Carbon monoxide equation. Curly gas: Formula and properties
Carbon monoxide (carbon monoxide, carbon monoxide, carbon oxide (II)) - colorless extremely toxic gas without taste and odor, lighter than air (under normal conditions). Chemical formula - CO.
The structure of the molecule
Due to the presence of a triple coupling, the CO molecule is very durable (dissociation energy 1069 kJ / mol, or 256 kcal / mol, which is more than any other dioment molecules) and has a small interstitial distance ( d. C≡O \u003d 0.1128 nm or 1.13 Å).
The molecule is slightly polarized, its electric dipole moment μ \u003d 0.04⋅10 -29 kl · m. Numerous studies have shown that a negative charge in the CO molecule is concentrated on the carbon atom C - ← o + (the direction of the dipole moment in the molecule is opposite to the previously expected). Ionization energy 14.0 eV, power constant k. = 18,6 .
Properties
Carbon (II) oxide is a colorless gas without taste and smell. Gulf. The so-called "the smell of carbon monoxide" is actually the smell of organic impurities.
| Standard Gibbs Energy Education Δ G. | -137,14 KJ / Mol (G.) (at 298 K) |
| Standard Entropy Education S. | 197.54 J / mol · k (g) (at 298 K) |
| Standard molar heat capacity C P. | 29.11 J / mol · k (g.) (At 298 K) |
| Enthalpy melting Δ. H. PL | 0,838 kJ / mole |
| Enthapia boiling Δ. H. kip | 6,04 kJ / mol |
| Critical temperature t. Crete | -140,23 ° C. |
| Critical pressure P. Crete | 3,499 MPa |
| Critical density ρ Crete | 0,301 g / cm³ |
The main types of chemical reactions in which carbon monoxide (II) participates, are reactions of attachment and redox reactions in which it exhibits reducing properties.
At room temperatures CO is low-effective, its chemical activity is significantly increased when heated and in solutions. So, in solutions it restores salt, and other to metals already at room temperature. When heated, other metals are restored, for example CO + Cuo → Cu + CO 2. It is widely used in pyrometallurgy. At the CO reaction in a solution with palladium chloride, a method of high-quality CO detection is based, see below.
The oxidation of C in solution often comes at a noticeable rate only in the presence of a catalyst. When selecting the latter, the nature of the oxidant plays the main role. So, KMNO 4 is faster than the whole in the presence of finely dredged silver, K 2 Cr 2 O 7 - in the presence of salts, KCLO 3 - in the presence of OSO 4. In general, according to its replacement properties, it looks like molecular hydrogen.
Below 830 ° C, a stronger reducing agent is CO, - above - hydrogen. Therefore, the equilibrium of the reaction
H 2 O + C O ⇄ C O 2 + H 2 (\\ DisplayStyle (\\ Mathsf (H_ (2) O + CO \\ RightleftarROWs Co_ (2) + H_ (2))))up to 830 ° C is shifted to the right, above 830 ° C left.
Interestingly, there are bacteria capable of oxidation from getting the energy they needed for life.
Carbon oxide (II) is lit with a blue flame (the temperature of the beginning of the reaction 700 ° C) in the air:
2 C O + O 2 → 2 C O 2 (\\ DisplayStyle (\\ MathSF (2CO + O_ (2) \\ Rightarrow 2CO_ (2)))) (Δ G. ° 298 \u003d -257 kJ, Δ S. ° 298 \u003d -86 j / k).CO combustion temperature can reach 2100 ° C. The combustion reaction is a chain, and the initiators are small amounts of hydrogen-containing compounds (water, ammonia, hydrogen sulfide, etc.)
Due to such a good calorific value, CO is a component of various technical gas mixtures (see, for example generator gas) used, including for heating. In the mixture with air are explosive; Bottom and upper concentration limits of flame distribution: from 12.5 to 74% (by volume).
halogens. The greatest practical application was the reaction with chlorine:
C O + C L 2 → C O C L 2. (\\ DisplayStyle (\\ Mathsf (CO + CL_ (2) \\ Rightarrow COCL_ (2))).)CO with F 2 reaction, except for COF 2 carbonyl fluoride, you can get a peroxide compound (FCO) 2 O 2. His characteristics: The melting point of -42 ° C, boiling is +16 ° C, has a characteristic odor (similar to the smell of ozone), when heated above 200 ° C is decomposed with an explosion (reaction products CO 2, O 2 and COF 2), in acidic The medium reacts with potassium iodide by equation:
(F C O) 2 O 2 + 2 K I → 2 K F + I 2 + 2 C O 2. (\\ DisplayStyle (\\ Mathsf ((FCO) _ (2) o_ (2) + 2ki \\ rightarrow 2kf + i_ (2) + 2CO_ (2).)))Carbon (II) oxide reacts with chalcogens. With gray forms a COS carbon server, the reaction goes when heated, by equation:
C O + S → C O S (\\ DisplayStyle (\\ Mathsf (CO + S \\ Rightarrow COS))) (Δ G. ° 298 \u003d -229 kJ, Δ S. ° 298 \u003d -134 j / k).Also obtained similar selexides of COSE carbon and carbon telecrusade Cote.
Restores SO 2:
2 C O + S O 2 → 2 C O 2 + S. (\\ DisplayStyle (\\ Mathsf (2CO + SO_ (2) \\ Rightarrow 2CO_ (2) + s.)))With transition metals, combustible and poisonous compounds are formed - carbonyls, such as ,,,,, etc., some of them are volatile.
N C O + M E → [M E (C O) N] (\\ DisplayStyle (\\ Mathsf (NCO + ME \\ Rightarrow)))Carbon oxide (II) is slightly dissolved in water, but does not respond to it. It also does not react with alkalis and acid solutions. However, it reacts with alkali melt to form the appropriate formates:
C O + K O H → H C O O K. (\\ DisplayStyle (\\ Mathsf (CO + KOH \\ Rightarrow HCook.)))Interesting carbon oxide reaction (II) with metallic potassium in ammonium solution. At the same time, the dioxodicarbonate of potassium dioxodicarbonate is formed:
2 K + 2 C O → K 2 C 2 O 2. (\\ DisplayStyle (\\ Mathsf (2K + 2Co \\ Rightarrow k_ (2) c_ (2) o_ (2).))) X C O + Y H 2 → (\\ DisplayStyle (\\ Mathsf (XCO + YH_ (2) \\ Rightarrow))) Alcohols + linear alkanes.This process is a source of production of such essential industrial products as methanol, synthetic diesel fuel, polyhydric alcohols, oils and lubricants.
Physiological action
Toxicity
Durchable gas is very toxic.
