Many gaseous substances that exist in nature and are obtained during production are strong toxic compounds. It is known that chlorine was used as a biological weapon, bromine vapor has a highly corrosive effect on the skin, hydrogen sulfide causes poisoning, and so on.

One of these substances is carbon monoxide or carbon monoxide, the formula of which has its own characteristics in the structure. About him and will be discussed further.

Chemical formula of carbon monoxide

The empirical form of the formula of the compound under consideration is as follows: CO. However, this form gives a characteristic only of the qualitative and quantitative composition, but does not affect the structural features and the order of connection of atoms in the molecule. And it differs from that in all other similar gases.

It is this feature that affects the physical and Chemical properties. What is this structure?

The structure of the molecule

First, the empirical formula shows that the valency of carbon in the compound is II. Just like oxygen. Therefore, each of them can form two formulas of carbon monoxide CO, this clearly confirms.

And so it happens. A double covalent polar bond is formed between the carbon and oxygen atom by the mechanism of socialization of unpaired electrons. Thus, carbon monoxide takes the form C=O.

However, the features of the molecule do not end there. According to the donor-acceptor mechanism, a third, dative or semipolar bond is formed in the molecule. What explains this? Since, after formation in the exchange order, oxygen has two pairs of electrons, and the carbon atom has an empty orbital, the latter acts as an acceptor of one of the pairs of the first. In other words, a pair of oxygen electrons is placed in a free orbital of carbon and a bond is formed.

So, carbon is an acceptor, oxygen is a donor. Therefore, the formula for carbon monoxide in chemistry takes the following form: C≡O. Such structurization imparts to the molecule additional chemical stability and inertness in the properties exhibited at normal conditions.

So, the bonds in the carbon monoxide molecule:

• two covalent polar, formed by the exchange mechanism due to the socialization of unpaired electrons;
• one dative, formed by the donor-acceptor interaction between a pair of electrons and a free orbital;
• There are three bonds in a molecule.

Physical properties

There are a number of characteristics that, like any other compound, carbon monoxide has. The formula of the substance makes it clear that crystal cell molecular, gaseous state under normal conditions. From this follow the following physical parameters.

1. C≡O - carbon monoxide (formula), density - 1.164 kg / m 3.
2. Boiling and melting points, respectively: 191/205 0 C.
3. Soluble in: water (slightly), ether, benzene, alcohol, chloroform.
4. Has no taste and smell.
5. Colorless.

From a biological point of view, it is extremely dangerous for all living beings, except certain types bacteria.

Chemical properties

In terms of reactivity, one of the most inert substances under normal conditions is carbon monoxide. The formula, which reflects all the bonds in the molecule, confirms this. It is precisely because of such a strong structure that this compound, at standard indicators, environment practically does not enter into any interactions.

However, it is necessary to heat the system at least a little, as the dative bond in the molecule collapses, as well as the covalent ones. Then carbon monoxide begins to show active reducing properties, and rather strong ones. So, it is able to interact with:

• oxygen;
• chlorine;
• alkalis (melts);
• with metal oxides and salts;
• with sulfur;
• slightly with water;
• with ammonia;
• with hydrogen.

Therefore, as already mentioned above, the properties that carbon monoxide exhibits, its formula largely explains.

Being in nature

The main source of CO in the Earth's atmosphere is forest fires. After all, the main way the formation of this gas in a natural way is incomplete combustion. different kind fuels, mostly organic.

Anthropogenic sources of air pollution with carbon monoxide are also important and mass fraction the same percentage as natural. These include:

• smoke from the work of factories and plants, metallurgical complexes and other industrial enterprises;
• exhaust gases from internal combustion engines.

Under natural conditions, carbon monoxide is easily oxidized by atmospheric oxygen and water vapor to carbon dioxide. This is the basis of first aid for poisoning with this compound.

Receipt

It is worth pointing out one feature. Carbon monoxide(formula), carbon dioxide(structure of the molecule) respectively look like this: C≡O and O=C=O. The difference is one oxygen atom. That's why industrial way obtaining monoxide is based on the reaction between dioxide and coal: CO 2 + C = 2CO. This is the simplest and most common way to synthesize this compound.

Various organic compounds, metal salts and complex substances are used in the laboratory, since the yield of the product is not expected to be too high.

