Hydrogen peroxide is an inorganic compound, chemical formula H ₂ O ₂, relative molecular weight 34.02, colorless liquid, relative density 1.465g/cm³，The melting point is - 1 ℃, and the boiling point is 150.2 ℃. Pure products are easy to be decomposed into water and oxygen, and the commercial products are 30% or 3%aqueous solutionIt is relatively stable in the dark, and will accelerate decomposition when exposed to light or impurities. A small amount of acidSodium stannate、Sodium pyrophosphate, ethanolAcetanilideOr acetylethoxyaniline can increase its stability.[3][4]
Hydrogen peroxide has oxidability and reducibility. The products of its oxidation, reduction or decomposition are water and (or) oxygen, which can be called clean oxidation-reduction agent.Hydrogen peroxide can be usedOxidant、bleaching agents、disinfectant、Dechlorination agent, also for productionRocket fuel、peroxideAnd foam plastics, etc[4]Hydrogen peroxide is also used in the production of inorganic and organic peroxides such as sodium perborate and peracetic acid.[3]
Hydrogen peroxide is used for indirect determination of substrates, enzymes, activators or inhibitors in medical clinical chemical analysis.[4]
Chinese name
hydrogen peroxide
Foreign name
hydrogen peroxide[2]
Alias
Ethane
chemical formula
H₂O₂
molecular weight
thirty-four point zero two[4]
CAS login number
7722-84-1
EINECS login number
231-765-0
Melting point
-1 ℃[3]
Boiling point
150.2 ℃[4](Disassembly)
Water solubility
mutually dissolvable
Density
1.465 g/cm³[4]
Appearance
Blue viscous liquid
Application
Disinfection of object surface, chemical production, odor removal
French chemist in 1818Thénard First, recrystallized barium nitrate (transition metal ions are removed) is heat treated to obtain barium oxide BaO, and then high-temperature oxidation is converted to barium peroxide BaO ₂;Then use hydrochloric acid to treat BaO ₂, and use the precipitation method to remove Ba with H ₂ SO ₄²Ion, adding Ag ₂ SO ₄ to remove Cl ⁻ ion, and adding BaO to remove SO ₄²After ⁻ ion, hydrogen peroxide (H ₂ O ₂) aqueous solution is obtained;Finally, vacuum distillation can produce almost anhydrous pure H ₂ O ₂.Thenard also made some research on its properties after preparing H ₂ O ₂, and found that when treating H ₂ O ₂ with MnO ₂, MnO ₂ would catalyze the decomposition of H ₂ O ₂ to release oxygen.According to the volume of oxygen released, Thenard concluded that hydrogen peroxide must contain twice as much oxygen as water.[7]
Physical and chemical properties
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physical property
Hydrogen peroxide (H ₂ O ₂) is commonly known as hydrogen peroxide.Pure hydrogen peroxide is a light blue viscous liquid, with a melting point of - 1 ℃, a boiling point of 150.2 ℃, and a density of 1.465g/cm at 0 ℃³。H ₂ O ₂ is a polar molecule, which can be mixed with water in any proportion. 3% and 35% aqueous solutions are commonly used.[3][4]
Physical properties of hydrogen peroxide
appearance
Blue viscous liquid;The aqueous solution is colorless and transparent.
melting point
-1 ℃ (the molecular configuration of pure hydrogen peroxide will change, so the melting and boiling points will also change)
Solubility
Soluble in water, alcohol and ether, insoluble in benzene and petroleum ether.
boiling point
152℃。
density
Solid density at freezing point is 1.71g/cm³，The density decreases with increasing temperature.
Association degree
The degree of association is greater than that of H ₂ O, so its dielectric constant and boiling point are higher than that of water.
chemical property
Hydrogen peroxide has weak acidity and can react with alkali to form metal peroxide.Aqueous solution of hydrogen peroxide is availableBarium peroxideAnd dilute H ₂ SO ₄.[3]
Hydrogen peroxide has poor stability and decomposes slowly at low temperature. When heated to above 153 ℃, it can decompose violently and release a lot of heat.MnO₂And many heavy metal ions, such as iron, manganese and copper, catalyze their decomposition in the presence of plasma.[3]
Heating and exposure will accelerate the decomposition of hydrogen peroxide.Therefore, hydrogen peroxide should be stored in a brown bottle and placed in a dark place. At the same time, stabilizers (such as sodium stannate, sodium pyrophosphate, etc.) can be added to inhibit its decomposition.[3]
Oxygenic in hydrogen peroxideValenceIt is - 1 valence, between zero valence and - 2 valence, so hydrogen peroxide is both oxidizing and reducing.H ₂ O ₂ is a strong oxidant in acidic solution, and a medium reducing agent in alkaline solution.
