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Hydrogen peroxide

Hydrogen peroxide

Overview
Hydrogen peroxide is the simplest peroxide
Peroxide
A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide...

 (a compound with an oxygen-oxygen single bond) and an oxidizer. Hydrogen peroxide is a clear liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

, slightly more viscous
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

 than water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...

 or cleaning agent. The oxidizing capacity of hydrogen peroxide is so strong that it is considered a highly reactive oxygen species
Reactive oxygen species
Reactive oxygen species are chemically reactive molecules containing oxygen. Examples include oxygen ions and peroxides. Reactive oxygen species are highly reactive due to the presence of unpaired valence shell electrons....

. Hydrogen peroxide is therefore used as a propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

 in rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

ry.
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Encyclopedia
Hydrogen peroxide is the simplest peroxide
Peroxide
A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide...

 (a compound with an oxygen-oxygen single bond) and an oxidizer. Hydrogen peroxide is a clear liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

, slightly more viscous
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

 than water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...

 or cleaning agent. The oxidizing capacity of hydrogen peroxide is so strong that it is considered a highly reactive oxygen species
Reactive oxygen species
Reactive oxygen species are chemically reactive molecules containing oxygen. Examples include oxygen ions and peroxides. Reactive oxygen species are highly reactive due to the presence of unpaired valence shell electrons....

. Hydrogen peroxide is therefore used as a propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

 in rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

ry. Hydrogen peroxide is also naturally produced in organisms as a by-product of oxidative metabolism. Nearly all living things (specifically, all obligate and facultative aerobes) possess enzymes known as catalyse peroxidase
Peroxidase
Peroxidases are a large family of enzymes that typically catalyze a reaction of the form:For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides...

s, which harmlessly and catalytically decompose low concentrations of hydrogen peroxide to water and oxygen.

Structure and properties


adopts a nonplanar structure of C2 symmetry
Symmetry group
The symmetry group of an object is the group of all isometries under which it is invariant with composition as the operation...

. Although chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

, the molecule undergoes rapid racemization
Racemization
In chemistry, racemization refers to the converting of an enantiomerically pure mixture into a mixture where more than one of the enantiomers are present...

. The flat shape of the anti conformer would minimize steric repulsions, the 90° torsion angle of the syn conformer would optimize mixing between the filled p-type orbital of the oxygen (one of the lone pair
Lone pair
In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...

s) and the LUMO
Lumo
Lumo is a 2007 documentary film about twenty-year-old Lumo Sinai, a woman who fell victim to "Africa's First World War." While returning home one day, Lumo and another woman were gang-raped by a group of soldiers fighting for control of the Democratic Republic of the Congo during the 1994 Rwandan...

 of the vicinal
Vicinal (chemistry)
In chemistry vicinal stands for any two functional groups bonded to two adjacent carbon atoms. For example the molecule 2,3-dibromobutane carries two vicinal bromine atoms and 1,3-dibromobutane does not....

 O-H bond. The observed anticlinal "skewed" shape is a compromise between the two conformers.

Although the O−O bond is a single bond, the molecule has a relatively high barrier to rotation, of 29.45 kJ/mol; the rotational barrier is 12.5 kJ/mol for the bulkier molecule ethane
Ethane
Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas....

. The increased barrier is ascribed to repulsion between nonbonding electrons (lone pairs) on the adjacent oxygen centres. The bond angles
Molecular geometry
Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity.- Molecular geometry determination...

 are affected by hydrogen bonding, which is relevant to the difference between the structure of gaseous and crystalline forms; indeed a wide range of values is seen in crystals containing .

Comparison with analogues


Analogues of hydrogen peroxide include the chemically identical deuterium peroxide, and hydrogen disulfide
Hydrogen disulfide
Hydrogen disulfide is an inorganic compound. This mal-odorous oil decomposes readily to hydrogen sulfide .-Structure:The structure of hydrogen disulfide is similar to that of hydrogen peroxide, with two central sulfur atoms and two outer hydrogen atoms...

. Hydrogen disulfide
Hydrogen disulfide
Hydrogen disulfide is an inorganic compound. This mal-odorous oil decomposes readily to hydrogen sulfide .-Structure:The structure of hydrogen disulfide is similar to that of hydrogen peroxide, with two central sulfur atoms and two outer hydrogen atoms...

 has a boiling point of only 70.7 °C despite having a higher molecular weight, indicating that hydrogen bonding increases the boiling point of hydrogen peroxide.

Physical properties of hydrogen peroxide solutions


The properties of aqueous solutions of hydrogen peroxide differ from those of the pure material, reflecting the effects of hydrogen bonding between water and hydrogen peroxide. Hydrogen peroxide and water form a eutectic mixture, exhibiting freezing-point depression
Freezing-point depression
Freezing-point depression describes the phenomenon in which the freezing point of a liquid is depressed when another compound is added, meaning that a solution has a lower freezing point than a pure solvent. This happens whenever a non-volatile solute is added to a pure solvent, such as water...

. Pure water melts and freezes at approximately 273 K, and pure hydrogen peroxide just 0.4 K below that, but a 50% (by volume) solution melts and freezes at 221 K.

pH of


Pure hydrogen peroxide has a pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 of 6.2; thus it is considered to be a weak acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

. The pH can be as low as 4.5 when diluted at approximately 60%.

History


Hydrogen peroxide was first described in 1818 by Louis Jacques Thénard
Louis Jacques Thénard
Louis Jacques Thénard , was a French chemist.His father, a poor peasant, managed to have him educated at the academy of Sens, and sent him at the age of sixteen to study pharmacy in Paris. There he attended the lectures of Antoine François Fourcroy and Louis Nicolas Vauquelin...

 by reacting barium peroxide
Barium peroxide
Barium peroxide is the chemical compound with the formula BaO2. This grey-white solid is one of the most common inorganic peroxides. Barium peroxide is an oxidizing agent, which is used for bleaching...

 with nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

. An improved version of this process used hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

, followed by sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

 to precipitate the barium sulfate
Barium sulfate
Barium sulfate is the inorganic compound with the chemical formula BaSO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium and materials prepared from it...

 byproduct. Thénard's process was used from the end of the 19th century until the middle of the 20th century. Modern production methods are discussed below.

For a long time, pure hydrogen peroxide was believed to be unstable, owing to failed attempts to separate the hydrogen peroxide from the water, which is present during synthesis. This instability was, however, due to traces of impurities (transition metals salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

s) that catalyze the decomposition of the hydrogen peroxide. One hundred percent pure hydrogen peroxide was first obtained through vacuum distillation
Vacuum distillation
Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure causing evaporation of the most volatile liquid...

 by Richard Wolffenstein
Richard Wolffenstein (chemist)
Richard Wolffenstein was a German chemist.He discovered acetone peroxide in 1895 by reacting acetone with hydrogen peroxide....

 in 1894. At the end of 19th century, Petre Melikishvili
Petre Melikishvili
thumb|right|250px|Petre Melikishvili Petre Melikishvili Georgian chemist . He was the co-founder of Tbilisi State University and the first Rector of TSU.- Biography :...

 and his pupil L. Pizarjevski showed that of the many proposed formulas of hydrogen peroxide, the correct one was H−O−O−H.