A high-quality reagent for the presence of carbon monoxide in air or a solution is palladium chloride. When they interact, a pure metal is formed, which causes a darkening of the solution or the surface of the paper.

Biological effect on the body

As mentioned above, carbon monoxide is a very poisonous, colorless, dangerous and deadly pest for human body. And not only human, but in general any living thing. Plants that are exposed to car exhaust fumes die very quickly.

What exactly is the biological effect of carbon monoxide on the internal environment of animal beings? It's all about the formation of strong complex compounds of the blood protein hemoglobin and the gas in question. That is, instead of oxygen, poison molecules are captured. Cellular respiration is instantly blocked, gas exchange becomes impossible in its normal course.

As a result, there is a gradual blocking of all hemoglobin molecules and, as a result, death. A defeat of only 80% is enough for the outcome of poisoning to become fatal. To do this, the concentration of carbon monoxide in the air should be 0.1%.

The first signs by which the onset of poisoning with this compound can be determined are:

• headache;
• dizziness;
• loss of consciousness.

First aid - get out on Fresh air, where carbon monoxide under the influence of oxygen will turn into carbon dioxide, that is, it will be neutralized. Cases of death from the action of the substance in question are very frequent, especially in homes with After all, when wood, coal and other types of fuel are burned, this gas is necessarily formed as a by-product. Compliance with safety regulations is extremely important to preserve human life and health.

There are also many cases of poisoning in garages, where many working car engines are assembled, but the fresh air supply is insufficiently supplied. Death, if the permissible concentration is exceeded, occurs within an hour. It is physically impossible to feel the presence of gas, because it has neither smell nor color.

Industrial use

In addition, carbon monoxide is used:

• for processing meat and fish products, which allows you to give them a fresh look;
• for the syntheses of some organic compounds;
• as a component of generator gas.

Therefore, this substance is not only harmful and dangerous, but also very useful for humans and their economic activities.

Carbon monoxide(II) – CO

(carbon monoxide, carbon monoxide, carbon monoxide)

Physical properties: colorless poisonous gas, tasteless and odorless, burns with a bluish flame, lighter than air, poorly soluble in water. The concentration of carbon monoxide in the air of 12.5-74% is explosive.

Molecule structure:

The formal oxidation state of carbon +2 does not reflect the structure of the CO molecule, in which, in addition to the double bond formed by the sharing of C and O electrons, there is an additional one formed by the donor-acceptor mechanism due to the lone pair of oxygen electrons (depicted by an arrow):

In this regard, the CO molecule is very strong and is able to enter into oxidation-reduction reactions only at high temperatures. Under normal conditions, CO does not interact with water, alkalis or acids.

Receipt:

The main anthropogenic source of carbon monoxide CO is currently the exhaust gases of internal combustion engines. Carbon monoxide is produced when fuel is burned in internal combustion engines at insufficient temperatures or a poorly tuned air supply system (not enough oxygen is supplied to oxidize carbon monoxide CO into carbon dioxide CO2). Under natural conditions, on the Earth's surface, carbon monoxide CO is formed during the incomplete anaerobic decomposition of organic compounds and during the combustion of biomass, mainly during forest and steppe fires.

1) In industry (in gas generators):

Video - experience "Getting carbon monoxide"

C + O 2 \u003d CO 2 + 402 kJ

CO 2 + C \u003d 2CO - 175 kJ

In gas generators, water vapor is sometimes blown through hot coal:

C + H 2 O \u003d CO + H 2 - Q ,

a mixture of CO + H 2 - called synthesis - gas .

2) In the laboratory- thermal decomposition of formic or oxalic acid in the presence of H 2 SO 4 (conc.):

HCOOH t˚C, H2SO4 → H2O + CO

H 2 C 2 O 4 t˚C,H2SO4 → CO + CO 2 + H 2 O

Chemical properties:

Under ordinary conditions, CO is inert; when heated - reducing agent;

CO - non-salt-forming oxide .

