- UN hazard class 2.3
- UN secondary hazard 2.1
The structure of the molecule
The CO molecule, like the isoelectronic nitrogen molecule, has a triple bond. Since these molecules are similar in structure, their properties are also similar - very low melting and boiling points, close values of standard entropies, etc.
Within the framework of the method of valence bonds, the structure of the CO molecule can be described by the formula: C≡O:, and the third bond is formed according to the donor-acceptor mechanism, where carbon is an electron pair acceptor, and oxygen is a donor.
Due to the presence of a triple bond, the CO molecule is very strong (the dissociation energy is 1069 kJ / mol, or 256 kcal / mol, which is more than that of any other diatomic molecules) and has a small internuclear distance (d C≡O = 0.1128 nm or 1, 13Å).
The molecule is weakly polarized, the electric moment of its dipole μ = 0.04·10 -29 C·m (direction of the dipole moment O - →C +). Ionization potential 14.0 V, force coupling constant k = 18.6.
Discovery history
Carbon monoxide was first produced by the French chemist Jacques de Lasson when zinc oxide was heated with coal, but was initially mistaken for hydrogen because it burned with a blue flame. The fact that this gas contains carbon and oxygen was discovered by the English chemist William Cruikshank. Carbon monoxide outside the Earth's atmosphere was first discovered by the Belgian scientist M. Mizhot (M. Migeotte) in 1949 by the presence of the main vibrational-rotational band in the IR spectrum of the Sun.
Carbon monoxide in the Earth's atmosphere
There are natural and anthropogenic sources of entry into the Earth's atmosphere. Under natural conditions, on the Earth's surface, CO is formed during the incomplete anaerobic decomposition of organic compounds and during the combustion of biomass, mainly during forest and steppe fires. Carbon monoxide is formed in the soil both biologically (excreted by living organisms) and non-biologically. The release of carbon monoxide due to phenolic compounds common in soils containing OCH 3 or OH groups in ortho- or para-positions with respect to the first hydroxyl group has been experimentally proven.
The overall balance of production of non-biological CO and its oxidation by microorganisms depends on specific environmental conditions, primarily on humidity and the value of . For example, from arid soils, carbon monoxide is released directly into the atmosphere, thus creating local maxima in the concentration of this gas.
In the atmosphere, CO is the product of chain reactions involving methane and other hydrocarbons (primarily isoprene).
The main anthropogenic source of CO is currently the exhaust gases of internal combustion engines. Carbon monoxide is formed when hydrocarbon fuels are burned in internal combustion engines at insufficient temperatures or a poorly tuned air supply system (not enough oxygen is supplied to oxidize CO to CO 2 ). In the past, a significant proportion of anthropogenic CO emissions into the atmosphere came from lighting gas used for indoor lighting in the 19th century. In composition, it approximately corresponded to water gas, that is, it contained up to 45% carbon monoxide. At present, in the municipal sector, this gas has been replaced by much less toxic natural gas (lower representatives of the homologous series of alkanes - propane, etc.)
The intake of CO from natural and anthropogenic sources is approximately the same.
Carbon monoxide in the atmosphere is in a rapid cycle: the average residence time is about 0.1 year, oxidized by hydroxyl to carbon dioxide.
Receipt
industrial way
2C + O 2 → 2CO (the thermal effect of this reaction is 22 kJ),
2. or when reducing carbon dioxide with hot coal:
CO 2 + C ↔ 2CO (ΔH=172 kJ, ΔS=176 J/K).
This reaction often occurs in a furnace furnace when the furnace damper is closed too early (until the coals have completely burned out). The resulting carbon monoxide, due to its toxicity, causes physiological disorders (“burnout”) and even death (see below), hence one of the trivial names - “carbon monoxide”. The picture of the reactions taking place in the furnace is shown in the diagram.
The carbon dioxide reduction reaction is reversible, the effect of temperature on the equilibrium state of this reaction is shown in the graph. The flow of the reaction to the right provides the entropy factor, and to the left - the enthalpy factor. At temperatures below 400°C, the equilibrium is almost completely shifted to the left, and at temperatures above 1000°C to the right (in the direction of CO formation). At low temperatures, the rate of this reaction is very slow, so carbon monoxide is quite stable under normal conditions. This equilibrium has a special name boudoir balance.
3. Mixtures of carbon monoxide with other substances are obtained by passing air, water vapor, etc. through a layer of hot coke, hard or brown coal, etc. (see producer gas, water gas, mixed gas, synthesis gas).
laboratory method
TLV (maximum threshold concentration, USA): 25 MPC r.z. according to Hygienic Standards GN 2.2.5.1313-03 is 20 mg/m³
Protection against carbon monoxide
Due to such a good calorific value, CO is a component of various technical gas mixtures (see, for example, generator gas) used, among other things, for heating.
halogens. The reaction with chlorine has received the greatest practical application:
CO + Cl 2 → COCl 2
The reaction is exothermic, its thermal effect is 113 kJ, in the presence of a catalyst (activated carbon) it proceeds already at room temperature. As a result of the reaction, phosgene is formed - a substance that has become widespread in various branches of chemistry (and also as a chemical warfare agent). By analogous reactions, COF 2 (carbonyl fluoride) and COBr 2 (carbonyl bromide) can be obtained. Carbonyl iodide was not received. The exothermicity of reactions rapidly decreases from F to I (for reactions with F 2, the thermal effect is 481 kJ, with Br 2 - 4 kJ). It is also possible to obtain mixed derivatives, such as COFCl (for details, see halogen derivatives of carbonic acid).
By the reaction of CO with F 2 , in addition to carbonyl fluoride, a peroxide compound (FCO) 2 O 2 can be obtained. Its characteristics: melting point -42°C, boiling point +16°C, has a characteristic odor (similar to the smell of ozone), decomposes with an explosion when heated above 200°C (reaction products CO 2 , O 2 and COF 2), in acidic medium reacts with potassium iodide according to the equation:
(FCO) 2 O 2 + 2KI → 2KF + I 2 + 2CO 2
Carbon monoxide reacts with chalcogens. With sulfur it forms carbon sulfide COS, the reaction proceeds when heated, according to the equation:
CO + S → COS ΔG° 298 = −229 kJ, ΔS° 298 = −134 J/K
Similar selenoxide COSe and telluroxide COTe have also been obtained.