The use of sterilization in biological safety cabinets and barrier isolators is a popular alternative to ethylene oxide
Ethylene oxide
Ethylene oxide, also called oxirane, is the organic compound with the formula . It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape . This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered...

 (EtO) as a safer, more efficient decontamination method. has long been widely used in the pharmaceutical industry. In aerospace research, is used to sterilize artificial satellites and space probes.

The U.S. FDA has granted 510(k) clearance to use in individual medical device manufacturing applications. EtO criteria outlined in ANSI/AAMI/ISO 14937 may be used as a validation guideline. Sanyo
Sanyo
is a major electronics company and member of the Fortune 500 whose headquarters is located in Moriguchi, Osaka prefecture, Japan. Sanyo targets the middle of the market and has over 230 Subsidiaries and Affiliates....

 was the first manufacturer to use the process in situ in a cell culture incubator, which is a faster and more efficient cell culture sterilization process.

Manufacture


Formerly, hydrogen peroxide was prepared by the electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 of an aqueous solution of sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

 or acidic ammonium bisulfate
Ammonium bisulfate
Ammonium bisulfate, also known as ammonium hydrogen sulfate, is a white, crystalline solid when it is completely pure, with formula HSO4. It is commonly collected as a byproduct of flue gas desulfurization, formed by partial neutralization of sulfuric acid aerosols by gaseous ammonia, NH3. ...

 , followed by hydrolysis
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...

 of the peroxodisulfate
Peroxodisulfate
The peroxodisulfate ion, S2O82−, is a sulfur oxoanion. It is commonly referred to as the persulfate ion, but this term also refers to the peroxomonosulfate ion, SO52−.-Compounds containing peroxodisulfate:* Na2S2O8* K2S2O8* 2S2O8...

  that is formed. Today, hydrogen peroxide is manufactured almost exclusively by the autoxidation
Autoxidation
Autoxidation is any oxidation that occurs in open air or in presence of oxygen and/or UV radiation and forms peroxides and hydroperoxides. A classic example of autoxidation is that of simple ethers like diethyl ether, whose peroxides can be dangerously explosive. It can be considered to be a slow,...

 of a 2-alkyl anthrahydroquinone (or 2-alkyl-9,10-dihydroxyanthracene) to the corresponding 2-alkyl anthraquinone in the so called anthraquinone process
Anthraquinone process
The anthraquinone process is a process for the production of hydrogen peroxide, which was developed by BASF. The technical production of hydrogen peroxide is based on the reduction of oxygen, as in the direct synthesis from the elements...

. Major producers commonly use either the 2-ethyl or the 2-amyl derivative. The cyclic reaction depicted below shows the 2-ethyl derivative, where 2-ethyl-9,10-dihydroxyanthracene  is oxidized to the corresponding 2-ethylanthraquinone
2-Ethylanthraquinone
2-Ethylanthraquinone also called2-Ethyl-9,10-anthraquinone ‎ is an aromatic organic compound with the formula C16H12O2. The slightly yellow powder is used in the production of hydrogen peroxide .-Production:...

  and hydrogen peroxide. Most commercial processes achieve this by bubbling compressed air
Compressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....

 through a solution of the derivatized anthracene
Anthracene
Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings. It is a component of coal-tar. Anthracene is used in the production of the red dye alizarin and other dyes...

, whereby the oxygen present in the air reacts with the labile hydrogen atoms (of the hydroxy group), giving hydrogen peroxide and regenerating the anthraquinone. Hydrogen peroxide is then extracted
Liquid-liquid extraction
Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent. It is an extraction of a substance from one liquid phase into another liquid...

 and the anthraquinone
Anthraquinone
Anthraquinone, also called anthracenedione or dioxoanthracene is an aromatic organic compound with formula . Several isomers are possible, each of which can be viewed as a quinone derivative...

 derivative is reduced back to the dihydroxy (anthracene) compound using hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 gas in the presence of a metal catalyst. The cycle then repeats itself.

This process is known as the Riedl-Pfleiderer process, having been first discovered by them in 1936. The overall equation for the process is deceptively simple:
+ →


The economics of the process depend heavily on effective recycling of the quinone
Quinone
A quinone is a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C– groups with any necessary rearrangement of double bonds," resulting in "a fully conjugated cyclic dione structure."...

 (which is expensive) and extraction solvents, and of the hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...

 catalyst.

In 1994, world production of was around 1.9 million tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...

s 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 US $0.54 per kg
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...

, equivalent to US $1.50 per kg (US $0.68 per lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

) on a "100% basis".

New developments


A new, so-called "high-productivity/high-yield" process, based on an optimized distribution of isomers of 2-amyl anthraquinone, has been developed by Solvay
Solvay (company)
Solvay S.A. is a Belgian chemical company with its head office in Ixelles, Brussels, Belgium. It was founded in 1863 by Ernest Solvay to produce sodium carbonate by the solvay process. Since then the company has diversified to two major sectors of activity: chemicals and plastics...

. In July 2008, this process allowed the construction of a "mega-scale" single-train plant in Zandvliet
Zandvliet
Zandvliet is a Belgian town forming part of the Antwerp district of Berendrecht-Zandvliet-Lillo. The place dates back to 1135 when it was known as Santflit, meaning "a navigable passage through sand"....

 (Belgium). The plant has an annual production capacity more than twice that of the world's next-largest single-train plant. An even-larger plant is scheduled to come onstream at Map Ta Phut (Thailand) in 2011. It is likely that this will lead to a reduction in the cost of production due to economies of scale
Economies of scale
Economies of scale, in microeconomics, refers to the cost advantages that an enterprise obtains due to expansion. There are factors that cause a producer’s average cost per unit to fall as the scale of output is increased. "Economies of scale" is a long run concept and refers to reductions in unit...

.

A process to produce hydrogen peroxide directly from the elements has been of interest for many years. The problem with the direct synthesis process is that, in terms of thermodynamics, the reaction of hydrogen with oxygen favors production of water. It had been recognized for some time that a finely dispersed catalyst is beneficial in promoting selectivity to hydrogen peroxide, but, while selectivity was improved, it was still not sufficiently high to permit commercial development of the process. However, an apparent breakthrough was made in the early 2000s by researchers at Headwaters Technology. The breakthrough revolves around development of a minute (nanometer-size) phase-controlled noble metal crystal particles on carbon support. This advance led, in a joint venture with Evonik Industries
Evonik Industries
Evonik Industries is an industrial corporation in Germany owned by RAG Foundation and one of the world´s leading specialty chemicals companies. It was created on 12 September 2007 as a result of restructuring of the mining and technology group RAG...

