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Hydrogen peroxide (hydrogen peroxide), 2 2 is the simplest representative of peroxides. Colorless liquid with "metal" taste, unlimited soluble in water, alcohol and ether. Concentrated aqueous solutions are explosive. Hydrogen peroxide is a good solvent. From the water is distinguished in the form of an unstable crystalline H 2 O 2 2H 2 O.
Hydrogen peroxide molecule has the following structure:
Physical properties
Pure hydrogen peroxide is very different from a familiar to all 3% solution H 2 O 2, which stands in a home first aid kit. First of all, it is almost one and a half times heavier than water (density at 20 ° C is 1.45 g / cm3). It freezes H 2 O 2 at a temperature, slightly smaller than the water freezing temperature - with minus 0.41 ° C, but if they quickly cool the clean fluid, it usually does not freeze, and is translated, turning into a transparent glassy mass. H 2 O 2 solutions are freezed at a significantly lower temperature: 30% solution - with minus 30 ° C, and 60% - with minus 53 ° C. Ring H 2 O 2 at a temperature higher than ordinary water, - at 150.2 ° C. wets the glass H 2 O 2 worse than water, and this leads to an interesting phenomenon with a slow distillation of aqueous solutions: while water is distilled off from the solution, it, as usual, comes from the refrigerator to the receiver in the form of droplets ; When H 2 O 2 begins to distils, the liquid comes out of the refrigerator in the form of a continuous thin flowing. On the skin, pure hydrogen peroxide and its concentrated solutions leave white spots and cause a feeling of burning pain due to a strong chemical burn.
Pure H 2 O 2, like sugar syrup, strongly refracts light. Indeed, the refractive index of anhydrous H 2 O 2 (1.41) is much larger than that of the water (1.33). However, either as a result of the wrong interpretation, or because of the poor translation from French, almost in all textbooks still write that the pure hydrogen peroxide is "thick syrup-like liquid", and even explain it to theoretically - the formation of hydrogen bonds. But the water also forms hydrogen bonds. In fact, the viscosity of H 2 O 2 is the same as in a slightly cooled (about 13 ° C) of water, but it cannot be said that cool water is thick, like syrup.
2N 2 O 2 → 2H 2 O + O 2
However, very pure hydrogen peroxide is stable.
Hydrogen peroxide exhibits very weak acid properties (K \u003d 1.4 · 10 -12). Under the action of a concentrated solution, H 2 O 2 on hydroxides in some cases, metal peroxides (Li 2 O 2, MgO 2, etc.) can be distinguished:
H 2 O 2 + 2NAOH → Na 2 O 2 + 2H 2 O
The peroxide group is -O-one in many substances. Such substances are called peroxides, or peroxide compounds. These include metals peroxides (Na 2 O 2, Bao 2, etc.), which can be considered as hydrogen peroxide salts. Acids containing a peroxide group are called peroxocosloids, for example, peroxomonophosphoric H 3 PO 5 and peroxide-sized H 2 S 2 O 8 acid.
Redox Properties
Hydrogen peroxide has strong oxidative, as well as reducing properties. It oxidizes nitrites into nitrates, it allocates iodis from metals iodides, splits unsaturated compounds at the place of double ties. Hydrogen peroxide restores the salt of gold and silver, as well as oxygen when reactions with potassium permanganate aqueous solution in an acidic environment.
When restoring H 2 O 2, H 2 O or it is formed, for example: H 2 O 2 + 2KI + H 2 SO 4 \u003d I 2 + K 2 SO 4 + 2H 2 O
Under the action of strong oxidizing agents H 2 O 2, it shows reducing properties, highlighting free oxygen:
O 2 2- - 2E - → O 2
The KMNO 4 C H 2 O 2 reaction is used in chemical analysis to determine the content H 2 O 2:
5H 2 O 2 + 2KMNO 4 + 3H 2 SO 4 → 5O 2 + 2MNSO 4 + K 2 SO 4 + 8H 2 O
The oxidation of organic compounds of hydrogen peroxide (for example, sulfides and thiols) is advisable to carry out in the medium of acetic acid.
Biological properties
The hydrogen peroxide refers to the reactive forms of oxygen and at elevated formation in the cell causes oxidative stress. Some enzymes, such as glucosoxide, form during the oxidative reducing reaction hydrogen peroxide, which can play a protective role as a bactericidal agent. There are no enzymes in mammalian cells that would restore oxygen to hydrogen peroxide. However, several enzyme systems (xanthine oxidase, over (φ) h-oxidase, cyclicoxygenase, etc.) produce a superoxide, which spontaneously or under the action of superoxiddismutase turns into hydrogen peroxide.
Obtaining
Hydrogen peroxide is obtained in industry by reaction with the participation of organic substances, in particular, the catalytic oxidation of isopropyl alcohol:
(CH 3) 2 CH (OH) + O 2 → CH 3 C (O) CH 3 + H 2 O 2
Acetone is a valuable by-product of this reaction.
In laboratory conditions, a reaction is used to obtain hydrogen peroxide
Bao 2 + H 2 SO 4 → H 2 O 2 + BASO 4
Concentration and purification of hydrogen peroxide are carried out by careful distillation.
Application
3% hydrogen peroxide solution
Due to its strong oxidative properties, hydrogen peroxide has found widespread use in everyday life and in industry, where it is used, for example, as a bleach in textile production and paper manufacturing. It is used as rocket fuel - as an oxidizing agent or as a single-component (with decomposition on the catalyst). Used in analytical chemistry, in medicine, as a foaming agent in the production of porous materials, in the production of disinfectants and bleaching agents. In the industry, hydrogen peroxide also finds its use as a catalyst, a hydrogenant agent as an epoxidizing agent in the epoxidation of olefins. In medicine, hydrogen peroxide solutions are used as an antiseptic agent. Upon contact with damaged skin and mucous membranes, hydrogen peroxide under the influence of the catalase enzyme decomposes with the release of oxygen, which contributes to the collapse of the blood and creates unfavorable conditions for the development of microorganisms. However, such an action is short and possesses a weak effect. However, hydrogen peroxide (pharmacy name - hydrogen peroxide, 3%) is used for primary processing of wounds (including open). Hydrogen peroxide is very effective for the treatment of small scratches, especially in children - it is not a "pinlet", there is no smell, colorless. However, it can cause a slight burning in the area of \u200b\u200ban open wound. The cost of a bubble of such a solution (for 2009) is about 6 rubles. In the food industry, hydrogen peroxide solutions are used to disinfect technological surfaces of equipment directly contact with products. In addition, in enterprises for the production of dairy products, juices, hydrogen peroxide solutions are used to disinfect packaging (Tetra Pak technology). For technical purposes, hydrogen peroxide is used in the production of electronic technology.
Forms of release
Produced in the form of aqueous solutions, standard concentration 3, 30, 38, 50, 60, 85, 90 and 98%. 30% aqueous hydrogen peroxide solution stabilized by the addition of sodium phosphates is called pergel.
Danger of application
Despite the fact that hydrogen peroxide is not toxic, its concentrated solutions when entering the skin, mucous membranes and in the respiratory tract causes burns. In large concentrations, no pure hydrogen peroxide can be explosive.