Restores SO 2:
SO 2 + 2CO → 2CO 2 + S
With transition metals, it forms very volatile, combustible and toxic compounds - carbonyls, such as Cr (CO) 6, Ni (CO) 4, Mn 2 CO 10, Co 2 (CO) 9, etc.
As stated above, carbon monoxide is slightly soluble in water, but does not react with it. Also, it does not react with solutions of alkalis and acids. However, it reacts with alkali melts:
CO + KOH → HCOOK
An interesting reaction is the reaction of carbon monoxide with metallic potassium in an ammonia solution. In this case, the explosive compound potassium dioxodicarbonate is formed:
2K + 2CO → K + O - -C 2 -O - K +
By reacting with ammonia at high temperatures, an important industrial compound, HCN, can be obtained. The reaction proceeds in the presence of a catalyst (oxide
Publication date 28.01.2012 12:18
Carbon monoxide- carbon monoxide, which is too often heard when it comes to poisoning by combustion products, accidents in industry or even at home. Due to the special toxic properties of this compound, an ordinary home gas water heater can cause the death of an entire family. There are hundreds of examples of this. But why is this happening? What is carbon monoxide, really? Why is it dangerous for humans?
What is carbon monoxide, formula, basic properties
Carbon monoxide formula which is very simple and denotes the union of an oxygen atom and carbon - CO, - one of the most toxic gaseous compounds. But unlike many other hazardous substances that are used only for narrow industrial purposes, carbon monoxide chemical contamination can occur during completely ordinary chemical processes, even in everyday life.
However, before moving on to how the synthesis of this substance occurs, consider what is carbon monoxide in general and what are 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;
- highly combustible with a high combustion temperature (up to 2100 degrees Celsius).
Carbon monoxide formation
In home or industry carbon monoxide formation usually occurs in one of several fairly simple ways, which easily explains the risk of accidental synthesis of this substance with a risk to the personnel of the enterprise or residents of the house where the heating equipment has malfunctioned or safety has been violated. Consider the main ways of formation of carbon monoxide:
- combustion of carbon (coal, coke) or its compounds (gasoline and other liquid fuels) in conditions of lack of oxygen. As you might guess, the lack of fresh air, dangerous from the point of view of the risk of carbon monoxide synthesis, easily occurs in internal combustion engines, domestic columns with impaired ventilation, industrial and conventional furnaces;
- interaction of ordinary carbon dioxide with hot coal. Such processes occur in the furnace constantly and are completely reversible, but, given the already mentioned lack of oxygen, with the damper closed, carbon monoxide is formed in much larger quantities, which is a mortal danger to people.
Why is carbon monoxide dangerous?
In sufficient concentration carbon monoxide properties which is explained by its high chemical activity, is extremely dangerous for human life and health. The essence of such poisoning lies, first of all, in the fact that the molecules of this compound instantly bind blood hemoglobin and deprive it of its ability to carry oxygen. Thus, carbon monoxide reduces the level of cellular respiration with the most serious consequences for the body.
Answering the question " Why is carbon monoxide dangerous?"It is worth mentioning that, unlike many other toxic substances, a person does not feel any specific smell, does not experience discomfort and is not able to recognize its presence in the air by any other means, without special equipment. As a result, the victim simply does not take no measures to escape, and when the effects of carbon monoxide (drowsiness and unconsciousness) become apparent, it may be too late.
Carbon monoxide is fatal within an hour at air concentrations above 0.1%. At the same time, the exhaust of a completely ordinary passenger car contains from 1.5 to 3% of this substance. And that's assuming the engine is in good condition. This easily explains the fact that carbon monoxide poisoning often occurs precisely in garages or inside a car sealed with snow.
Other most dangerous cases in which people have been poisoned by carbon monoxide at home or at work are ...
- overlap or breakdown of the ventilation of the heating column;
- illiterate use of wood or coal stoves;
- on fires in enclosed spaces;
- close to busy highways;
- at industrial enterprises where carbon monoxide is actively used.
Carbon monoxide (carbon monoxide, carbon monoxide, carbon(II) oxide) is a colorless, extremely toxic, tasteless and odorless gas, lighter than air (under normal conditions). The chemical formula is CO.
The structure of the molecule
Due to the presence of a triple bond, the CO molecule is very strong (the dissociation energy is 1069 kJ / mol, or 256 kcal / mol, which is more than that of any other diatomic molecules) and has a small internuclear distance ( d C≡O = 0.1128 nm or 1.13 Å).
The molecule is weakly polarized, its electric dipole moment μ = 0.04⋅10 −29 C m . Numerous studies have shown that the 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 that previously assumed). Ionization energy 14.0 eV, force coupling constant k = 18,6 .
Properties
Carbon monoxide(II) is a colorless, odorless and tasteless gas. combustible The so-called "carbon monoxide smell" is actually the smell of organic impurities.
| Standard Gibbs energy of formation Δ G | −137.14 kJ/mol (g) (at 298 K) |
| Standard Entropy of Education S | 197.54 J/mol K (g) (at 298 K) |
| Standard molar heat capacity Cp | 29.11 J/mol K (g) (at 298 K) |
| Enthalpy of melting Δ H pl | 0.838 kJ/mol |
| Boiling enthalpy Δ H kip | 6.04 kJ/mol |
| Critical temperature t Crete | -140.23°C |
| critical pressure P Crete | 3.499 MPa |
| Critical density ρ crit | 0.301 g/cm³ |
The main types of chemical reactions in which carbon monoxide (II) is involved are addition reactions and redox reactions, in which it exhibits reducing properties.
At room temperature, CO is inactive, its chemical activity increases significantly when heated and in solutions. So, in solutions, it restores salts,, and others to metals already at room temperature. When heated, it also reduces other metals, for example CO + CuO → Cu + CO 2. This is widely used in pyrometallurgy. The method for the qualitative detection of CO is based on the reaction of CO in solution with palladium chloride, see below.