The toxic effect of carbon oxide (II) is due to the formation of carboxygemoglobin - a significantly more durable carbonyl complex with hemoglobin, compared with the hemoglobin complex with oxygen (oxygemoglobin). Thus, the processes of transportation of oxygen and cellular respiration are blocked. The concentration in the air is more than 0.1% leads to death for one hour.
- The victim should be taken on fresh air. In the poisoning of a light degree sufficiently hyperventilation of light oxygen.
- Artificial ventilation lungs.
- Lobelin or caffeine under the skin.
- Carboxylase intravenously.
World medicine unknown reliable antidots for use in case of carbon monoxide poisoning.
Carbon Oxide Protection (II)
Endogenous carbon monoxide
Endogenous carbon monoxide is produced in the normal cells of the human body and animals and performs the function of the signal molecule. It plays a well-known physiological role in the body, in particular, is a neurotransmitter and causes vasodilation. Due to the role of endogenous carbon monoxide in the body, its metabolic disorders are associated with various diseases, such as neurodegenerative diseases, atherosclerosis of blood vessels, hypertensive disease, heart failure, various inflammatory processes.
Endogenous carbon black gas is formed in the body due to the oxidizing action of the hemoxygenase enzyme on the gem, which is a product of the destruction of hemoglobin and myoglobin, as well as other gem-containing proteins. This process causes a small amount of carboxygemoglobin in the blood of a person, even if a person does not smoke and breathe not atmospheric air (always containing small amounts of exogenous carbon monoxide), and pure oxygen or a nitrogen mixture with oxygen.
Following the first data that appeared in 1993, that endogenous carbon monoxide is a normal neurotransmitter in the human body, as well as one of three endogenous gases, which normally modulate the course of inflammatory reactions in the body (two other - nitrogen oxide (II) and hydrogen sulfide ), endogenous carbon monoxide gas attracted considerable attention to clinicians and researchers as an important biological regulator. It was shown that in many tissues, all three of the above gas are anti-inflammatory substances, vasodilators, and also cause angiogenesis. However, not everything is so simple and definitely. Angiogenesis is not always a useful effect, since it, in particular, plays a role in the growth of malignant tumors, and is also one of the causes of damage to the retina in macular degeneration. In particular, it is important to note that smoking (the main source of carbon monoxide in the blood, which gives several times a large concentration of it than natural products) increases the risk of macular degeneration of the retina 4-6 times.
There is a theory that in some synapses of nerve cells, where there is a long-term memory of information, the receiving cell in response to the received signal generates endogenous carbon monoxide, which transmits a signal back by the transmitting cell than reports to her readiness and in the future receive signals from her and increasing the activity of the signal transmitter cell. Some of these nerve cells contain a guanillatcyclase, an enzyme that is activated when exposed to endogenous carbon monoxide gas.
Studies on the role of endogenous carbon monoxide as an anti-inflammatory substance and cytoprotector were carried out in a variety of laboratories around the world. These properties of endogenous carbon monoxide make an impact on its metabolism of an interesting therapeutic target for the treatment of such different pathological conditions, as tissue damage caused by ischemia and subsequent reperfusion (and this, for example, myocardial infarction, ischemic stroke), transplant rejection, vessel atherosclerosis, severe sepsis , severe malaria, autoimmune diseases. Including clinical trials on a person, but their results are not yet published.
Summating, what is known for 2015 on the role of endogenous carbon monoxide in the body can be stated as follows:
- Endogenous carbon monoxide is one of the important endogenous signal molecules;
- Endogenous carbon monoxide modulates the functions of the CNS and the cardiovascular system;
- Endogenous carbon black gas inhibits platelet aggregation and their adhesion to vessel walls;
- The impact on the exchange of endogenous carbon monoxide in the future may be one of the important therapeutic strategies under a number of diseases.
History opening
The toxicity of the smoke that is distinguished by coal burning was described by Aristotle and Galen.
Carbon oxide (II) was first obtained by the French chemist Jacques de Lasson in when heated zinc oxide with coal, but it was originally mistaken for hydrogen, since he burned in a blue flame.
The fact that carbon and oxygen enters the composition of this gas, found out in the English chemist William Kryikshenk. Gaza toxicity was investigated in 1846 by the French physician Claude Bernarr in the experiments on dogs.
Carbon oxide (II) Outside the atmosphere of the Earth was first discovered by the Belgian scientist M. Mizhoth (M. Migeotte) in 1949 on the presence of the main oscillating-rotational strip in the IR Sun spectrum. Carbon (II) oxide (II) was found in the interior media in 1970
Obtaining
Industrial way
- It is formed during the combustion of carbon or compounds based on it (for example, gasoline) under conditions of lack of oxygen:
- or when the carbon dioxide is restored with hot corner:
This reaction occurs during a furnace fire, when the furnace flap is too early (so far the coals did not finally be burned). The resulting carbon oxide (II) due to its poisonousness causes physiological disorders ("Ugra") and even death (see below), hence one of the trivial names is "carbonaceous gas".
The reaction of the recovery of carbon dioxide is reversible, the effect of temperature on the equilibrium state of this reaction is given on the graph. The reaction flow to the right provides the entropy factor, and the left is enthalpy. At temperatures below 400 ° C, the equilibrium is almost completely shifted to the left, and at temperatures above 1000 ° C to the right (towards Education CO). At low temperatures, the speed of this reaction is very small, so carbon oxide (II) under normal conditions is quite stable. This equilibrium wears a special name. equilibrium Bouara.
- Mixtures of carbon oxide (II) with other substances are obtained by passing air, water vapor, etc. Through the layer of hot coke, stone or brown coal, etc. (see generator gas, water gas, mixed gas, synthesis gas ).
Laboratory method
- Decomposition of liquid formic acid under the action of hot concentrated sulfuric acid or transmission of gaseous formic acid over phosphorus oxide P 2 O 5. Reaction scheme:
- Heating the mixture of oxal and concentrated sulfuric acids. The reaction goes by equation:
- Heating the mixture of potassium hexaciaticanoferrate (II) with concentrated sulfuric acid. The reaction goes by equation:
- Restoration of zinc carbonate with magnesium when heated:
Determination of carbon oxide (II)
It can be qualitative to determine the presence of CO on the darkening of palladium chloride solutions (or impregnated with this paper solution). The darkening is associated with the release of fine metal palladium according to the scheme:
P d C L 2 + C O + H 2 O → P D ↓ + C O 2 + 2 H C L. (\\ DisplayStyle (\\ Mathsf (PDCL_ (2) + CO + H_ (2) O \\ Rightarrow PD \\ DOWNARW + CO_ (2) + 2HCl.)))This reaction is very sensitive. Standard solution: 1 gram palladium chloride per liter of water.