Links
Literature
- Akhmetov N.S. "General and Inorganic Chemistry" M.: Higher School, 2001
- Karapetyanz M.Kh. Drakin S.I. General and inorganic chemistry. M.: Chemistry 1994
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Watch what is "hydrogen peroxide" in other dictionaries:
HYDROGEN PEROXIDE - (Hydrogenium Hy Peroxy Datum, Hydrogenium Peroxy Datum), H202, syrup-like liquid, transparent, in thin layers colorless, in thick blue color, in 1x / 2 times heavier than water, metal acute taste, dissolves in any respect to ... ... Big medical encyclopedia
HYDROGEN PEROXIDE - colorless liquid; well mixed with water; It is used as a disinfectant (for rinsing the throat, with small cuts, etc.) and whitening means. Used to bleach cotton, flax, woolen and silk fabrics, feathers and ... Brief Encyclopedia
- (H2O2), a liquid consisting of hydrogen and oxygen is usually sold in aqueous solutions. The peroxide is obtained by electrolytic oxidation of sulfuric acid and methods based on the reduction of oxygen. The hydrogen peroxide solution is used ... ... Scientific and Technical Encyclopedic Dictionary
Hydrogen peroxide, the same as hydrogen peroxide ... Modern encyclopedia
Same as hydrogen peroxide ... Big Encyclopedic Dictionary
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Hydrogen peroxide - hydrogen peroxide, the same as hydrogen peroxide. ... Illustrated Encyclopedic Dictionary
hydrogen peroxide - inorganic substance, quickly decomposing in the body (under the action of catalase enzyme) to form molecular oxygen: H2O2. [Arefiev V.A., L. L. L. Anglo Russian Dictionary of Genetic Terms 1995 407s.] Themes ... ... Technical translator directory
I (tech) finds recently use in fairly broad sizes for silk and woolen products, as well as feathers. Compared to the sulfuric acid that has long been used for this purpose, hydrogen peroxide whitens ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
See hydrogen peroxide. * * * Hydrogen peroxide peroxide hydrogen peroxide, the same as hydrogen peroxide (see hydrogen peroxide) ... encyclopedic Dictionary
Hydrogen peroxide (hydrogen peroxide), H 2 O 2 is the simplest representative of peroxides. Colorless liquid with "metal" taste, unlimited soluble in water, alcohol and ether. Concentrated aqueous solutions are explosive. Hydrogen peroxide is a good solvent. From the water is distinguished in the form of an unstable crystalline H 2 O 2 2H 2 O.
The structure of the molecule
H 2 O 2 molecule contains in its composition peroxide anion O 2 -2. Each oxygen atom forms 2 covalent bonds, but has a degree of oxidation equal to -1. In a simplified form, the structure of the molecule reflects the graphic formula:
H +1 -O -1 -O -1 -H +1
Physical properties
In a clean anhydrous form H 2 O 2 - Beszlev. Syropo-shaped liquid with a density of 1.45 g / cm 3 (m. pl. -0.41 ° C, t. Kip. 150.2 ° C). Mixed with water in any ratios, is also dissolved in alcohol, ether. 30% rr H 2 O 2 is called perhydro. Like water, H 2 O 2 is a good polar solvent, in which substances with ion and polar covalent bond dissociate into ions.
Chemical properties
Decomposition H 2 O 2 (Disproportionation)
2N 2 O 2 \u003d 2N 2 O + O 2
2O -1 - 2E - → O 2 0
2O -1 + 2e - → 2O -2
At T\u003e 90 ° C hydrogen peroxide decomposes almost completely. The cause of the fragility of H 2 O 2 molecules is the instability of an oxygen atom in oxidation -1 precipitation.
H 2 O 2 - Weak Acid
H 2 O 2 molecules are slightly dissociated in an aqueous solution according to the scheme:
H 2 O 2 \u003d H + + HO 2 -
(To diss \u003d 1.5 * 10 -12 at 20 ° C)
Acid properties are manifested in alkalis reactions to the formation of salts - medium (peroxides) and acidic (hydroperoxides), for example:
H 2 O 2 + VA (OH) 2 \u003d Wao 2 + 2N 2 O Peroxide Barium
Metal peroxide hydrolysis
Although the composition of peroxides resemble oxides, they actually possess the properties of salts. In aqueous solutions, it is completely hydrolyzed with highlighting H 2 O 2:
K 2 O 2 + 2N 2 O \u003d 2CON + H 2 O 2
Getting H 2 O 2 of Metal Peroxides
Since H 2 O 2 is very weak acid, it is supplanted from their salts as strong acids and weak, for example:
Wao 2 + H 2 SO 4 \u003d H 2 O 2 + BASO 4 ↓
Wao 2 + CO 2 + H 2 O \u003d H 2 O 2 + VOO 3 ↓
H 2 O 2 strong oxidizer
Oxygen atoms that are in an unstable degree of oxidation -1 seek to acquire another electron to go to a steady state. Therefore, hydrogen peroxide exhibits very strong oxidative properties, especially in an acidic environment:
H 2 O - 2 + 2H + + 2E - → 2N 2 O -2
Oxidation of inorganic substances
ZN 2 O 2 + 2NH 3 \u003d N 2 + 6N 2 O
4N 2 O 2 + H 2 S \u003d H 2 SO 4 + 4N 2 O
H 2 O 2 + 2HI \u003d I 2 + 2N 2 O
4N 2 O 2 + PBS \u003d PBSO 4 + 4N 2 O
ZN 2 O 2 + 2CRSL 3 + 10CON \u003d 2K 2 SRO 4 + 6KCL + 8H 2 O
H 2 O 2 + 2FESO 4 + H 2 SO 4 \u003d Fe 2 (SO 4) 3 + 2N 2 O
Oxidation of organic substances
Conc. Aqueous solutions H 2 O 2 in a mixture with organic substances are capable of ignition and explosion when hitting. For example, organic acids are oxidized to CO 2 and H 2 O (as when burning in O 2):
4N 2 O 2 + CH 3 COOH \u003d 2CO 2 + 6N 2 O
H 2 O 2 + H 2 C 2 O 4 \u003d 2CO 2 + 2N 2 O
Slate peroxides. ME - very strong oxidizers
Oxidize many inorganic and organic substances, for example:
4NA 2 O 2 + CH 3 coxy \u003d 2NA 2 CO 3 + 4NAOH
Na 2 O 2 + SO 2 \u003d Na 2 SO 4
An important reaction is the disproportionation of peroxide Na when interacting with carbon dioxide:
2NA 2 O 2 + 2CO 2 \u003d 2NA 2 CO 3 + O 2
On this reaction, the use of Na 2 O 2 in autonomous respiratory devices and in closed rooms for absorbing CO 2 and Education O 2 is based.
H 2 O 2 is a weak reducing agent (in reactions with very strong oxidizing agents)
The oxidation of hydrogen peroxide usually flows according to the scheme:
2N 2 O - 2 - 2E - → O 0 2 + 2H +
Examples of reactions:
5N 2 O 2 + 2kmno 4 + 3H 2 SO 4 \u003d 5O 2 + 2MNSO 4 + K 2 SO 4 + 8H 2 O
ZN 2 O 2 + K 2 CR 2 O 7 + 4H 2 SO 4 \u003d 3O 2 + CR 2 (SO 4) 3 + K 2 SO 4 + 7N 2 O
3H 2 O 2 + KCLO 3 \u003d 3O 2 + KCL + 3N 2 O
3H 2 O 2 + 2AUCL 3 \u003d 3O 2 + 2AU + 6HCl
Probably it is difficult to find a person who would never have come across in life with hydrogen peroxide, because small bottles of dark glass are almost every first-aid kit. It may seem that hydrogen peroxide is completely harmless and is absolutely necessary in every home. But if, about its need, questions do not arise, then about absolute harmlessness they still have - this is a substance, despite its seeming simplicity, still causes a living interest, and even disputes ...
By the way, it is interesting where the hydrogen peroxide came from, because in nature the substance with the chemical formula H 2 O 2 does not exist ... The history of the peroxide began almost two hundred years ago, in the already distant 1818, when the Frenchman Louis Tenaro, spending chemical experiments with different substances, decided Connect barium peroxide and sulfuric acid.
It is as a result of this chemical reaction that a substance was obtained, very similar to ordinary water, but differing from water, which was one and a half times harder, evaporated noticeably slower and in any proportions could be dissolved in ordinary water. The new substance got the name "Oxidized Water".