Oxidation of CO in solution often proceeds at a noticeable rate only in the presence of a catalyst. When choosing the latter, the nature of the oxidizing agent plays the main role. So, KMnO 4 most rapidly oxidizes CO in the presence of finely divided silver, K 2 Cr 2 O 7 - in the presence of salts, KClO 3 - in the presence of OsO 4. In general, CO is similar in its reducing properties to molecular hydrogen.
Below 830 °C, CO is a stronger reducing agent, and higher, hydrogen. So 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 shifted to the right, above 830 °C to the left.
Interestingly, there are bacteria capable of obtaining the energy they need for life due to the oxidation of CO.
Carbon monoxide (II) burns with a blue flame (reaction start temperature 700 ° C) in air:
2 C O + O 2 → 2 C O 2 (\displaystyle (\mathsf (2CO+O_(2)\rightarrow 2CO_(2)))) (Δ G° 298 = −257 kJ, Δ S° 298 = −86 J/K).The combustion temperature of CO can reach 2100 °C. The combustion reaction is a chain one, 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, among other things, for heating. Explosive when mixed with air; lower and upper concentration limits of flame propagation: from 12.5 to 74% (by volume) .
halogens. The reaction with chlorine has received the greatest practical application:
C O + C l 2 → C O C l 2 . (\displaystyle (\mathsf (CO+Cl_(2)\rightarrow COCl_(2))).)By reacting CO with F 2 , in addition to COF 2 carbonyl fluoride, a peroxide compound (FCO) 2 O 2 can be obtained. Its characteristics: melting point -42 ° C, boiling point +16 ° C, has a characteristic odor (similar to the smell of ozone), when heated above 200 ° C, it decomposes with an explosion (reaction products CO 2 , O 2 and COF 2), in acidic medium reacts with potassium iodide according to the 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 monoxide(II) reacts with chalcogens. With sulfur it forms carbon sulfide COS, the reaction proceeds when heated, according to the equation:
C O + S → C O S (\displaystyle (\mathsf (CO+S\rightarrow COS))) (Δ G° 298 = −229 kJ, Δ S° 298 = −134 J/K).Similar carbon selenoxide COSe and carbon telluroxide COTe have also been obtained.
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, it forms combustible and toxic compounds - 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 monoxide(II) is slightly soluble in water, but does not react with it. Also, it does not react with solutions of alkalis and acids. However, it reacts with alkali melts to form the corresponding formates:
C O + K O H → H C O O K . (\displaystyle (\mathsf (CO+KOH\rightarrow HCOOK.)))An interesting reaction is the reaction of carbon monoxide (II) with metallic potassium in an ammonia solution. This forms the explosive compound potassium dioxodicarbonate:
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 the source of critical industrial products such as methanol, synthetic diesel fuel, polyhydric alcohols, oils and lubricants.
Physiological action
Toxicity
Carbon monoxide is highly toxic.
The toxic effect of carbon monoxide (II) is due to the formation of carboxyhemoglobin - a much stronger carbonyl complex with hemoglobin, compared with the complex of hemoglobin with oxygen (oxyhemoglobin). Thus, the processes of oxygen transport and cellular respiration are blocked. Air concentrations greater than 0.1% result in death within one hour.
- The victim should be taken out to fresh air. In case of mild poisoning, hyperventilation of the lungs with oxygen is sufficient.
- Artificial ventilation of the lungs.
- Lobeline or caffeine under the skin.
- Carboxylase intravenously.
World medicine does not know reliable antidotes for use in case of carbon monoxide poisoning.
Protection against carbon monoxide(II)
endogenous carbon monoxide
Endogenous carbon monoxide is produced normally by the cells of the human and animal body and acts as a signaling molecule. It plays a known physiological role in the body, in particular being a neurotransmitter and inducing 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, hypertension, heart failure, and various inflammatory processes.
Endogenous carbon monoxide is formed in the body due to the oxidizing action of the heme oxygenase enzyme on heme, which is a product of the destruction of hemoglobin and myoglobin, as well as other heme-containing proteins. This process causes the formation of a small amount of carboxyhemoglobin in the human blood, even if the person does not smoke and breathes not atmospheric air (always containing small amounts of exogenous carbon monoxide), but pure oxygen or a mixture of nitrogen and oxygen.
Following the first evidence that appeared in 1993 that endogenous carbon monoxide is a normal neurotransmitter in the human body, as well as one of three endogenous gases that normally modulate the course of inflammatory reactions in the body (the other two are nitric oxide (II) and hydrogen sulfide ), endogenous carbon monoxide has received considerable attention from clinicians and researchers as an important biological regulator. In many tissues, all three of the aforementioned gases have been shown to be anti-inflammatory agents, vasodilators, and also induce angiogenesis. However, not everything is so simple and unambiguous. Angiogenesis is not always a beneficial effect, since it plays a role in the growth of malignant tumors in particular, and is also one of the causes of retinal damage in macular degeneration. In particular, it is important to note that smoking (the main source of carbon monoxide in the blood, giving several times higher concentration than natural production) increases the risk of macular degeneration of the retina by 4-6 times.
There is a theory that in some synapses of nerve cells, where information is stored for a long time, the receiving cell, in response to the received signal, produces endogenous carbon monoxide, which transmits the signal back to the transmitting cell, which informs it of its readiness to receive signals from it in the future. and increasing the activity of the signal transmitter cell. Some of these nerve cells contain guanylate cyclase, an enzyme that is activated when exposed to endogenous carbon monoxide.
Research on the role of endogenous carbon monoxide as an anti-inflammatory agent and cytoprotector has been carried out in many laboratories around the world. These properties of endogenous carbon monoxide make the effect on its metabolism an interesting therapeutic target for the treatment of various pathological conditions such as tissue damage caused by ischemia and subsequent reperfusion (for example, myocardial infarction, ischemic stroke), transplant rejection, vascular atherosclerosis, severe sepsis , severe malaria , autoimmune diseases. Human clinical trials have also been conducted, but their results have not yet been published.
