There is no return ”(W. Shakespeare). When ingested, cyanide produces an inhibitory effect. Or, for ordinary mortals, it creates conditions under which the cells of the body cease to assimilate the oxygen contained in the blood. And then there is a kind of suffocation at the cellular level. Scary? In this place, it seems, you can put an end to all senses and sentence the substance to eternal torment in the ninth hell, where it itself sent many people. But ... not everything is so simple. It turns out that potassium cyanide has acquired a lot of legends during its existence.

Mythology of cyanide

We debunk myths.

A bit of history

At times ancient rome there were such special people- soothsayers or priests. They chewed laurel leaves and then gave out a roundup of news for the upcoming reporting period. And if without jokes, they had strong hallucinations, which in those days were given great value. And, as you may have guessed, it was precisely bay leaves or common lavrushka, which is now successfully used in cooking.

Indeed, the leaves of this plant contain potassium cyanide, or rather hydrocyanic acid, as well as many other substances. But it was thanks to the poison in micro doses that the rulers of the Roman Empire received the "blessing of the gods" or their "disfavor".

And again the question, what about cooking? Stop using such a pleasant spice? Not at all! Recall that dried leaves are added to the soup, which were stored for an unknown amount of time, first in the supplier's warehouse, and then in the store. And the priests preferred a fresh product. So… bon appetit!

And a few more words

Not so simple.

Not everything is so simple with potassium cyanide. He's dangerous and not really. He can "connect with the gods" or send them straight to an audience without a return ticket. In any case, you should not experiment with this extremely dangerous substance, which humanity singled out to its own misfortune.

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• More about cyanide

There are millions of different animals in the world. Some of them are completely harmless to people, and some become a threat to human life.

One of the most dangerous animals are mosquitoes that carry tropical. They live a little south of the Sahara. The danger of mosquitoes lies in the fact that they easily move in space, they can quietly sit on a person and infect him with malaria with their bite.

Poisonous have become another dangerous animal. They have a huge number and reach a length of about four and a half meters. Note that poison capsules are in each of their tentacles. In this regard, they can kill more than fifty people in a year.

Because of poisonous snakes more than 55,000 people die each year worldwide. However, the most life-threatening are efa, gyurza and cobra. They are found mainly in the territory of the CIS countries.

Who can attack a person

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Organic cyanides have one or more cyano groups: these include cyanohydrins and nitriles. Acetone cyanohydrin (CH3) 2C (OH) CN dissociates completely in solution, forming an equivalent amount of cyanides, as follows from the results of the determination of free cyanides. Of course, it is completely destroyed when it is detected by other methods. Nitriles practically do not break down with the formation of cyanides. In the case of acetonitrile CH3CN and adiponitrile NC (CH2) 4CN, no significant presence of free, simple and total cyanides was found. However, acrylonitrile CH2CHCN releases about 15% cyanide after UV exposure. These differences between cyanohydrins and nitriles are very significant and should be taken into account when assessing the impact on the environment.

Organic cyanides are converted in the body into thiocyanates, the content of which in the urine of animals increases after poisoning.

Nitriles - organic cyanides (acrylonitrile, acetonitrile, isobutyl nitrile) are transported in cans up to 60 liters, made of sheet steel with a minimum wall thickness of 1 mm and having a double closure system (two stoppers, one of which is screwed), or in steel drums with a wall thickness of at least 125 mm and a similar closure system.

Nitriles (also called organic cyanides) are organic compounds that contain a characteristic cyanide group (-CN) and have general formula RCN. When hydrolyzed, they form an acid that contains that number of carbon atoms. Nitriles are very dangerous, because when heated, they decompose, emit hydrogen cyanide.

The most potentially dangerous is skin contact with aromatic amino and nitro compounds (aniline, nitrobenzene), as well as with chlorinated hydrocarbons, organophosphorus insecticides, and organic cyanides.

Organic cyanides generally do not hydrolyze to hydrogen cyanide.

Amines, as well as anilines, which are a special case of amines, were described in Sec. Here we will consider nitro compounds (RNO2, sect. RCN), also called organic cyanides (sect. Many other compounds containing nitrogen were briefly mentioned in sect.

Cyanides or nitriles have general structure R - C N. Although structurally they can be considered as esters of hydrocyanic acid, the properties of nitriles differ markedly from those of esters. Hydrocyanic acid is so weak that organic cyanides cannot be produced by the reaction of hydrocyanic acid with alcohols.

The first member of the nitrile series is formonitrile or hydrocyanic acid, HCN. This compound has both the properties of a weak acid and the properties of a nitrile. Hydrocyanic acid is extremely poisonous; its toxicity is partly based on the formation of a strong complex with hemoglobin. Organic cyanides are less toxic and many have a pleasant smell.

A thick wire (-3 mm) of red copper is calcined in an oxidizing flame gas burner until the flame stops polling green. When introduced into the flame of a burner, the flame turns green due to the formation of volatile copper halide. This is a very sensitive test for C1, Br and I, but much less sensitive for F. Organic cyanides also give this reaction in the absence of halides.

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DAMAGES BY POISONING SUBSTANCES OF GENERAL TOXIC ACTION: PRUSIAN ACID AND POTASSIUM CYANIDE