Louis Tenero and other chemists became interested in an unstable and easily disintegrating substance and continued experiments. Industrial production of substances with the chemical formula H 2 O 2 began in 1873 in Berlin, but the shelf life of the resulting fluid remained very small and did not exceed two weeks.
Interestingly, during World War II, German scientists were able to create a fighter, developing speeds almost up to a thousand kilometers per hour and operating on a substance that was obtained as a result of a chemical reaction of hydrogen peroxide and methanol. In addition, the peroxide (peroxide) of hydrogen with a concentration of 80% was used in ballistic missiles ...
So the fate of the most ordinary and long ago all acquaintance of hydrogen peroxide was not easy and rather entertaining. So, hydrogen peroxide: the benefits and harm of this, at first glance, a very simple substance.
Use of hydrogen peroxide
Hydrogen peroxide, the chemical formula of which H 2 O 2 , upon contact with water, disintegrates to the components, that is, water and oxygen, so hydrogen peroxide is completely considered an environmentally friendly substance that cannot cause any harm to the environment.
As for the unconditional benefit of hydrogen peroxide, it is, first of all, its use for medical purposes. As you know, according to official recommendations, for medical purposes, 3 percent hydrogen peroxide is used, and the appointment of this means is extremely external - processing of minor skin damage (abrasion, scratches, wounds of small size), stopping minor bleeding, as well as use for rinsing with stomatitis.
What explains the effect of disinfection, which has a hydrogen peroxide on various damage to the skin? The disinfection (antiseptic) effect is explained by the fact that the oxygen appears when the hydrogen is in contact with the skin (foam appears), and, as a result, the wound gets the opportunity to clean the mechanical method - the resulting oxygen foam cleans the wound simply mechanically, washing the microbes, dirt and even necrotic Education that could already appear in the wound.
Composition of hydrogen peroxide 3% (Hydrogen Peroxide)
However, hydrogen peroxide cannot be considered the only and fully reliable way to clean the wounds, since the antibacterial effect of this fund is quite short. In addition, some microorganisms on hydrogen peroxide react in any way, because they have resistance to this tool, which is explained by the presence of enzymes that simply destroys the peroxide.
Also, some people, including some medical workers, believe that it may be useful to use hydrogen peroxide 3% inside. As an explanation, the argument is put forward that any human body cells constantly need oxygen, namely oxygen and is released during the decay of the peroxide.
Opponents of this method of applying hydrogen peroxide suggest that during the decay of hydrogen peroxide to the body, not only molecular oxygen falls, but also free radicals that are capable of destroyably acting on any protein formation in the body and even devastively to the cellular structure.
Researchers report that it is free radicals that are in the body that are able to cause the development of very serious diseases, including atherosclerosis, diabetes and even oncological diseases.
Researchers also warn that free radicals adversely affect cell division, slowing down this process, the consequence of which becomes earlier aging of the skin, and any wound surfaces, injuries and damage are healing for a longer time.
Processing of wounds using hydrogen peroxide
Traditionally, a three-percent solution of hydrogen peroxide is handled small and shallow wound surfaces. However, the results of some studies argue that such a method for processing wounds, although it cleans the wound, and also disinfects it, but still slows down healing. That is, really good cleansing abilities of hydrogen peroxide (peroxide) do not have a positive impact on healing any wound surfaces, including even conventional abrasions.
The studies found that those concentrations of hydrogen peroxide, which can provide antiseptic (disinfection) effect, are able to damage the cells that are adjacent to the wound, and that is why it takes a longer time for healing. In addition, convincing evidence appeared that hydrogen peroxide could lead to the destruction of the newly formed cell cover cells, so the wound healing is complicated and slows down, and scars are formed on the skin.
But medicine cannot refuse the use of hydrogen peroxide for the process of high-quality processing of the Russian Academy of Sciences, especially if it concerns wounds of complex, deep or any purulent - precisely in such cases the peroxide (peroxide) of hydrogen remains a preparation of the first choice, that is, it is precisely a hydrogen peroxide to give preference before Other antiseptic means.
This is explained not only by the ability of the antiseptic, that is, the disinfectant, exposure, but also in the fact that, as a result of the use of hydrogen peroxide, a significant amount of foam appears due to the interaction with peroxidase (enzyme). Namely, the resulting foam softens and makes it possible to practically painlessly separate from the living tissues of the pus, blood clot, dead (necrotized) tissue sites.
Softened and separated from living fabrics dangerous for wound elements are easily squared from the wound using an antiseptic solution used in a particular case. But from the thoroughly non-treated hydrogen peroxide wounds, dead particles and pathological formations are extremely difficult to remove, which worsens the wound condition and the state of the victim, and also increases the time that is required for healing.
Researchers and clinical doctors warn that processing the skin and the wound surfaces of hydrogen peroxide should be very neat and very important not to overdo it, since hydrogen peroxide not only destroys bacteria, but also can destroy the living cells of the body, thereby destroying the protective layer formed on skin. As a result, too frequent or too active the use of hydrogen peroxide, even with the most good intentions, makes the skin more sensitive, in addition, the skin becomes vulnerable to the effects of malicious microorganisms: microbes, viruses and bacteria.
Attention! Using hydrogen peroxide, it is necessary to process complex (especially purulent) wounds that need careful cleaning. Simple and shallow wounds of hydrogen peroxide treatment do not require - for their processing, other antiseptic (disinfection) means can be used.
Rinsing hydrogen peroxide
In addition to other types of use of the beneficial properties of hydrogen peroxide, this substance is used to rinse the throat in case of diseases of the angina of any etiology or pharyngitis in order to reduce pain and speed up the process of recovery.
It should be noted that with any inflammatory processes that occur in the throat, it is very important that the mucous membrane of the throat receives sufficient moisture and did not swap, and so that different pathogenic microorganisms be removed from the surface of the mucously, including microbes and viruses, which will significantly accelerate recovery.
Disinfectants and purifying properties of hydrogen peroxide are widely used in various fields of medicine, including in LOR-Practice in the treatment of throat disease.
Otolaryngologists doctors can recommend hydrogen peroxide for local use as an antiseptic agent in treating diseases such as distinction of different etiology (especially often for the treatment of purulent angina); Faringitis, colds, in which the throat is damaged, as well as in the treatment of stomatitis of various etiology.
All listed diseases combines one feature - on the mucous membrane of the throat or on the mucous membrane of the surface of the oral cavity can be formed, in which purulent contents are assembled, as well as a small amount of blood and some substances having a protein nature. IN
on the time of rinsing the throat and the oral cavity with a solution of peroxide (peroxide) of oxygen, that is, at the contact of this chemical with damaged surfaces, the reaction of the release of active oxygen begins and foam is formed; As a result of this, the throat and oral oxygen in the mucous membranes and the oral oral cavity are separated from the purulent contents, from blood and blood clots, as well as from any protein nature substances that interfere with wound healing and recovery.
Hydrogen peroxide is very effective if it becomes necessary to remove the flare from the almond surface in the throat.
Of course, the use of hydrogen peroxide in the treatment of diseases of the throat and the oral cavity is reduced only to mechanical effects on purulent formations and on the accumulation of pus, which simply wash out from the surface of the mucous membrane and are removed.
However, it is precisely the mechanical removal of malicious purulent formations that it is very important that the body can more effectively deal with any infection, since the procedures with hydrogen peroxide reduce the amount of infectious agents and are able to significantly reduce intoxicating the body and its consequences.
However, when ringed the throat using hydrogen peroxide, some rules should be followed.
In order for hydrogen peroxide to rinse the throat, 3% hydrogen peroxide must be diluted in water. It is necessary because it is possible to damage the throat even stronger, which will require a long and complex treatment.
For the preparation of safe for the throat, but effective when combating malicious microorganisms of the solution should be taken 100 ml of boiled and chilled water and dissolve a tablespoon (but not more than!) Conventional three-percent hydrogen peroxide. Use for rinsing throats a stronger solution is prohibited because it is dangerous!