1) with oxygen

2 C +2 O + O 2 t ˚ C →2 C +4 O 2

2) with metal oxides CO + Me x O y = CO 2 + Me

C +2 O + CuO t ˚ C → Сu + C +4 O 2

3) with chlorine (in the light)

CO + Cl 2 light → COCl 2 (phosgene is a poisonous gas)

4)* reacts with alkali melts (under pressure)

CO+NaOHP → HCOONa (sodium formate)

The effect of carbon monoxide on living organisms:

Carbon monoxide is dangerous because it makes it impossible for the blood to carry oxygen to vital organs like the heart and brain. Carbon monoxide combines with hemoglobin, which carries oxygen to the cells of the body, as a result of which it becomes unsuitable for transporting oxygen. Depending on the amount inhaled, carbon monoxide impairs coordination, exacerbates cardiovascular disease and causes fatigue, headache, weakness, The effect of carbon monoxide on human health depends on its concentration and time of exposure to the body. A concentration of carbon monoxide in the air above 0.1% leads to death within one hour, and a concentration of more than 1.2% within three minutes.

Application of carbon monoxide :

Carbon monoxide is mainly used as a combustible gas mixed with nitrogen, the so-called generator or air gas, or water gas mixed with hydrogen. In metallurgy for the recovery of metals from their ores. To obtain high purity metals by decomposition of carbonyls.

FIXING

No. 1. Complete the reaction equations, draw up an electronic balance for each of the reactions, indicate the processes of oxidation and reduction; oxidizing agent and reducing agent:

CO 2 + C =

C + H 2 O =

With O + O 2 \u003d

CO + Al 2 O 3 \u003d

No. 2. Calculate the amount of energy required to produce 448 liters of carbon monoxide according to the thermochemical equation

CO 2 + C \u003d 2CO - 175 kJ

Signs that carbon monoxide (carbon monoxide (II), carbon monoxide, carbon monoxide) has formed in the air in dangerous concentrations are difficult to determine - invisible, may not smell, accumulates in the room gradually, imperceptibly. It is extremely dangerous for human life: it has a high toxicity, excessive content in the lungs leads to severe poisoning and death. Every year, a high death rate from gas poisoning is recorded. The risk of poisoning can be reduced by following simple rules and the use of special carbon monoxide sensors.

What is carbon monoxide

Natural gas is formed during the combustion of any biomass, in industry it is a combustion product of any carbon-based compounds. In both cases prerequisite outgassing is a lack of oxygen. Large volumes of it enter the atmosphere as a result of forest fires, in the form of exhaust gases generated during the combustion of fuel in car engines. For industrial purposes, it is used in the production of organic alcohol, sugar, processing of animal meat and fish. A small amount of monoxide is also produced by the cells of the human body.

Properties

From the point of view of chemistry, monoxide is an inorganic compound with a single oxygen atom in the molecule, chemical formula- SO. it Chemical substance, which does not have characteristic color, taste and smell, it is lighter than air, but heavier than hydrogen, and is inactive at room temperature. A person who smells, feels only the presence of organic impurities in the air. Belongs to the category of toxic products, death at a concentration in the air of 0.1% occurs within one hour. The characteristic of the maximum permissible concentration is 20 mg / m3.

The effect of carbon monoxide on the human body

For humans, carbon monoxide is a deadly hazard. Its toxic effect is explained by the formation of carboxyhemoglobin in blood cells, a product of the addition of carbon monoxide (II) to blood hemoglobin. High level the content of carboxyhemoglobin causes oxygen starvation, insufficient oxygen supply to the brain and other tissues of the body. With mild intoxication, its content in the blood is low, destruction in a natural way is possible within 4-6 hours. At high concentrations, only medications work.

Carbon monoxide poisoning

Carbon monoxide is one of the most dangerous substances. In case of poisoning, intoxication of the body occurs, accompanied by deterioration general condition person. It is very important to recognize the signs of carbon monoxide poisoning early. The result of treatment depends on the level of the substance in the body and on how soon help arrived. In this case, minutes count - the victim can either recover completely, or remain sick forever (it all depends on the speed of the rescuers' response).

Symptoms

Depending on the degree of poisoning, headaches, dizziness, tinnitus, heart palpitations, nausea, shortness of breath, flickering in the eyes, general weakness can be observed. Drowsiness is often observed, which is especially dangerous when a person is in a gassed room. In case of inhalation a large number toxic substances, convulsions, loss of consciousness are observed, in especially severe cases - coma.

