هیدروژن پراکسید یا آباکسیژنه (H۲O۲) یک اکسنده متداول است که به عنوان سفید کننده استفاده می شود. هیدروژن پراکسید سادهترین پراکسید است (پراکسیدها ترکیباتی هستند که دارای یک پیوند یگانه اکسیژن-اکسیژن هستند). آب اکسیژنه خالص H۲O۲ یک مایع ناروانی است که کمی آبی رنگ میباشد و با زحمت زیاد میتوان آنرا تهیه نمود. آب اکسیژنهای که در داروخانهها به اسم آب اکسیژنه رقیق فروخته میشود محلولی است از آب اکسیژنه در آب که در ۱۰۰ قسمت آن سه قسمت آب اکسیژنه است، مانند آب بیرنگ و بیبوست، مزه تلخی دارد و کمی اسیدی است. این مایع اکسید کننده یی قوی است.
تجزیه این ماده باعث ایجاد رادیکالهای OH میشود که بیش از چند ثانیه در دسترس نمی باشند و در این مدت با خاصیت شدید اکسیدکنندگی خود، مواد آلی و معدنی را اکسید میکند.
خصوصیات آب اکسیژنه [ویرایش]
به مرور آب اکسیژنه تجزیه و تبدیل به آب و اکسیژن میگردد. این عمل تجزیه در محیط بازی سریعتر و در محیط اسیدی کندتر از محیط خنثی صورت میگیرد. اگر مدت مدیدی آب اکسیژنه را انبار کنند، ممکن است کاملا تجزیه و تبدیل به آب گردد. بر اثر گرد بعضی اجسام عمل تخریب آب اکسیژنه تسریع میگردد مانند گرد بیاکسید منگنز و گرد فلزات .
اگر بر روی محلول آب قدری از اجسام پایدار کننده مانند اسید فسفریک، اوره، اسید بنزوئیک و نظیر آنها بیافزایند، عمل تخریب بسیار کند میگردد. آب اکسیژنه اثر میکروب کشی و بوبری دارد چنانکه اگر یک تکه کالباس قرمز را درون ظرف محتوی آب اکسیژنه قرار دهیم پس از چند روز محتویات ظرف کاملا بیبو است و بوی گندیده نمیدهد. آب اکسیژنه رنگها را نیز تخریب میکند بهمین دلیل تکه کالباس درون ظرف بعد از مدتی بیرنگ میشود.
موارد استعمال آب اکسیژنه [ویرایش]
لکه شراب قرمز، خون، قهوه و غیره را هم میتوان بوسیله آب اکسیژنه پاک نمود. محلول غلیظ H۲O۲ به عنوان یک اکسیدان برای سوخت موشکها نیز مورد استفاده قرار می گیرد. برخی از خمیر دندانها و سایر اجسامی که برای پاک کردن دندانها بکار میرود در موقع استعمال تولید آب اکسیژنه میکنند و اکسیژن این آب اکسیژنه دندان را سفید مینماید.
آب اکسیژنه در بیرنگ کردن شاخ، پشم گوسفند، پنبه، کتان، کنف، کاه، چوب، کاغذ، روغن، چربی، واکس، صابون، ابریشم، عاج، پر و غیره بکار میرود. رنگ بعضی لکههای صورت را هم آب اکسیژنه تخریب میکند. اگر موی سیاه را پس از شستن با کربنات سدیم ( تا چربی آن برطرف شود ) در محلول آب اکسیژنه بگذارند به رنگ روشن در میآید.اگر موی سیاه سر را با مخلوطی از ۱۰۰ گرم آب اکسیژنه ۳۰% و چهار قطره محلول ۲۵% آمونیاک تر نمایند و پس از ۱۰ تا ۲۰ دقیقه با آب خالص و سپس با محلول اسید استیکدار بشویند، بور مایل به قرمز میشود. وجود آمونیاک از این جهت لازم است که آب اکسیژنه در حضور قلیاییها سریعتر اکسیژن میدهد و در نتیجه موها تندتر بور میشوند. مصرف مکرر آب اکسیژنه برای مو مضر است زیرا که مو را شکننده مینماید. در جنگ جهانی دوم آب اکسیژنه ۸۵%برای اکسیداسیون سریع الکل در زیر دریاییها و موشکها مصرف میکردند.