Alternatively, you can use hydroperite tablets. To obtain a solution suitable for rinsing, one tablet of this substance must be dissolved in boiled and cooled water, which will require 200 ml.
- Rule number 1. Rinse the throat with a solution of hydrogen peroxide can not be more common than once every three hours. A total of four to five rinsings should be carried out during the day.
- Rule number 2 (this is very important!).
After rinsing the throat and oral cavity with a solution of hydrogen peroxide, it is necessary to rinse immediately (rinse) throat and oral cavity with another solution to wash the foam in which infectious agents have already been dissolved and to completely clean the throat.
Also, an additional rinse neutralizes the action of hydrogen peroxide on the mucous membranes of the oral cavity and throat, and they are not damaged.
To carry out additional rinsing of the throat after the procedures using hydrogen peroxide solution, you can rinse the throat with a solution of soda, herbal decoction (use for the preparation of chamomile, sage and other herbs); of a weak solution (barely pink) permanganate potassium (manganese); Seawater (water with dissolved sea salt) or even with the help of conventional boiled and cooled water.
Rinsing with hydrogen peroxide should be carried out until the almonds are cleaned of the plaque, that is, the formation of purulent content will not stop.
In addition to rinsing with a solution of hydrogen peroxide, with tonsillitis and other infectious diseases, the doctor sometimes prescribes the almond lubrication with a solution of hydrogen peroxide, however, a more concentrated solution of the drug is used to lubricate almonds.
The concentrated solution of hydrogen peroxide preparation for lubricating certain parts of the throat (in particular almonds) is also easy to prepare. To do this, in 100 ml of warm boiled water, three tablespoons of three percent hydrogen peroxide should be dissolved. The resulting solution should be lubricated by almonds using special cotton wands. In addition, the same solution can be applied to patients with almonds using them with cotton swabs, which were pre-moistened in a cooked solution.
Attention! Hydrogen peroxide is a very strong oxidizing agent, and even the use of solutions require increased caution. If with the help of a hydrogen peroxide solution, the throat is carried out, it should be remembered that this solution should be swallowed. For young children, rinse the throat with hydrogen peroxide is completely unacceptable!
Use to treat the throat of hydrogen peroxide solutions is completely unacceptable, if it is known about the individual intolerance to this drug or an allergic response to the drug is possible.
As for undesirable reactions, such as burning or any damage to the mucous membrane of the throat due to the use of rinsing with hydrogen peroxide, then such unwanted reactions are completely excluded if the solutions are prepared correctly (that is, no more peroxide has been used than necessary), as well as If the procedure is performed not more than appointed the attending physician.
The use of peroxide in industry and in everyday life
Of course, such a unique oxidizing agent like hydrogen peroxide is used in a variety of industrial industries and in various spheres of everyday life.
The main scope of the application of hydrogen peroxide is the whitening of various materials, and not at all medicine, where the extremely minor part of this drug is used.
Why does the industry prefers to use hydrogen peroxide for bleaching procedures? The fact is that this oxidizing agent has a very soft effect and does not have any harmful effect directly on the material that blends, that is, does not damage its structure.
Another important feature of hydrogen peroxide when using it in industrial processes is that the use for bleaching hydrogen peroxide does not cause any harm to the environment, that is, the use of this substance is not able to worsen the environmental situation. After all, bleaching, in fact, is produced using oxygen, so neither the contamination of the atmosphere nor the pollution of water resources is simply impossible. That is why many productions, including cellulose combines, refused to whiten by their products using chlorine, which was used to be used for this purpose.
It was also repeatedly noted that even at home bleaching with chlorine is extremely undesirable because it is unsafe for health, destroys fabrics, and the effect is far from ideal. However, recently there have been a lot of anti-oxygen-based means in which all the same hydrogen peroxide has been operating. Such a wash is much more effective, safer, fabrics are preserved longer, and an unpleasant smell, as when bleaching chlorine, is absent at all.
Any woman knows another way of applying hydrogen peroxide - hair lightening. And although the industry offers a considerable amount of various colors for hair, however, hydrogen peroxide (hydroperite) remains a very popular means, especially considering not only its effectiveness, but also low cost.
A very important scope of hydrogen peroxide is an industry where hydrogen peroxide solutions in a very large concentration (more than 80%) are used as a source of energy and even as an oxidizing agent for reactive fuel.
The chemical industry uses hydrogen peroxide in the production of polymeric materials, including some porous substances.
Found the use of hydrogen peroxide and in the wine industry, where it is successfully used for rapid artificial aging of wines.
An important sphere of application of hydrogen peroxide remains textile production and pulp and paper industry, where the fabrics and paper are whitched with peroxide.
As for the use of hydrogen peroxide into everyday life, this substance is known as a very effective cleaning agent. With the help of hydrogen peroxide, you can purify the plumbing sinks, surfaces of pipes and even furniture surfaces.
Many hostesses use hydrogen peroxide as a perfectly proven tool for washing the floor - for this in four liters of hot water, about a third or quarter of a glass (100-150 g) peroxide should be dissolved.
Attention! When using hydrogen peroxide in everyday life should not forget that this substance is heavier than water by about one and a half times.
If fungus and mold appeared in the dwelling, then you can fight them too with all the same peroxide. To obtain a positive result, pour two parts of water in the household sprayer and one part of the peroxide (by volume) and spray the mixture on the infected with fungus surface. Ten minutes later, the surface must be carefully cleaned.
In the kitchen, hydrogen peroxide also does not remain without work. This substance has proven itself when washing dishes. To do this, about 100 g of peroxide should be added to the water sink and then wash the dishes, as usual.
It is very useful to process hydrogen peroxide cutting boards, especially for fish and meat - such treatment will destroy all dangerous microorganisms on the boards, viruses and bacteria, including salmonella, which is very dangerous to health.
It is recommended to use hydrogen peroxide for sanitary wrap, especially toilet. In order for the toilet to become truly clean, the hydrogen peroxide and clean water should be mixed in an equal proportion and spray the resulting mixture on the toilet surface, after which it is washed off with water. Any microbes cannot withstand contact with hydrogen peroxide, that is, with ordinary peroxide.
Hydrogen peroxide can be useful to maintain the necessary cleanliness and to disinfect the toothbrush, on the surface of which a variety of pathogens can be collected. To get rid of unnecessary microorganisms, a toothbrush is useful from time to time to hold in a three-percent solution of hydrogen peroxide (for no more than two minutes), and then thoroughly rinse with running water.
Hydrogen peroxide is useful and in the kitchen to save longer some products. For this, hydrogen peroxide should be mixed with water in equal proportion and spray fruits and vegetables from the sprayer, which should then be thoroughly penetrated in flow water. Thus processed products will be stored for a longer time.
To maintain the purity of the kitchen sponge, it should also be omitted in the same (1: 1) solution of hydrogen peroxide. Then the sponge should be carefully rinsed and dried, and only then continue to use.
Attention! Applying hydrogen peroxide For teeth whitening, specialists are not categorically recommended, since the whitening effect is based on oxidative processes that inevitably lead to the destruction of tissues, including tooth tissues.
Hydrogen peroxide is widely used in the food industry, since it allows to effectively and safely disinfect equipment (its technological surfaces). In the production of fruit and vegetable juices and dairy products, which are packaged in cardboard packages "Tetra Pak", hydrogen peroxide is used as disinfector.
Interesting! In the aquarium, a three-percent solution of hydrogen peroxide (peroxide) is used to clean the aquariums from unwanted microorganisms and even for resuscitation of the aquarium fish ingred from the lack of oxygen.
Hydrogen peroxide
As for the use of hydrogen peroxide in the country areas, then, of course, this tool is necessary for the processing of injuries obtained, which are very likely in the country.
But the use of this tool in the country conditions is not limited to medical purposes.
Experienced gardeners and amateur gardeners argue that watering plants with a weak solution of hydrogen peroxide improves the growth and condition of any plant.
