هیدروژن پراکسید یا آباکسیژنه (H۲O۲) یک اکسنده متداول است که به عنوان سفید کننده استفاده میشود.آب اکسیژنه برای حذف مواد آلی و معدنی که موجب فاسد شدن آب استخر میشوند بکار میرود. 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 %۳ آن آب اکسیژنه است، مانند آب بیرنگ و بیبوست، مزه تلخی دارد و کمی اسیدی است. این مایع اکسید کنندهای قوی است.
تجزیه این ماده باعث ایجاد رادیکالهای OH میشود که بیش از چند ثانیه در دسترس نمیباشند 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. همچنین در نور یا گرما تجزیه میشود بنابراین باید در ظرف کدر و دور از گرما نگهداری شود. اگر مدت مدیدی آب اکسیژنه را انبار کنند، ممکن است کاملاً 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 بیفزایند، عمل تخریب بسیار کند میگردد. آب اکسیژنه اثر میکروب کشی ، بوبری و سفید کنندگی دارد چنانکه اگر یک تکه کالباس قرمز را درون ظرف محتوی آب اکسیژنه قرار دهیم پس از چند روز محتویات ظرف کاملاً 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 میگیرد. 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 سیاهسر 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.
هیدروژن پراکسید در سلول های جانوری و گیاهی نیز تولید می شود، در اندامکی به نام پراکسی زوم، چون پراکسید هیدروژن تولید شده ماده ای سمی است توسط آنزیم کاتالاز به سرعت بسیار بالا به آب H2O و اکسیژن O2 تجزیه میشود تاهم سمیتش از بین برود و هم به لیپید های تولید شده توسط اندامک شبکه آندوپلاسمی آسیبی نرساند.
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.,و در ساختن داروهای سرما خوردگی تاثیر دارد
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 نمیباشند 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 مییابد.
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 غیرقابل 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 نمیکند. ۴. خورنده نیست و در نتیجه به تجهیزات و تاسیسات آسیب نمیرساند. ۵. ایجاد کف نمیکند، بیبو و بی طعم است. ۶. غیر سمی است ۷. ایجاد رسوب نکرده و در نتیجه آب کاملاً شفاف میماند.
شناسایی آب اکسیژنه[ویرایش]
در یک لوله آزمایشی که قبلاً 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 اریتزون ثابت نمود.
تهیه آب اکسیژن در صنعت با روش خود اکسایش[ویرایش]
در این فرایند یکی از مشتقات آتراکینون بر اثر واکنش با هیدروژن در مجاورت کاتالیزور پالادیوم به آنتراهیدروکینون تبدیل میشود. با عبور هوا از ماده اخیر، محلول پراکسید هیدروژن ۲۰ درصد وزنی بدست میآید.
در ایران برای نخستین بار شرکت فرآیند گستر تامین از زیر مجموعه های شرکت سرمایه گذاری تامین اجتماعی -شستا- موفق شد با روش اتواکسیداسیون آنتراکینون این ماده را در مقیاس صنعتی تولید کند.
Hydrogen peroxide is a chemical compound with the formula H
Hydrogen peroxide is unstable and slowly decomposes in the presence of base or a catalyst. Because of its instability, hydrogen peroxide is typically stored with a stabilizer in a weakly acidic solution. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases.
The boiling point of H
In aqueous solutions hydrogen peroxide differs from the pure material due to 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 has a melting point of 0 °C and pure hydrogen peroxide of −0.43 °C. The boiling point of the same mixtures is also depressed in relation with the mean of both boiling points (125.1 °C). It occurs at 114 °C. This boiling point is 14 °C greater than that of pure water and 36.2 °C less than that of pure hydrogen peroxide.