First aid for carbon monoxide poisoning

The injured person must be provided on the spot first aid in carbon monoxide poisoning. It is necessary to immediately move it to fresh air and call a doctor. You should also remember about your safety: you need to enter a room with a source of this substance only by inhaling deeply, do not breathe inside. Until the doctor arrives, it is necessary to facilitate the access of oxygen to the lungs: unfasten buttons, remove or loosen clothes. If the victim has lost consciousness and stopped breathing, artificial ventilation of the lungs is necessary.

Antidote for poisoning

A special antidote (antidote) for carbon monoxide poisoning is a drug that actively prevents the formation of carboxyhemoglobin. The action of the antidote leads to a decrease in the body's need for oxygen, support for organs sensitive to a lack of oxygen: the brain, liver, etc. It is administered intramuscularly at a dosage of 1 ml immediately after the patient is removed from the area with a high concentration of toxic substances. You can re-enter the antidote no earlier than an hour after the first injection. It can be used for prevention.

Treatment

In the case of mild exposure to carbon monoxide, treatment is carried out on an outpatient basis, in severe cases, the patient is hospitalized. Already in the ambulance he is given oxygen bag or a mask. In severe cases, in order to give the body a large dose of oxygen, the patient is placed in a pressure chamber. An antidote is administered intramuscularly. The level of gas in the blood is constantly monitored. Further rehabilitation is medical, the actions of doctors are aimed at restoring the functioning of the brain, cardiovascular system, and lungs.

Effects

Exposure to carbon monoxide in the body can cause serious illnesses: the working capacity of the brain, behavior, consciousness of a person change, inexplicable headaches appear. Especially the influence harmful substances memory is affected - that part of the brain that is responsible for the transition short term memory in the long term. The patient may feel the consequences of carbon monoxide poisoning only after a few weeks. Most victims fully recover after a period of rehabilitation, but some feel the consequences for a lifetime.

How to detect carbon monoxide in a room

Carbon monoxide poisoning is easy at home, and it doesn't just happen during a fire. The concentration of carbon monoxide is formed by careless handling of the stove damper, during the operation of a faulty geyser or ventilation. The source of carbon monoxide can be gas stove. If there is smoke in the room, this is already a reason to sound the alarm. For constant monitoring of the gas level, there are special sensors. They monitor the level of gas concentration and report the excess of the norm. The presence of such a device reduces the risk of poisoning.

Video

colorless gas Thermal Properties Melting temperature -205°C Boiling temperature -191.5°C Enthalpy (st. arb.) −110.52 kJ/mol Chemical properties Solubility in water 0.0026 g/100 ml Classification CAS number

• 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 electric moment 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. Greatest practical use received a reaction with chlorine:

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 +

Reaction with ammonia at high temperatures it is possible to obtain an important industrial compound - hydrogen cyanide HCN. The reaction proceeds in the presence of a catalyst (oxide

Everyone who has had to deal with work knows how dangerous carbon monoxide is for humans. heating systems, - stoves, boilers, boilers, water heaters, designed for domestic fuel in any form. It is quite difficult to neutralize it in a gaseous state, there are no effective home methods to deal with carbon monoxide, so most of the protective measures are aimed at preventing and timely detection of carbon monoxide in the air.

Properties of a toxic substance

There is nothing unusual about the nature and properties of carbon monoxide. In fact, it is a product of the partial oxidation of coal or coal-containing fuels. The formula for carbon monoxide is simple and uncomplicated - CO, in chemical terms - carbon monoxide. One carbon atom is connected to an oxygen atom. The nature of fossil fuel combustion processes is arranged in such a way that carbon monoxide is an integral part of any flame.

Coals, related fuels, peat, firewood, when heated in a furnace, are gasified into carbon monoxide, and only then are they burned out by air flow. If carbon monoxide has leaked from the combustion chamber into the room, then it will remain in a stable state until the moment when the carbon monoxide flow is removed from the room by ventilation or accumulates, filling the entire space, from floor to ceiling. In the latter case, only an electronic carbon monoxide detector can save the situation, reacting to the slightest increase in the concentration of toxic fumes in the atmosphere of the room.

What you need to know about carbon monoxide:

• Under standard conditions, the density of carbon monoxide is 1.25 kg / m 3, which is very close to specific gravity air 1.25 kg / m 3. Hot and even warm monoxide easily rises to the ceiling, settles and mixes with air as it cools;
• Carbon monoxide is tasteless, colorless and odorless, even at high concentrations;
• To start the formation of carbon monoxide, it is enough to heat the metal in contact with carbon to a temperature of 400-500 o C;
• The gas is able to burn in air with the release of a large amount of heat, approximately 111 kJ / mol.