To prepare a solution for watering, a 25 g of a three-percent hydrogen peroxide solution should be dissolved in a liter of pure water. The resulting agent can be used not only for watering plants, but also in order to spray trees and bushes - thus, it is possible to avoid many diseases of garden and garden plants.
Also, experienced gardeners are advised to soak in a solution of hydrogen peroxide seeds before planting - for the faster germination. To prepare a solution desired to soak the seed, 25 g of three percent peroxide is mixed with 500 ml of water. Pumping seeds should not be short - no more than three hours.
Attention! When preparing solutions for garden work, it should be remembered that hydrogen peroxide is one and a half times heavier than water, therefore 25 g of peroxide is not 25 ml, as in the case of water, but only about 16 ml.
Some gardeners argue that hydrogen peroxide helps and sick garden trees. In order for the trees to feel better, it is necessary to prepare the so-called peroxidant water, for which one part of hydrogen peroxide should be mixed with 32 parts of water, and then this mixture it is necessary to spray unhealthy trees.
Another way to apply hydrogen peroxide in the country area is the preparation of animal feed. It's no secret that there remains the tops of various plants on the household plots, then straw, then some other waste. It's a pity to throw away all this, and the compost pits are far from all. But it's not so difficult to turn these diverse residues to nutritional food for domestic animals. To do this, it is necessary, for example, a straw or tops to soak in a solution of hydrogen peroxide. A few hours in such a solution makes food much more attractive for pets, because it becomes more nutritious and digested significantly easier.
Harp of hydrogen peroxide
When people with delight use the beneficial properties of peroxide, then they often forget that this substance may not only be useful, but also dangerous because it is a very strong oxidizing agent. It does not interfere with paying attention to what proportion even a three-percent solution of peroxide should be breed, which means that it is not so safe this substance.
Of course, if the hydrogen peroxide is used only for processing wound surfaces, there are no special problems foreseen. The main thing is not to overdo it and do not process the wound too actively or too often.
However, many people believe that the body is simply needed to receive hydrogen peroxide inside and that this simple means can become a real panacea from all diseases, since blood can, therefore, can obtain additional oxygen. Is it really? We should not forget that hydrogen peroxide is the most powerful oxidant and that even for external use is used in very strong dilution. Moreover, even the external hydrogen peroxide is used only to stop the blood and clean the wound - the oxidative properties of the peroxide do not allow this tool to accelerate the healing of any wounds, but slow down the healing process is a means if it can be easily used, may well.
As for the reception of hydrogen peroxide inside, it should not be forgotten that the reception of this substance may cause very negative phenomena, among which vomiting or simply nausea, and skin rash and other allergic reactions, and sleep disorders, and other neurological symptoms are noted.
The concentrated solutions of hydrogen peroxide (hydrogen peroxide) are very dangerous - they are caused by burns, and sometimes quite serious (in pharmacy institutions, hydrogen peroxide is most often sold in pharmacy institutions). Among other things, it does not hurt to keep in mind that hydrogen peroxide in pure form (the so-called pure hydrogen peroxide) is an explosive substance capable of simultaneously separating large amounts of free oxygen.
Doctors warn against attempts to take inside the concentrated solutions of hydrogen peroxide, since their action resembles the action of alkalis and can lead to serious destructive (destructive) changes in the body, including the fatal outcome. A lethal dose is the amount of from 50 to 100 ml of a thirty-percent solution of hydrogen peroxide (perhydron, hydrogen peroxide), which has fallen inside the organism (esophagus, gastrointestinal tract).
What treats hydrogen peroxide?
An excellent report of Professor Medicine Neumyvakin I.P. About what is treated with hydrogen peroxide. We look:
conclusions
Open in distant 1818 by the French chemist Louis Tenaro of hydrogen peroxide today became something ordinary and familiar. Abrasion? Run per peroxide? Draw, bite or some other wound?
At first, the peroxide is urged to the aid and only the other options for salvation are searched. And at the cottage, and in the cabinet aquarium, and when cleaning the house, hydrogen peroxide is indispensable. But it is not necessary to forget that this is the familiar substance from childhood is not such a harmless and non-hazardous, as any product of chemistry, like any drug. Peroxide is so easy ...
But it should not forget that peroxide is very difficult and even sometimes deadly. And in this case it is very appropriate to the expression of the most famous medieval doctor of Paracelsa, who argued that the medicine and poison differ only for a dose. What is there to add? Is that, in addition to a dose, in the case of peroxide is no less important and method of use.
Hydrogen peroxide- (The old name is hydrogen peroxide), the compound of hydrogen and oxygen H 2 O 2, containing a record amount of oxygen - 94% by weight. In molecules, H 2 O 2 contains peroxide groups -O-O- ( cm. Peroxidians), which largely determine the properties of this compound.
For the first time, hydrogen peroxide received in 1818 French chemist Louis Jacques Tenar (1777 - 1857), acting a strongly cooled hydrochloric acid for barium peroxide:
Bao 2 + 2HCl BACL 2 + H 2 O 2. Barium peroxide, in turn, received the burning of the metal barium. To release from the solution, H 2 O 2 TENAR removed from it the resulting barium chloride: BACL 2 + AG 2 SO 4 2AGCl + BASO 4. In order not to use the expensive silver salt subsequent to obtain H 2 O 2, sulfuric acid was used: Bao 2 + H 2 SO 4 Baso 4 + H 2 O 2, since at the same time barium sulfate remains in sediment. Sometimes another method was used: carbon dioxide was passed into the suspension of WAO 2 in water: Bao 2 + H 2 O + CO 2 Baco 3 + H 2 O 2, since barium carbonate is also insoluble. This method proposed the French chemist Antoine Zherom Barlar (1802-1876), famous for the discovery of a new chemical element of bromine (1826). More exotic methods were used, for example, the effect of an electric discharge on a mixture of 97% oxygen and 3% hydrogen at a temperature of liquid air (about -190 ° C), so 87% H 2 O 2 was obtained.
Concentrated H 2 O 2 by cautious evaporation of very pure solutions on a water bath at a temperature not higher than 70-75 ° C; So you can get about 50% solution. It is impossible to heat more - it is decomposition of H 2 O 2, therefore the water was distilled off under reduced pressure, using a strong difference in the pressure of vapors (and, therefore, at the boiling point) H 2 O and H 2 O 2. So, at a pressure of 15 mm Hg.st. First, water is distilled off mainly, and at 28 mm Hg. and a temperature of 69.7 ° C, pure hydrogen peroxide is distilled off. Another method of concentration is freezing, since when you freezing weak solutions, the ice almost does not contain H 2 O 2. You can finally dehydrate the absorption of water vapor with sulfuric acid in the cold under a glass bell.
Many researchers of the 19th century, who received pure hydrogen peroxide, noted the danger of this compound. So, when they tried to separate H 2 o 2 of the water by extraction from dilute solutions with diethyl ether, followed by distillation of a flying ether, the resulting substance sometimes exploded without visible reasons. In one of these experiments, the German chemist Yu.V. Bruil received anhydrous H 2 O 2, which had the smell of ozone and exploded against the touch of an unknown glass stick. Despite the small quantities H 2 O 2 (only 1-2 ml), the explosion was such a force that struck the round hole in the table board, destroyed the contents of its drawer, as well as on the table and nearby flasks and appliances.