Hydrogen peroxide (H
The molecular structures of gaseous and crystalline H
Comparison with analogues
Hydrogen peroxide has several structural analogues with Hm−X−X−Hn bonding arrangements (water also shown for comparison). It has the highest (theoretical) boiling point of this series (X = O, N, S). Its melting point is also fairly high, being comparable to that of hydrazine and water, with only hydroxylamine crystallising significantly more readily, indicative of particularly strong hydrogen bonding. Diphosphane and hydrogen disulfide exhibit only weak hydrogen bonding and have little chemical similarity to hydrogen peroxide. All of these analogues are thermodynamically unstable. Structurally, the analogues all adopt similar skewed structures, due to repulsion between adjacent lone pairs.
Nineteen years later Louis Jacques Thénard recognized that this compound could be used for the preparation of a previously unknown compound, which he described as oxidized water – subsequently known as hydrogen peroxide.  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.
Thénard and Joseph Louis Gay-Lussac synthesized sodium peroxide in 1811. The bleaching effect of peroxides and their salts on natural dyes became known around that time, but early attempts of industrial production of peroxides failed, and the first plant producing hydrogen peroxide was built in 1873 in Berlin. The discovery of the synthesis of hydrogen peroxide by electrolysis with sulfuric acid introduced the more efficient electrochemical method. It was first implemented into industry in 1908 in Weißenstein, Carinthia, Austria. The anthraquinone process, which is still used, was developed during the 1930s by the German chemical manufacturer IG Farben in Ludwigshafen. The increased demand and improvements in the synthesis methods resulted in the rise of the annual production of hydrogen peroxide from 35,000 tonnes in 1950, to over 100,000 tonnes in 1960, to 300,000 tonnes by 1970; by 1998 it reached 2.7 million tonnes.
Pure hydrogen peroxide was long believed to be unstable, as early attempts to separate it from the water, which is present during synthesis, all failed. This instability was due to traces of impurities (transition-metal salts), which catalyze the decomposition of the hydrogen peroxide. Pure hydrogen peroxide was first obtained in 1894—almost 80 years after its discovery—by Richard Wolffenstein, who produced it by vacuum distillation.
Determination of the molecular structure of hydrogen peroxide proved to be very difficult. In 1892 the Italian physical chemist Giacomo Carrara (1864–1925) determined its molecular mass by freezing-point depression, which confirmed that its molecular formula is H2O2. At least half a dozen hypothetical molecular structures seemed to be consistent with the available evidence. In 1934, the English mathematical physicist William Penney and the Scottish physicist Gordon Sutherland proposed a molecular structure for hydrogen peroxide that was very similar to the presently accepted one.
Previously, hydrogen peroxide was prepared industrially by hydrolysis of the ammonium peroxydisulfate, which was itself obtained by the electrolysis of a solution of ammonium bisulfate (NH
Today, hydrogen peroxide is manufactured almost exclusively by the anthraquinone process, which was formalized in 1936 and patented in 1939. It begins with the reduction of an anthraquinone (such as 2-ethylanthraquinone or the 2-amyl derivative) to the corresponding anthrahydroquinone, typically by hydrogenation on a palladium catalyst; the anthrahydroquinone then undergoes autoxidation to regenerate the starting anthraquinone, with hydrogen peroxide as a by-product. Most commercial processes achieve oxidation 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 groups), 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 simple:
A process to produce hydrogen peroxide directly from the elements has been of interest for many years. Direct synthesis is difficult to achieve, as the reaction of hydrogen with oxygen thermodynamically favours production of water. Systems for direct synthesis have been developed, most of which are based around finely dispersed metal catalysts. None of these has yet reached a point where they can be used for industrial-scale synthesis.
Hydrogen peroxide is most commonly available as a solution in water. For consumers, it is usually available from pharmacies at 3 and 6 wt% concentrations. The concentrations are sometimes described in terms of the volume of oxygen gas generated; one milliliter of a 20-volume solution generates twenty milliliters of oxygen gas when completely decomposed. For laboratory use, 30 wt% solutions are most common. Commercial grades from 70% to 98% are also available, but due to the potential of solutions of more than 68% hydrogen peroxide to be converted entirely to steam and oxygen (with the temperature of the steam increasing as the concentration increases above 68%) these grades are potentially far more hazardous and require special care in dedicated storage areas. Buyers must typically allow inspection by commercial manufacturers.