In summary, what is known as of 2015 about the role of endogenous carbon monoxide in the body can be summarized as follows:
- Endogenous carbon monoxide is one of the important endogenous signaling molecules;
- Endogenous carbon monoxide modulates CNS and cardiovascular functions;
- Endogenous carbon monoxide inhibits platelet aggregation and their adhesion to vessel walls;
- Influencing the exchange of endogenous carbon monoxide in the future may be one of the important therapeutic strategies for a number of diseases.
Discovery history
The toxicity of the smoke emitted during the combustion of coal was described by Aristotle and Galen.
Carbon monoxide (II) was first obtained by the French chemist Jacques de Lasson in the heating of zinc oxide with coal, but was initially mistaken for hydrogen, as it burned with a blue flame.
The fact that this gas contains carbon and oxygen was discovered by the English chemist William Kruikshank. The toxicity of the gas was investigated in 1846 by the French physician Claude Bernard in experiments on dogs.
Carbon monoxide (II) outside the Earth's atmosphere was first discovered by the Belgian scientist M. Mizhot (M. Migeotte) in 1949 by the presence of the main vibrational-rotational band in the IR spectrum of the Sun. Carbon(II) oxide was discovered in the interstellar medium in 1970.
Receipt
industrial way
- It is formed during the combustion of carbon or compounds based on it (for example, gasoline) in conditions of lack of oxygen:
- or when reducing carbon dioxide with hot coal:
This reaction occurs during the furnace furnace, when the furnace damper is closed too early (until the coals have completely burned out). The resulting carbon monoxide (II), due to its toxicity, causes physiological disorders (“burnout”) and even death (see below), hence one of the trivial names - “carbon monoxide”.
The carbon dioxide reduction reaction is reversible, the effect of temperature on the equilibrium state of this reaction is shown in the graph. The flow of the reaction to the right provides the entropy factor, and to the left - the enthalpy factor. At temperatures below 400 °C, the equilibrium is almost completely shifted to the left, and at temperatures above 1000 °C to the right (in the direction of CO formation). At low temperatures, the rate of this reaction is very low; therefore, carbon monoxide (II) is quite stable under normal conditions. This equilibrium has a special name boudoir balance.
- Mixtures of carbon monoxide (II) with other substances are obtained by passing air, water vapor, etc. through a layer of hot coke, hard 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 passing gaseous formic acid over phosphorus oxide P 2 O 5 . Reaction scheme:
- Heating a mixture of oxalic and concentrated sulfuric acids. The reaction goes according to the equation:
- Heating a mixture of potassium hexacyanoferrate(II) with concentrated sulfuric acid. The reaction goes according to the equation:
- Recovery from zinc carbonate by magnesium when heated:
Determination of carbon monoxide (II)
Qualitatively, the presence of CO can be determined by the darkening of palladium chloride solutions (or paper impregnated with this solution). Darkening is associated with the release of finely dispersed metallic 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\downarrow +CO_(2)+2HCl.)))This reaction is very sensitive. Standard solution: 1 gram of palladium chloride per liter of water.
The quantitative determination of carbon monoxide (II) is based on the 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 monoxide(II) is an intermediate reagent used in reactions with hydrogen in the most important industrial processes for the production of organic alcohols and straight hydrocarbons.
- Carbon monoxide (II) is used to process animal meat and fish, giving them a bright red color and a look of freshness, without changing the taste (technologies clear smoke and Tasteless smoke). The permissible concentration of CO is 200 mg/kg of meat.
- Carbon monoxide(II) is the main component of generator gas used as a fuel in natural gas vehicles.
- Carbon monoxide from engine exhaust was used by the Nazis during World War II to massacre people by poisoning.
Carbon monoxide(II) in the Earth's atmosphere
There are natural and anthropogenic sources of entry into the Earth's atmosphere. Under natural conditions, on the Earth's surface, CO is formed during the incomplete anaerobic decomposition of organic compounds and during the combustion of biomass, mainly during forest and steppe fires. Carbon monoxide (II) is formed in the soil both biologically (excreted by living organisms) and non-biologically. The release of carbon monoxide (II) due to phenolic compounds common in soils containing OCH 3 or OH groups in ortho- or para-positions with respect to the first hydroxyl group has been experimentally proven.
The overall balance of production of non-biological CO and its oxidation by microorganisms depends on specific environmental conditions, primarily on humidity and the value of . For example, from arid soils, carbon monoxide(II) is released directly into the atmosphere, thus creating local maxima in the concentration of this gas.
In the atmosphere, CO is the product of chain reactions involving methane and other hydrocarbons (primarily isoprene).
The main anthropogenic source of CO currently is the exhaust gases of internal combustion engines. Carbon monoxide is formed when hydrocarbon fuels are burned in internal combustion engines at insufficient temperatures or a poorly tuned air supply system (not enough oxygen is supplied to oxidize CO to CO 2 ). In the past, a significant proportion of anthropogenic CO emissions into the atmosphere came from lighting gas used for indoor lighting in the 19th century. In composition, it approximately corresponded to water gas, that is, it contained up to 45% carbon monoxide (II). In the public sector, it is not used due to the presence of a much cheaper and more energy-efficient analogue -
Carbon monoxide, carbon monoxide (CO) is a colorless, odorless and tasteless gas that is slightly less dense than air. It is toxic to hemoglobin animals (including humans) if concentrations are above about 35 ppm, although it is also produced in normal animal metabolism in small amounts, and is believed to have some normal biological functions. In the atmosphere, it is spatially variable and rapidly decaying, and has a role in the formation of ozone at ground level. Carbon monoxide is made up of one carbon atom and one oxygen atom linked by a triple bond, which consists of two covalent bonds, as well as one dative covalent bond. It is the simplest carbon monoxide. It is isoelectronic with the cyanide anion, the nitrosonium cation, and molecular nitrogen. In coordination complexes, the carbon monoxide ligand is called the carbonyl.
