon contact with organic compounds. Distillation of hydrogen peroxide at normal pressures is highly dangerous. It is also corrosive, especially when concentrated, but even domestic-strength solutions may cause irritation to the eyes, mucous membranes, and skin.For example, see aAdverse effects on wounds
Historically hydrogen peroxide was used for disinfecting wounds, partly because of its low cost and prompt availability compared to otherUse in alternative medicine
Practitioners of alternative medicine have advocated the use of hydrogen peroxide for various conditions, including emphysema, influenza, AIDS, and in particular cancer. There is no evidence of effectiveness and in some cases it has proved fatal.Hydrogen Peroxide, 3%. 3. Hazards IdentificationHistorical incidents
* On 16 July 1934, in Kummersdorf, Germany, a propellant tank containing an experimental monopropellant mixture consisting of hydrogen peroxide and ethanol exploded during a test, killing three people. * During the World War II, Second World War, doctors in Nazi concentration camps, German concentration camps experimented with the use of hydrogen peroxide injections in the killing of human subjects. * In April 1992, an explosion occurred at the hydrogen peroxide plant at Jarrie in France, due to technical failure of the computerised control system and resulting in one fatality and wide destruction of the plant. * Several people received minor injuries after a hydrogen peroxide spill on board a flight between the U.S. cities of Orlando and Memphis on 28 October 1998. * The Russian submarine Russian submarine Kursk (K-141), K-141 ''Kursk'' sailed to perform an exercise of firing dummy torpedoes at the Russian battlecruiser Pyotr Velikiy, Pyotr Velikiy, a Kirov-class battlecruiser, ''Kirov''-class battlecruiser. On 12 August 2000, at 11:28 local time (07:28 UTC), Russian submarine Kursk explosion, there was an explosion while preparing to fire the torpedoes. The only credible report to date is that this was due to the failure and explosion of one of the Kursk's hydrogen peroxide-fueled torpedoes. It is believed that High test peroxide, HTP, a form of highly concentrated hydrogen peroxide used as propellant for the torpedo, seeped through its container, damaged either by rust or in the loading procedure back on land where an incident involving one of the torpedoes accidentally touching ground went unreported. The vessel was lost with all hands. A similar incident was responsible for the loss of HMS Sidon (P259), HMS ''Sidon'' in 1955. * On 15 August 2010, a spill of about of cleaning fluid occurred on the 54th floor of 1515 Broadway, in Times Square, New York City. The spill, which a spokesperson for the New York City fire department said was of hydrogen peroxide, shut down Broadway between West 42nd and West 48th streets as fire engines responded to the HAZMAT, hazmat situation. There were no reported injuries.See also
* FOX reagent, used to measure levels of hydrogen peroxide in biological systems. * Hydrogen chalcogenide * Retr0bright, a process utilizing hydrogen peroxide to restore yellowed items such as plastic Home computer, computer cases and Video game console, game consoles.References
Notes Bibliography * * A great description of properties & chemistry of . * *External links