Physical properties.Pure hydrogen peroxide is very different from a familiar to all 3% solution H 2 O 2, which stands in a home first aid kit. First of all, it is almost one and a half times heavier than water (density at 20 ° C is 1.45 g / cm 3). It freezes H 2 O 2 at a temperature of a bit less than water freezing - with minus 0.41 ° C, but if it is quickly cooling a clean liquid, it usually does not freeze, and is translated, turning into a transparent glassy mass. H 2 O 2 solutions are freezed at a significantly lower temperature: 30% solution - with minus 30 ° C, and 60% - with minus 53 ° C. Ring H 2 O 2 at a temperature higher than ordinary water, - at 150.2 ° C. wets the glass H 2 O 2 worse than water, and this leads to an interesting phenomenon with a slow distillation of aqueous solutions: while water is distilled off from the solution, it, as usual, comes from the refrigerator to the receiver in the form of droplets ; When H 2 O 2 begins to distils, the liquid comes out of the refrigerator in the form of a continuous thin flowing. On the skin, pure hydrogen peroxide and its concentrated solutions leave white spots and cause a feeling of burning pain due to a strong chemical burn.
In the article on obtaining hydrogen peroxide, Tenar did not very well compared this substance with syrup, perhaps he meant that it was pure H 2 o 2, like sugar syrup, strongly refracts the light. Indeed, the refractive index of anhydrous H 2 O 2 (1.41) is much larger than that of the water (1.33). However, either as a result of the wrong interpretation, or because of the poor translation from French, almost in all textbooks still write that the pure hydrogen peroxide is "thick syrup-like liquid", and even explain it to theoretically - the formation of hydrogen bonds. But the water also forms hydrogen bonds. In fact, the viscosity of H 2 O 2 is the same as in a slightly cooled (about 13 ° C) of water, but it cannot be said that cool water is thick, like syrup.
Reaction decomposition.Pure hydrogen peroxide - the substance is very dangerous, since under some conditions it is possible its explosive decomposition: H 2 O 2 H 2 O + 1/2 O 2 with the release of 98 kJ to mol H 2 o 2 (34 g). This is a very big energy: it is greater than that that is released during the formation of 1 praying HCl when the mixture of hydrogen and chlorine is exploded; It is enough to fully evaporate 2.5 times more water than it is formed in this reaction. Concentrated aqueous solutions H 2 O 2 are dangerous, many organic compounds are easily self-proposal in their presence, and when they hit, such mixtures can explode. For the storage of concentrated solutions, vessels of particularly pure aluminum or paraffinated glass vessels are used.
More often it is necessary to meet with a less concentrated 30% solution of H 2 O 2, which is called perhydroly, but also such a solution is dangerous: causes burns on the skin (during its action, the skin immediately whites due to the discoloration of the coloring substances), when impurities are injected Explosive boiling. The decomposition of H 2 O 2 and its solutions, including explosive, causes many substances, for example, the ions of heavy metals, which at the same time play the role of the catalyst, and even dust.
The explosions of H 2 O 2 are explained by the strong exothermic of the reaction, the chain nature of the process and a significant decrease in the activation energy of the decomposition of H 2 O 2 in the presence of various substances, which can be judged by the following data:
The catalase enzyme is contained in the blood; It is due to it "boils" from the separation of oxygen pharmacy "hydrogen peroxide", when it is used for disinfection of the chopped finger. The reaction of the decomposition of a concentrated solution H 2 O 2 under the action of catalase uses not only a person; It is this reaction that helps the beetle-scomber to fight enemies, which produces a hot jet in them ( cm. EXPLOSIVES). Another enzyme-peroxidase acts otherwise: it does not decompose H 2 O 2, but in its presence there is oxidation of other substances with hydrogen peroxide.
Enzymes affecting hydrogen peroxide reactions play a major role in the vital cells of the cell. The energy of the body supply oxidation reactions with the participation of incoming oxygen. In these reactions, H 2 O 2 is intermediately formed, which is harmful to the cell, since it causes irreversible damage to various biomolecules. Catalase and peroxidase are jointly converting H 2 O 2 into water and oxygen.
The decomposition reaction H 2 O 2 often flows through a radical chain mechanism ( cm. Chain reactions), with the role of the catalyst consists in initiating free radicals. So, in the mixture of aqueous solutions H 2 O 2 and FE 2+ (the so-called fenton reaction) is a reaction of electron transfer from the Fe 2+ ion on the H 2 O 2 molecule to form a FE 3+ ion and a very unstable anion radical . - who immediately disintegrates on the anion he - and the free hydroxyl radical he . (cm. Free radicals). Radical ON. . Very active. If there are organic compounds in the system, then their diverse reactions with hydroxyl radicals are possible. Thus, aromatic compounds and oxy acids are oxidized (benzene, for example, turns into phenol), unsaturated compounds can attach hydroxyl groups for dual bond: CH 2 \u003d CH-CH 2 it + 2 . NASN 2 -CH (OH) -CH 2 -on, and can enter the polymerization reaction. In the absence of suitable reagents he . Reacts with H 2 O 2 with the formation of a less active radical but 2 . which is able to restore FE 2+ ions, which closes the catalytic cycle:
H 2 O 2 + FE 2+ Fe 3+ + Oh . + Oh -
IS HE . + H 2 O 2 H 2 O + HO 2 .
HO 2 . + Fe 3+ FE 2+ + O 2 + H +
H + + OH - H 2 O.
Under certain conditions, the chain decomposition of H 2 O 2, the simplified mechanism of which can be submitted by the scheme
IS HE . + H 2 O 2 H 2 O + HO 2 . 2 . + H 2 O 2 H 2 O + O 2 + OH . etc.
The decomposition reactions H 2 O 2 go in the presence of various valence variable metals. Related to complex compounds, they often significantly increase their activity. For example, copper ions are less active than iron ions, but connected to ammonia complexes 2+, they cause a rapid decomposition of H 2 O 2. Similar effects are Mn 2+ ions related to complexes with some organic compounds. In the presence of these ions managed to measure the length of the reaction chain. To do this, first measured the reaction rate in the velocity from the oxygen solution. Then, in a very low concentration (about 10 -5 mol / l), an inhibitor was introduced into the solution, effectively reacting with free radicals and thus tearing the chain. The release of oxygen immediately ceased, but after about 10 minutes, when the entire inhibitor was spent, resumed again at the same speed. Knowing the reaction rate and the speed of the circuit breakage, it is easy to calculate the length of the chain, which was equal to 10 3 units. The high length of the chain causes high decomposition efficiency of H 2 O 2 in the presence of the most efficient catalysts, which at high speed generate free radicals. At the same time of the chain, the decomposition rate H 2 O 2 actually increases a thousand times.
Sometimes a noticeable decomposition of H 2 O 2 is also caused by traces of impurities that are almost not detected analytically. Thus, one of the most effective catalysts was the solo osmium sol: a strong catalytic effect was observed even during dilution 1:10 9, i.e. 1 g OS on 1000 tons of water. The active catalysts are colloidal solutions of palladium, platinum, iridium, gold, silver, as well as solid oxides of some metals - MNO 2, CO 2 O 3, PBO 2, etc., which do not change themselves. Decomposition can go very violently. So, if a small pinch of MNO 2 is thrown into a tube with a 30% solution H 2 O 2, a pair of splashes with splashes is broken from the tube. With more concentrated solutions there is an explosion. The decomposition on the surface of platinum flows more calmly. At the same time, the condition of the surface has a strong effect on the reaction rate. German chemist Walter Spring spent at the end of 19 century. Such experience. In a carefully purified and polished platinum cup, the decomposition reaction of a 38% solution H 2 O 2 was not even when heated to 60 ° C. If you need to make a needle on the bottom of the cup, it is already cold (at 12 ° C) a solution starts Oxygen bubbles on the spot are scratched, and when heated, decomposition along this place is noticeably enhanced. If you enter the spongy platinum, having a very large surface, then the explosive decomposition is possible.
Quick decomposition N 2 O 2 can be used for spectacular lecture experience, if the surfactant (soap, shampoo) is added before making a catalyst. The release oxygen creates a rich white foam, which was called "dental paste for an elephant."
H 2 O 2 + 2i - + 2H + 2H 2 O + I 2
I 2 + H 2 O 2 2i - + 2H + + O 2.