, to the construction of a pilot plant in Germany in late 2005. It is claimed that there are reductions in investment cost because the process is simpler and involves less equipment; however, the process is also more corrosive and unproven. This process results in low concentrations of hydrogen peroxide (about 5–10 wt% versus about 40 wt% through the anthraquione process).

In 2009, another catalyst development was announced by researchers at Cardiff University
Cardiff University
Cardiff University is a leading research university located in the Cathays Park area of Cardiff, Wales, United Kingdom. It received its Royal charter in 1883 and is a member of the Russell Group of Universities. The university is consistently recognised as providing high quality research-based...

. This development also relates to the direct synthesis, but, in this case, using gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 nanoparticles. Under normal circumstances, the direct synthesis must be carried out in an acid medium to prevent immediate decomposition of the hydrogen peroxide once it is formed. Whereas hydrogen peroxide tends to decompose on its own (which is why, even after production, it is often necessary to add stabilisers to the commercial product when it is to be transported or stored for long periods), the nature of the catalyst can cause this decomposition to accelerate rapidly. It is claimed that the use of this gold-palladium catalyst reduces this decomposition and, as a consequence, little to no acid is required. The process is in a very early stage of development and currently results in very low concentrations of hydrogen peroxide being formed (less than about 1–2 wt%). Nonetheless, it is envisaged by the inventors that the process will lead to an inexpensive, efficient, and environmentally friendly process.

A novel electrochemical process for the production of alkaline hydrogen peroxide has been developed by Dow
Dow Chemical Company
The Dow Chemical Company is a multinational corporation headquartered in Midland, Michigan, United States. As of 2007, it is the second largest chemical manufacturer in the world by revenue and as of February 2009, the third-largest chemical company in the world by market capitalization .Dow...

. The process employs a monopolar cell to achieve an electrolytic reduction of oxygen in a dilute sodium hydroxide solution.

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 >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 submit to inspection by the small number of commercial manufacturers.

Decomposition



Hydrogen peroxide decomposes (disproportionates) exothermically
Exothermic reaction
An exothermic reaction is a chemical reaction that releases energy in the form of light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:-Overview:...

 into water and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 gas spontaneously
Spontaneous process
A spontaneous process is the time-evolution of a system in which it releases free energy and moves to a lower, more thermodynamically stable energy state...

:
2 → 2 +


This process is thermodynamically favorable. It has a ΔHo
Standard enthalpy change of reaction
The standard enthalpy of reaction is the enthalpy change that occurs in a system when one mole of matter is transformed by a chemical reaction under standard conditions.For a generic chemical reaction...

 of −98.2 kJ·mol−1 and a ΔS
Entropy
Entropy is a thermodynamic property that can be used to determine the energy available for useful work in a thermodynamic process, such as in energy conversion devices, engines, or machines. Such devices can only be driven by convertible energy, and have a theoretical maximum efficiency when...

 of 70.5 J·mol−1·K−1. The rate of decomposition is dependent on the temperature (cool environment slows down decomposition, therefore hydrogen peroxide is often stored in refrigerator) and concentration of the peroxide, as well as the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 and the presence of impurities and stabilizers. Hydrogen peroxide is incompatible with many substances that catalyse its decomposition, including most of the transition metal
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...

s and their compounds. Common catalysts include manganese dioxide, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

, and platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

. The same reaction is catalysed by the enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 catalase
Catalase
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...

, found in the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, whose main function in the body is the removal of toxic byproducts of metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 and the reduction of oxidative stress
Oxidative stress
Oxidative stress represents an imbalance between the production and manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage...

. The decomposition occurs more rapidly in alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

, so acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

 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
High test peroxide
High-test peroxide or HTP is a high -concentration solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it decomposes into a high-temperature mixture of steam and oxygen, with no remaining liquid water...

, 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 as or , the decomposition may take a different path, with free radicals such as HO· (hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

) and HOO· being formed. A combination of and is known as Fenton's reagent
Fenton's reagent
Fenton's reagent is a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene and tetrachloroethylene ....

.

A common concentration for hydrogen peroxide is 20-volume, which means that, when 1 volume of hydrogen peroxide is decomposed, it produces 20 volumes of oxygen. A 20-volume concentration of hydrogen peroxide is equivalent to 1.667 mol/dm3 (Molar solution) or about 6%.

Redox reactions



In acidic solutions, is one of the most powerful oxidizers known—stronger than chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

, chlorine dioxide
Chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching....

, and potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...

. Also, through catalysis, can be converted into hydroxyl radical
Hydroxyl radical
The hydroxyl radical, •OH, is the neutral form of the hydroxide ion . Hydroxyl radicals are highly reactive and consequently short-lived; however, they form an important part of radical chemistry. Most notably hydroxyl radicals are produced from the decomposition of hydroperoxides or, in...

s (.OH), which are highly reactive.
Oxidant/Reduced product Oxidation potential, V
Fluorine
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

/Hydrogen fluoride
3.0
Ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

/Oxygen
2.1
Hydrogen peroxide/Water 1.8
Potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...

/Manganese dioxide
1.7
Chlorine dioxide
Chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching....

/HClO
1.5
Chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

/Chloride
1.4


In aqueous solutions, hydrogen peroxide can oxidize or reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 gas is also produced.

In acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic solutions is oxidized to (hydrogen peroxide acting as an oxidizing agent),
2 (aq) + + 2 (aq) → 2 (aq) + 2(l)


and sulfite
Sulfite
Sulfites are compounds that contain the sulfite ion SO. The sulfite ion is the conjugate base of bisulfite. Although the acid itself is elusive, its salts are widely used.-Structure:...

  is oxidized to sulfate
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 . However, potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...

 is reduced to by acidic . Under alkaline conditions, however, some of these reactions reverse; for example, is oxidized to (as ).

Other examples of hydrogen peroxide's action as a reducing agent are reaction with sodium hypochlorite or potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...

, which is a convenient method for preparing oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 in the laboratory.
NaOCl + → + NaCl +

2 + 3 → 2 + 2 KOH + 2 + 3


Hydrogen peroxide is frequently used as an oxidizing agent
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 in organic chemistry. One application is for the oxidation of thioether
Thioether
A thioether is a functional group in organosulfur chemistry with the connectivity C-S-C as shown on right. Like many other sulfur-containing compounds, volatile thioethers have foul odors. A thioether is similar to an ether except that it contains a sulfur atom in place of the oxygen...

s to sulfoxide
Sulfoxide
A sulfoxide is a chemical compound containing a sulfinyl functional group attached to two carbon atoms. Sulfoxides can be considered as oxidized sulfides...

s. For example, methyl phenyl sulfide was oxidized to methyl phenyl sulfoxide in 99% yield in methanol in 18 hours (or 20 minutes using a catalyst):
Ph + → Ph +


Alkaline hydrogen peroxide is used for epoxidation of electron-deficient alkenes such as acrylic acid
Acrylic acid
Acrylic acid is an organic compound with the formula CH2=CHCO2H. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols,...

s, and also for oxidation of alkylboranes to alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

s, the second step of hydroboration-oxidation.