Story
Aristotle (384-322 BC) first described the process of burning coal, which leads to the formation of toxic fumes. In ancient times, there was a method of execution - to close the criminal in a bathroom with smoldering coals. However, at that time the mechanism of death was unclear. The Greek physician Galen (AD 129-199) suggested that there was a change in the composition of the air that harmed a person when inhaled. In 1776, the French chemist de Lasson produced CO by heating zinc oxide with coke, but the scientist erroneously concluded that the gaseous product was hydrogen because it burned with a blue flame. The gas was identified as a compound containing carbon and oxygen by the Scottish chemist William Cumberland Cruikshank in 1800. Its toxicity in dogs was thoroughly investigated by Claude Bernard around 1846. During World War II, a gas mixture containing carbon monoxide was used to fuel motor vehicles operating in parts of the world where gasoline and diesel were scarce. External (with some exceptions) charcoal or wood gas generators were installed and a mixture of atmospheric nitrogen, carbon monoxide and small amounts of other gasification gases was fed to the gas mixer. The gas mixture resulting from this process is known as wood gas. Carbon monoxide was also used on a large scale during the Holocaust in some German Nazi death camps, most notably in the Chelmno gas vans and in the T4 "euthanasia" killing program.
Sources
Carbon monoxide is formed during the partial oxidation of carbon-containing compounds; it forms when there is not enough oxygen to produce carbon dioxide (CO2), such as when working on a stove or internal combustion engine, in a confined space. In the presence of oxygen, including atmospheric concentrations, carbon monoxide burns with a blue flame, producing carbon dioxide. Coal gas, which was widely used until the 1960s for indoor lighting, cooking and heating, contained carbon monoxide as a significant fuel component. Some processes in modern technology, such as iron smelting, still produce carbon monoxide as a by-product. Worldwide, the largest sources of carbon monoxide are natural sources, due to photochemical reactions in the troposphere, which generate about 5 × 1012 kg of carbon monoxide per year. Other natural sources of CO include volcanoes, forest fires, and other forms of combustion. In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on heme from the breakdown of hemoglobin. This process produces a certain amount of carboxyhemoglobin in normal people, even if they do not inhale carbon monoxide. Since the first report that carbon monoxide was a normal neurotransmitter in 1993, as well as one of the three gases that naturally modulate inflammatory responses in the body (the other two being nitric oxide and hydrogen sulfide), carbon monoxide has received much attention as a biological regulator. In many tissues, all three gases act as anti-inflammatory agents, vasodilators, and promoters of neovascular growth. Small amounts of carbon monoxide are being clinically tested as a drug. However, excessive amounts of carbon monoxide cause carbon monoxide poisoning.
Molecular properties
Carbon monoxide has a molecular weight of 28.0, making it slightly lighter than air, which has an average molecular weight of 28.8. According to the ideal gas law, CO is therefore less dense than air. The bond length between the carbon atom and the oxygen atom is 112.8 pm. This bond length is consistent with a triple bond, as in molecular nitrogen (N2), which has a similar bond length and almost the same molecular weight. The carbon-oxygen double bonds are much longer, for example 120.8 m for formaldehyde. The boiling point (82 K) and melting point (68 K) are very similar to N2 (77 K and 63 K, respectively). The bond dissociation energy of 1072 kJ/mol is stronger than that of N2 (942 kJ/mol) and represents the strongest known chemical bond. The ground state of the carbon monoxide electron is singlet, as there are no unpaired electrons.
Bonding and dipole moment
Carbon and oxygen together have a total of 10 electrons in the valence shell. Following the octet rule for carbon and oxygen, two atoms form a triple bond, with six electrons in common in three bonding molecular orbitals, rather than the usual double bond found in organic carbonyl compounds. Since four of the shared electrons come from the oxygen atom and only two from the carbon, one bonding orbital is occupied by two electrons from the oxygen atoms, forming a dative or dipole bond. This results in a C ← O polarization of the molecule, with a small negative charge on carbon and a small positive charge on oxygen. The other two bonding orbitals each occupy one electron from carbon and one from oxygen, forming (polar) covalent bonds with reversed C → O polarization, since oxygen is more electronegative than carbon. In free carbon monoxide, the net negative charge δ- remains at the end of the carbon, and the molecule has a small dipole moment of 0.122 D. Thus, the molecule is asymmetric: oxygen has more electron density than carbon, and also a small positive charge, compared to carbon, which is negative. In contrast, the isoelectronic dinitrogen molecule does not have a dipole moment. If carbon monoxide acts as a ligand, the polarity of the dipole can reverse with a net negative charge at the oxygen end, depending on the structure of the coordination complex.
Bond polarity and oxidation state
Theoretical and experimental studies show that, despite the greater electronegativity of oxygen, the dipole moment proceeds from the more negative end of carbon to the more positive end of oxygen. These three bonds are actually polar covalent bonds that are highly polarized. The calculated polarization to the oxygen atom is 71% for the σ bond and 77% for both π bonds. The oxidation state of carbon to carbon monoxide in each of these structures is +2. It is calculated as follows: all bonding electrons are considered to belong to more electronegative oxygen atoms. Only two non-bonding electrons on carbon are assigned to carbon. In this count, 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 fatal air poisoning in many countries. Carbon monoxide is a colorless substance, odorless and tasteless, but highly toxic. It combines with hemoglobin to form carboxyhemoglobin, which "usurps" the site in hemoglobin that normally carries oxygen but is inefficient for delivering oxygen to body tissues. Concentrations as low as 667 ppm can cause up to 50% of the body's hemoglobin to be converted to carboxyhemoglobin. 50% carboxyhemoglobin levels can lead to convulsions, coma and death. In the United States, the Department of Labor limits long-term levels of carbon monoxide exposure in the workplace to 50 parts per million. For a short period of time, absorption of carbon monoxide is cumulative, as its half-life is about 5 hours in 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 weak. Affected families often believe they are victims of food poisoning. Babies can be irritable and feed poorly. Neurological symptoms include confusion, disorientation, blurred vision, fainting (loss of consciousness), and seizures. Some descriptions of carbon monoxide poisoning include retinal hemorrhage as well as an abnormal cherry-red color to the blood. In most clinical diagnoses, these features are rare. One difficulty with the usefulness of this "cherry" effect is that it corrects, or masks, an otherwise unhealthy appearance, since the main effect of removing venous hemoglobin is to make the suffocated person appear more normal, or a dead person appears alive, similar to the effect of red dyes in embalming composition. This staining effect in anoxic CO-poisoned tissue is due to the commercial use of carbon monoxide in meat staining. Carbon monoxide also binds to other molecules such as myoglobin and mitochondrial cytochrome oxidase. Exposure to carbon monoxide can cause significant damage to the heart and central nervous system, especially in the globus pallidus, often associated with long-term chronic conditions. Carbon monoxide can have serious adverse effects on the fetus of a pregnant woman.