Hydrocyanic acid and potassium cyanide are toxic substances of general toxic action, as well as sodium, cyanogen chloride, cyanogen bromide, carbon monoxide.
For the first time, hydrocyanic acid was synthesized by the Swedish scientist Karl Scheele in 1782. History knows cases of the use of cyanides for the mass destruction of people. During the First World War (1916 on the Somme River), the French army used hydrocyanic acid as a poisonous substance, in the Nazi extermination camps the Nazis (1943-1945) used poisonous gases, cyclones (cyanoformic acid esters), American troops in South Vietnam (1963) used toxic organic cyanides (CS-type gases) against civilians. It is also known that in the United States the death penalty is applied by poisoning convicts with hydrocyanic acid vapors in a special chamber.
Due to its high chemical activity and ability to interact with numerous compounds various classes cyanides are widely used in many industries, agriculture, and scientific research, and this creates many opportunities for intoxication.
Thus, hydrocyanic acid and a large number of its derivatives are used in the extraction of precious metals from ores, in galvanoplastic gilding and silvering, in the production of aromatic substances, chemical fibers, plastics, rubber, organic glass, plant growth stimulants, herbicides. Cyanides are also used as insecticides, fertilizers and defoliants. Hydrocyanic acid is released in a gaseous state at many production processes. There may also be cyanide poisoning due to the consumption of large amounts of seeds of almonds, peaches, apricots, cherries, plums and other plants of the Rosaceae family or tinctures from their fruits. It turned out that they all contain amygdalin glycoside, which decomposes in the body under the influence of the emulsin enzyme to form hydrocyanic acid, benzaldehyde and 2 glucose molecules. The largest number amygdalin is found in bitter almonds (up to 3%) and apricot seeds (up to 2%).
Physico-chemical properties and toxicity of hydrocyanic acid
Hydrocyanic acid - HCN - is a colorless, easily boiling (at 26 ° C) liquid with the smell of bitter almonds, with a specific gravity of 0.7, freezes at - 13.4 C. Cyanide poisoning develops when inhaled vapors of a toxic substance, when absorbed through the skin and through the mouth. In wartime, the most probable is the inhalation route of their entry into the body. According to WHO, Lt50 of hydrocyanic acid is 2 g/min/m3. When poisoning through the mouth, lethal doses for humans are: HCN - 1 mg / kg, KCN - 2.5 mg / kg; NaSN - 1.8 mg/kg.
Mechanism of toxic action
The mechanism of action of hydrocyanic acid has been studied in some detail. It is a substance that causes oxygen starvation of the tissue type. At the same time, a high oxygen content is observed both in arterial and venous blood and thus a decrease in the arterio-venous difference, a sharp decrease in oxygen consumption by tissues with a decrease in the formation of carbon dioxide in them.
It has been established that cyanides interfere with redox processes in tissues, disrupting oxygen activation by cytochrome oxidase. (The lecturer can dwell in more detail on modern concepts of cellular respiration).
Hydrocyanic acid and its salts, dissolved in the blood, reach the tissues, where they interact with the ferric form of cytochrome oxidase iron. Having combined with cyanide, cytochrome oxidase loses the ability to transfer electrons to molecular oxygen. Due to the failure of the final link of oxidation, the entire respiratory chain is blocked and tissue hypoxia develops. Oxygen is delivered to the tissues in sufficient quantities with arterial blood, but is not absorbed by them and passes unchanged into the venous bed. At the same time, the processes of formation of macroergs necessary for the normal activity of various organs and systems are disrupted. Glycolysis is activated, that is, the exchange from aerobic to anaerobic is rebuilt. The activity of other enzymes - catalase, peroxidase, lactate dehydrogenase - is also suppressed.
The effect of cyanides on various organs and systems
Action on the nervous system. As a result of tissue hypoxia, which develops under the influence of hydrocyanic acid, the functions of the central nervous system are primarily impaired. Cyanides in toxic doses cause at the beginning the excitation of the central nervous system, and then its depression. In particular, at the beginning of intoxication, excitation of the respiratory and vasomotor centers is observed. This is manifested by a rise in blood pressure and the development of severe shortness of breath. An extreme form of excitation of the central nervous system are clonic-tonic convulsions. Pronounced excitation of the nervous system is replaced by paralysis (respiratory and vasomotor centers).
Action on the respiratory system. In the picture of acute poisoning, a pronounced increase in the frequency and depth of breathing is observed. Developing shortness of breath, apparently, should be considered as a compensatory reaction of the body to hypoxia. The stimulating effect of cyanides on respiration is due to the excitation of the chemoreceptors of the carotid sinus and the direct action of the poison on the cells of the respiratory center. The initial excitation of respiration, as intoxication develops, is replaced by its oppression up to a complete stop. The causes of these disorders are tissue hypoxia and depletion of energy resources in the cells of the carotid sinus and in the centers of the medulla oblongata.
Action on the cardiovascular system. In the initial period of intoxication, a slowing of the heart rate is observed. An increase in blood pressure and an increase in cardiac output occur due to the excitation of chemoreceptors of the carotid sinus and cells of the vasomotor center by cyanides, on the one hand, the release of catecholamines from the adrenal glands and, as a result, vasospasm, on the other. As poisoning progresses arterial pressure falls, the pulse quickens, acute cardiovascular failure develops and cardiac arrest occurs.
Changes in the blood system. The content of erythrocytes in the blood increases, which is explained by the reflex contraction of the spleen in response to developing hypoxia. The color of venous blood becomes bright scarlet due to the excess oxygen content not absorbed by the tissues. The arterio-venous difference in oxygen sharply decreases. When tissue respiration is suppressed, both the gas and biochemical composition of the blood changes. The content of CO2 in the blood decreases due to less formation and increased release during hyperventilation. This leads at the beginning of the development of intoxication to gas alkalosis, which changes to metabolic acidosis, which is a consequence of the activation of glycolysis processes. Unoxidized metabolic products accumulate in the blood. The content of lactic acid increases, the content of acetone bodies increases, hyperglycemia is noted. The development of hypothermia is explained by the violation of redox processes in tissues. Thus, hydrocyanic acid and its salts cause the phenomena of tissue hypoxia and associated respiratory, circulatory, metabolic, and central nervous system disorders, the severity of which depends on the severity of intoxication.
CLINICAL PICTURE OF CYANIDE POISONING
Cyanide poisoning is characterized by the early onset of signs of intoxication, the rapid development of oxygen starvation, the predominant lesion of the central nervous system and the likely lethal outcome in a short time.
Distinguish between fulminant and delayed forms. When poison enters the body in large quantities, death can occur almost instantly. The affected person immediately loses consciousness, breathing becomes frequent and superficial, the pulse quickens, arrhythmic, convulsions occur. The convulsive period is short, breathing stops and death occurs. With a delayed form, the development of poisoning can be extended in time and proceed in various ways.
Mild degree of poisoning characterized mainly by subjective disorders: irritation of the upper respiratory tract, conjunctiva of the eyes, an unpleasant burning-bitter taste in the mouth, the smell of bitter almonds is felt, weakness, dizziness appear. A little later, there is a feeling of numbness of the oral mucosa, salivation and nausea. At the slightest physical effort, shortness of breath and severe muscle weakness, tinnitus, difficulty in speech appear, and vomiting is possible. After the cessation of the action of the poison, all unpleasant sensations subside. However, headaches, muscle weakness, nausea, and a feeling of general weakness may remain for several days. With a mild degree of intoxication, complete recovery occurs.
With intoxication medium degree at first, the subjective disorders described above are noted, and then a state of excitement arises, a feeling of fear of death appears. The mucous membranes and skin become scarlet, the pulse is slow and tense, blood pressure rises, breathing becomes shallow, short-term clonic convulsions may occur. With timely assistance and removal from the contaminated atmosphere, the poisoned quickly regains consciousness. In the next 3-6 days, weakness, malaise, general weakness, headache, discomfort in the heart area, tachycardia, restless sleep are noted.