کاربرد در پزشکی [ویرایش]
آب اکسیژنه در گذشته به دلیل خاصیت ضدعفونی کننده آن در پانسمان زخمهای عفونی استفاده میشد ولی امروزه به دلیل آسیبی که به بافتهای مجاور وارد میکند دیگر در پانسمان استفاده نمیشود و فقط گاه برای ضدعفونی لوازم یا سطوح استفاده میشود.از آنجایی که آب اکسیژنه بوبر است گاه در درمان زخمهای بدبو مورد استعمال قرار میگیرد. در قرصهای اریتزون ۳۶% آب اکسیژنه به ۶۴% اوره متصل است و چون این قرصها را در دهان بگذارند، اکسیژن میدهد. پس هم میکروبهای دهان را میکشد و هم دندانها را سفید مینماید.آب اکسیژن رقیق را برای قرقره کردن هم بکار میبرند.
کاربرد در بهداشت استخرها [ویرایش]
آب اکسیژنه برای حذف مواد آلی و معدنی که موجب فاسد شدن آب استخر میشوند بکار میرود. تزریق این عنصر قبل از دستگاه UV باعث ایجاد رادیکالهای OH میشود که بیش از چند ثانیه در دسترس نمی باشند و در این مدت با خاصیت شدید اکسید کنندگی خود، مواد باقیمانده آلی و معدنی را تجزیه میکند. بدین ترتیب نیاز به تعویض آب استخرها کاهش می یابد.
در صورتی که از آب اکسیژنه در آب استخرها استفاده شود دارای مزایا به شرح زیر است: ۱. آب اکسیژنه موجود در آب با دوز صحیح، برای شناگر غیر قابل تشخیص است. ۲. با آب بخوبی مخلوط میشود، غیر فرار است و تا زمان اکسید کردن مواد آلی در آب باقی میماند. ۳. خالص است و ایجاد املاح نمی کند. ۴. خورنده نیست و در نتیجه به تجهیزات و تاسیسات آسیب نمی رساند. ۵. ایجاد کف نمی کند، بی بو و بی طعم است. ۶. غیر سمی است ۷. ایجاد رسوب نکرده و در نتیجه آب کاملا شفاف می ماند.
شناسایی آب اکسیژنه [ویرایش]
در یک لوله آزمایشی که قبلا چند سانتیمتر مکعب محلول بیکرمات پتاسیم و قدری اسید سولفوریک رقیق ریختهایم آب اکسیژنه میافزاییم در نتیجه رنگ آبی تند که بعداً تبدیل به سبز میشود، ظاهر میگردد. بهمین طریق میتوان وجود آب اکسیژنه را در اریتزن ثابت نمود.
تهیه آب اکسیژن در صنعت با روش خود اکسایش [ویرایش]
در این فرآیند یکی از مشتقات آتراکینون بر اثر واکنش با هیدروژن در مجاورت کاتالیزور پالادیوم به آنتراهیدروکینون تبدیل می شود. با عبور هوا از ماده اخیر، محلول پراکسید هیدروژن ۲۰ درصد وزنی بدست می آید.
رقیه قدیم خانی و دکتر لطفعلی سقط فروش، آزمایشگاه شیمی معدنی ۱، انتشارات پیام نور
Hydrogen peroxide (H2O2) is the simplest peroxide (a compound with an oxygen-oxygen single bond). It is also a strong oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. Due to its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent. The oxidizing capacity of hydrogen peroxide is so strong that it is considered a highly reactive oxygen species. Concentrated hydrogen peroxide, or 'high-test peroxide', is therefore used as a propellant in rocketry. Organisms also naturally produce hydrogen peroxide as a by-product of oxidative metabolism. Consequently, nearly all living things (specifically, all obligate and facultative aerobes) possess enzymes known as catalase peroxidases, which harmlessly and catalytically decompose low concentrations of hydrogen peroxide to water and oxygen.