The inappropriate reaction is also in the case of oxidation of FE 2+ ions in acidic solutions: 2feso 4 + H 2 O 2 + H 2 SO 4 Fe 2 (SO 4) 3 + 2H 2 O.
Since there are almost always traces of various catalysts in aqueous solutions (the ions of metals contained in glass can also catalyze the decomposition of H 2 O 2, even diluted, inhibitors and stabilizers binding metal ions are added during their long-term storage. In this case, the solutions slightly acidify, since under the action of pure water on the glass, a slightly alkaline solution is obtained, which contributes to the decomposition of H 2 O 2.
All these features of the decomposition of H 2 O 2 allow you to resolve the contradiction. To obtain pure H 2 O 2, it is necessary to carry out distillation under reduced pressure, since the substance decomposes when heated above 70 ° C and even, although very slowly, at room temperature (as stated in the chemical encyclopedia, with a speed of 0.5% per year). In this case, how the boiling point in the same encyclopedia is obtained at atmospheric pressure equal to 150.2 ° C? Usually, in such cases, physico-chemical patterns are used: the logarithm of the fluid pair pressure linearly depends on the inverse temperature (on the Kelvin scale), therefore, if you precisely measure the pressure of steam H 2 O 2 with several (low) temperatures, it can be easily calculated at what temperature This pressure will reach 760 mm Hg. And this is the boiling point under normal conditions.
Theoretically radical ON. . It may be formed in the absence of initiators, as a result of a weaker communication of Oh, but for this you need a fairly high temperature. Despite the relatively small energy of the breaking of this connection in a molecule H 2 O 2 (it is equal to 214 kJ / mol, which is 2.3 times less than for the connection of H-it in the water molecule), the connection of Oh is still quite durable, So that hydrogen peroxide is absolutely stable at room temperature. And even at boiling point (150 ° C), it should be very slow. The calculation shows that at this temperature, the decomposition of 0.5% should also occur quite slowly, even if the chain length is 1000 units. The inconsistency of calculations and experimental data is explained by the catalytic decomposition caused by the smallest impurities in the liquid and the walls of the reaction vessel. Therefore, by many authors, the activation energy of the decomposition of H 2 O 2 is always significantly less than 214 kJ / mol even "in the absence of a catalyst". In fact, the decomposition catalyst is always there - and in the form of insignificant impurities in the solution, and in the form of the vessel walls, which is why the heating of anhydrous H 2 O 2 to boiling under atmospheric pressure has repeatedly caused explosions.
In some conditions, the decomposition H 2 O 2 occurs very unusual, for example, if heated with sulfuric acid solution H 2 O 2 in the presence of potassium intake KIO 3, then at certain concentrations of reagents, an oscillating reaction is observed, while the oxygen is released periodically, and then resumes With a period of 40 to 800 seconds.
Chemical properties N. 2 ABOUT 2 . Hydrogen peroxide - acid, but very weak. The dissociation constant H 2 O 2 H + + HO 2 - at 25 ° C is 2.4 · 10 -12, which is 5 orders of magnitude less than for H 2 S. The average salts of H 2 O 2 alkaline and alkaline earth metals are usually called peroxides ( cm. Peroxidians). When dissolved in water, they are almost completely hydrolyzed: Na 2 O 2 + 2H 2 O 2NaOH + H 2 O 2. Hydrolysis contributes to acidification of solutions. As acidic salts, for example, VA (but 2) 2, NaHO 2, etc., acidic salts are less susceptible to hydrolysis, but are easily decomposed when heated with oxygen release: 2NAHO 2 2NAOH + O 2. The stitching alkali, as in the case of H 2 O 2, contributes to the decomposition.
H 2 O 2 solutions, especially concentrated, possess a strong oxidative effect. So, under the action of a 65% solution of H 2 O 2 on paper, sawdust and other combustible substances they are flammable. Less concentrated solutions discolor many organic compounds, for example, indigo. Formaldehyde oxidation is unusual: H 2 O 2 is restored not to water (as usual), and to free hydrogen: 2nsno + H 2 O 2 2NCon + H 2. If you take a 30% solution of H 2 O 2 and 40% solution of NMNO, then after a small heating, a stormy reaction begins, the liquid boils and foams. The oxidative effect of dilute solutions H 2 O 2 is most manifested in an acidic medium, for example, H 2 O 2 + H 2 C 2 O 4 2H 2 O + 2CO 2, but oxidation is possible and in an alkaline medium:
Na + H 2 O 2 + NaOH Na 2; 2K 3 + 3H 2 O 2 2KCRO 4 + 2KOH + 8H 2 O.
The oxidation of the black sulfide of lead to the white sulfate PBS + 4H 2 O 2 PBSO 4 + 4H 2 O can be used to restore the darkened lead whiten on old paintings. Under the action of light there is oxidation and hydrochloric acid:
H 2 O 2 + 2HCl 2H 2 O + CL 2. Adding H 2 O 2 to acids greatly increases their action to metals. So, in the mixture H 2 O 2 and the diluted H 2 SO 4, copper, silver and mercury dissolve; The iodine in an acidic medium is oxidized to iodine acid HIO 3, sulfur gas - to sulfuric acid, etc.
The oxidation of the potassium-sodium salt of wine acid (ferronetic salt) is occurring in the presence of cobalt chloride as a catalyst. During the reaction of KOOC (CHOH) 2 Coona + 5H 2 O 2 KHCO 3 + NaHCO 3 + 6H 2 O + 2CO 2 Pink COCL 2 changes the color to green due to the formation of a complex compound with a tartrate-anion of wine-acid. As the reaction and oxidation of the tartrate, the complex collapses and the catalyst is reproaches again. If instead of cobalt chloride, use copper vigor as a catalyst, the intermediate compound, depending on the ratio of the initial reagents, will be painted in orange or green. After the end of the reaction is restored blue color of copper mood.
Otherwise, hydrogen peroxide is reacting in the presence of strong oxidants, as well as substances that are easily given oxygen. In such cases, H 2 O 2 may also act as a reducing agent with simultaneous oxygen release (the so-called reduction decay of H 2 O 2), for example:
2kmno 4 + 5h 2 O 2 + 3H 2 SO 4 K 2 SO 4 + 2MNSO 4 + 5O 2 + 8H 2 O;
AG 2 O + H 2 O 2 2AG + H 2 O + O 2;
O 3 + H 2 O 2 H 2 O + 2O 2;
Naocl + H 2 O 2 NaCl + H 2 O + O 2.
The last reaction is interesting in that the excited oxygen molecules are formed, which emit orange fluorescence ( cm. Chlorine Active). Similarly, metal gold is highlighted from gold salts solutions, metallic mercury is obtained from mercury oxide, etc. Such an unusual property H 2 O 2 allows, for example, to oxidation of potassium hexaciatorrate (II), and then, changing the conditions, restore the reaction product to the initial connection using the same reagent. The first reaction goes to an acidic environment, the second is alkaline:
2k 4 + H 2 O 2 + H 2 SO 4 2K 3 + K 2 SO 4 + 2H 2 O;
2K 3 + H 2 O 2 + 2KOH 2K 4 + 2H 2 O + O 2.
("Dual character" H 2 O 2 allowed one chemistry teacher to compare hydrogen peroxide with the hero of the story of the famous English writer Stevenson Strange Story of Dr. Jekyla and Mr. Heyda, under the influence of the composition invented by him, he could dramatically change his character, turning from a good gentleman in the bloodthirsty maniac.)
Obtaining N. 2 ABOUT 2 . H 2 O 2 molecules are always obtained in small quantities when combustion and oxidation of various connections. With burning, H 2 O 2 is formed either when the hydrogen atoms are separated from the initial compounds by intermediate hydroperoxide radicals, for example: HO 2 . + CH 4 H 2 O 2 + CH 3 . or as a result of recombination of active free radicals: 2H . H 2 O 2, N . + But 2. . H 2 O 2. For example, if the oxygen-hydrogen flame is sent to a piece of ice, then the waters will contain in the noticeable amounts H 2 O 2, which was formed as a result of the recombination of free radicals (in the flame of the H 2 O 2 molecule immediately disintegrate). A similar result is obtained at the burning of other gases. Education H 2 O 2 may occur at low temperature as a result of various redox processes.