In the clinical picture severe intoxication There are four stages: initial, dyspnoetic, convulsive and paralytic. The initial stage is characterized mainly by subjective sensations, as described above in the description of mild poisoning. It is short-lived and moves on to the next one. For the dyspnoetic stage, some signs of oxygen starvation of the tissue type are typical: scarlet color mucous membranes and skin, gradually increasing weakness, general anxiety, discomfort in the region of the heart. The poisoned person develops a feeling of fear of death, the pupils dilate, the pulse slows down, breathing becomes frequent and deep. In the convulsive stage, the condition of the affected person deteriorates sharply. Consciousness is lost, the corneal reflex is sluggish, the pupils do not react to light. Exophthalmos appears, breathing becomes arrhythmic, rare, blood pressure rises, the pulse rate decreases. There are widespread clonic-tonic convulsions. The scarlet color of the skin and mucous membranes is preserved. The duration of this stage can vary from several minutes to several hours. With further deterioration of the condition of the affected person, the paralytic stage develops. Convulsions by this time stop, however, the patient has a deep coma with a complete loss of sensitivity and reflexes, muscle adynamia, involuntary urination and defecation are possible. Breathing is rare, irregular. Then comes a complete cessation of breathing, the pulse quickens, becomes arrhythmic, blood pressure drops and after a few minutes cardiac activity stops.
Consequences and complications characteristic of severe intoxication. For several weeks after the injury, persistent and profound changes in the neuropsychic sphere may persist. As a rule, asthenic syndrome persists for 10-15 days. Patients complain of increased fatigue, decreased performance, headache, poor sleep. There may be violations of motor coordination, persistent disorders of the cerebellar nature, paresis and paralysis of various muscle groups, difficulty in speech, mental disorders. From co-
matic complications in the first place is pneumonia. Its occurrence is facilitated by aspiration of mucus, vomit, prolonged stay of patients in a supine position. Changes are also observed in the cardiovascular system. Within 1-2 weeks, discomfort in the region of the heart, single extrasystoles, tachycardia, lability of the pulse and blood pressure indicators are noted, ECG changes (signs of coronary insufficiency) are traced.
DIAGNOSTICS OF POISONING WITH PRUSIAN ACID
The diagnosis of hydrocyanic acid damage is based on the following signs: the sudden onset of symptoms of the lesion, the sequence of development and the transience of the clinical picture, the smell of bitter almonds in the exhaled air, the scarlet color of the skin and mucous membranes, wide pupils and exophthalmos.
TREATMENT OF POISONING WITH PRUSIAN ACID
The effect of helping those poisoned by cyanide depends on the speed of application of antidotes and agents that normalize the functions of vital organs and systems.
Methemoglobin-forming substances, substances containing sulfur and carbohydrates have antidote properties. Methemoglobin-forming agents include anticyan, amyl nitrite, sodium nitrite, methylene blue. They oxidize the iron in hemoglobin, turning it into methemoglobin. Methemoglobin containing ferric iron is able to compete with cytochrome oxidase for cyanide. It should be borne in mind that methemoglobin is not able to bind with oxygen, therefore, it is necessary to use strictly defined doses of these agents, since hemic hypoxia develops when hemoglobin is inactivated by more than 25-30%. Methemoglobin binds primarily to cyanide dissolved in the blood. With a decrease in the concentration of cyanide in the blood, conditions are created for the restoration of cytochrome oxidase activity and the normalization of tissue respiration. This is due reverse current cyanide from tissues into the blood - towards a lower concentration. The formed cyan-methemoglobin complex is a fragile compound. After 1-1.5 hours, this complex begins to gradually decompose with the formation of hemoglobin and cyanide. Therefore, a relapse of intoxication is possible. However, the dissociation process is extended in time, which makes it possible to neutralize the poison with other antidotes.
The standard antidote from the group of methemoglobin-forming agents is anticyan.
In case of hydrocyanic acid poisoning, the first injection of anticyan in the form of a 20% solution is made in a volume of 1.0 ml intramuscularly or 0.75 ml intravenously. When administered intravenously, the drug is diluted in 10 ml of 25-40% glucose solution or saline, the rate of administration is 3 ml per minute. If necessary after 30 min. the antidote can be re-introduced at a dose of 1.0 ml, but only intramuscularly. After another 30-40 min. a third administration at the same dose can be given if indicated.
Sodium nitrite is a powerful methemoglobin former. Aqueous solutions of the drug are prepared ex tempore, as they are unstable during storage. When assisting poisoned sodium nitrite is administered intravenously slowly in the form of a 1-2% solution in a volume of 10-20 ml.
Amyl nitrite, propyl nitrite has a methemoglobin-forming effect. Methylene blue has a partial methemoglobin-forming effect.
Substances containing sulfur. When substances containing sulfur interact with cyanide, non-toxic rhodanide compounds are formed. Sodium thiosulfate turned out to be the most effective sulfur donator. It is administered intravenously in 20-50 ml of a 30% solution. It reliably neutralizes the OV. The disadvantage is the relatively slow action.
The next group of antidotes has the property of converting cyan into non-toxic cyanohydrins. This property is observed in carbohydrates. Glucose has a pronounced antitoxic effect, which is recommended to be administered at a dose of 30-50 ml of a 25% solution. In addition, glucose has beneficial effect on respiration, cardiac function and increases diuresis.
An antidote effect is observed when cobalt salts are used, which, when interacting with cyanides, lead to the formation of non-toxic cyano-cobalt compounds.
The effect of antidotes is enhanced when they are used against the background of oxygen barotherapy. It has been shown that oxygen under pressure contributes to a more rapid recovery of cytochrome oxidase activity.
There is evidence of a favorable therapeutic effect of unitiol, which, being a sulfur donator, activates the enzyme rhodonase, and thus accelerates the detoxification process. Therefore, it is advisable to introduce unithiol along with sulfur donors.
Antidote therapy for lesions with hydrocyanic acid, as a rule, is carried out in combination: first, methemoglobin formers are used, then sulfur donors and substances that promote the formation of cyanohydrins.
In addition to the use of antidotes, it is necessary to carry out all general principles treatment of poisoned (removal of non-absorbed and absorbed poison, prevention of further ingress of poison into organs - by the method of forced removal, symptomatic therapy, resuscitation).
STAGE TREATMENT
Poisoning develops quickly, so medical care is in the nature of an emergency.
First aid in the outbreak includes putting on a gas mask on the poisoned person. Then evacuation is carried out outside the outbreak. Affected in an unconscious state and the convulsive stage of intoxication need to be evacuated lying down.
First aid is carried out outside the hearth, which allows you to remove the gas mask. Antician is introduced - 1 ml intramuscularly, if necessary, cordiamin, mechanical ventilation.
First aid. The anticant is reintroduced. If it was not prescribed at the stage of first aid, it is desirable to carry out the first injection intravenously with 10 ml of a 25-40% glucose solution. Subsequently, 20-50 ml of a 30% solution of sodium thiosulfate is injected intravenously. According to the indications, 2 ml of a solution of etimizole and cordiamine are used intramuscularly, mechanical ventilation.
Further evacuation is carried out only after the elimination of convulsions and normalization of breathing. Along the way, it is necessary to provide assistance in case of recurrence of intoxication.
Qualified therapeutic assistance consists in carrying out, first of all, urgent measures: repeated administration of antidotes (anticyan, sodium thiosulfate, glucose), injections of cordiamine, etimizol, mechanical ventilation (hardware method). Delayed measures of qualified therapeutic care include the introduction of antibiotics, sulfonamides, desensitizing agents, vitamins.
Those affected in a coma and convulsive state are not transportable. The evacuation of the seriously injured is carried out in the VPTG, in the presence of neurological disorders - in the VPNG, those who have undergone mild intoxication remain in the medical hospital (OMO).
Specialized assistance is provided in the corresponding therapeutic hospitals (VPTG, VPNG) in full. At the end of treatment, convalescents are transferred to HPRL, in the presence of persistent changes in the nervous, cardiovascular, respiratory systems patients are subject to referral to the IHC.