Structure and properties 
Hydrogen peroxide (H2O2) is not a flat molecule; it adopts a nonplanar (twisted) structure of C2 symmetry. Although chiral (the twist can be left or right-handed), the molecule undergoes rapid racemization, the result of which is that the left and right-handed twist forms cannot be isolated as they can quickly "flip" their handed-ness. The observed anticlinal "skewed" shape is a compromise between two conformers, called syn and anti. If the molecule had the flat shape of the anti conformer, it would minimize steric repulsions. However, if it had the 90° torsion angle of the syn conformer, there would be optimized mixing between the filled p-type orbital of the oxygen (one of the lone pairs) and the LUMO of the vicinal O-H bond. The compromise angle has the lowest energy state. The bond angles can also be affected by hydrogen bonding between molecules. As the molecules in gasses are too far apart for hydrogen bonding, the molecular structure of the gaseous and crystalline forms is different; indeed a wide range of values is seen in crystals containing H2O2.
Although the O−O bond is a single bond, the molecule has a relatively high barrier to rotation, of 29.45 kJ/mol; for comparison, the rotational barrier for the bulkier molecule ethane is 12.5 kJ/mol. The increased barrier is ascribed to repulsion between nonbonding electrons (lone pairs) of the adjacent oxygen atoms.
Comparison with analogues 
Analogues of hydrogen peroxide include the chemically identical deuterium peroxide, and hydrogen disulfide. Hydrogen disulfide 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 
In aqueous solutions hydrogen peroxide differs from the pure material. This demonstrates the effects of hydrogen bonding between water and hydrogen peroxide molecules. Hydrogen peroxide and water form a eutectic mixture, exhibiting freezing-point depression. 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. The boiling point of the same mixture is less than the average (398 K) of the boiling points of pure water (373 K) and hydrogen peroxide (423 K) at 387 K.
pH of H2O2 
Louis Jacques Thénard first described hydrogen peroxide in 1818. He produced it by reacting barium peroxide with nitric acid. An improved version of this process used hydrochloric acid, followed by addition of sulfuric acid to precipitate the barium sulfate 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.
Pure hydrogen peroxide was long believed to be unstable. This was because of failed attempts to separate the hydrogen peroxide from the water, which is present during synthesis. However, this instability was due to traces of impurities (transition metals salts) that catalyze the decomposition of the hydrogen peroxide. One hundred percent pure hydrogen peroxide was first obtained through vacuum distillation by Richard Wolffenstein in 1894. At the end of the 19th century, Petre Melikishvili 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 H2O2 sterilization in biological safety cabinets and barrier isolators is a popular alternative to ethylene oxide (EtO) as a safer, more efficient decontamination method. H2O2 has long been widely used in the pharmaceutical industry. In aerospace research, H2O2 is used to sterilize artificial satellites and space probes.
The U.S. FDA has granted 510(k) clearance to use H2O2 in individual medical device manufacturing applications. EtO criteria outlined in ANSI/AAMI/ISO 14937 may be used as a validation guideline. Sanyo was the first manufacturer to use the H2O2 process in situ in a cell culture incubator, which is a faster and more efficient cell culture sterilization process.
Formerly, hydrogen peroxide was prepared by the electrolysis of an aqueous solution of sulfuric acid or acidic ammonium bisulfate (NH4HSO4), followed by hydrolysis of the peroxodisulfate S2O82− that is formed.
Today, hydrogen peroxide is manufactured almost exclusively by the Riedl-Pfleiderer or anthraquinone process which was formalized in 1936 and patented in 1939, and involves the autoxidation of a 2-alkyl anthrahydroquinone (or 2-alkyl-9,10-dihydroxyanthracene) to the corresponding 2-alkyl anthraquinone. 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 (C16H12(OH)2) is oxidized to the corresponding 2-ethylanthraquinone (C16H12O2) and hydrogen peroxide. Most commercial processes achieve this by bubbling compressed air through a solution of the derivatized anthracene, 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 and the anthraquinone derivative is reduced back to the dihydroxy (anthracene) compound using hydrogen gas in the presence of a metal catalyst. The cycle then repeats itself.
The simplified overall equation for the process is deceptively simple:
In 1994, world production of H2O2 was around 1.9 million tonnes and grew to 2.2 million in 2006, most of which was at a concentration of 70% or less. In that year bulk 30% H2O2 sold for around US $0.54 per kg, equivalent to US $1.50 per kg (US $0.68 per lb) on a "100% basis".