Formation of peroxide compounds


Hydrogen peroxide is a weak acid, and it can form hydroperoxide or peroxide
Peroxide
A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide...

 salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

s or derivatives of many metals.

For example, on addition to an aqueous solution of chromic acid
Chromic acid
The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. This kind of chromic acid may be used as a cleaning mixture for glass. Chromic acid may also refer to the...

  or acidic solutions of dichromate salts, it will form an unstable blue peroxide CrO(. In aqueous solution it rapidly decomposes to form oxygen gas and chromium salts.

It can also produce peroxoanions by reaction with anions; for example, reaction with borax
Borax
Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.Borax has a wide variety of uses...

 leads to sodium perborate
Sodium perborate
Sodium perborate is a white, odorless, water-soluble chemical compound with the chemical composition 3. It crystallizes as the monohydrate, NaBO3·H2O, trihydrate, NaBO3·3H2O and tetrahydrate, NaBO3·4H2O. The monohydrate and tetrahydrate are the commercially important forms...

, a bleach used in laundry detergents:
+ 4 + 2 NaOH → 2 +


converts carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

s (RCOOH) into peroxy acids (RCOOOH), which are themselves used as oxidizing agents. Hydrogen peroxide reacts with acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...

 to form acetone peroxide
Acetone peroxide
Acetone peroxide is an organic peroxide and a primary high explosive. It takes the form of a white crystalline powder with a distinctive bleach-like odor....

, and it interacts with ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

 to form hydrogen trioxide, also known as trioxidane
Trioxidane
Trioxidane, hydrogen trioxide or dihydrogen trioxide is an unstable molecule with the formula H2O3 or HOOOH. It is one of the hydrogen polyoxides. In aqueous solutions, trioxidane decomposes to form water and singlet oxygen:...

. Reaction with urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 produces carbamide peroxide
Carbamide peroxide
Carbamide peroxide, also called urea peroxide, urea hydrogen peroxide , and percarbamide, an adduct of hydrogen peroxide and urea. Like hydrogen peroxide, it is an oxidizer. This compound is a white crystalline solid which dissolves in water to give free hydrogen peroxide; the solubility of...

, used for whitening teeth. An acid-base adduct with triphenylphosphine oxide
Triphenylphosphine oxide
Triphenylphosphine oxide is the chemical compound with the formula OP3. Often chemists abbreviate the formula by writing Ph3PO or PPh3O . This white crystalline compound is a common side product in reactions involving triphenylphosphine...

 is a useful "carrier" for in some reactions.

Alkalinity


Hydrogen peroxide can still form adducts with very strong acids. The superacid
Superacid
According to the classical definition superacid is an acid with an acidity greater than that of 100% pure sulfuric acid, which has a Hammett acidity function of −12. According to the modern definition, superacid is a medium, in which the chemical potential of the proton is higher than in pure...

  forms unstable compounds containing the ion.

Municipal wastewater applications


For over 50 years the standard way to deal with odors entering wastewater treatment plants was to pre-chlorinate the influent sewers. Recently, however, an increasing number of POTW
Publicly owned treatment works
A publicly owned treatment works is a term used in the United States for a sewage treatment plant that is owned, and usually operated, by a government agency. In the U.S., POTWs are typically owned by local government agencies, and are usually designed to treat domestic sewage and not industrial...

s have revisited this issue and come up with a different answer - hydrogen peroxide . Their results show that hydrogen peroxide can replace chlorine with little to no increase in costs, and with notable benefits to downstream operations. This paper looks at four recent studies conducted at large municipalities and identifies the factors that led them to select hydrogen peroxide for liquid-phase headworks odor control. http://www.h2o2.com/municipal-applications/wastewater-treatment.aspx?pid=146&name=Article-H2S-Control-Headworks-Odor-Control

Cost Effective Control of Hydrogen Sulfide in Municipal Sludge


In many municipal treatment facilities, the processing of wastewater sludge (or biosolids) poses operational and safety challenges due to hydrogen sulfide (H2S) generation. In addition to being a hazard to operations personnel ( is a poisonous gas), odors generated during sludge processing can cause community complaints and make plant working conditions unpleasant. Furthermore, damage to equipment and concrete structures caused by H2S initiated corrosion can be substantial. Typical areas where problems occur include gravity thickeners, mix tanks, and dewatering presses.

Hydrogen sulfide is generated in sludge via the same mechanism as in collection systems - conversion of sulfates to sulfides by bacteria. This biochemical generation of H2S is brought about by anaerobic or oxygen limited conditions. There are numerous chemical and non-chemical treatment technologies available which can control H2S in municipal sludge processing operations. http://www.h2o2.com/municipal-applications/wastewater-treatment.aspx?pid=149&name=Case-Study-Municipal-Sludge

Industrial applications


About 50% of the world's production of hydrogen peroxide in 1994 was used for pulp- and paper-bleaching
Bleaching of wood pulp
Bleaching of wood pulp is the chemical processing carried out on various types of wood pulp to decrease the color of the pulp, so that it becomes whiter. The main use of wood pulp is to make paper where whiteness is an important characteristic...

. Other bleaching applications are becoming more important as hydrogen peroxide is seen as an environmentally benign alternative to chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

-based bleaches.

Sulfide Oxidation with Hydrogen Peroxide


Sulfide is found throughout the environment as a result of both natural and industrial processes. Most sulfide found in nature was produced biologically (under anaerobic conditions) and occurs as free hydrogen sulfide (H2S) - characterized by its rotten egg odor. We are most likely to encounter biogenic H2S in sour groundwaters, swamps and marshes, natural gas deposits, and sewage collection/treatment systems. Manmade sources of H2S typically occur as a result of natural materials containing sulfur (e.g., coal, gas and oil) being refined into industrial products. For a variety of reasons - aesthetics (odor control), health (toxicity), ecological (oxygen depletion in receiving waters), and economic (corrosion of equipment and infrastructure) - sulfide laden wastewaters must be handled carefully and remediated before they can be released to the environment. Typical discharge limits for sulfide are < 1 mg/L. Sulfide Oxidation

BOD and COD Removal in Wastewater Using Hydrogen Peroxide


Hydrogen peroxide has been used to reduce the BOD
Biochemical oxygen demand
Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for...

 and COD
Chemical oxygen demand
In environmental chemistry, the chemical oxygen demand test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water or wastewater, making COD a useful measure of water quality...

 of industrial wastewaters for many years. While the cost of removing BOD/COD through chemical oxidation is typically greater than that through physical or biological means, there are nonetheless specific situations which justify its use. These include:
  • Predigestion of wastewaters which contain moderate to high levels of compounds that are toxic, inhibitory, or recalcitrant to biological treatment (e.g., pesticides, plasticizers, resins, coolants, and dyestuffs);
  • Pretreatment of high strength / low flow wastewaters – where biotreatment may not be practical – prior to discharge to a Publicly Owned Treatment Works (POTW);
  • Enhanced separation of entrained organics by flotation and settling processes; and

Supply of supplemental Dissolved Oxygen (DO) when biological treatment systems experience temporary overloads or equipment failure.