“I took out a box of potassium cyanide from the dispenser and put it on the table next to the cakes. Dr. Lazavert put on rubber gloves, took a few crystals of poison from it, and ground it to powder. Then he removed the top of the cakes, sprinkled the filling with powder in an amount capable, according to him, of killing an elephant. Silence reigned in the room. We followed his actions with excitement. It remains to put the poison in the glasses. We decided to put it down at the last moment so that the poison would not evaporate ... "

This is not an excerpt from a detective novel, and the words do not belong to a fictional character. Here are the memoirs of Prince Felix Yusupov about the preparation of one of the most famous crimes in Russian history - the murder of Grigory Rasputin. It happened in 1916. If, until the middle of the 19th century, arsenic was the main assistant to poisoners, then after the Marsh method was introduced into forensic practice (see the article “Mouse, Arsenic and Kale the Detective”, “Chemistry and Life”, No. 2, 2011), arsenic was resorted to less and less. But increasingly, potassium cyanide, or potassium cyanide (potassium cyanide, as it was called before), began to be used.

What it is...

Potassium cyanide is a salt of hydrocyanic, or hydrocyanic, acid H-CN, its composition is reflected by the formula KCN. Hydrocyanic acid in the form of an aqueous solution was first obtained by the Swedish chemist Carl Wilhelm Scheele in 1782 from yellow blood salt K 4 . The reader already knows that Scheele developed the first method for the qualitative determination of arsenic (see "Mouse, Arsenic and Kale the Detective"). He also discovered the chemical elements chlorine, manganese, oxygen, molybdenum and tungsten, received arsenic acid and arsine, barium oxide and other inorganic substances. Over half of the organic compounds known in the 18th century were also identified and described by Karl Scheele.

Anhydrous hydrocyanic acid was obtained in 1811 by Joseph Louis Gay-Lussac. He also established its composition. Hydrogen cyanide is a colorless volatile liquid that boils at 26°C. The root "cyan" in its name (from the Greek - azure) and the root of the Russian name "hydrocyanic acid" are similar in meaning. This is no coincidence. Ions CN - form blue compounds with iron ions, including the composition KFe. This substance is used as a pigment for gouache, watercolors and other paints under the names Prussian blue, Milori, Prussian blue. Perhaps you are familiar with these paints from gouache or watercolor sets.

The authors of the detective stories unanimously claim that hydrocyanic acid and its salts have a "smell of bitter almonds." Of course, they did not sniff hydrocyanic acid (as well as the author of this article). Information about the "smell of bitter almonds" is taken from reference books and encyclopedias. There are other opinions as well. The author of "Chemistry and Life" A. Kleschenko, who graduated from the Faculty of Chemistry of Moscow State University and is familiar with hydrocyanic acid firsthand, writes in the article "How to poison a hero" ("Chemistry and Life", 1999, No. 2) that the smell of hydrocyanic acid is not like almond.

Detective writers have fallen victim to a long-standing delusion. But on the other hand, the reference book "Harmful chemical substances” were also compiled by specialists. It would be possible, after all, to get hydrocyanic acid and smell it. But something scary!