normal human physiology
Carbon monoxide is produced naturally in the human body as a signaling molecule. Thus, carbon monoxide may have a physiological role in the body as a neurotransmitter or blood vessel relaxant. Due to the role of carbon monoxide in the body, abnormalities in its metabolism are associated with various diseases, including neurodegeneration, hypertension, heart failure, and inflammation.
CO functions as an endogenous signaling molecule.
CO modulates the functions of the cardiovascular system
CO inhibits platelet aggregation and adhesion
CO may play a role as a potential therapeutic agent
Microbiology
Carbon monoxide is a nutrient for methanogenic archaea, a building block for acetyl coenzyme A. This is a topic for a new field of bioorganometallic chemistry. Extremophilic microorganisms can thus metabolize carbon monoxide in places such as the heat vents of volcanoes. In bacteria, carbon monoxide is produced by the reduction of carbon dioxide by the enzyme carbon monoxide dehydrogenase, a Fe-Ni-S-containing protein. CooA is a carbon monoxide receptor protein. The scope of its biological activity is still unknown. It may be part of the signaling pathway in bacteria and archaea. Its prevalence in mammals has not been established.
Prevalence
Carbon monoxide is found in various natural and man-made environments.
Carbon monoxide is present in small amounts in the atmosphere, mainly as a product of volcanic activity, but is also a product of natural and man-made fires (eg forest fires, crop residue burning, and sugarcane burning). The burning of fossil fuels also contributes to the formation of carbon monoxide. Carbon monoxide occurs in dissolved form in molten volcanic rocks at high pressures in the Earth's mantle. Because natural sources of carbon monoxide are variable, it is extremely difficult to accurately measure natural gas emissions. Carbon monoxide is a rapidly decaying greenhouse gas and also exerts indirect radiative forcing by increasing concentrations of methane and tropospheric ozone through chemical reactions with other atmospheric constituents (e.g. hydroxyl radical, OH) that would otherwise destroy them. As a result of natural processes in the atmosphere, it is eventually oxidized to carbon dioxide. Carbon monoxide is both short-lived in the atmosphere (lasting about two months on average) and has a spatially variable concentration. In the atmosphere of Venus, carbon monoxide is created by the photodissociation of carbon dioxide by electromagnetic radiation with a wavelength shorter than 169 nm. Because of its long viability in the middle troposphere, carbon monoxide is also used as a transport tracer for pollutant plumes.
Urban pollution
Carbon monoxide is a temporary atmospheric pollutant in some urban areas, mainly from the exhaust pipes of internal combustion engines (including vehicles, portable and standby generators, lawn mowers, washing machines, etc.) and from incomplete combustion various other fuels (including firewood, coal, charcoal, oil, wax, propane, natural gas, and garbage). Large CO pollution can be observed from space over cities.
Role in the formation of ground-level ozone
Carbon monoxide, along with aldehydes, is part of a series of chemical reaction cycles that form photochemical smog. It reacts with the hydroxyl radical (OH) to give the radical intermediate HOCO, which rapidly transfers the radical hydrogen O2 to form a peroxide radical (HO2) and carbon dioxide (CO2). The peroxide radical then reacts with nitric oxide (NO) to form nitrogen dioxide (NO2) and a hydroxyl radical. NO 2 gives O(3P) through photolysis, thereby forming O3 after reacting 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 the photon of light absorbed by the NO2 molecule in the sequence) Although the creation NO2 is an important step in producing low level ozone, it also increases the amount of ozone in another, somewhat mutually exclusive way, by reducing the amount of NO that is available to react with ozone.
indoor air pollution
In enclosed environments, the concentration of carbon monoxide can easily rise to lethal levels. On average, 170 people die every year in the United States from non-automotive consumer products that produce carbon monoxide. However, according to the Florida Department of Health, "More than 500 Americans die every year from accidental exposure to carbon monoxide and thousands more in the US require emergency medical attention for non-fatal carbon monoxide poisoning." These products include faulty fuel combustion appliances such as stoves, cookers, water heaters, and gas and kerosene room heaters; mechanically driven equipment such as portable generators; fireplaces; and charcoal, which is burned in homes and other enclosed spaces. The American Association of Poison Control Centers (AAPCC) reported 15,769 cases of carbon monoxide poisoning, which resulted in 39 deaths in 2007. In 2005, CPSC reported 94 deaths related to carbon monoxide poisoning from a generator. Forty-seven of those deaths occurred during power outages due to severe weather, including Hurricane Katrina. However, people are dying from carbon monoxide poisoning from non-food items such as cars left running in garages attached to homes. The Centers for Disease Control and Prevention reports that every year, several thousand people go to the hospital emergency room for carbon monoxide poisoning.
Presence in the 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 the blood from tissues, and thus is present in all normal tissues, even if it is not inhaled into the body. Normal levels of carbon monoxide circulating in the blood are between 0% and 3%, and are higher in smokers. Carbon monoxide levels cannot be assessed through a physical examination. Laboratory tests require a blood sample (arterial or venous) and a laboratory analysis for a CO-oximeter. In addition, non-invasive carboxyhemoglobin (SPCO) with pulsed CO oximetry is more effective than invasive methods.