As indicated by these examples, H2O2 can be used as a stand-alone treatment or as an enhancement to existing physical or biological treatment processes, depending on the situation. BOD-COD Removal

High Strength Wastewater Pretreatment


Hydrogen peroxide is one of the most versatile, dependable and environmentally compatible oxidizing agents. The relative safety and simplicity of its use as an oxidizing agent has led to the development of a number of applications in refinery wastewater systems.

“Uncatalyzed” Hydrogen Peroxide
The strong oxidizing power of H2O2 makes it suitable for the destruction of a variety of pollutants. Optimization of conditions using H2O2 to destroy these pollutants can involve control of pH, temperature and reaction time. No additional additives are required.

“Catalyzed” Hydrogen Peroxide
Pollutants that are more difficult to oxidize require H2O2 to be activated with catalysts such as iron. Catalyzed oxidation can also be used to destroy easily oxidized pollutants more rapidly.

Under acid pH conditions, the addition of iron salts to a wastewater solution activates H2O2 to generate free radicals, which can attack a variety of organic compounds. Other metal salts and conditions can apply (e.g. in cyanide destruction, a copper catalyst can be used at a pH of 8.5 - 11.5). High Strength Wastewater Pretreatment

Nitrogen Oxides (NOx) Abatement with Hydrogen Peroxide


Nitrogen oxides are major pollutants in the atmosphere, being a precursor to acid rain, photochemical smog, and ozone accumulation. The oxides are mainly nitric oxide (NO) and nitrogen dioxide (NO2) both of which are corrosive and hazardous to health. With the use of catalytic converters on automobiles, the initial regulatory focus of controlling of mobile NOx emissions has reached the point where further restriction has become economically impractical. Consequently, the stationary sources of NOx emissions are now being subjected to more stringent standards in many areas of the U.S. Stationary sources include nitric acid manufacturing plants, manufacturers of nitrated materials such as fertilizer and explosives, and industrial manufacturers (metallurgical processors, glass manufacturers, cement kilns, power generators, etc.) where high processing temperatures are used. Because of the environmental concerns posed by air pollution, a great deal of research time and money has been expended to develop methods for controlling NOx emissions. Nitrogen Oxide Abatement (NOx)

Other major industrial applications for hydrogen peroxide include the manufacture of sodium percarbonate
Sodium percarbonate
Sodium percarbonate is a chemical, an adduct of sodium carbonate and hydrogen peroxide , with formula Na2CO3 · 1.5H2O2. It is a colorless, crystalline, hygroscopic and water-soluble solid...

 and sodium perborate
Sodium perborate
Sodium perborate is a white, odorless, water-soluble chemical compound with the chemical composition 3. It crystallizes as the monohydrate, NaBO3·H2O, trihydrate, NaBO3·3H2O and tetrahydrate, NaBO3·4H2O. The monohydrate and tetrahydrate are the commercially important forms...

, used as mild bleaches in laundry
Laundry
Laundry is a noun that refers to the act of washing clothing and linens, the place where that washing is done, and/or that which needs to be, is being, or has been laundered...

 detergents. It is used in the production of certain organic peroxides, such as dibenzoyl peroxide, used in polymerisations
Radical polymerization
Free radical polymerization is a method of polymerization by which a polymer forms by the successive addition of free radical building blocks. Free radicals can be formed via a number of different mechanisms usually involving separate initiator molecules...

 and other chemical processes. Hydrogen peroxide is also used in the production of epoxides, such as propylene oxide
Propylene oxide
Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics...

. Reaction with carboxylic acids produces a corresponding peroxy acid
Peroxy acid
A peroxy acid is an acid which contains an acidic -OOH group. The two main classes are those derived from conventional mineral acids, especially sulfuric acid, and the organic derivatives of carboxylic acids...

. Peracetic acid and meta-chloroperoxybenzoic acid
Meta-Chloroperoxybenzoic acid
meta-Chloroperoxybenzoic acid is a peroxycarboxylic acid used widely as an oxidant in organic synthesis. mCPBA is often preferred to other peroxy acids because of its relative ease of handling...

 (commonly abbreviated mCPBA) are prepared from acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 and meta-chlorobenzoic acid, respectively. The latter is commonly reacted with alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s to give the corresponding epoxide
Epoxide
An epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...

.

In the PCB
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

 manufacturing process, hydrogen peroxide mixed with sulfuric acid was used as the microetch chemical for copper surface roughening preparation.

A combination of a powdered precious metal-based catalyst, hydrogen peroxide, methanol and water can produce superheated steam in one to two seconds, releasing only and high-temperature steam for a variety of purposes.

Recently, there has been increased use of vaporized hydrogen peroxide
Vaporized hydrogen peroxide
Vaporized hydrogen peroxide is a gaseous form of hydrogen peroxide with applications as a low-temperature antimicrobial gas used to decontaminate enclosed and sealed areas such as laboratory workstations, isolation and pass-through rooms, and even aircraft interiors. It is registered by the U.S...

 in the validation and bio-decontamination of half-suit and glove-port isolators in pharmaceutical production.

Nuclear pressurized water reactor
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...

s (PWRs) use hydrogen peroxide during the plant shutdown to force the oxidation and dissolution of activated corrosion products deposited on the fuel. The corrosion products are then removed with the cleanup systems before the reactor is disassembled.

Hydrogen peroxide is also used in the oil and gas exploration industry to oxidize rock matrix in preparation for micro-fossil analysis.

Chemical applications


A method of producing propylene oxide
Propylene oxide
Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics...

 from hydrogen peroxide has been developed. The process is claimed to be environmentally friendly, since the only significant byproduct is water. It is also claimed the process has significantly lower investment and operating costs. Two of these "HPPO" (hydrogen peroxide to propylene oxide) plants came onstream in 2008: One of them located in Belgium is a Solvay
Solvay
Solvay may refer to* Solvay , an international chemicals and plastics company* the Solvay process* Ernest Solvay, its inventor* Solvay Conference* the Solvay Business School* Solvay, New York* Solvay Hut, on the Matterhorn...