Quantitative determination of carbon oxide (II) is based on a iodometric reaction:
5 C O + I 2 O 5 → 5 C O 2 + I 2. (\\ DisplayStyle (\\ Mathsf (5Co + I_ (2) O_ (5) \\ RightarRow 5CO_ (2) + I_ (2).)))Application
- Carbon oxide (II) is an intermediate reagent used in hydrogen reactions in the most important industrial processes to obtain organic alcohols and unbreakable hydrocarbons.
- Carbon (II) oxide is used to handle meat animals and fish, gives them a bright red color and a kind of freshness, without changing taste (technology Clear Smoke and Tasteless Smoke). The permissible concentration of CO is 200 mg / kg of meat.
- Carbon oxide (II) is the main component of the generator gas used as fuel in gas generator vehicles.
- Curmarket gas from engine exhaust was used by the Nazis during the Second World War for the mass kill of people by poisoning.
Carbon Oxide (II) in the Earth's Atmosphere
There are natural and anthropogenic sources of income into the atmosphere of the Earth. In natural conditions, on the surface of the Earth, CO is formed with incomplete anaerobic decomposition of organic compounds and during biomass combustion, mainly during forest and steppe fires. Carbon oxide (II) is formed in the soil as a biological way (allocating by living organisms) and nebiological. Experimentally proved the release of carbon oxide (II) due to the usual phenolic compounds, containing OCH 3 or OH groups in ortho or para-positions with respect to the first hydroxyl group.
The overall balance of the production of nebiological CO and its oxidation by microorganisms depends on specific environmental conditions, primarily on humidity and value. For example, carbon (II) arid soils is released directly into the atmosphere, thus creating local maxima of the concentration of this gas.
In the atmosphere CO is the product of chains of reactions with the participation of methane and other hydrocarbons (first of all, isoprene).
The main anthropogenic source of CO is currently exhaust gases of internal combustion engines. Carbon oxide is formed during the combustion of hydrocarbon fuel in internal combustion engines with insufficient temperatures or poor adjustment of the air supply system (an insufficient amount of oxygen is supplied for CO 2 oxidation). In the past, a significant proportion of anthropogenic CO admission to the atmosphere was provided by the lighting gas used to illuminate the premises in the XIX century. In composition, it approximately matched water gas, that is, it contained up to 45% carbon oxide (II). In the communal sphere, it is not applied in mind the presence of a much cheaper and energy efficient analogue -
Signs that damp gas (carbon monoxide (II), carbon monoxide, carbon monoxide) was formed in the air in a dangerous concentration, it is difficult to determine - invisible, may not smell, accumulates in the room gradually, imperceptibly. For a person's life, it is extremely dangerous: it has high toxicity, excessive content in the lungs leads to severe poisoning and fatal outcomes. Every year a high mortality rate from gas poisoning is recorded. Reduce the threat of poisoning can be compliance with simple rules and the use of special carbon monoxide sensors.
What is a ditch gas
Natural gas is formed when burning any biomass, in industry is a product of combustion of any carbon-based compounds. And in that, in another case, the prerequisite for the release of gas is the lack of oxygen. Large volumes are entered into the atmosphere as a result of forest fires, in the form of exhaust gases formed during the combustion of fuel in car engines. For industrial purposes, used in the production of organic alcohol, sugar, processing of animal meat and fish. A small amount of monoxide produce human cell cells.
Properties
From the point of view of Monoxide chemistry - an inorganic compound with a single oxygen atom in the molecule, the chemical formula - CO. This is a chemical that does not have a characteristic color, taste and odor, it is lighter than air, but heavier than hydrogen, at room temperatures inactive. A person who felt the smell, only feels the presence of organic impurities in the air. It refers to the discharge of toxic products, death at a concentration in the air 0.1% occurs within one hour. The characteristic of the maximum permissible concentration is 20 mg / cubic meters.
Carbon monoxide action on the human body
For a person, carbon monoxide is a deadly danger. Its toxic effect is due to the formation of carboxygemoglobin blood in the blood cells - the carbon oxide (II) product to the hemoglobin of blood. The high level of carboxygemoglobin content causes oxygen starvation, insufficient oxygen flow to the brain and other tissues of the body. With weak intoxication, its content in the blood is low, the destruction is naturally possible for 4-6 hours. With high concentrations, only medications operate.
Carrying gas poisoning
Carbon monoxide is one of the most dangerous substances. In case of poisoning, the body intoxication occurs, accompanied by a deterioration in the overall state of the person. It is very important to recognize signs of carbon monoxide poisoning. The result of treatment depends on the level of the substance in the body and on how help immediately arrived. In this case, the bill goes for a minute - the victim can or cure finally, or remain sick forever (it all depends on the speed of rescuer response).
Symptoms
Depending on the degree of poisoning, headaches may be observed, dizziness, noise in the ears, rapid heartbeat, nausea, shortness of breath, flickering in the eyes, general weakness. Often there is drowsiness, which is especially dangerous when a person is in a ridden room. If a large number of poisonous substances come into the respiration organs, convictions, loss of consciousness, in particularly severe cases - coma.
First aid in charge of carbon monoxide
A trial assistance in place should be provided with a carbon monoxide. We must immediately move it to fresh air and call a doctor. It should be remembered about its safety: to enter the room with the source of this substance it is only necessary to breathe deeply, inside not breathing. Until the doctor did not come to facilitate oxygen access to easy: unbutton the buttons, remove or loosen the clothes. If the victim lost consciousness and stopped breathing, artificial ventilation of the lungs is necessary.
Antidote with poisoning
Special antidote (antidote) in the oxide poisoning of carbon is a drug-based drug that actively prevents the formation of carboxygemoglobin. The effect of antidote leads to a decrease in the need of an organism in oxygen, supporting organs sensitive to the lack of oxygen: brain, liver, etc. is administered intramuscularly with a dosage of 1 ml immediately after the patient is removed from the zone with a high concentration of poisonous substances. Repeated antidot not earlier than an hour after the first introduction. It is allowed to use it for prophylaxis.
Treatment
In case of easy impact of carbon monoxide, treatment is carried out outpatient, in severe cases, the patient is hospitalized. Already in an ambulance carrier, it is given an oxygen pillow or mask. In severe cases, to give the body a large oxygen dose, the patient is placed in the barocamera. An antidote is intramuscularly introduced. The level of gas in the blood is constantly monitored. Further rehabilitation is medicated, the actions of the doctors are aimed at restoring the work of the brain, the cardiovascular system, lungs.