New developments 
A new high-productivity/high-yield process, based on an optimized distribution of isomers of 2-amyl anthraquinone, has been developed by Solvay. In July 2008, this process allowed the construction of a mega-scale single-train plant in Zandvliet (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 was commissioned in October 2011 by a joint venture of Solvay and Dow in Map Ta Phut (Thailand). This plant has a projected production capacity of 330,000 tons of hydrogen peroxide per year at 100% concentration. It is likely that this will lead to a reduction in the cost of production due to economies of scale.
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 minute (nanometer-size) phase-controlled noble metal crystal particles on carbon support. This advance led, in a joint venture with Evonik Industries, 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 anthraquinone process).
In 2009, another catalyst development was announced by researchers at Cardiff University. This development also relates to direct synthesis, but in this case using gold–palladium nanoparticles. Under normal circumstances, direct synthesis must be carried out in an acid medium to prevent decomposition of the hydrogen peroxide as soon as it is formed. (Hydrogen peroxide in any case 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.) However the nature of a catalyst can cause this decomposition to accelerate rapidly, and it is claimed that this gold-palladium catalyst reduces the 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. The process employs a monopolar cell to achieve an electrolytic reduction of oxygen in a dilute sodium hydroxide solution.
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 allow inspection by commercial manufacturers.
This process is thermodynamically favorable. It has a ΔH
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 accelerated by the oxygen released from the decomposing hydrogen peroxide. High test peroxide, or HTP (also called high-strength peroxide) must be stored in a suitable, vented container to prevent the buildup of oxygen gas, which would otherwise lead to the eventual rupture of the container.
In the presence of certain catalysts, such as Fe2+ or Ti3+, the decomposition may take a different path, with free radicals such as HO· (hydroxyl) and HOO· (hydroperoxyl) being formed. A combination of H2O2 and Fe2+ is known as Fenton's reagent.
A common concentration for hydrogen peroxide is 20-volume, which means that, when 1 volume of this solution of hydrogen peroxide is decomposed, it produces 20 volumes of oxygen (STP). A 20-volume concentration of hydrogen peroxide is equivalent to 1.761 mol/dm3 (Molar solution) or about 6.08%(w/v).
Redox reactions 
In acidic solutions, H2O2 is one of the most powerful oxidizers known—stronger than chlorine, chlorine dioxide, and potassium permanganate. Also, through catalysis, H2O2 can be converted into hydroxyl radicals (•OH), which are highly reactive.
In aqueous solutions, hydrogen peroxide can oxidize or reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen gas is also produced.
In acidic solutions Fe2+ is oxidized to Fe3+ (hydrogen peroxide acting as an oxidizing agent),
and sulfite (SO2−
Hydrogen peroxide is frequently used as an oxidizing agent in organic chemistry. One application is for the oxidation of thioethers to sulfoxides. For example, methyl phenyl sulfide can be readily oxidized in high yield to methyl phenyl sulfoxide:
Formation of peroxide compounds 
For example, on addition to an aqueous solution of chromic acid (CrO3) or acidic solutions of dichromate salts, it will form an unstable blue peroxide CrO(O2)2. In aqueous solution it rapidly decomposes to form oxygen gas and chromium salts.
H2O2 converts carboxylic acids (RCOOH) into peroxy acids (RCOOOH), which are themselves used as oxidizing agents. Hydrogen peroxide reacts with acetone to form acetone peroxide, and it interacts with ozone to form hydrogen trioxide, also known as trioxidane. Reaction with urea produces the adduct hydrogen peroxide - urea, used for whitening teeth. An acid-base adduct with triphenylphosphine oxide is a useful "carrier" for H2O2 in some reactions.
Municipal wastewater applications 
Hydrogen peroxide is replacing prechlorination as a way to deal with odors entering wastewater treatment plants. The processing of wastewater sludge (or biosolids) can cause the generation of hydrogen sulfide (H2S), a poisonous and odoriferous gas. Hydrogen sulfide can also damage equipment and concrete structures. Hydrogen peroxide has been utilized to minimize hydrogen sulfide formation.
Industrial applications 
About 50% of the world's production of hydrogen peroxide in 1994 was used for pulp- and paper-bleaching. Other bleaching applications are becoming more important as hydrogen peroxide is seen as an environmentally benign alternative to chlorine-based bleaches.
Sulfide oxidation 
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. Biogenic H2S is encountered 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.