, Dow-BASF joint venture, and the other in Korea is a EvonikHeadwaters, SK Chemicals joint venture. A caprolactam
Caprolactam
Caprolactam is an organic compound with the formula 5CNH. This colourless solid is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually...

 application for hydrogen peroxide has been commercialized. Potential routes to phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 and epichlorohydrin
Epichlorohydrin
Epichlorohydrin is an organochlorine compound and an epoxide. This is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar organic solvents. Epichlorohydrin is a highly reactive compound and is used in the production of glycerol, plastics,...

 utilizing hydrogen peroxide have been postulated.

Biological function


Hydrogen peroxide is also one of the two chief chemicals in the defense system of the bombardier beetle
Bombardier beetle
Bombardier beetles are ground beetles in the tribes Brachinini, Paussini, Ozaenini, or Metriini—more than 500 species altogether—which are most notable for the defense mechanism that gives them their name: When disturbed, the beetle ejects a noxious chemical spray in a rapid burst of pulses from...

, reacting with hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...

 to discourage predators.

A study published in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

found that hydrogen peroxide plays a role in the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

. Scientists found that hydrogen peroxide inside of cells increased after tissues are damaged in zebra fish, which is thought to act as a signal to white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

s to converge on the site and initiate the healing process. When the genes required to produce hydrogen peroxide were disabled, white blood cells did not accumulate at the site of damage. The experiments were conducted on fish; however, because fish are genetically similar to humans, the same process is speculated to occur in humans. The study in Nature suggested asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...

 sufferers have higher levels of hydrogen peroxide in their lungs than healthy people, which could explain why asthma sufferers have inappropriate levels of white blood cells in their lungs.

Hydrogen peroxide has important roles as a signaling molecule in the regulation of a variety of biological processes. Hydrogen peroxide also plays an important role in aging and cancer.

Domestic uses


  • Diluted (between 3% and 8%) is used to bleach human hair
    Hair
    Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

     when mixed with ammonium hydroxide
    Ammonium hydroxide
    Ammonia solution, also known as ammonium hydroxide, ammonia water, ammonical liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or simply ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3...

    , hence the phrase "peroxide blonde".
  • It is absorbed by skin
    Skin
    -Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

     upon contact and creates a local skin capillary
    Capillary
    Capillaries are the smallest of a body's blood vessels and are parts of the microcirculation. They are only 1 cell thick. These microvessels, measuring 5-10 μm in diameter, connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste...

     embolism
    Embolism
    In medicine, an embolism is the event of lodging of an embolus into a narrow capillary vessel of an arterial bed which causes a blockage in a distant part of the body.Embolization is...

     that appears as a temporary whitening of the skin.
  • It is used to whiten bone
    Bone
    Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

    s that are to be put on display.
  • 3% 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 treated blood
    Blood
    Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

    .
  • Some horticulturalists and users of hydroponics
    Hydroponics
    Hydroponics is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, or coconut husk.Researchers discovered in the 18th...

     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
    Root rot
    Root rot is a condition found in both indoor and outdoor plants, although more common in indoor plants with poor drainage. As the name states, the roots of the plant rot. Usually, this is a result of overwatering. In houseplants, it is a very common problem, and is slightly less common in outdoor...

     (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 to catalysts such as 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. Hydrogen peroxide oxidizes the hydrogen sulfide and promotes bio-oxidation of organic odors. Hydrogen peroxide decomposes to oxygen and water, adding dissolved oxygen to the system, thereby negating some Biochemical Oxygen Demand (BOD).
  • Mixed with baking soda and a small amount of hand soap, hydrogen peroxide is effective at removing skunk
    Skunk
    Skunks are mammals best known for their ability to secrete a liquid with a strong, foul odor. General appearance varies from species to species, from black-and-white to brown or cream colored. Skunks belong to the family Mephitidae and to the order Carnivora...

     odor.
  • Hydrogen peroxide is used with phenyl oxalate ester
    Phenyl oxalate ester
    Diphenyl oxalate is a solid ester whose oxidation products are responsible for the chemiluminescence in a glowstick. It can be synthesized by fully esterifying phenol with oxalic acid...

     and an appropriate dye
    Dye
    A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....

     in glow sticks as an oxidizing agent
    Oxidizing agent
    An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...

    . It reacts with the ester to form an unstable dimer, which excites the dye to an excited state
    Excited state
    Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....

    ; the dye emits a photon
    Photon
    In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

     (light) when it spontaneously relaxes
    Spontaneous emission
    Spontaneous emission is the process by which a light source such as an atom, molecule, nanocrystal or nucleus in an excited state undergoes a transition to a state with a lower energy, e.g., the ground state and emits a photon...

     back to the ground state
    Ground state
    The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state...

    .
  • Hydrogen peroxide can be combined with vinegar
    Vinegar
    Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...

     and table salt to form a substitute for industrial chemicals such as ferric chloride, ammonium persulfate
    Ammonium persulfate
    Ammonium persulfate 2S2O8 is a strong oxidizing agent. It is very soluble in water; the dissolution of the salt in water is endothermic. It is a radical initiator. It is used to etch copper on printed circuit boards as an alternative to ferric chloride solution...

    , or hydrochloric acid
    Hydrochloric acid
    Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

     as a hobbyist's printed circuit board
    Printed circuit board
    A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

     etchant.
  • Hydrogen peroxide can be used to clean tile and grout on floors. Sometimes it is recommended to clean with baking soda together with the hydrogen peroxide.

Propellant


High concentration is referred to as HTP or High test peroxide
High test peroxide
High-test peroxide or HTP is a high -concentration solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it decomposes into a high-temperature mixture of steam and oxygen, with no remaining liquid water...

. It can be used either as a monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...

 (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 600 °C, which is expelled through a nozzle
Nozzle
A nozzle is a device designed to control the direction or characteristics of a fluid flow as it exits an enclosed chamber or pipe via an orifice....

, generating thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....

. monopropellant produces a maximum specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

 (Isp) of 161 s (1.6 kN·s
Newton-second
The newton-second or newton second is the derived SI unit of impulse and momentum. It can also be expressed as the kilogram metre per second...

/kg), which makes it a low-performance monopropellant. Peroxide generates much less thrust than hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...

, but is not toxic. The Bell Rocket Belt
Bell Rocket Belt
The Bell Rocket Belt is a low-power rocket propulsion device that allows an individual to safely travel or leap over small distances. It is a type of rocket pack.-Overview:...

 used hydrogen peroxide 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 Isp than liquid oxygen, but is dense, storable, noncryogenic and can be more easily used to drive gas turbines to give high pressures using an efficient closed cycle. It can also be used for regenerative cooling of rocket engines. Peroxide was used very successfully as an oxidizer in World-War-II German rockets (e.g. T-Stoff
T-Stoff
T-Stoff was the oxidizer part of a bipropellant rocket fuel combination used in Germany during World War II. It is a stabilized high test peroxide...