Effects
The impact of carbon monoxide on the body can cause serious diseases: the performance of the brain, the behavior, human consciousness, appear inexplicable headaches. Especially the influence of harmful substances is subject to memory - the part of the brain, which is responsible for the transition of short-term memory into long-term. The consequences of patient with carbon monoxide may feel only a few weeks later. Most victims are completely restored after the rehabilitation period, but some feel the consequences of the whole life.
How to determine the carbonate gas indoors
To poison carbon oxide is easily at home, and this happens not only during a fire. The carbon carbon concentration is formed with an inactive handling of the furnace, during operation of a faulty gas column or ventilation. A corrosion source can be a gas stove. If there is a smoke in the room - this is the reason to beat the alarm. For permanent control over the gas level, there are special sensors. They control the level of gas concentration and report on exceeding the norm. The presence of such a device reduces the risk of poisoning.
Video
Many gaseous substances existing in nature and produced in production are strong poisoning compounds. It is known that chlorine was used as a biological weapon, bromine pairs have a strongly corrosive effect on the skin, hydrogen sulfide causes poisoning and so on.
One of these substances is both carbon monoxide or carbon monoxide, the formula of which has its own characteristics in the structure. About him and will be discussed further.
Chemical carbon monoxide
The empirical formula of the compound under consideration is as follows: CO. However, this form gives a characteristic only about high-quality and quantitative composition, but does not affect the characteristics of the structure and the order of the compound of atoms in the molecule. And it differs from this in all other similar gases.
It is this feature that affects the existing compound physical and chemical properties. What is this structure?
The structure of the molecule
First, according to the empirical formula, it can be seen that carbon valence in the compound is equal to II. Just like oxygen. Consequently, each of them can form two carbon monoxide formulas with this visually confirms.
So happens. Between the carbon and oxygen atom on the mechanism of socialization of unpaired electrons, the formation of a double covalent polar communication. Thus, carbon monoxide takes the type C \u003d O.
However, on this features of the molecule do not end. According to the donor-acceptor mechanism in the molecule, the formation of a third, dative or semi -olar communication occurs. What is this explained? Since after the formation of an exchange order, two pairs of electrons remain in oxygen, and the carbon atom is an empty orbital, the latter acts as an acceptor of one of the first pairs. In other words, the pair of electron oxygen is placed on the free orbit of carbon and the formation of communication.
So, carbon is an acceptor, oxygen - donor. Therefore, the carbon monoxide formula in chemistry takes the following form: S≡o. Such structurement informs the molecule additional chemical stability and inertia in the manifested properties under normal conditions.
So, connections in the carbon monoxide molecule:
- two covalent polar, formed by the exchange mechanism due to the socialization of unpaired electrons;
- one donative, formed by donor-acceptor interaction between the pair of electrons and the free orbital;
- total connections in the molecule - three.
Physical properties
There are a number of characteristics, which, like any other compound, has damp gas. The substance formula clearly makes it clear that the crystalline lattice is molecular, condition under normal gaseous conditions. From here, the following physical parameters flow.
- S≡o - carbon black gas (formula), density - 1,164 kg / m 3.
- Boiling and melting point, respectively: 191/205 0 S.
- Dissolves in: water (insignificant), ether, benzene, alcohol, chloroform.
- There is no taste and smell.
- Bedless.
From a biological point of view, it is extremely dangerous for all living beings, except for certain types of bacteria.
Chemical properties
From the point of view of chemical activity, one of the most inert substances under normal conditions is a carbon monoxide. The formula, which reflects all links in the molecule, confirms this. It is because of such a solid structure that this compound is practically not entering into the standard environmental indicators.
However, at least a little heat the system, as a feedback in the molecule, collapses, like covalent. Then carbon monoxide begins to show active rehabilitation properties, and strong enough. So, he is able to interact with:
- oxygen;
- chlorine;
- alkalis (melts);
- with oxides and salts of metals;
- with gray;
- slightly with water;
- with ammonia;
- with hydrogen.
Therefore, as already stipulated above, the properties that the carbon monoxide exhibits is largely explained by its formula.
Finding in nature
The main source of CO in the atmosphere of the Earth is forest fires. After all, the main method of formation of this gas naturally is incomplete combustion of various types of fuel, mainly organic nature.
Anthropogenic sources of air pollution with carbon monoxide are also important and produced by the mass fraction of the same percentage as natural. These include:
- smoke from the work of factories and factories, metallurgical complexes and other industrial enterprises;
- exhaust gases from internal combustion engines.
In natural conditions, carbon black gas is easily oxidized by air oxygen and water vapor to carbon dioxide. This is based first assistance in poisoning by this compound.
Obtaining
It is worth indicating one feature. The carbon black gas (formula), carbon dioxide (the structure of the molecule), respectively, look like this: С≡o and o \u003d c \u003d o. The difference is one oxygen atom. Therefore, the industrial method of obtaining monoxide is based on the reaction between dioxide and coal: CO 2 + C \u003d 2CO. This is the easiest and most common method of synthesizing this compound.
In the laboratory, various organic compounds, metals salts and complex substances, as the yield of the product is not expecting too large.
A qualitative reagent for the presence of carbon monoxide in air or a solution of palladium chloride. With their interaction, a pure metal is formed, which causes a darkening of the solution or the surface of the paper.
Biological effect on the body
As already stipulated above, carbon monoxide is a very poisonous colorless, dangerous and deadly pest for the human body. And not only exactly the human, but in general any living. Plants that are under the influence of car exhaust gases are dying very quickly.
What exactly is the biological effects of carbon monoxide on the internal environment of animal beings? It's all about the formation of durable complex compounds of blood protein hemoglobin and gas under consideration. That is, instead of oxygen, the poison molecules are captured. Cellular respiration is instantly blocked, gas exchange becomes impossible in its normal flow.
As a result, there is a gradual blocking of all hemoglobin molecules and, as a result, death. There is enough damage to only 80% so that the outcome of poisoning becomes fatal. For this, the concentration of carbon monoxide in the air should be 0.1%.
The first signs for which you can determine the onset of poisoning by this compound are:
- headache;
- dizziness;
- loss of consciousness.
First aid - to go out on fresh air, where the carbon monoxide under the influence of oxygen will turn into carbon dioxide, that is, it will be neutral. Cases of deaths from the action of the substance under consideration are very frequent, especially in the homes, because of the combustion of firewood, coal and another type of fuel, this gas is necessarily formed as a by-product. Compliance with safety regulations is extremely important for the preservation of human life and health.
Also, many cases of poisoning in garage rooms, where a lot of engine running engines are assembled, but the influx of fresh air is not enough. Death in exceeding the permissible concentration occurs after an hour. Feel the presence of gas is physically impossible, because neither smell, nor the color of him.