In 1994, world production of H
Hydrogen peroxide occurs in surface water, groundwater and in the atmosphere. It forms upon illumination or natural catalytic action by substances contained in water. Sea water contains 0.5 to 14 μg/L of hydrogen peroxide, freshwater 1 to 30 μg/L and air 0.1 to 1 parts per billion.
The rate of decomposition increases with rising temperature, concentration and pH, with cool, dilute, acidic solutions showing the best stability. Decomposition is catalysed by various compounds, including most transition metals and their compounds (e.g. manganese dioxide, silver, and platinum). Certain metal ions, such as Fe2+
Hydrogen peroxide exhibits oxidizing and reducing properties, depending on pH.
In acidic solutions, H
In acidic solutions Fe2+
and sulfite (SO2−
In basic solution, hydrogen peroxide can reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen gas is also produced. For example, hydrogen peroxide will reduce sodium hypochlorite and potassium permanganate, which is a convenient method for preparing oxygen in the laboratory:
Alkaline hydrogen peroxide is used for epoxidation of electron-deficient alkenes such as acrylic acid derivatives, and for the oxidation of alkylboranes to alcohols, the second step of hydroboration-oxidation. It is also the principal reagent in the Dakin oxidation process.
Precursor to other peroxide compounds
It also converts metal oxides into the corresponding peroxides. For example, upon treatment with hydrogen peroxide, chromic acid(CrO
The peroxide anion is a stronger nucleophile than hydroxide and displaces hydroxyl from oxyanions e.g. forming perborates and percarbonates. Sodium perborate and sodium percarbonate are important consumer and industrial bleaching agents; they stabilize hydrogen peroxide and limit side reactions (e.g. reduction and decomposition note below). The peroxide anion forms an adduct with urea, hydrogen peroxide–urea.
Hydrogen peroxide is both an oxidizing agent and reducing agent. The oxidation of hydrogen peroxide by sodium hypochlorite yields singlet oxygen. The net reaction of a ferric ion with hydrogen peroxide is a ferrous ion and oxygen. This proceeds via single electron oxidation and hydroxyl radicals. This is used in some organic chemistry oxidations, e.g. in the Fenton's reagent. Only catalytic quantities of iron ion is needed since peroxide also oxidizes ferrous to ferric ion. The net reaction of hydrogen peroxide and permanganate or manganese dioxide is manganous ion; however, until the peroxide is spent some manganous ions are reoxidized to make the reaction catalytic. This forms the basis for common monopropellant rockets.
Hydrogen peroxide is formed in human and animals as a short-lived product in biochemical processes and is toxic to cells. The toxicity is due to oxidation of proteins, membrane lipids and DNA by the peroxide ions. The class of biological enzymes called SOD (superoxide dismutase) is developed in nearly all living cells as an important antioxidant agent. They promote the disproportionation of superoxide into oxygen and hydrogen peroxide, which is then rapidly decomposed by the enzyme catalase to oxygen and water.
Peroxisomes are organelles found in virtually all eukaryotic cells. They are involved in the catabolism of very long chain fatty acids, branched chain fatty acids, D-amino acids, polyamines, and biosynthesis of plasmalogens, etherphospholipids critical for the normal function of mammalian brains and lungs. Upon oxidation, they produce hydrogen peroxide in the following process:
This reaction is important in liver and kidney cells, where the peroxisomes neutralize various toxic substances that enter the blood. Some of the ethanol humans drink is oxidized to acetaldehyde in this way. In addition, when excess H2O2 accumulates in the cell, catalase converts it to H2O through this reaction:
Another origin of hydrogen peroxide is the degradation of adenosine monophosphate which yields hypoxanthine. Hypoxanthine is then oxidatively catabolized first to xanthine and then to uric acid, and the reaction is catalyzed by the enzyme xanthine oxidase:
Eggs of sea urchin, shortly after fertilization by a sperm, produce hydrogen peroxide. It is then quickly dissociated to OH· radicals. The radicals serve as initiator of radical polymerization, which surrounds the eggs with a protective layer of polymer.