Astrophysics
Outside the Earth, carbon monoxide is the second most abundant molecule in the interstellar medium, after molecular hydrogen. Due to its asymmetry, the carbon monoxide molecule produces much brighter spectral lines than the hydrogen molecule, making CO much easier to detect. Interstellar CO was first detected by radio telescopes in 1970. It is currently the most commonly used tracer of molecular gas in the interstellar medium of galaxies, and molecular hydrogen can only be detected using ultraviolet light, requiring space telescopes. Observations of carbon monoxide provide most of the information about the molecular clouds in which most stars form. Beta Pictoris, the second brightest star in the constellation Pictor, exhibits an excess of infrared radiation compared to normal stars of its type, due to the large amount of dust and gas (including carbon monoxide) near the star.
Production
Many methods have been developed to produce carbon monoxide.
industrial production
The main industrial source of CO is producer gas, a mixture containing mainly carbon monoxide and nitrogen, formed when carbon is burned in air at high temperature when there is an excess of carbon. In the oven, air is forced through a bed of coke. Initially produced CO2 is balanced with the remaining hot coal to produce CO. The reaction of CO2 with carbon to produce CO is described as the Boudouard reaction. Above 800°C, CO is the dominant product:
CO2 + C → 2 CO (ΔH = 170 kJ/mol)
Another source is "water gas", a mixture of hydrogen and carbon monoxide produced by an endothermic reaction of steam and carbon:
H2O + C → H2 + CO (ΔH = +131 kJ/mol)
Other similar "syngas" can be obtained from natural gas and other fuels. Carbon monoxide is also a by-product of the reduction of metal oxide ores with carbon:
MO + C → M + CO
Carbon monoxide is also produced by the direct oxidation of carbon in a limited amount of oxygen or air.
2C (s) + O 2 → 2CO (g)
Since CO is a gas, the reduction process can be controlled by heating using the positive (favorable) entropy of the reaction. The Ellingham diagram shows that CO production is favored over CO2 at high temperatures.
Preparation in the laboratory
Carbon monoxide is conveniently obtained in the laboratory by dehydration of formic acid or oxalic acid, for example with concentrated sulfuric acid. Another way is to heat a homogeneous mixture of powdered zinc metal and calcium carbonate, which releases CO and leaves zinc oxide and calcium oxide:
Zn + CaCO3 → ZnO + CaO + CO
Silver nitrate 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 lower oxidation states will combine with carbon monoxide ligands. This is because sufficient electron density is needed to facilitate reverse donation from the metallic DXZ orbital, to the π* molecular orbital from CO. The lone pair on the carbon atom in CO also donates electron density in dx²-y² on the metal to form a sigma bond. This electron donation is also manifested by the cis effect, or labilization of CO ligands in the cis position. Nickel carbonyl, for example, is formed by the direct combination of carbon monoxide and metallic nickel:
Ni + 4 CO → Ni(CO) 4 (1 bar, 55 °C)
For this reason, the nickel in the tube or part of it must not come into prolonged contact with carbon monoxide. Nickel carbonyl readily decomposes back to Ni and CO upon contact with hot surfaces, and this method is used for commercial nickel refining in the Mond process. In nickel carbonyl and other carbonyls, the electron pair on the carbon interacts with the metal; carbon monoxide donates an electron pair to the metal. In such situations, carbon monoxide is called a carbonyl ligand. One of the most important metal carbonyls is iron pentacarbonyl, Fe(CO)5. Many metal-CO complexes are made by decarbonylation of organic solvents rather than from CO. For example, iridium trichloride and triphenylphosphine react in refluxing 2-methoxyethanol or DMF to give 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 Koch-Haaf reaction. In the Guttermann-Koch reaction, arenes are converted to benzaldehyde derivatives in the presence of AlCl3 and HCl. Organolithium compounds (such as butyllithium) react with carbon monoxide, but these reactions have little scientific application. Although CO reacts with carbocations and carbanions, it is relatively unreactive with organic compounds without the intervention of metal catalysts. With reagents from the main group, CO undergoes several remarkable reactions. CO chlorination is an industrial process that produces the important phosgene compound. With borane, CO forms an adduct, H3BCO, which is isoelectronic with the acylium + cation. CO reacts with sodium to create products derived from the C-C bond. The compounds cyclohexahehexone or triquinoyl (C6O6) and cyclopentanepentone or leuconic acid (C5O5), which have so far only been obtained in trace amounts, can be regarded as polymers of carbon monoxide. At pressures above 5 GPa, carbon monoxide is converted into a solid polymer of carbon and oxygen. It is metastable at atmospheric pressure, but it is a powerful explosive.
Usage
Chemical industry
Carbon monoxide is an industrial gas that has many uses in the production of bulk chemicals. Large amounts of aldehydes are obtained by the reaction of hydroformylation of alkenes, carbon monoxide and H2. Hydroformylation in the Shell process makes it possible to create detergent precursors. Phosgene, suitable for producing isocyanates, polycarbonates and polyurethanes, is produced by passing purified carbon monoxide and chlorine gas through a bed of porous activated carbon which serves as a catalyst. World production of this compound in 1989 was estimated at 2.74 million tons.
CO + Cl2 → COCl2
Methanol is produced by the hydrogenation of carbon monoxide. In a related reaction, the hydrogenation of carbon monoxide involves the formation of a C-C bond, as in the Fischer-Tropsch process, where carbon monoxide is hydrogenated to liquid hydrocarbon fuels. This technology allows coal or biomass to be converted into diesel fuel. In the Monsanto process, carbon monoxide and methanol react in the presence of a rhodium-based catalyst and homogeneous hydroiodic acid to form acetic acid. This process is responsible for much of the industrial production of acetic acid. On an industrial scale, pure carbon monoxide is used to purify nickel in the Mond process.
meat coloring
Carbon monoxide is used in modified atmospheric packaging systems in the United States, primarily in fresh meat products such as beef, pork, and fish, to maintain their fresh appearance. Carbon monoxide combines with myoglobin to form carboxymyoglobin, a bright cherry red pigment. Carboxymyoglobin is more stable than the oxidized form of myoglobin, oxymyoglobin, which can oxidize to the brown pigment metmyoglobin. This stable red color can last much longer than conventional packaged meat. Typical carbon monoxide levels used in plants using this process are 0.4% to 0.5%. This technology was first recognized as "generally safe" (GRAS) by the US Food and Drug Administration (FDA) in 2002 for use as a secondary packaging system, and does not require labelling. In 2004, the FDA approved CO as the primary packaging method, stating that CO does not mask the smell of spoilage. Despite this ruling, it remains debatable whether this method masks food spoilage. In 2007, a bill was proposed in the US House of Representatives to call the modified packaging process using carbon monoxide a color additive, but the bill was not passed. This packaging process is banned in many other countries, including Japan, Singapore, and countries in the European Union.