Use in industry
In addition, carbon monoxide is used:
- for processing meat and fish products, which allows them to give them a fresh look;
- for the synthesis of certain organic compounds;
- as a generator gas component.
Therefore, this substance is not only malicious and dangerous, but also very useful for humans and its economic activity.
Publication date 01/28/2012 12:18
Carbon monoxide - Carbon oxide, which is too often heard, if it comes to poisoning combustion products, accidents in industry or even in everyday life. By virtue of the special poisonous properties of this compound, the usual home gas column can cause the death of a whole family. Examples of this - hundreds. But why is it going on? What is a carbon monoxide actually? What is he dangerous for a person?
What is carbon monoxide, formula, basic properties
Durgeary gas, formula which is very simple and denotes an alliance of the oxygen and carbon atom - CO, is one of the most poisonous gaseous compounds. But unlike many other hazardous substances that are used only to solve narrow industrial problems, carbon monoxide chemical contamination may occur during completely ordinary chemical processes, possible even in everyday life.
However, before proceeding to how the synthesis of this substance occurs, consider what is a ditch gas In general, and what is its main physical properties:
- colorless gas without taste and smell;
- extremely low melting and boiling points: -205 and -191.5 degrees Celsius, respectively;
- density 0.00125 g / cc. M.;
- very fuel with high burning temperature (up to 2100 degrees Celsius).
The formation of carbon monoxide
In household or industry the formation of carbon monoxide It usually occurs one of several sufficiently simple ways, which easily explains the risk of random synthesis of this substance with risk for the staff of the enterprise or residents of the house, where heating equipment malfunction has arisen or the safety technique has arisen. Consider the main ways to form carbon monoxide:
- the combustion of carbon (coal, coke) or its compounds (gasoline and other liquid fuel) under conditions of oxygen shortage. As it is easy to guess, fresh air deficiency, dangerous in terms of risk of carbon monoxide, easily occurs in internal combustion engines, household columns with impaired ventilation, industrial and conventional furnaces;
- the interaction of ordinary carbon dioxide with hot coal. Such processes occur in the furnaces are constantly and completely reversible, but, provided that the lack of oxygen is already mentioned, with a closed flap, the carbon black gas is formed in much larger quantities, which is a deadly danger to people.
What is dangerous carbon monoxide?
In sufficient concentration curly gas, properties Which explains its high chemical activity is extremely dangerous for human life and health. The essence of such poisoning is, first of all, in the fact that the molecules of this compound instantly bind hemoglobin of blood and deprive its ability to carry oxygen. Thus, carbon monoxide reduces cellular respiratory level with the most serious consequences for the body.
Answering the question " What is dangerous carbon monoxide?"It is worth mentioning that, in contrast to many other toxic substances, a person does not feel any specific smell, does not experience unpleasant sensations and is not able to recognize its presence in the air by any other ways, without having special equipment. As a result, the victim simply does not accept There are no measures to escape, and when the actual carbon monoxide (drowsiness and loss of consciousness) becomes obvious, it may be too late.
Curmarket gas leads to death for an hour at a concentration in the air over 0.1%. At the same time, in the exhaust of a completely ordinary passenger car, it contains from 1.5 to 3% of this substance. And this is still a good condition of the motor. It easily explains the fact that carrying gas poisoning It often occurs in garages or inside the machine, sealed with snow.
Other hazardous cases in which people poisoned by carbon monoxide in everyday life or at work is ...
- overlapping or vents breakage of the heating column;
- illiterate use of wood or coal ovens;
- on fires in closed rooms;
- near lively car highways;
- in industrial enterprises where carbon monoxide is actively used.
Carbon black, carbon monoxide (CO) is a colorless gas without smell and taste, which is slightly less dense than air. It is toxic for hemoglobine animals (including a person) if its concentrations are above about 35 parts per million, although it is also produced in the usual metabolism of animals in small quantities, and, as believed, has some normal biological functions. In the atmosphere, it is spatially variable and fast, and has a certain role in the formation of ozone at the ground level. Carbon monoxide consists of one carbon atom and one oxygen atom associated with a triple bond, which consists of two covalent bonds, as well as one dative covalent bond. This is the easiest carbon oxide. It is an isoelectron with an anion cyanide, nitrosonium cation and molecular nitrogen. In coordination complexes, carbon monoxide ligand is called carbonyl.
History
Aristotle (384-322 BC) for the first time described the process of burning coal, which leads to the formation of toxic vapors. In antiquity there was a way of execution - to close the criminal in the bathroom with smoldering coals. However, at that time the death mechanism was incomprehensible. Greek doctor Galen (129-199 AD) suggested that there was a change in air composition, which caused man harm when inhaled. In 1776, the French chemist de Lasson produced by heating zinc oxide with coke, but the scientist came to the erroneous conclusion that the gaseous product was hydrogen, since he burned a blue flame. Gas has been identified as a compound containing carbon and oxygen, Scottish chemist William Cumberland Croiccanom in 1800. Its toxicity on dogs was carefully investigated by Claude Bernarr around 1846. During the Second World War, a gas mixture, including carbon monoxide, was used to maintain mechanical vehicles operating in some parts of the world, where there was little gasoline and diesel fuel. External (with some exceptions) Charcoal or gas generators obtained from wood were installed, and a mixture of atmospheric nitrogen, carbon monoxide and small quantities of other gases formed during gasification entered the gas mixer. A gas mixture obtained as a result of this process is known as a woody gas. Carbon oxide was also used on a large scale during the Holocaust in some German Nazi death camps, the most clearly - in gas vans in Helmno and in the Calculation program T4 "Euthanasia".
Sources
Carbon monoxide is formed during the partial oxidation of carbon-containing compounds; It is formed when there is not enough oxygen to form carbon dioxide (CO2), for example, when working with a stove or an internal combustion engine, in a closed space. In the presence of oxygen, including its concentrations in the atmosphere, carbon monoxide is burning with a blue flame, producing carbon dioxide. Coal gas, which was widely used until the 1960s for internal lighting, cooking and heating, contained carbon monoxue as a significant fuel component. Some processes in modern technology, such as cast iron smelting, still produce carbon monoxide as a by-product. Around the world, the largest sources of carbon monoxide are natural sources, due to photochemical reactions in the troposphere, which generate about 5 × 1012 kg of carbon oxide per year. Other natural sources of CO include volcanoes, forest fires and other forms of combustion. In biology, carbon monoxide is naturally produced under the action of hemoxygenase 1 and 2 on the gem from the decay of hemoglobin. This process produces a certain amount of carboxygemoglobin in normal people, even if they do not inhale carbon monoxide. After the first report that carbon monoxide is a normal neurotiator in 1993, as well as one of three gases, which naturally modulate inflammatory reactions in the body (two other nitrogen oxide and hydrogen sulfide), carbon monoxide received great attention to scientists as biological Regulator. In many tissues, all three gas, act as anti-inflammatory agents, vasodilators and promoters of neovascular growth. Clinical trials of small amounts of carbon monoxide continue as a drug. Nevertheless, the excessive amounts of carbon monoxide causes carbon monoxide poisoning.