It remains to be assumed that the perception of smells is an individual matter. And what reminds one of the smell of almonds, for another has nothing to do with almonds. This idea is confirmed by Peter McInnis in the book Silent Killers. World History of Poisons and Poisoning": "Detective novels invariably mention the aroma of bitter almonds, which is associated with sodium cyanide, potassium cyanide and hydrogen cyanide (hydrocyanic acid), but only 40-60 percent ordinary people able to at least smell this specific smell. Moreover, the resident middle lane As a rule, Russia is not familiar with bitter almonds: its seeds, unlike sweet almonds, are not eaten and are not sold.

...and why do they eat it?

We will return to almonds and their smell later. And now - about potassium cyanide. In 1845, the German chemist Robert Bunsen, one of the authors of the spectral analysis method, obtained potassium cyanide and developed a method for industrial production. If today this substance is in chemical laboratories and in production under strict control, then at the turn of the 19th and 20th centuries, potassium cyanide was available to anyone (including intruders). For example, in Agatha Christie's story " Vespiary» Potassium cyanide was bought at a pharmacy supposedly to kill wasps. The crime was thwarted only by the intervention of Hercule Poirot.

Entomologists have used (and still use) small amounts of potassium cyanide in insect stains. Several crystals of poison are placed on the bottom of the stain and poured with plaster. Cyanide slowly reacts with carbon dioxide and water vapor, releasing hydrogen cyanide. Insects inhale the poison and die. The stain filled in this way is valid for more than a year. Nobel Laureate Linus Pauling told how he was supplied with potassium cyanide to make stains by the caretaker of the dental college. He also taught the boy to handle this dangerous substance. It was in 1912. As you can see, in those years, the storage of the “king of poisons” was treated rather lightly.

Where from potassium cyanide such popularity among real and fictional criminals? The reasons are not difficult to understand: the substance is highly soluble in water, does not have a pronounced taste, the lethal (lethal) dose is small - on average, 0.12 g is enough, although individual susceptibility to poison, of course, differs. A high dose of potassium cyanide causes an almost instantaneous loss of consciousness and then respiratory paralysis. Let us add here the availability of a substance in early XIX century, and the choice of Rasputin's murderous conspirators becomes clear.

Hydrocyanic acid is just as poisonous as cyanides, but inconvenient to use: it has a specific smell (for cyanides it is very weak) and cannot be used unnoticed by the victim, besides, due to its high volatility, it is dangerous for everyone around, and not only for the one for whom it is intended. But it also found use as a poisonous substance. During the First World War, hydrocyanic acid was in service with the French army. In some US states, it was used to execute criminals in " gas rooms". It is also used to process wagons, barns, ships inhabited by insects - the principle is the same as that of young Pauling's stain.

How does it work?

It's time to figure out how such a simple substance acts on the body. Back in the 60s of the XIX century, it was established that the venous blood of cyanide-poisoned animals has a scarlet color. This is characteristic, if you remember, of arterial blood rich in oxygen. This means that the body poisoned by cyanide is not able to absorb oxygen. Hydrocyanic acid and cyanides somehow inhibit the process of tissue oxidation. Oxyhemoglobin (the combination of hemoglobin with oxygen) circulates in vain throughout the body, without giving oxygen to the tissues.

The reason for this phenomenon was unraveled by the German biochemist Otto Warburg in the late 1920s. During tissue respiration, oxygen must accept electrons from a substance undergoing oxidation. Enzymes under the general name "cytochromes" participate in the process of electron transfer. These are protein molecules containing a non-protein heme moiety bound to an iron ion. The cytochrome containing the Fe 3+ ion accepts an electron from the oxidized substance and turns into the Fe 2+ ion. That, in turn, transfers an electron to the molecule of the next cytochrome, being oxidized to Fe 3+. So the electron is transferred along the chain of cytochromes, like a ball, which "a chain of basketball players passes from one player to another, inexorably bringing it closer to the basket (oxygen)". This is how the English biochemist Stephen Rose described the work of tissue oxidation enzymes. The last player in the chain, the one who throws the ball into the oxygen basket, is called cytochrome oxidase. In the oxidized form, it contains the Fe 3+ ion. This form of cytochrome oxidase serves as a target for cyanide ions, which can form covalent bonds with metal cations and prefer Fe 3+ .

By binding cytochrome oxidase, cyanide ions remove molecules of this enzyme from the oxidative chain, and the transfer of an electron to oxygen is disrupted, that is, oxygen is not absorbed by the cell. Was discovered interesting fact: hedgehogs in hibernation, are able to tolerate doses of cyanide many times greater than the lethal one. And the reason is that at low temperatures, the absorption of oxygen by the body slows down, like everything else. chemical processes. Therefore, a decrease in the amount of the enzyme is easier to tolerate.

Readers of detective stories sometimes have the idea that potassium cyanide is the most toxic substance on Earth. Not at all! Nicotine and strychnine (substances of plant origin) are ten times more toxic. The degree of toxicity can be judged by the mass of toxin per 1 kg of laboratory animal weight, which is required to cause death in 50% of cases (LD 50). For potassium cyanide, it is 10 mg / kg, and for nicotine - 0.3. Next come: dioxin, a poison of artificial origin - 0.022 mg / kg; tetrodotoxin secreted by puffer fish - 0.01 mg/kg; batrachotoxin secreted by the Colombian tree frog - 0.002 mg/kg; ricin contained in castor seeds - 0.0001 mg / kg (an underground laboratory of terrorists for the manufacture of ricin was uncovered by British intelligence services in 2003); β-bungarotoxin, venom of the South Asian snake Bungaros, 0.000019 mg/kg; tetanus toxin - 0.000001 mg/kg.

The most poisonous is botulinum toxin (0.0000003 mg/kg), which is produced by a certain type of bacteria that develops under anaerobic conditions (without air access) in canned food or sausage. Of course, they must first get there. And from time to time they get, especially in home-made canned food. Homemade sausage is now rare, but once upon a time it was often the source of botulism. Even the name of the disease and its causative agent comes from the Latin botulus- "sausage". The botulinum bacillus in the process of life releases not only a toxin, but also gaseous substances. Therefore swollen cans should not be opened.