It is dangerous not only to inhale carbon monoxide, the gas-air mixture can explode when a volume concentration of 12.5% ​​to 74% is reached. In this sense, the gas mixture is similar to domestic methane, but much more dangerous than network gas.

Methane is lighter than air and less toxic when inhaled; moreover, due to the addition of a special additive, mercaptan, to the gas stream, its presence in the room is easy to detect by smell. With a slight gas contamination of the kitchen, you can enter the room without health consequences and ventilate it.

With carbon monoxide, everything is more complicated. The close relationship between CO and air prevents effective removal toxic gas cloud. As it cools, the gas cloud will gradually settle in the floor area. If a carbon monoxide detector has tripped, or a leak of combustion products from a stove or solid fuel boiler has been detected, ventilation measures must be taken immediately, otherwise children and pets will be the first to suffer.

A similar property of a carbon monoxide cloud was previously widely used to control rodents and cockroaches, but the effectiveness of a gas attack is much lower. modern means, and the risk of earning poisoning is disproportionately higher.

Note! A CO gas cloud, in the absence of ventilation, is able to maintain its properties unchanged for a long time.

If carbon monoxide accumulation is suspected in basements, utility rooms, boiler rooms, cellars, the first step is to ensure maximum ventilation with a gas exchange rate of 3-4 units per hour.

Conditions for the appearance of fumes in the room

Carbon monoxide can be produced with dozens of options chemical reactions, but this requires specific reagents and conditions for their interaction. The risk of earning gas poisoning in this way is practically zero. The main reasons for the appearance of carbon monoxide in the boiler room or in the kitchen are two factors:

• Poor draft and partial overflow of combustion products from the combustion source into the kitchen;
• Improper operation of boiler, gas and furnace equipment;
• Fires and local foci of ignition of plastic, wiring, polymer coatings and materials;
• Exhaust gases from sewer communications.

A source of carbon monoxide can be the secondary combustion of ash, loose soot deposits in chimneys, soot and tar that have eaten into brickwork fireplace mantels and soot extinguishers.

Most often, smoldering coals that burn out in the furnace with the valve closed become the source of CO gas. Especially a lot of gas is released during the thermal decomposition of firewood in the absence of air, about half of the gas cloud is occupied by carbon monoxide. Therefore, any experiments with smoking meat and fish on the smoke obtained from smoldering shavings should only be carried out outdoors.

A small amount of carbon monoxide can also appear during cooking. For example, everyone who has encountered the installation of closed-fired gas boilers in the kitchen knows how carbon monoxide sensors react to fried potatoes or any food cooked in boiling oil.

The insidious nature of carbon monoxide

The main danger of carbon monoxide is that it is impossible to feel and feel its presence in the atmosphere of the room until the gas enters the respiratory organs with air and dissolves in the blood.

The consequences of inhaling CO depend on the concentration of the gas in the air and the length of stay in the room:

• Headache, malaise and the development of a drowsy state begin when the volumetric content of gas in the air is 0.009-0.011%. Physically healthy man able to withstand up to three hours in a gassed atmosphere;
• Nausea, strong pain in muscles, convulsions, fainting, loss of orientation may develop at a concentration of 0.065-0.07%. The time spent in the room until the onset of inevitable consequences is only 1.5-2 hours;
• At a concentration of carbon monoxide above 0.5%, even a few seconds of being in a gassed space means a fatal outcome.

Even if a person safely got out of a room with a high concentration of carbon monoxide on his own, you still need to health care and the use of antidotes, since the effects of poisoning circulatory system and circulatory disorders of the brain will still appear, only a little later.

Carbon monoxide molecules are readily absorbed by water and saline solutions. Therefore, ordinary towels, napkins moistened with any available water are often used as the first available means of protection. This allows you to stop the ingress of carbon monoxide into the body for a few minutes, until it becomes possible to leave the room.

Often this property of carbon monoxide is abused by some owners of heating equipment in which CO sensors are built. When a sensitive sensor is triggered, instead of airing the room, the device is often simply covered with a wet towel. As a result, after a dozen such manipulations, the carbon monoxide sensor fails, and the risk of poisoning increases by an order of magnitude.