Molecular properties
Carbon monoxide has a molecular weight of 28.0, which makes it a little easier than air whose average molecular weight is 28.8. According to the law of perfect gas, CO, therefore, has a smaller density than air. The length of the connection between the carbon atom and the oxygen atom is 112.8 PM. This communication length is consistent with a triple bond, as in molecular nitrogen (N2), which has a similar communication length and almost the same molecular weight. Double bonds carbon-oxygen is much longer, for example, 120.8 m in formaldehyde. The boiling point (82 K) and the melting point (68 K) are very similar to N2 (77 K and 63 K, respectively). 1072 KJ / mol connection dissociation energy is stronger than N2 (942 kJ / mol) and is the strongest chemical bond. The main state of the carbon monoxide electron is a singlet, as there are no unpaired electrons.
Binding and dipole moment
Carbon and oxygen together have, a total of 10 electrons in the valence shell. Following the accumulation rule for carbon and oxygen, the two atoms form a triple bond, with six second electrons in three binding molecular orbitals, and not a conventional double bond, as in organic carbonyl compounds. Since four of the total electrons come from an oxygen atom and only two of carbon, one binder orbital is occupied by two electrons from oxygen atoms, forming a ditch or dipole communication. This leads to C ← o Polarization of the molecule, with a small negative charge on carbon and a small positive charge on oxygen. Two other binding orbitals occupy each one carbon and one of the oxygen, forming (polar) covalent bonds with reverse C → O polarization, since oxygen is more electronegative than carbon. In the free carbon oxide, the net negative charge Δ- remains at the end of carbon, and the molecule has a small dipole moment 0.122 D. Thus, an asymmetric molecule: oxygen has more density of electrons than carbon, as well as a small positive charge, compared to carbon, which is negative. In contrast, the isoelectronic diazot molecule does not have a dipole moment. If carbon monoxide acts as a ligand, the polarity of the dipole may vary with a pure negative charge at the end of the oxygen, depending on the structure of the coordination complex.
Polarity of communication and oxidation state
Theoretical and experimental studies show that, despite the greater electronegability of oxygen, the dipole moment comes from a more negative carbon end to a more positive end of the oxygen. These three bonds are actually polar covalent bonds that are strongly polarized. The calculated polarization to the oxygen atom is 71% for σ-bond and 77% for both π - connections. The degree of carbon oxidation in carbon monoxide in each of these structures is +2. It is calculated: all binders are considered to be belong to more electronegative oxygen atoms. Only two unconvisory electrons on the carbon belong to carbon. With such a calculation, carbon has only two valence electrons in the molecule compared to four in a free atom.
Biological and physiological properties
Toxicity
Carbon monoxide poisoning is the most common type of deadly air poisoning in many countries. Carbon oxide is a colorless substance that does not have smell and taste, but very toxic. It is connected to hemoglobin to produce carboxygemoglobin, which "usurps" a section in hemoglobin, which usually transfers oxygen, but ineffective to deliver oxygen to the tissues of the body. Such low concentrations as 667 parts per million can cause conversion to 50% hemoglobin in the body into carboxygemoglobin. 50% Carboxygemoglobin levels can lead to cramps, coma and death. In the United States, the Ministry of Labor limits the long-term levels of carbon monoxide in the workplace to 50 parts per million. Within a short period of time, the absorption of carbon monoxide is accumulative, since its half-life is about 5 hours in the fresh air. The most common symptoms of carbon monoxide poisoning can be similar to other types of poisoning and infections, and include symptoms such as headache, nausea, vomiting, dizziness, fatigue and feeling of weakness. The affected families often believe that they are victims of food poisoning. Babies can be irritable and eat badly. Neurological symptoms include confusion, disorientation, violation of vision, fainting (loss of consciousness) and convulsions. Some descriptions of carbon monoxide poisoning include hemorrhages of the retina, as well as an abnormal cherry-red blood shade. In most clinical diagnoses, these signs are rarely observed. One of the difficulties associated with the usefulness of this "cherry" effect is related to the fact that it adjusts, or disguises, in the reverse case, an unhealthy appearance, since the main effect of removal of venous hemoglobin is associated with the fact that the stuffed person seems more normal, or A dead person seems alive, like the effect of red dyes in the embodiment. Such an effect of staining in an oxygen-free CO-poisoned tissue is associated with commercial use of carbon monoxide when staining meat. Carbon oxide is also associated with other molecules, such as Mioglobin and mitochondrial cytochromoxidase. The effects of carbon monoxide can lead to significant damage to the heart and the central nervous system, especially in the pale ball, often this is due to long-term chronic pathological conditions. Carbon monoxide may have serious adverse effects for the fetus of a pregnant woman.
Normal human physiology
Carbon monoxide is produced naturally in the human body as a signal molecule. Thus, carbon monoxide may have a physiological role in the body as a neurotransmitter or relaxant of blood vessels. Due to the role of carbon monoxide in the body, disorders in its metabolism are associated with various diseases, including neurodegeneration, hypertension, heart failure and inflammation.
CO functions as an endogenous signal molecule.
CO modulates cardiovascular functions
CO inhibits aggregation and tombstick adhesion
CO can play a role as a potential therapeutic agent.
Microbiology
Carbon monoxide is a nutrient medium for methanogenic archae, the building unit for Acetylcooferment A. This is a topic for a new area of \u200b\u200bbioorganetallic chemistry. Extremophilic microorganisms can thus metabolizing carbon monoxide in places such as thermal vulcanov. In bacteria, carbon monoxide is carried out by restoring carbon dioxide by the enzyme of carbon monoxide dehydrogenase, Fe-Ni-S-containing protein. COOA is a receptor carbon oxide protein. The sphere of its biological activity is still unknown. It can be part of the signal path in bacteria and arche. His prevalence in mammals is not installed.
Prevalence
Carbon monoxide is found in various natural and artificial media.