Botulinum toxin is a neurotoxin. It breaks work nerve cells that transmit impulse to the muscles. Muscles stop contracting, paralysis sets in. But if you take a toxin in a low concentration and act pointwise on certain muscles, the body as a whole will not suffer, but the muscle will be relaxed. The drug is called "botox" (botulinum toxin), it is both a medicine for muscle spasms and a cosmetic product for smoothing wrinkles.

As you can see, the most poisonous substances in the world were created by nature. It is much more difficult to extract them than to obtain a simple KCN compound. It is clear that potassium cyanide is both cheaper and more accessible.

However, the use of potassium cyanide for criminal purposes does not always give a guaranteed result. Let's see what Felix Yusupov writes about the events that took place in the basement on the Moika on a cold December night in 1916:

“... I offered him eclairs with cyanide. He refused at first.

I do not want, - he said, - painfully sweet.

However, he took one, then another. I watched in horror. The poison should have taken effect immediately, but, to my amazement, Rasputin continued talking as if nothing had happened. Then I offered him our homemade Crimean wines...

I stood beside him and watched his every move, expecting him to collapse...

But he drank, smacked, savored the wine like real connoisseurs. Nothing has changed in his face. At times he raised his hand to his throat, as though he had a spasm in his throat. Suddenly he stood up and took a few steps. When I asked what happened to him, he replied:

But nothing. Tickle in throat.

The poison, however, did not work. The "old man" calmly paced the room. I took another glass of poison, poured it and gave it to him.

He drank it. No impression. The last, third glass remained on the tray.

In desperation, I poured myself a drink too, so as not to let Rasputin drink his wine…”

All in vain. Felix Yusupov went up to his office. “... Dmitry, Sukhotin and Purishkevich, as soon as I entered, rushed to meet me with questions:

Well? Ready? Is it over?

The poison didn't work, I said. Everyone was shocked into silence.

Can not be! Dimitri exclaimed.

Elephant dose! Did he swallow everything? the others asked.

Everything, I said.

But still, potassium cyanide had some effect on the body of the old man: “He hung his head, breathed intermittently ...

Are you unwell? I asked.

Yes, the head is heavy and it burns in the belly. Come on, have a little. Maybe it'll get easier."

Indeed, if the dose of cyanide is not so large as to cause instant death, at the initial stage of poisoning, scratching in the throat, a bitter taste in the mouth, numbness of the mouth and throat, redness of the eyes, muscle weakness, dizziness, staggering, headache, palpitations, nausea, vomit. Breathing is somewhat rapid, then becomes deeper. Yusupov noticed some of these symptoms in Rasputin. If at this stage of poisoning the flow of poison into the body stops, the symptoms disappear. Obviously, poison was not enough for Rasputin. It is worth understanding the reasons, because the organizers of the crime calculated the "elephant" dose. Speaking of elephants. Valentin Kataev in his book "A Broken Life, or the Magic Horn of Oberon" describes the case of an elephant and potassium cyanide.

In pre-revolutionary times, in the Odessa tent circus Lorberbaum, the elephant Yambo fell into a rage. The behavior of the enraged elephant became dangerous, and they decided to poison him. What do you think? “They decided to poison him with potassium cyanide, put in cakes, to which Yambo was a big hunter,” writes Kataev. And further: “I didn’t see this, but I vividly imagined how a cab driver drove up to Lorberbaum’s booth and how the attendants brought cakes into the booth, and there a special medical commission ... with the greatest precautions, wearing black gutta-percha gloves, stuffed cakes with tweezers crystals of potassium cyanide ... "Isn't it very reminiscent of Dr. Lazowert's manipulations? It should only be added that the schoolboy boy draws an imaginary picture for himself. It is no coincidence that this boy later became a famous writer!

But back to Yambo:

“Oh, how vividly my imagination painted this picture ... I groaned in a half-sleep ... Nausea approached my heart. I felt like I was poisoned by potassium cyanide... It seemed to me that I was dying... I got out of bed and the first thing I did was to grab the Odessa Leaf, confident that I would read about the death of an elephant. Nothing like this!

The elephant who ate cakes stuffed with cyanide, it turns out, is still alive and alive and, apparently, is not going to die. The poison had no effect on him. The elephant just got more violent."

You can read about the further events that happened with the elephant and with Rasputin in books. And we are interested in the reasons for the "inexplicable nonsense", as Odessky Leaf wrote about the case with the elephant. There are two such reasons.

First, HCN is a very weak acid. Such an acid can be displaced from its salt by a stronger acid and volatilize. Even carbonic acid is stronger than hydrocyanic acid. Carbonic acid is formed when carbon dioxide dissolves in water. That is, under the action of moist air containing both water and carbon dioxide, potassium cyanide gradually turns into carbonate:

KCN + H 2 O + CO 2 \u003d HCN + KHCO 3

If the potassium cyanide used in the cases described was kept in contact with humid air for a long time, it might not work.

Secondly, the salt of weak hydrocyanic acid is subject to hydrolysis:

KCN + H 2 O \u003d HCN + KOH.

The released hydrogen cyanide is able to attach to a molecule of glucose and other sugars containing a carbonyl group:

CH 2 OH-CHOH-CHOH-CHOH-CHOH-CH=O + HC≡N →
CH 2 OH-CHOH-CHOH-CHOH-CHOH-CHOH-C≡N

Substances formed as a result of the addition of hydrogen cyanide to the carbonyl group are called cyanohydrins. Glucose is a product of the hydrolysis of sucrose. People who work with cyanide know that to prevent poisoning, you should hold a piece of sugar behind your cheek. Glucose binds cyanides in the blood. That part of the poison that has already penetrated into the cell nucleus, where tissue oxidation occurs in mitochondria, is inaccessible to sugars. If an animal has elevated blood glucose, it is more resistant to cyanide poisoning, like birds. The same is observed in patients with diabetes mellitus. When small portions of cyanide are ingested, the body can neutralize them on its own with the help of glucose contained in the blood. And in case of poisoning, 5% or 40% glucose solutions administered intravenously are used as an antidote. But this remedy works slowly.

For both Rasputin and the elephant Yambo, cakes containing sugar were stuffed with potassium cyanide. They were not eaten immediately, but in the meantime, potassium cyanide released hydrocyanic acid, and it joined the glucose. Some of the cyanide had definitely been rendered harmless. We add that cyanide poisoning occurs more slowly on a full stomach.