The bombardier beetle has a device which allows it to shoot corrosive and foul-smelling bubbles at its enemies. The beetle produces and stores hydroquinone and hydrogen peroxide, in two separate reservoirs in the rear tip of its abdomen. When threatened, the beetle contracts muscles that force the two reactants through valved tubes into a mixing chamber containing water and a mixture of catalytic enzymes. When combined, the reactants undergo a violent exothermic chemical reaction, raising the temperature to near the boiling point of water. The boiling, foul-smelling liquid partially becomes a gas (flash evaporation) and is expelled through an outlet valve with a loud popping sound.
Hydrogen peroxide has roles as a signalling molecule in the regulation of a wide variety of biological processes. The compound is a major factor implicated in the free-radical theory of aging, based on how readily hydrogen peroxide can decompose into a hydroxyl radical and how superoxide radical byproducts of cellular metabolism can react with ambient water to form hydrogen peroxide. These hydroxyl radicals in turn readily react with and damage vital cellular components, especially those of the mitochondria. At least one study has also tried to link hydrogen peroxide production to cancer. These studies have frequently been quoted in fraudulent treatment claims.
The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. Sodium percarbonate, which is an adduct of sodium carbonate and hydrogen peroxide, is the active ingredient in such products as OxiClean and Tide laundry detergent. When dissolved in water, it releases hydrogen peroxide and sodium carbonate:
Production of organic compounds
It is used in the production of various organic peroxides with dibenzoyl peroxide being a high volume example. It is used in polymerisations, as a flour bleaching agent and as a treatment for acne. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid are also produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide.
Hydrogen peroxide is used in certain waste-water treatment processes to remove organic impurities. In advanced oxidation processing, the Fenton reaction gives the highly reactive hydroxyl radical (·OH). This degrade organic compounds, including those that are ordinarily robust, such as aromatic or halogenated compounds. It can also oxidize sulfur based compounds present in the waste; which is beneficial as it generally reduces their odour.
Hydrogen peroxide can be used for the sterilization of various surfaces, including surgical tools and may be deployed as a vapour (VHP) for room sterilization. H2O2 demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. In general, greater activity is seen against Gram-positive than Gram-negative bacteria; however, the presence of catalase or other peroxidases in these organisms can increase tolerance in the presence of lower concentrations. Higher concentrations of H2O2 (10 to 30%) and longer contact times are required for sporicidal activity.
Hydrogen peroxide is seen as an environmentally safe alternative to chlorine-based bleaches, as it degrades to form oxygen and water and it is generally recognized as safe as an antimicrobial agent by the U.S. Food and Drug Administration (FDA).
Historically hydrogen peroxide was used for disinfecting wounds, partly because of its low cost and prompt availability compared to other antiseptics. It is now thought to inhibit healing and to induce scarring because it destroys newly formed skin cells. Only a very low concentration of H2O2 can induce healing, and only if not repeatedly applied. Surgical use can lead to gas embolism formation. Despite this it is still used for wound treatment in many developing countries.
Dermal exposure to dilute solutions of hydrogen peroxide cause whitening or bleaching of the skin due to microembolism caused by oxygen bubbles in the capillaries.
Use in alternative medicine
Practitioners of alternative medicine have advocated the use of hydrogen peroxide for various conditions, including emphysema, influenza, AIDS and cancer, although there is no evidence of effectiveness and in some cases it may even be fatal.