, containing oxyquinoline stabilizer, for the Me-163), and for the low-cost British Black Knight
Black Knight (rocket)
Black Knight was a British launch vehicle to test and verify the design of a re-entry vehicle for the Blue Streak missile.The United Kingdom's first indigenous rocketry project, Black Knight was manufactured by Saunders-Roe on the Isle of Wight, had its engines tested at The Needles and was...

 and Black Arrow
Black Arrow
Black Arrow, officially capitalised BLACK ARROW, was a British satellite carrier rocket. Developed during the 1960s, it was used for four launches between 1969 and 1971...

 launchers.

In the 1940s and 1950s, the Walter
Hellmuth Walter
Hellmuth Walter was a German engineer who pioneered research into rocket engines and gas turbines...

 turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....

 used hydrogen peroxide for use in submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

s while submerged; it was found to be too noisy and require too much maintenance compared to diesel-electric power systems. Some torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

es used hydrogen peroxide as oxidizer or propellant, but this was dangerous and has been discontinued by most navies
Navy
A navy is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...

. Hydrogen peroxide leaks were blamed for the sinkings of HMS Sidon
HMS Sidon (P259)
HMS Sidon was a submarine of the Royal Navy, launched in September 1944, one of the third group of S-class submarines built by Cammell Laird & Co Limited, Birkenhead...

 and the Russian submarine Kursk. It was discovered, for example, by the Japanese Navy in torpedo trials, that the concentration of in right-angle bends in HTP pipework can often lead to explosions in submarines and torpedoes. 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
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

 as a fuel in a bipropellant system.

While rarely used now as a monopropellant for large engines, small hydrogen peroxide attitude control thrusters are still in use on some satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

s. They are easy to throttle, and safer to fuel and handle before launch than hydrazine thrusters. However, hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...

 is more often used in spacecraft because of its higher specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

 and lower rate of decomposition.

Therapeutic use


Hydrogen peroxide is generally recognized as safe
Generally recognized as safe
Generally recognized as safe is an American Food and Drug Administration designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act food additive tolerance requirements.-History:On January 1, 1958,...

(GRAS) as an antimicrobial agent, an oxidizing agent and for other purposes by the U.S. FDA. For example, 35% hydrogen peroxide is used to prevent infection transmission in the hospital environment, and hydrogen peroxide vapor is registered with the US EPA as a sporicidal sterilant.

It is a common misconception that hydrogen peroxide is a disinfectant or antiseptic
Antiseptic
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction...

 for treating wounds. While it is an effective cleaning agent, hydrogen peroxide is not an effective agent for reducing bacterial infection of wounds. Further, hydrogen peroxide applied to wounds can impede healing
Healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....

 and lead to scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

ring because it destroys newly formed skin cells
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

.
  • Hydrogen peroxide can be used as a toothpaste, or oral debriding
    Debridement (dental)
    In dentistry, debridement refers to the necessary removal of plaque and calculus that have accumulated on the teeth in order to maintain oral health. Debridement in this case may be performed using ultrasonic instruments, which fracture the calculus, thereby facilitating its removal, as well as...

     agent, when mixed with correct quantities of baking soda and salt. This use is no more effective than toothpaste alone, however.
  • Hydrogen peroxide and benzoyl peroxide
    Benzoyl peroxide
    Benzoyl peroxide is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. Its structural formula is [C6H5C]2O2. It is one of the most important organic peroxides in terms of applications and the scale of its production...

     are sometimes used to treat acne
    Acne vulgaris
    Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...

    .
  • Hydrogen peroxide is used as an emetic in veterinary practice.

Alternative uses


  • Following the call by alternative medicine
    Alternative medicine
    Alternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....

     advisors for drinking diluted hydrogen peroxide, and using it in various ways such as in shampoo and as an additive to toothpaste, as a treatment to illness in general and cancer in particular, the American Cancer Society
    American Cancer Society
    The American Cancer Society is the "nationwide community-based voluntary health organization" dedicated, in their own words, "to eliminating cancer as a major health problem by preventing cancer, saving lives, and diminishing suffering from cancer, through research, education, advocacy, and...

     states that "there is no scientific evidence that hydrogen peroxide is a safe, effective or useful cancer treatment", and advises cancer patients to "remain in the care of qualified doctors who use proven methods of treatment and approved clinical trials of promising new treatments."
  • Another controversial alternative medical procedure is inhalation
    Inhalation
    Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....

     of hydrogen peroxide at a concentration of about 1%. Intravenous usage of hydrogen peroxide has been linked to several deaths.

Improvised explosive device / home-made bomb precursor


Hydrogen peroxide was the main ingredient in the 7 July 2005 London bombings
7 July 2005 London bombings
The 7 July 2005 London bombings were a series of co-ordinated suicide attacks in the United Kingdom, targeting civilians using London's public transport system during the morning rush hour....

 that killed 52 London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

 and bus passengers. The bomb-making ingredients are reported to be easier to buy than large numbers of aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...

 pills.

Safety


Regulations vary, but low concentrations, such as 3%, 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 are typically accompanied by a Material Safety Data Sheet
Material safety data sheet
A Material Safety Data Sheet is a form with data regarding the properties of a particular substance....

 (MSDS). In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...

, high concentrations of will react violently.

High-concentration hydrogen peroxide streams, typically above 40%, should be considered a D001 hazardous waste, due to concentrated hydrogen peroxide's meeting the definition of a DOT
United States Department of Transportation
The United States Department of Transportation is a federal Cabinet department of the United States government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967...

 oxidizer according to U.S. regulations, if released into the environment. The EPA
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 Reportable Quantity (RQ) for D001 hazardous wastes is 100 pounds (45.4 kg), or approximately 10 gallons (37.9 l), 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 filter out light.

Hydrogen peroxide, either in pure or diluted form, can pose several risks:
  • Explosive vapors. Above roughly 70% concentrations, hydrogen peroxide can give off vapor that can detonate above 70 °C (158 °F) at normal atmospheric pressure. This can then cause a boiling liquid expanding vapor explosion (BLEVE
    BLEVE
    A boiling liquid expanding vapor explosion occurs when a vessel containing a pressurized liquid above its boiling point ruptures.-Mechanism:...