There are other antidotes to cyanide. Firstly, these are compounds that easily split off sulfur. The body contains such substances - the amino acids cysteine, glutathione. They, like glucose, help the body cope with small doses of cyanide. If the dose is large, a 30% solution of sodium thiosulfate Na 2 S 2 O 3 (or Na 2 SO 3 S) can be specially injected into the blood or muscle. It reacts in the presence of oxygen and the enzyme rhodanase with hydrocyanic acid and cyanides according to the scheme:

2HCN + 2Na 2 S 2 O 3 + O 2 \u003d 2НNCS + 2Na 2 SO 4

In this case, thiocyanates (thiocyanates) are formed, which are much less harmful to the body than cyanides. If cyanides and hydrocyanic acid belong to the first class of danger, then thiocyanates are substances of the second class. They adversely affect the liver, kidneys, cause gastritis, and also inhibit the thyroid gland. People who are systematically exposed to small doses of cyanide develop thyroid diseases caused by the constant formation of thiocyanates from cyanide. Thiosulfate in the reaction with cyanides is more active than glucose, but also acts slowly. It is usually used in combination with other anticyanides.

The second type of antidotes against cyanides are the so-called methemoglobin formers. The name says that these substances form methemoglobin from hemoglobin (see "Chemistry and Life", 2010, No. 10). The hemoglobin molecule contains four Fe 2+ ions, and in methemoglobin they are oxidized to Fe 3+. Therefore, it is not able to reversibly bind oxygen Fe 3+ and does not carry it around the body. This can happen under the influence of oxidizing substances (among them nitrogen oxides, nitrates and nitrites, nitroglycerin and many others). It is clear that these are poisons that “disable” hemoglobin and cause hypoxia (oxygen deficiency). "Spoiled" by these poisons, hemoglobin does not carry oxygen, but it is able to bind cyanide ions, which experience an irresistible attraction to the Fe 3+ ion. The cyanide that enters the blood is bound by methemoglobin and does not have time to get into the mitochondria of the cell nuclei, where it will inevitably “spoil” the entire cytochrome oxidase. And this is much worse than "spoiled" hemoglobin.

The American writer, biochemist and popularizer of science Isaac Asimov explains it this way: “The fact is that the body has a very large amount of hemoglobin ... Hemic enzymes are present in very small quantities. Just a few drops of cyanide is enough to destroy most of these enzymes. If this happens, the conveyor that oxidizes the combustible substances of the body stops. In a few minutes, the cells of the body die from a lack of oxygen as inevitably as if someone grabbed a person by the throat and simply strangled him.

In this case, we observe an instructive picture: some poisons that cause hemic (blood) hypoxia inhibit the action of other poisons that also cause hypoxia, but of a different type. A direct illustration of the Russian idiomatic expression: "knock out a wedge with a wedge." The main thing is not to overdo it with a methemoglobin former, so as not to change the awl for soap. The content of methemoglobin in the blood should not exceed 25-30% of total weight hemoglobin. Unlike glucose or thiosulfate, methemoglobin not only binds cyanide ions circulating in the blood, but also helps the respiratory enzyme “spoiled” by cyanides to get rid of cyanide ions. This is due to the fact that the process of combining cyanide ions with cytochrome oxidase is reversible. Under the action of methemoglobin, the concentration of these ions in the blood plasma decreases - and as a result, new cyanide ions are split off from the complex compound with cytochrome oxidase.

The reaction of formation of cyanmethemoglobin is also reversible, therefore, over time, cyanide ions enter the blood again. To bind them, simultaneously with an antidote (usually nitrite), a solution of thiosulfate is injected into the blood. The most effective mixture of sodium nitrite with sodium thiosulfate. It can help even in the last stages of cyanide poisoning - convulsive and paralytic.

Where can you meet him?

Does it have a chance a common person, not the hero of a detective novel, get poisoned with potassium cyanide or hydrocyanic acid? Like any substances of the first class of danger, cyanides are stored with special precautions and are inaccessible to an ordinary attacker, unless he is an employee of a specialized laboratory or workshop. Yes, and there are similar substances on strict account. However, cyanide poisoning can occur without the involvement of the villain.

First, cyanides occur naturally. Cyanide ions are part of vitamin B 12 (cyanocobolamine). Even in the blood plasma of a healthy person, there are 140 μg of cyanide ions per 1 liter. In the blood of smokers, the content of cyanide is more than twice as high. But the body tolerates such concentrations painlessly. Another thing is if cyanides contained in some plants come with food. Serious poisoning is possible here. Among the sources of hydrocyanic acid available to everyone, one can name the seeds of apricots, peaches, cherries, bitter almonds. They contain the glycoside amygdalin.

Amygdalin belongs to the group of cyanogenic glycosides that form hydrocyanic acid upon hydrolysis. This glycoside was isolated from the seeds of bitter almonds, for which it received its name (Greek μ - "almonds"). The amygdalin molecule, as it should be for a glycoside, consists of a sugary part, or glycone (in this case, it is the disaccharide residue of gentibiose), and a non-sugar part, or aglycone. In the gencibiose residue, in turn, two β-glucose residues are linked by a glycosidic bond. The role of aglycone is benzaldehyde cyanohydrin - mandelonitrile, or rather, its residue associated with glycosidic bond.

Upon hydrolysis, the amygdalin molecule decomposes into two glucose molecules, a benzaldehyde molecule, and a hydrocyanic acid molecule. It happens in acidic environment or by the action of the enzyme emulsin contained in the stone. Due to the formation of hydrocyanic acid, one gram of amygdalin is a lethal dose. This corresponds to 100 g of nucleoli apricot kernels. There are known cases of poisoning of children who ate 10-12 apricot seeds.

In bitter almonds, the content of amygdalin is three to five times higher, but you will hardly want to eat its seeds. In extreme cases, they should be subjected to heat. This will destroy the enzyme emulsin, without which hydrolysis will not go. It is thanks to amygdalin that bitter almond seeds have their bitter taste and almond smell. More precisely, it is not amygdalin itself that has an almond smell, but its hydrolysis products - benzaldehyde and hydrocyanic acid (we have already discussed the smell of hydrocyanic acid, but the smell of benzaldehyde is undoubtedly almond).