The latter reaction can oxidize black PbS into white PbSO ₄, which can be used for cleaning oil paintings.[3]
In acid medium, when H ₂ O ₂ reacts with stronger oxidants, H ₂ O ₂ shows reducibility.[3]
Preparation method
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Industrial preparation
Acidolysis peroxide method
As early as the middle of the 19th century, hydrogen peroxide produced on an industrial scale was produced by the action of an acid on barium peroxide.Barium peroxide used is either obtained by reducing oxygen in the atmosphere with metal barium, or as when Thenard discovered hydrogen peroxide, it is obtained by first pyrolysis BaO from Ba (NO ₂) ₂, and then injecting air free of CO ₂ and water into hot BaO.Later, BaO was obtained by thermal decomposition of BaCO ≮, and low concentration (2-5%) HCI and/or H ₂ PO ₄ were added to the H ₂ SO ₄ used.If barite is used as raw material to produce H ₂ O ₂, the steps are roughly as follows:
The reaction is slow because the generated BaSO ₄ is easy to apply on BaO ₂.In order to avoid this phenomenon, BaO ₂ is generally changed into BaO ∨ 8H ₂ O first, and then it is added to the cold ≮ H ₂ SO ₄ containing low concentrations of HCl and/or H ₂ PO ₄.With this method, 10% - 20% H ₂ O ₂ solution can be obtained.It is reported that the conversion of BaO ₂ to H ₂ O ₂ with hydrated carbon dioxide has achieved some success.[8]
Laboratory preparation
Considering that H ₂ O ₂ is a weak acid, it can be prepared by acidification of its salt.For example:[10]
application area
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Industrial use
bleaching agents
In industry, hydrogen peroxide is widely used to bleach many different substances, including cotton fabrics, raw silk, wool, fur, feathers, hair, animal bones, ivory, fat, paper pulp and headstones;Hydrogen peroxide is also used to produce inorganic and organic peroxides such as sodium perborate, sodium percarbonate, peracetic acid, thioperoxide, etc., and as a catalyst for polymer polymerization;Hydrogen peroxide is also used to produce 401 resistant pesticide and thiram insecticide;It can be used to remove iron when purifying inorganic salts;It can remove the inorganic impurities in the electroplating solution to improve the quality of the plated parts.High concentration (more than 90%) hydrogen peroxide can be mixed with some combustibles to produce explosives;In modern high-energy technology, it was used as high-energy oxidant and single component fuel of rocket fuel.[9]
Medical use
Hydrogen peroxide solution
The main use of hydrogen peroxide is based on its oxidizability.Dilute hydrogen peroxide solution can be used as disinfectant, bactericide and deodorant in medicine.30% hydrogen peroxide solution is often used as oxidant in the laboratory.[9]
Safety measures
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Wear protective clothing, gloves made of polyethylene or polyvinyl chloride, and transparent protective glasses and masks made of polymer materials when working in contact.Rinse with warm water if touching skin or splashing eyes.[5]
Toxicological data
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Frequent exposure often leads to dermatitis and bronchial and lung diseases.When poisoned by mouth, abdominal pain, chest pain, dyspnea, vomiting, elevated temperature, conjunctival and skin bleeding may occur, and visual impairment, spasm, and paresis may occur in some cases.The maximum allowable concentration in the United States is usually 1.4mg/m³。[5]
Hydrogen peroxide is incombustible, but it can react with combustibles to release a large amount of heat and oxygen, causing ignition and explosion.Hydrogen peroxide is the most stable when the pH value is 3.5-4.5. It is very easy to decompose in alkaline solution. It can also decompose in strong light, especially when exposed to short wave radiation.When heated to more than 100 ℃, it starts to decompose rapidly.Hydrogen peroxide forms explosive mixtures with many organic substances such as sugar, starch, alcohols, petroleum products, etc., which can explode under the action of impact, heating or electric spark.Hydrogen peroxide will decompose rapidly after contacting with many inorganic compounds or impurities, resulting in explosion, releasing a lot of heat, oxygen and water vapor.Most heavy metals (such as iron, copper, silver, lead, mercury, zinc, cobalt, nickel, chromium, manganese, etc.) and their oxides and salts are active catalysts, and dust, cigarette ash, carbon powder, rust, etc. can also accelerate the decomposition.Hydrogen peroxide with a concentration of more than 74% can produce gas phase explosion in a closed container with appropriate ignition source or temperature.[6]
Storage and transportation
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Storage method
Store in a cool, dry and well ventilated special warehouse, away from kindling and heat sources.The storage temperature shall not exceed 30 ℃, and the relative humidity shall not exceed 80%.Keep container sealed.It shall be stored separately from combustible (combustible) materials, reducing agents, active metal powders, etc., and mixed storage is strictly prohibited.The storage area shall be equipped with leakage emergency treatment equipment and appropriate materials.[6]
Transport method
It shall be transported separately, and the container shall not leak, collapse, fall or be damaged during transportation.It is strictly prohibited to transport together with acids, inflammables, organics, reducing agents, spontaneous combustion materials, inflammables in wet conditions, etc.During transportation, the speed should not be too fast, and forced overtaking is not allowed.Road transportation shall be carried out according to the specified route.Transport vehicles shall be thoroughly cleaned before and after loading and unloading. It is strictly prohibited to mix with organic substances, combustibles and other impurities.
Relevant regulations
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On October 27, 2017, the list of carcinogens released by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily sorted out for reference, and hydrogen peroxide was included in the list of category 3 carcinogens.[1]