    ) of the remaining liquid. Distillation
    Distillation
    Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....

     of hydrogen peroxide at normal pressures is thus highly dangerous.
  • Hazardous reactions. Hydrogen peroxide vapors can form sensitive contact explosives with hydrocarbons such as greases. Hazardous reactions ranging from ignition to explosion have been reported with alcohol
    Alcohol
    In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

    s, ketone
    Ketone
    In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

    s, carboxylic acid
    Carboxylic acid
    Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

    s (particularly acetic acid
    Acetic acid
    Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

    ), amine
    Amine
    Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...

    s and phosphorus
    Phosphorus
    Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

    .
  • Spontaneous ignition. Concentrated hydrogen peroxide, if spilled on clothing (or other flammable materials), will preferentially evaporate water until the concentration reaches sufficient strength, at which point the material may spontaneously ignite.
  • Corrosive. Concentrated hydrogen peroxide (>50%) is corrosive, and even domestic-strength solutions can cause irritation to the eyes, mucous membrane
    Mucous membrane
    The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...

    s and skin. Swallowing hydrogen peroxide solutions is particularly dangerous, as decomposition in the stomach releases large quantities of gas (10 times the volume of a 3% solution) leading to internal bleeding. Inhaling over 10% can cause severe pulmonary irritation.
  • Bleach agent. Low concentrations of hydrogen peroxide, on the order of 3% or less, will chemically bleach many types of clothing to a pinkish hue. Caution should be exercised when using common products that may contain hydrogen peroxide, such as facial cleaner or contact lens solution, which easily splatter upon other surfaces.
  • Internal ailments. Large oral doses of hydrogen peroxide at a 3% concentration may cause "irritation and blistering to the mouth, (which is known as Black hairy tongue) throat, and abdomen", as well as "abdominal pain, vomiting, and diarrhea".
  • Vapor pressure. Hydrogen peroxide has a significant vapor pressure (1.2 kPa at 50 oC[CRC Handbook of Chemistry and Physics, 76th Ed, 1995-1996]) and exposure to the vapor is potentially hazardous. Hydrogen peroxide vapor is a primary irritant, primarily affecting the eyes and respiratory system and the NIOSH Immediately dangerous to life and health limit (IDLH) is only 75 ppm. Long term exposure to low ppm concentrations is also hazardous and can result in permanent lung damage and Occupational Safety and Health Administration
    Occupational Safety and Health Administration
    The United States Occupational Safety and Health Administration is an agency of the United States Department of Labor. It was created by Congress of the United States under the Occupational Safety and Health Act, signed by President Richard M. Nixon, on December 29, 1970...

     (OSHA) has established a permissible exposure limit of 1.0 ppm calculated as an eight hour time weighted average (29 CFR 1910.1000, Table Z-1) and hydrogen peroxide has also been classified by the American Conference of Governmental Industrial Hygienists
    American Conference of Governmental Industrial Hygienists
    The American Conference of Governmental Industrial Hygienists is a professional association of industrial hygienists and practitioners of related professions, with headquarters in Cincinnati, Ohio...

     (ACGIH) as a "known animal carcinogen, with unknown relevance on humans.[2008 Threshold Limit Values for Chemical Substances and Physical Agents & Biological Exposure Indices, ACGIH] In applications where high concentrations of hydrogen peroxide are used, suitable personal protective equipment should be worn and it is prudent in situations where the vapor is likely to be generated, such as hydrogen peroxide gas or vapor sterilization, to ensure that there is adequate ventilation and the vapor concentration monitored with a continuous gas monitor for hydrogen peroxide. Continuous gas monitors for hydrogen peroxide are available from several suppliers. Further information on the hazards of hydrogen peroxide is available from OSHA and from the ATSDR.
  • Skin disorders. Vitiligo
    Vitiligo
    Vitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress,...

     is an acquired skin disorder with the loss of native skin pigment, which affects about 0.5-1% of the world population. Recent studies have discovered increased levels in the epidermis and in blood are one of many hallmarks of this disease.

Historical incidents

  • On July 16, 1934, in Kummersdorf
    Kummersdorf
    Kummersdorf is the name of an estate near Luckenwalde at , around 25km south of Berlin, in the Brandenburg region of Germany. Until 1945 Kummersdorf hosted the weapon office of the German Army which ran a development centre for future weapons as well as an artillery range.In 1929 the Army Weapons...

    , Germany, a rocket engine using hydrogen peroxide exploded, killing three people. As a result of this incident, Wernher von Braun
    Wernher von Braun
    Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

     decided not to use hydrogen peroxide as an oxidizer in the rockets he developed afterward.
  • Several people received minor injuries after a hydrogen peroxide spill on board Northwest Airlines flight 957 from Orlando to Memphis on October 28, 1998 and subsequent fire on Northwest Airlines flight 7.
  • During the Second World War
    World War II
    World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

    , doctors in Nazi
    Nazi Germany
    Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...

     concentration camps
    Nazi concentration camps
    Nazi Germany maintained concentration camps throughout the territories it controlled. The first Nazi concentration camps set up in Germany were greatly expanded after the Reichstag fire of 1933, and were intended to hold political prisoners and opponents of the regime...

     experimented with the use of hydrogen peroxide injections in the killing of human subjects.
  • Hydrogen peroxide was said to be one of the ingredients in the bombs that failed to explode in the July 21, 2005 London bombings.
  • The Russia
    Russia
    Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

    n submarine K-141 Kursk sailed out to sea to perform an exercise of firing dummy torpedoes at the Pyotr Velikiy, a Kirov class battlecruiser
    Kirov class battlecruiser
    The Kirov-class battlecruiser is a class of nuclear-powered military ships of the Russian Navy, the largest and heaviest surface combatant warships currently in active operation in the world. The Russian designation is heavy nuclear-powered guided missile cruiser...

    . On August 12, 2000 at 11:28 local time (07:28 UTC), there was an explosion
    Russian submarine Kursk explosion
    On 12 August 2000, the Russian Oscar II class submarine Kursk sank in the Barents Sea after an explosion. The investigation showed that a leak of hydrogen peroxide in a torpedo led to explosion of its fuel, causing the submarine to hit the bottom which in turn triggered the detonation of further...

     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 HTP
    High test peroxide
    High-test peroxide or HTP is a high -concentration solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it decomposes into a high-temperature mixture of steam and oxygen, with no remaining liquid water...

    , a form of highly concentrated hydrogen peroxide used as propellant for the torpedo, seeped through rust in the torpedo casing. A similar incident was responsible for the loss of HMS Sidon
    HMS Sidon (P259)
    HMS Sidon was a submarine of the Royal Navy, launched in September 1944, one of the third group of S-class submarines built by Cammell Laird & Co Limited, Birkenhead...

     in 1955
  • On August 16, 2010 a spill of about 10 gallons (37.9 l) of cleaning fluid spilled on the 53rd 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 a number of fire engines responded to the hazmat
    Hazmat
    Hazmat, HazMat and similar terms can refer to:* Hazardous materials and items—see Dangerous goods** Hazchem—a system of hazardous chemical classification and firefighting modes** A hazmat suit is a type of protective clothing...

     situation. There were no reported injuries.

External links