Carbon oxide is present in small amounts in the atmosphere, mainly as a product of volcanic activity, but also is a product of natural and technogenic fires (for example, forest fires, burning plant residues, as well as incineration of sugar cane). The burning of fossil fuels also contributes to the formation of carbon monoxide. Carbon monoxide is found in dissolved form in molten volcanic rocks at high pressures in the mantle of the Earth. Since natural sources of carbon monoxide variables are extremely difficult to accurately measure the natural gas emissions. Carbon oxide is a fast-waving greenhouse gas, and also shows an indirect radiation effect by increasing the concentration of methane and tropospheric ozone as a result of chemical reactions with other components of the atmosphere (for example, hydroxyl radical, it), which, otherwise, would destroy them. As a result of natural processes in the atmosphere, it ultimately is oxidized to carbon dioxide. Carbon monoxide is simultaneously short-lived in the atmosphere (it remains on average for about two months) and has a spatially variable concentration. In the atmosphere of Venus, carbon monoxide is created as a result of carbon dioxide photodissociation with electromagnetic radiation with a wavelength of 169 nm. Due to its long-term viability in the middle troposphere, carbon monoxide is also used as a traceser for transporting harmful substances.
Pollution of cities
Carbon monoxide is a temporary pollutant in the atmosphere in some urban areas, mainly from exhaust pipes of internal combustion engines (including vehicles, portable and backup generators, lawn mowers, washing machines, etc.), as well as incomplete combustion various other types of fuel (including firewood, coal, charcoal, oil, paraffin, propane, natural gas and trash). Large CO pollution can be observed from cosmos over cities.
Role in the formation of surface ozone
Carbon monoxide, along with aldehydes, is part of a series of cycles of chemical reactions that form a photochemical could. It reacts with a hydroxyl radical (OH) to produce a radical intermediate HOCO, which quickly transmits radical hydrogen O2 to form a peroxide radical (n2) and carbon dioxide (CO2). The peroxidant radical then reacts with nitrogen oxide (NO) to form nitrogen dioxide (NO2) and hydroxyl radical. NO 2 gives O (3P) through a photo gallery, thereby forming O3 after reaction with O2. Since the hydroxyl radical is formed during the formation of NO2, the balance of the sequence of chemical reactions, starting with carbon monoxide, leads to the formation of ozone: CO + 2O2 + Hν → CO2 + O3 (where Hν refers to photon of light absorbed by the NO2 molecule in the sequence) although the creation NO2 is an important step leading to the formation of a low-level ozone, it also increases the amount of ozone to another, somewhat mutually exclusive, by reducing the amount of NO, which is available for reaction with ozone.
Air pollution indoors
In closed media, the concentration of carbon monoxide can easily increase to death. On average, in the United States annually from non-automotive consumer goods producing carbon monoxide, 170 people die. Nevertheless, in accordance with the data of the Department of Health Florida, "Every year more than 500 Americans die from the accidental impact of carbon monoxide and thousands of more people in the United States require emergency medical care for non-vertical carbon monoxide poisoning." These products include faulty fuel intensity fuel, such as furnaces, kitchen stoves, water heaters and gas and kerosene rooms; Equipment with mechanical drive, such as portable generators; fireplaces; And charcoal, which is burned in homes and other indoor rooms. The American Association of Poison Control Centers (AAPCC) reported on 15769 cases of carbon monoxide poisoning, which led to 39 deaths in 2007. In 2005, CPSC reported on 94 deaths associated with the poisoning of carbon monoxide from the generator. Forty seven of these deaths took place during interruptions in the supply of electricity due to severe weather conditions, including because of Hurricane Katrina. Nevertheless, people die from carbon monoxide poisoning produced by non-food goods, such as cars left by working in garages adjacent to the house. Centers for the control and prevention of diseases report that, every year, several thousand people turn to an ambulance hospital in carbon monoxide poisoning.
The presence of blood
Carbon monoxide is absorbed through breathing and enters the bloodstream through gas exchange in the lungs. It is also produced during the metabolism of hemoglobin and enters blood from tissues, and thus present in all normal tissues, even if it does not fall into the body when breathing. Normal levels of carbon monoxide, circulating in blood, range from 0% to 3%, and higher in smokers. Carbon monoxide levels can not be assessed using a physical inspection. Laboratory tests require the presence of a sample of blood (arterial or venous) and laboratory analysis on the co-hydroxymeter. In addition, non-invasive carboxygemoglobin (SPCO) with a pulsed co-hydroxymeter is more efficient compared to invasive methods.
Astrophysics
Outside the land, carbon monoxide is the second most common molecule in the interstellar medium, after molecular hydrogen. Because of its asymmetry, carbon monoxide molecule produces much stronger spectral lines than hydrogen molecule, thanks to which it is much easier to detect. The inter-storage CO was first discovered with the help of radio telescope in 1970. Currently, it is the most commonly used molecular gas indicator in the interstellar medium of galaxies, and molecular hydrogen can be detected only with ultraviolet light, which requires space telescopes. Carbon monoxide observations provide most of the information about molecular clouds in which most stars are formed. Beta Pictoris, the second in the brightness of the star in the constellation Pictor, demonstrates an excess of infrared radiation compared to normal stars of its type, which is due to a large amount of dust and gas (including carbon oxide) near the star.
Production
A variety of methods have been developed for the production of carbon monoxide.
Industrial production
The main industrial source of CO is generator gas, a mixture containing mainly carbon monoxide and nitrogen, formed when combustion of carbon in the air at high temperatures, when there is an excess carbon. In the oven, the air is passed through the coke layer. The initially produced CO2 is balanced with the remaining hot coal with the receipt of CO. CO2 reaction with carbon with obtaining CO is described as a reaction of Bouire. At temperatures above 800 ° C, CO is a predominant product:
CO2 + C → 2 CO (ΔH \u003d 170 kJ / mol)
Another source of "water gas", a mixture of hydrogen and carbon monoxide obtained by the endothermic reaction of steam and carbon:
H2O + C → H2 + CO (ΔH \u003d +131 kJ / mole)
Other similar "synthetic gases" can be obtained from natural gas and other types of fuel. Carbon oxide is also a bypass product restoration of metal oxide ore with carbon:
MO + C → M + CO
Carbon monoxide is also obtained by direct carbon oxidation in a limited amount of oxygen or air.
2c (S) + O 2 → 2 → 2 (G)
Since CO is gas, the reduction process can be controlled by heating, using a positive (favorable) entropy of the reaction. The Ellingam diagram shows that the formation of CO is given preference compared to CO2 at high temperatures.