The medicine
In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on heme from the breakdown of hemoglobin. This process produces a certain amount of carboxyhemoglobin in normal people, even if they do not inhale carbon monoxide. Since the first report that carbon monoxide was a normal neurotransmitter in 1993, as well as one of three gases that naturally modulate inflammatory responses in the body (the other two being nitric oxide and hydrogen sulfide), carbon monoxide has received a great deal of clinical attention as a biological regulator. . In many tissues, all three gases are known to act as anti-inflammatory agents, vasodilators, and neovascular growth enhancers. However, these issues are complex because neovascular growth is not always beneficial, as it plays a role in tumor growth as well as in the development of wet macular degeneration, a disease whose risk is increased 4 to 6-fold by smoking (a major source of carbon monoxide). in the blood, several times more than natural production). There is a theory that in some nerve cell synapses, when long-term memories are stored, the receiving cell produces carbon monoxide, which is passed back to the transmitting chamber, causing it to be transmitted more easily in the future. Some of these nerve cells have been shown to contain guanylate cyclase, an enzyme that is activated by carbon monoxide. Many laboratories around the world have conducted research involving carbon monoxide regarding its anti-inflammatory and cytoprotective properties. These properties can be used to prevent the development of a number of pathological conditions, including ischemic reperfusion injury, transplant rejection, atherosclerosis, severe sepsis, severe malaria, or autoimmune diseases. Human clinical trials have been conducted, but the results have not yet been released.
The physical properties of carbon monoxide (carbon monoxide CO) at normal atmospheric pressure are considered depending on the temperature at its negative and positive values.
In tables the following physical properties of CO are presented: carbon monoxide density ρ , specific heat capacity at constant pressure Cp, thermal conductivity coefficients λ and dynamic viscosity μ .
The first table shows the density and specific heat of carbon monoxide CO in the temperature range from -73 to 2727°C.
The second table gives the values of such physical properties of carbon monoxide as thermal conductivity and its dynamic viscosity in the temperature range from minus 200 to 1000°C.
The density of carbon monoxide, as well as, depends significantly on temperature - when carbon monoxide CO is heated, its density decreases. For example, at room temperature, the density of carbon monoxide is 1.129 kg / m 3, but in the process of heating to a temperature of 1000 ° C, the density of this gas decreases by 4.2 times - to a value of 0.268 kg / m 3.
Under normal conditions (temperature 0°C) carbon monoxide has a density of 1.25 kg/m 3 . If we compare its density with or other common gases, then the density of carbon monoxide relative to air is less important - carbon monoxide is lighter than air. It is also lighter than argon, but heavier than nitrogen, hydrogen, helium and other light gases.
The specific heat capacity of carbon monoxide under normal conditions is 1040 J/(kg deg). As the temperature of this gas rises, its specific heat capacity increases. For example, at 2727°C its value is 1329 J/(kg deg).
| t, °С | ρ, kg / m 3 | C p , J/(kg deg) | t, °С | ρ, kg / m 3 | C p , J/(kg deg) | t, °С | ρ, kg / m 3 | C p , J/(kg deg) |
|---|---|---|---|---|---|---|---|---|
| -73 | 1,689 | 1045 | 157 | 0,783 | 1053 | 1227 | 0,224 | 1258 |
| -53 | 1,534 | 1044 | 200 | 0,723 | 1058 | 1327 | 0,21 | 1267 |
| -33 | 1,406 | 1043 | 257 | 0,635 | 1071 | 1427 | 0,198 | 1275 |
| -13 | 1,297 | 1043 | 300 | 0,596 | 1080 | 1527 | 0,187 | 1283 |
| -3 | 1,249 | 1043 | 357 | 0,535 | 1095 | 1627 | 0,177 | 1289 |
| 0 | 1,25 | 1040 | 400 | 0,508 | 1106 | 1727 | 0,168 | 1295 |
| 7 | 1,204 | 1042 | 457 | 0,461 | 1122 | 1827 | 0,16 | 1299 |
| 17 | 1,162 | 1043 | 500 | 0,442 | 1132 | 1927 | 0,153 | 1304 |
| 27 | 1,123 | 1043 | 577 | 0,396 | 1152 | 2027 | 0,147 | 1308 |
| 37 | 1,087 | 1043 | 627 | 0,374 | 1164 | 2127 | 0,14 | 1312 |
| 47 | 1,053 | 1043 | 677 | 0,354 | 1175 | 2227 | 0,134 | 1315 |
| 57 | 1,021 | 1044 | 727 | 0,337 | 1185 | 2327 | 0,129 | 1319 |
| 67 | 0,991 | 1044 | 827 | 0,306 | 1204 | 2427 | 0,125 | 1322 |
| 77 | 0,952 | 1045 | 927 | 0,281 | 1221 | 2527 | 0,12 | 1324 |
| 87 | 0,936 | 1045 | 1027 | 0,259 | 1235 | 2627 | 0,116 | 1327 |
| 100 | 0,916 | 1045 | 1127 | 0,241 | 1247 | 2727 | 0,112 | 1329 |
The thermal conductivity of carbon monoxide under normal conditions is 0.02326 W/(m deg). It increases with its temperature and at 1000°C becomes equal to 0.0806 W/(m deg). It should be noted that the thermal conductivity of carbon monoxide is slightly less than this value y.
The dynamic viscosity of carbon monoxide at room temperature is 0.0246·10 -7 Pa·s. When carbon monoxide is heated, its viscosity increases. Such a character of the dependence of dynamic viscosity on temperature is observed in . It should be noted that carbon monoxide is more viscous than water vapor and carbon dioxide CO 2 , but has a lower viscosity compared to nitric oxide NO and air.