BOD and COD removal from wastewater 
Hydrogen peroxide has been used to reduce the BOD and COD 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:
Supply of supplemental Dissolved Oxygen (DO) when biological treatment systems experience temporary overloads or equipment failure.
As indicated by these examples, hydrogen peroxide can be used as a stand-alone treatment or as an enhancement to existing physical or biological treatment processes, depending on the situation.
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.
The strong oxidizing power of hydrogen peroxide makes it suitable for the destruction of a variety of pollutants. Optimization of conditions using hydrogen peroxide to destroy these pollutants can involve control of pH, temperature and reaction time. No additional additives are required.
Pollutants that are more difficult to oxidize require hydrogen peroxide 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 hydrogen peroxide 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).
Nitrogen oxide (NOx) abatement 
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.
Other major industrial applications for hydrogen peroxide include the manufacture of sodium percarbonate and sodium perborate, used as mild bleaches in laundry detergents. It is used in the production of certain organic peroxides, such as dibenzoyl peroxide, used in polymerisations and other chemical processes. Hydrogen peroxide is also used in the production of epoxides, such as propylene oxide. Reaction with carboxylic acids produces a corresponding peroxy acid. Peracetic acid and meta-chloroperoxybenzoic acid (commonly abbreviated mCPBA) are prepared from acetic acid and meta-chlorobenzoic acid, respectively. The latter is commonly reacted with alkenes to give the corresponding epoxide.
In the PCB 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 CO2 and high-temperature steam for a variety of purposes.
Recently, there has been increased use of vaporized hydrogen peroxide in the validation and bio-decontamination of half-suit and glove-port isolators in pharmaceutical production.
Nuclear pressurized water reactors (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 from hydrogen peroxide has been developed. The process is claimed to be environmentally friendly, since the only significant byproduct is water. Two of these "HPPO" (hydrogen peroxide to propylene oxide) plants came onstream in 2008: One of them located in Belgium is a Solvay, Dow-BASF joint venture, and the other in Korea is an EvonikHeadwaters, SK Chemicals joint venture. A caprolactam application for hydrogen peroxide has been commercialized. Potential routes to phenol and epichlorohydrin utilizing hydrogen peroxide have been postulated.
Biological function 
A study published in Nature found that hydrogen peroxide plays a role in the immune system. 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 cells 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 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.
Domestic uses 
High concentration H2O2 is referred to as High Test Peroxide (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98+% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over 600 °C (1,112 °F), which is expelled through a nozzle, generating thrust. H2O2 monopropellant produces a maximum specific impulse (Isp) of 161 s (1.6 kN·s/kg), which makes it a low-performance monopropellant. Peroxide generates much less thrust than hydrazine. The Bell Rocket Belt used hydrogen peroxide monopropellant.
As a bipropellant H2O2 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, containing oxyquinoline stabilizer, for the Me-163), and for the low-cost British Black Knight and Black Arrow launchers.
In the 1940s and 1950s, the Walter turbine used hydrogen peroxide for use in submarines while submerged; it was found to be too noisy and require too much maintenance compared to diesel-electric power systems. Some torpedoes used hydrogen peroxide as oxidizer or propellant, but this was dangerous and has been discontinued by most navies. Hydrogen peroxide leaks were blamed for the sinkings of HMS Sidon and the Russian submarine Kursk. It was discovered, for example, by the Japanese Navy in torpedo trials, that the concentration of H2O2 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 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 satellites.They are easy to throttle, and safer to fuel and handle before launch than hydrazine thrusters. However, hydrazine is more often used in spacecraft because of its higher specific impulse and lower rate of decomposition.
Therapeutic use 
Hydrogen peroxide is generally recognized as safe (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.
Alternative uses 
Improvised explosive device / home-made bomb precursor 
Hydrogen peroxide was the main ingredient in the 7 July 2005 London bombings that killed 52 London Underground and bus passengers. The bomb-making ingredients are reported to be easier to buy than large numbers of aspirin pills.
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 (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, high concentrations of H2O2 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 oxidizer according to U.S. regulations, if released into the environment. The EPA Reportable Quantity (RQ) for D001 hazardous wastes is 100 pounds (45 kg), or approximately 10 US gallons (38 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:
Historical incidents 
See also