Preparation in the laboratory
Carbon monoxide is conveniently obtained in a laboratory by dehydrating formic acid or oxalic acid, for example, with a concentrated sulfuric acid. Another way is the heating of a homogeneous mixture of powdered metal zinc and calcium carbonate, which releases CO and leaves zinc oxide and calcium oxide:
Zn + Caco3 → Zno + Cao + Co
Nitrate of silver and iodoform also give carbon monoxide:
CHI3 + 3AGNO3 + H2O → 3HNO3 + CO + 3AGI
Coordination Chemistry
Most metals form coordination complexes containing covalently attached carbon monoxide. Only metals in the lower degrees of oxidation will be connected to the ligands of carbon monoxide. This is due to the fact that there is a sufficient density of electrons to facilitate the opposite donation from the metal DXZ orbital, to π * molecular orbitals from CO. The vapor pair on the carbon atom in CO also sacrifice electron density in DX²-Y² on a metal for the formation of a sigma-bond. This electron donation is also manifested by a cis-effect, or a mabilization from ligands in the cis-position. Nickel carbonyl, for example, is formed by direct combination of carbon monoxide and metal nickel:
Ni + 4 Co → Ni (CO) 4 (1 bar, 55 ° C)
For this reason, nickel in the tube or part of it should not enter into long-term contact with carbon monoxide. Nickel carbonyl is easily decomposed back to NI and CO when contact with hot surfaces, and this method is used for industrial cleaning of nickel during the monda. In carbonyl nickel and other carbonyls, electronic steam on carbon interacts with the metal; Carbon monoxide donates electronic pair of metal. In such situations, carbon monoxide is called carbonyl ligand. One of the most important carbonyl metals is pentarbonyl iron, FE (CO) 5. Many metal-CO complexes are obtained by decarboning organic solvents, and not from CO. For example, iridium trichloride and triphenylphosphine are reacting in a boiling 2-methoxyethanol or DMF, to obtain IRCl (CO) (PPH3) 2. Metal carbonyls in coordination chemistry are usually studied using infrared spectroscopy.
Organic chemistry and chemistry of the main groups of elements
In the presence of strong acids and water, carbon monoxide reacts with alkenes to form carboxylic acids in a process known as the Koh Haaf reaction. In the reaction of Gatterman-Koch, the areenes are converted into benzaldehyde derivatives in the presence of AlCl3 and HCl. Lithiumorganic compounds (for example, butyl lithium) react with carbon monoxide, but these reactions are not applicable to these reactions. Despite the fact that CO reacts with carboats and carbanions, it is relatively non-reactive to organic compounds without interference with metal catalysts. With reagents from the main group, CO passes several remarkable reactions. CO chlorination is an industrial process leading to the formation of an important compound of phosgene. With boaram, CO forms adduct, H3BCO, which is isoelectronic with the cation of Atzil +. CO reacts with sodium, creating products obtained from C-s. Compounds of cyclohexagegexon or trocinyl (C6O6) and cyclopentanepenon or leafic acid (C5O5), which have so far obtained only in trace amounts, can be considered as carbon monoxide polymers. With a pressure of more than 5 GPa, carbon monoxide turns into a solid carbon and oxygen polymer. This is a metastable substance at atmospheric pressure, but it is a powerful explosive.
Using
Chemical industry
Carbon monoxide is an industrial gas that has many applications in the production of bulk chemicals. Large amounts of aldehydes are obtained by reacting hydroforming alkenes, carbon monoxide and H2. Hydraoformaling in the Shell process makes it possible to create precursors of detergents. Fosgene, suitable for obtaining isocyanates, polycarbonates and polyurethanes, is carried out by passing the purified carbon monoxide and gaseous chlorine through a layer of porous activated carbon, which serves as a catalyst. The global production of this compound in 1989 was estimated at 2.74 million tons.
CO + CL2 → COCL2
Methanol is obtained by hydrogenation of carbon monoxide. In a related reaction, hydrogenation of carbon monoxide is associated with the formation of C-C communication, as in the Fischer-Tropsch process, where carbon monoxide is hydrogenated to liquid hydrocarbon fuels. This technology allows you to transform coal or biomass into diesel fuel. In the process of Monsanto, carbon monoxide and methanol are reacting in the presence of a catalyst based on rhodium and homogeneous hydrochloric acid to form acetic acid. This process is responsible for most of the industrial production of acetic acid. On an industrial scale, clean carbon monoxide is used to clean nickel during monda.
Coloring meat
Carbon monoxide is used in modified atmospheric packaging systems in the US, mainly when packing fresh meat products, such as beef, pork and fish to keep their fresh appearance. Carbon monoxide is connected to the Mioglobin with the formation of carboxymoglobin, bright-cherry-red pigment. Carboxyimioglobin is more stable than the oxidized form of myoglobin, oxyoglobin, which can oxidize to the brown pigment of methmioglobin. This stable red can be saved much longer than the usual packaged meat. Typical carbon monoxide levels used in installations using this process are from 0.4% to 0.5%. This technology is first recognized as "generally safe" (GRAS) for US and drug control and drug control (FDA) in 2002 for use as a secondary packaging system, and does not require labeling. In 2004, FDA approved Co as the main packaging method, stating that CO does not hide the smell of damage. Despite this, the decision remains a controversial question of whether this method will mask product damage. In 2007, a bill was proposed in the US House of Representatives, offering a modified packaging process using carbon oxide with a color additive, but the bill was not adopted. Such a packaging process is prohibited in many other countries, including Japan, Singapore and European Union countries.
Medicine
In biology, carbon monoxide is naturally produced under the action of hemoxygenase 1 and 2 on the gem from the decay of hemoglobin. This process produces a certain amount of carboxygemoglobin in normal people, even if they do not inhale carbon monoxide. After the first report that carbon monoxide is a normal neurotransmitter in 1993, as well as one of three gases, which naturally modulate inflammatory reactions in the body (two other - nitrogen oxide and hydrogen sulfide), carbon monoxide received great clinical attention as a biological regulator . In many tissues, all three gas, as you know, act as anti-inflammatory agents, vasodilators and amplifiers of neovascular growth. Nevertheless, these issues are difficult, since non-unuscular growth is not always useful, as it plays a certain role in the growth of the tumor, as well as in the development of wet maculodyfia, the disease, the risk of which increases from 4 to 6 times during smoking (main source of carbon monoxide In the blood, several times more than natural production). There is a theory that in some synapses of nerve cells, when long-term memories are postponed, the receiving cell produces carbon monoxide, which is back transmitted to the transmitting chamber forcing it more easily in the future. Some such nervous cells, as shown, contain a guanillates, an enzyme that is activated by carbon oxide. In many laboratories around the world, studies have been conducted with carbon monoxide relative to its anti-inflammatory and cytoprotective properties. These properties can be used to prevent the development of a number of pathological conditions, including ischemic reperfusion damage, transplant rejection, atherosclerosis, severe sepsis, severe malaria or autoimmune diseases. Clinical trials were held with the participation of people, but their results were not yet issued.
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