In the industry, hydrogen peroxide has long been not obtained by a tensar method - from barium peroxide, and more modern methods use. One of them is the electrolysis of sulfuric acid solutions. At the same time, on the anode, sulfate ions are oxidized to supervalfate ions: 2SO 4 2- - 2E S 2 O 8 2-. Superstic acid then hydrolyzed:
H 2 S 2 O 8 + 2H 2 O H 2 O 2 + 2H 2 SO 4.
At the cathode, as usual, hydrogen is separated, so that the total reaction is described by the equation 2H 2 O H 2 O 2 + H 2. But the main modern method (over 80% of the world production) is the oxidation of certain organic compounds, for example, the etylentrahydroquinone, air oxygen in the organic solvent, and the anthrahydroquinone is formed by H 2 O 2 and the corresponding anthraquinone, which is then reduced by hydrogen on the catalyst in anthrahydroquinone. Hydrogen peroxide is removed from a mixture with water and concentrated by distillation. A similar reaction proceeds and when using isopropyl alcohol (it comes with an intermediate formation of hydroperoxide): (CH 3) 2 Sonya + o 2 (CH 3) 2 C (UN) It \u200b\u200bis (CH 3) 2 CO + H 2 O 2. If necessary, the resulting acetone can also be restored to isopropyl alcohol.
Application N. 2 ABOUT 2 . Hydrogen peroxide is widely used, and its world production is calculated by hundreds of thousands of tons per year. It is used to obtain inorganic peroxides such as oxidizing agent of rocket fuels, in organic synthesis, for whitening oils, fats, tissues, paper for cleaning semiconductor materials, to extract valuable metals from ores (for example, uranium by transferring its insoluble form to soluble), For disposal of wastewater. In medicine, H 2 O 2 solutions are used for rinsing and lubrication in inflammatory diseases of the mucous membranes (stomatitis, angina), for the treatment of purulent wounds. In Penals to store contact lenses in the lid, a very small amount of platinum catalyst is sometimes placed. The lenses for their disinfection are poured in a 3% solution of H 2 O 2 with a 3% solution, but since this solution is harmful to the eye, the penalty in a while turns over. In this case, the catalyst in the lid quickly decomposes H 2 O 2 on clean water and oxygen.
Once it was fashionable to discolor hair "peroxide", now there are safer compounds for hair color.
In the presence of some salts, hydrogen peroxide forms as it were of a solid "concentrate", which is more convenient to transport and use. So, if a strongly cooled saturated solution of fusion sodium (borants) add H 2 O 2 in the presence, large transparent sodium peroxoborate crystals Na 2 [(BO 2) 2 (OH) 4] are gradually formed. This substance is widely used for bleaching tissues and as a component of detergents. H 2 O 2 molecules, as well as water molecules, are able to embed into the crystal structure of salts, forming the similarity of crystallohydrates - peroxohydrates, for example, to 2 CO 3 · 3H 2 O 2, Na 2 CO 3 · 1.5H 2 O; The last connection is widespread called "Person". The so-called "hydroperite" CO (NH 2) 2 · H 2 O 2 is a clathrate - a compound of switching on molecules H 2 O 2 in the voids of the crystal urea lattice.
In analytical chemistry, some metals can be determined using hydrogen peroxide. For example, if we add hydrogen peroxide to a solution of titanium salt (IV), the solution acquires a bright orange color due to the formation of non-needed acid:
Tioso 4 + H 2 SO 4 + H 2 O 2 H 2 + H 2 O. Colorless Moiribdate Ion Moo 4 2- oxidizes H 2 O 2 V intensively painted in orange color peroxide anion. The acidified solution of potassium dichromate in the presence of H 2 O 2 forms a suprachic acid: K 2 Cr 2 O 7 + H 2 SO 4 + 5H 2 O 2 H 2 CR 2 O 12 + K 2 SO 4 + 5H 2 O, which is pretty fast decomposes: H 2 CR 2 O 12 + 3H 2 SO 4 CR 2 (SO 4) 3 + 4H 2 O + 4O 2. If you add these two equations, the reaction of the reduction of hydrogen peroxide of potassium dichromate is obtained:
K 2 CR 2 O 7 + 4H 2 SO 4 + 5H 2 O 2 CR 2 (SO 4) 3 + K 2 SO 4 + 9H 2 O + 4O 2.
Opechromic acid can be removed from an aqueous solution with ether (in a solution of ether it is significantly more stable than in water). The ether layer is painted in intense blue.
Ilya Leenson
LITERATURE
Dolflosk B.A., Tinakova E.I. Generating free radicals and their reaction. M., Chemistry, 1982 Chemistry and hydrogen peroxide technology. L., Chemistry, 1984
Hydrogen peroxide (formula H 2 O 2) is the simplest representative of peroxides. Most often, this substance is called hydrogen peroxide.
Properties
It is a colorless liquid having a metal taste, which in any relations is dissolved with water, alcohol and ether. The aqueous peroxide solutions are explosive: for example, if sodium iodide is omitted into it, then such a reaction will occur (photo on the left).
Also, this is a good solvent, which forms an unstable crystal hydrate when highlighting it. The hydrogen peroxide can serve as an oxidizing agent and a reducing agent, since all oxygen atoms in it have an intermediate degree of oxidation, equal to -1. An example of the demonstration of its oxidative properties can be a sodium sulfite reaction. Products of this reaction will be sodium sulfate (sulfate) and water. If strong oxidizers interact with this peroxide, then in such a reaction it is restored to oxygen. For example, lowered silver nitrate in clean hydrogen, then silver, gaseous oxygen (which immediately disappears) and nitric acid. The compound discussed is now unstable and therefore can easily decompose. Spontaneously disproportifies water and oxygen when mixed with dilute solutions. However, in its pure form, hydrogen peroxide is a very stable substance. If the concentrated solution of this compound is to act on some hydroxides, the reaction ends with the formation of metal peroxides discussed as its salts. The hydrogen peroxide is a reactive form of oxygen, and its increased formation in the cell leads to oxidative stress. In a living organism, it can be obtained due to the redox reactions of some enzymes, where it acts as a protective role as a bactericidal agent. Mammals do not have enzymes restoring hydrogen peroxide from oxygen. However, some enzyme systems can produce superoxide, subsequently turning into the desired substance.
Obtaining hydrogen peroxide
In industry, hydrogen peroxide is formed in reactions in which organic substances are involved, for example, catalytically oxidize isopropyl alcohol. In addition to the desired peroxide, even the valuable side product is also obtained - acetone. Also, hydrogen peroxide is also formed with sulfuric acid electrolysis. In the laboratory it is obtained by the interaction of barium oxide and sulfuric acid. Products of this reaction are barium sulfate and the desired peroxide. It is concentrated and cleaned with careful distillation.
Application
In textile manufacturing and paper manufacturing, hydrogen peroxide is used as a bleach. It is also needed as rocket fuel and for driving turbocharging units. Hydrogen peroxide is necessary for analytical chemistry as a catalyst, an epoxidizing and a hydrogen agent, as well as a foaming agent, with which porous materials, disinfecting and bleaching agents produce. This peroxide purifies the wounds, discolor the hair and whiten the teeth. The food industry is also obliged to many hydrogen peroxide solutions, since they disinfect the technological surfaces of the equipment that directly contact with the products, as well as packaging. This peroxide is capable of displaying the spots of the oxide of a tetravalent manganese, and this property is extensively used in everyday life.
Conclusion
That is why hydrogen peroxide is useful. As you can see, it is needed not only in medicine, but also in many other industries.