Technical carbon monoxide registration systems

In fact, today there is only one way to successfully deal with carbon monoxide, to use special electronic devices and sensors that register the excess of CO concentration in the room. You can, of course, do it easier, for example, equip powerful ventilation, as lovers of relaxation do by a real brick fireplace. But in such a decision there is a certain risk of earning carbon monoxide poisoning when changing the direction of the draft in the pipe, and besides, living under a strong draft is also not very healthy.

Carbon monoxide detector device

The problem of controlling the content of carbon monoxide in the atmosphere of residential and utility rooms today is as topical as the presence of a fire or burglar alarm.

In specialized salons of heating and gas equipment Several options for gas monitoring devices are available:

• Chemical alarms;
• infrared scanners;
• solid state sensors.

The sensitive sensor of the device is usually equipped with an electronic board that provides power, calibration and signal conversion into an understandable form of indication. It can be just green and red LEDs on the panel, a sound siren, digital information for issuing a signal to a computer network, or a control pulse for automatic valve blocking the supply of domestic gas to the heating boiler.

It is clear that the use of sensors with a controlled shut-off valve is a necessary measure, but often manufacturers heating equipment deliberately build in "fool protection" to avoid all sorts of manipulations with the safety of gas equipment.

Chemical and solid state control instruments

The cheapest and most available version of the chemical indicator sensor is made in the form of a mesh flask that is easily permeable to air. Inside the flask there are two electrodes separated by a porous partition impregnated with an alkali solution. The appearance of carbon monoxide leads to carbonization of the electrolyte, the conductivity of the sensor drops sharply, which is immediately read by the electronics as an alarm signal. After installation, the device is in an inactive state and does not work until traces of carbon monoxide appear in the air that exceed the permissible concentration.

Solid-state sensors use two-layer bags of tin and ruthenium dioxide instead of an alkali-soaked piece of asbestos. The appearance of gas in the air causes a breakdown between the contacts of the sensor device and automatically triggers an alarm.

Scanners and electronic watchmen

Infrared sensors that work on the principle of scanning the surrounding air. The built-in infrared sensor perceives the glow of the laser LED, and by changing the intensity of absorption of thermal radiation by the gas, the trigger device is activated.

CO absorbs the thermal part of the spectrum very well, so such devices operate in watchman or scanner mode. The scan result can be displayed as a two-color signal or an indication of the amount of carbon monoxide in the air on a digital or linear scale.

Which sensor is better

For correct selection For a carbon monoxide sensor, it is necessary to take into account the mode of operation and the nature of the room in which the sensor device is to be installed. For example, chemical sensors, which are considered obsolete, work great in boiler rooms and utility rooms. An inexpensive carbon monoxide detector can be installed in a country house or workshop. In the kitchen, the grid quickly becomes covered with dust and grease, which dramatically reduces the sensitivity of the chemical cone.

Solid-state carbon monoxide sensors work equally well in all conditions, but they require a powerful external power source to function. The cost of the device is higher than the price of chemical sensor systems.

Infrared sensors are by far the most common. They are actively used to complete the security systems of apartment boilers. individual heating. At the same time, the sensitivity of the control system practically does not change over time due to dust or air temperature. Moreover, such systems, as a rule, have built-in testing and calibration mechanisms, which allows you to periodically check their performance.

Installation of carbon monoxide monitoring devices

Carbon monoxide sensors should only be installed and serviced by qualified personnel. Instruments must be periodically checked, calibrated, serviced and replaced.

The sensor must be installed at a distance from the gas source from 1 to 4 m, the body or remote sensors are mounted at a height of 150 cm above the floor and must be calibrated according to the upper and lower sensitivity thresholds.

The service life of apartment carbon monoxide sensors is 5 years.

Conclusion

The fight against the formation of carbon monoxide requires accuracy and a responsible attitude to the installed equipment. Any experiments with sensors, especially of the semiconductor type, sharply reduce the sensitivity of the device, which ultimately leads to an increase in the carbon monoxide content in the atmosphere of the kitchen and the entire apartment, and the slow poisoning of all its inhabitants. The problem of carbon monoxide control is so serious that perhaps the use of sensors in the future may be made mandatory for all categories of individual heating.