Hydrogen cyanide: formula, hazard class

Hydrogen cyanide is called cyanide or hydrocyanic acid. It is colorless, very volatile and mobile, easily flammable, has a characteristic smell of almonds. Extremely toxic.

Properties

Hydrogen cyanide (HCN formula) is found in nature, it is accumulated by some plants, its share is also in the smoke of tobacco, coke, excretion is observed during the thermal decomposition of polyurethanes and nylon. This substance is a natural insecticide and protects the seeds and seeds of many plants from pest damage. For example, it is contained in the nuclei of apricots, plums, cherries, almonds.

Easily mixed at any ratio with diethyl alcohol, ethanol and water, aldehyde also reacts with it. Hydrogen cyanide becomes solid at -13.3 degrees Celsius, the structure of the ice is fibrous. It is converted to gas at +25.7 degrees. Gas is lighter than air.

Various materials easily absorb hydrocyanic acid. This, for example, rubber, fabric, concrete, brick, as well as any food products. Hydrogen cyanide in a mixture with air forms a flammable, explosive mixture, the explosive power of which is greater than that of TNT.

Using

Cyanic acid is used in the manufacture of acrylonitrile, acrylates, which are subsequently used for the manufacture of plastics. It is also necessary for the production of chlorcyan, acrylonitrile, amino acids and fumigants used in agriculture for the destruction of pests. It participates in the synthesis of nitrile rubbers and synthetic fibers, lactic acid and plexiglas. Successfully applied in the fight against rodents, for disinfection and destruction of pests of fruit trees.

Transportation and storage

For transportation of hydrogen cyanide, cylinders and containers, railway tanks, are used as temporary storage. For permanent storage, surface vertical cylindrical tanks with the volume from fifty to five thousand cubic meters (filling factor 0.9-0.95) are used. The pressure is atmospheric, the temperature in the cylinders does not decrease. The maximum allowable storage volume is two tons.

Poison

Headache, irritation of mucous membranes, a feeling of bitterness in the mouth, panic - all this can cause cyanide hydrogen. Effects on humans begin after overcoming the threshold of 0.3 mg / m ³ (in a cube) - this is the maximum permissible concentration in the air for work premises. Atmospheric air of settlements should not contain more than 0.01 mg / m ³ .

The person begins to feel the characteristic smell of almonds at a concentration of 2-5 mg / m ³ . When the concentration increases to 5-20 mg / m ^{3, the} first symptoms are manifested: headaches and dizziness, irritation of the mucous membranes and eyes, bitterness is felt in the mouth, and an unreasonable sense of fear also appears. Prolonged inhalation of fumes with a concentration of 50-60 mg / m ³ causes nausea and vomiting, palpitations, pupil dilated, convulsions and loss of consciousness. For a lethal outcome, it is sufficient to inhale vapor at a concentration of 130 mg / m ³ for an hour, and at a concentration of 220 mg / m ^{3, the} time is reduced to five minutes. The lethal concentration is 1500 mg / m ³ .

Physiological effects

Cyanic acid is a substance capable of causing oxygen starvation in tissues. When poisoning in the human body there is an increase in oxygen in the venous and arterial blood, thus reducing the arterial-venous difference, as a result, oxygen consumption of tissues is sharply reduced. Hydrogen cyanide and its salts, being dissolved in the blood, enter the tissues and react with cytochrome oxidase. After the cyanide is combined with this trivalent form of iron, the function of electron transfer to oxygen molecules is disrupted. Due to the fact that the final link of oxidation breaks down, the whole process of breathing is disrupted, tissues suffer from hypoxia, because although oxygen is delivered in the right amount, it is not digested and is sent to the venous blood in an unchanged form.

During poisoning with hydrocyanic acid, activation of glycolysis is observed: the metabolism changes from aerobic to anaerobic.

Elimination of accidents

Hydrogen cyanide (hazard class 2) can be deadly to humans. During the elimination of accidents that are associated with the discharge or the NCH, the danger zone is 400 meters. It is necessary to isolate it and remove people, remove any sources of flame, and it is also forbidden to smoke. You should be on the leeward side.

When staying within the danger zone, it is mandatory to use protective equipment (insulating masks or breathing apparatus, as well as skin protection agents L-1, FIR-5 and FIR-4). Outside the four-hundred-meter zone, you can not use skin protection products and dispense with industrial and civil gas masks to protect yourself from poisoning.

Gas masks and other protective equipment

Combined-arms filter masks are effective if the concentration of hydrogen cyanide in the air is less than 2500 mg / m ³ . Industrial filtering gas masks are used at the maximum allowable concentration of 6000 mg / m ³ . However, if the proportion of prussic acid vapors in the air is 7000-12000 mg / m ³ (7-12 g), even after wearing a gas mask, a person will feel symptoms of poisoning in a few minutes because of penetration through the skin. That is why, at high concentrations or for prolonged work in the accident zone, it is absolutely necessary to use full protective equipment.