The practice calls for the daily consumption of hydrogen peroxide, either orally or by injection and is, in general, based around two precepts. First, that hydrogen peroxide is naturally produced by the body to combat infection; and second, that human pathogens (including cancer: See Warburg hypothesis) are anaerobic and cannot survive in oxygen-rich environments. The ingestion or injection of hydrogen peroxide is therefore believed to kill disease by mimicking the immune response in addition to increasing levels of oxygen within the body. This makes it similar to other oxygen-based therapies, such as ozone therapy and hyperbaric oxygen therapy.
Both the effectiveness and safety of hydrogen peroxide therapy is scientifically questionable. Hydrogen peroxide is produced by the immune system but in a carefully controlled manner. Cells called phagocytes engulf pathogens and then use hydrogen peroxide to destroy them. The peroxide is toxic to both the cell and the pathogen and so is kept within a special compartment, called a phagosome. Free hydrogen peroxide will damage any tissue it encounters via oxidative stress; a process which also has been proposed as a cause of cancer. Claims that hydrogen peroxide therapy increase cellular levels of oxygen have not been supported. The quantities administered would be expected to provide very little additional oxygen compared to that available from normal respiration. It should also be noted that it is difficult to raise the level of oxygen around cancer cells within a tumour, as the blood supply tends to be poor, a situation known as tumor hypoxia.
Large oral doses of hydrogen peroxide at a 3% concentration may cause irritation and blistering to the mouth, throat, and abdomen as well as abdominal pain, vomiting, and diarrhea. Intravenous injection of hydrogen peroxide has been linked to several deaths.
The American Cancer Society states that "there is no scientific evidence that hydrogen peroxide is a safe, effective or useful cancer treatment." Furthermore, the therapy is not approved by the U.S. FDA.
As a bipropellant, H
In the 1940s and 1950s, the Hellmuth Walter KG-conceived 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. Operator error in the use of hydrogen-peroxide torpedoes was named as possible causes for the sinkings of HMS Sidon and the Russian submarine Kursk. SAAB Underwater Systems is manufacturing the Torpedo 2000. This torpedo, used by the Swedish Navy, is powered by a piston engine propelled by HTP as an oxidizer and kerosene as a fuel in a bipropellant system.
Hydrogen peroxide has various domestic uses, primarily as a cleaning and disinfecting agent.
Some horticulturalists and users of hydroponics advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat root rot (cellular root death due to lack of oxygen) and a variety of other pests.
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. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide.
Regulations vary, but low concentrations, such as 6%, 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 H
High-concentration hydrogen peroxide streams, typically above 40%, should be considered hazardous 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 block light.
Hydrogen peroxide, either in pure or diluted form, can pose several risks, the main one being that it forms explosive mixtures upon contact with organic compounds. Highly concentrated hydrogen peroxide itself is unstable and can cause a boiling liquid expanding vapour explosion (BLEVE) of the remaining liquid. Distillation of hydrogen peroxide at normal pressures is thus highly dangerous. It is also corrosive, especially when concentrated, but even domestic-strength solutions can cause irritation to the eyes, mucous membranes 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 bloating. Inhaling over 10% can cause severe pulmonary irritation.
With a significant vapour pressure (1.2 kPa at 50 °C), hydrogen-peroxide vapour is potentially hazardous. According to U.S. NIOSH, the immediately dangerous to life and health (IDLH) limit is only 75 ppm. The U.S. Occupational Safety and Health Administration (OSHA) has established a permissible exposure limit of 1.0 ppm calculated as an 8-hour time-weighted average (29 CFR 1910.1000, Table Z-1). Hydrogen peroxide has also been classified by the American Conference of Governmental Industrial Hygienists (ACGIH) as a "known animal carcinogen, with unknown relevance on humans". For workplaces where there is a risk of exposure to the hazardous concentrations of the vapours, continuous monitors for hydrogen peroxide should be used. Information on the hazards of hydrogen peroxide is available from OSHA and from the ATSDR.