Secondly, cyanide poisoning can occur in industries where they are used to create electroplating coatings or to extract precious metals from ores. Ions of gold and platinum form strong complex compounds with cyanide ions. Noble metals are not able to be oxidized by oxygen, because their oxides are fragile. But if oxygen acts on these metals in a solution of sodium or potassium cyanide, then the metal ions formed during oxidation are bound by cyanide ions into a strong complex ion and the metal is completely oxidized. Sodium cyanide itself does not oxidize noble metals, but helps the oxidizer to fulfill its mission:

4Au + 8NaCN + 2H 2 O = 4Na + 4NaOH.

Workers in these industries are chronically exposed to cyanide. Cyanides are poisonous both when ingested, and when inhaled dust and splashes during the maintenance of galvanic baths, and even when it comes into contact with the skin, especially if there are wounds on it. No wonder Dr. Lazowert wore rubber gloves. There was a case of fatal poisoning with a hot mixture containing 80% that came into contact with the worker's skin.

Even people not employed in mining and processing or electroplating industries can be affected by cyanide. There are cases when rivers fell wastewater such industries. In 2000, 2001 and 2004, Europe was alarmed by the release of cyanide into the waters of the Danube in Romania and Hungary. This led to severe consequences for the inhabitants of the rivers and residents of coastal villages. There have been cases of poisoning by fish caught in the Danube. Therefore, it is useful to know the precautions for handling cyanide. And it will be more interesting to read about potassium cyanide in detective stories.

Bibliography:
Azimov A. Chemical agents of life. M.: Publishing house of foreign literature, 1958.
Harmful chemicals. Directory. L.: Chemistry, 1988.
Kataev V. Broken Life, or the Magic Horn of Oberon. Moscow: Soviet writer, 1983.
Oksengendler G.I. Poisons and antidotes. L.: Nauka, 1982.
Rose S. Chemistry of life. Moscow: Mir, 1969.
Encyclopedia for children "Avanta +". T.17. Chemistry. Moscow: Avanta+, 2001.
Yusupov F. Memoirs. Moscow: Zakharov, 2004.

Almost all people know that potassium cyanide is a poison that can cause instant death of a person.

However, there are more dangerous poisons, and accidents associated with this substance most often occur at work.

What should a person know about potassium cyanide, and how to act in case of poisoning with this substance?

What it is

Potassium cyanide is a powdered substance that has White color. Perfectly soluble in water and hot alcohol. It is a derivative of hydrocyanic acid. Chemical formula of the substance KCN.

What does cyanide smell like? The common belief that the poison smells like bitter almonds is not entirely true. The dry powder does not smell, but when interacting with water vapor and carbon dioxide, the smell may appear. However, only fifty percent of all people feel it.

In the production of potassium cyanide, they work very carefully, using gloves and hoods. Many experimenters, thinking how to get this poison at home, conduct various experiments. However, in such cases, poisoning with vapors of such potassium can occur.

Potassium cyanide: where is it found

Where can you get potassium cyanide? In nature, this substance is found in some plants. It is present in the seeds of fruits such as apricots, peaches, cherries, plums. The lethal dose is 100 grams, so do not get carried away with such products. Almonds should also be bought only in trusted places to avoid hydrocyanic acid poisoning.

The cyanide used in production is produced chemically. The areas of application of such potassium are quite diverse.

Application:

• mining,
• jewelry industry,
• photography,
• paints for artists
• entomology (various stains for insects).

As already written above, you can get potassium cyanide at home, but you should think very carefully before doing this. By the way, on the Internet the question of where you can get or how to make cyanide is quite common.

However, you can't buy it anywhere. The substance is poisonous, so in the laboratories it is strictly accounted for. At the same time, it is worth knowing that given potassium cannot be stored for a long time, so there is no stock of it.

Action on the body

How does potassium cyanide affect the human body? When ingested, an important cellular enzyme, cytochrome oxidase, is blocked.

Oxygen starvation of cells develops, they simply do not absorb it. Oxygen remains in the blood, which turns bright red.

As a result of such exposure to poison, cells begin to die, organs cease to function normally, and death occurs.

The effect of potassium cyanide on a person can be compared to suffocation, when the victim simply suffocates from a lack of oxygen.

Intoxication can occur as a result of the ingestion of poison through the oral cavity, through the respiratory tract when the powder or vapors of the substance are inhaled.

You should know that the effect of potassium cyanide is slightly neutralized with glucose. Therefore, in laboratories, workers always keep a piece of sugar in their mouths. In addition, in a full stomach, the poison lasts longer, which makes it possible to have time to provide the necessary assistance to a person.

Video: about potassium cyanide

Symptoms and signs of potassium poisoning

How to understand that intoxication has occurred? What should you pay attention to? It is worth knowing that a small dose of poison does not immediately provoke death, so it is quite possible to help the victim.

Cyanide poisoning can be acute or chronic. Each case has different symptoms.

Signs of acute poisoning:

• nausea, vomiting,
• numbness in the mouth,
• salivation,
• metallic taste,
• dizziness,
• rapid breathing,
• feeling of suffocation,
• eye protrusion,
• pupil dilation,
• convulsions,
• involuntary urination and defecation,
• loss of consciousness,
• lack of reflexes and sensitivity,
• coma,
• stop breathing.

With assistance at the initial stage of a person, it is quite possible to save.

Chronic poisoning occurs as a result of the constant ingestion of potassium cyanide in the human body.

Signs of chronic intoxication:

• persistent headaches,
• frequent dizziness,
• memory problems,
• cardiac dysfunction,
• weight loss,
• frequent urination,
• increased sweating.

May also occur allergic reactions on the skin, exacerbate various diseases.

If signs of poisoning are found, it is necessary to call doctors and provide the person with the necessary assistance.

First aid and treatment

When intoxication with potassium cyanide is detected, no time should be wasted. It is necessary to provide assistance to the victim as soon as possible. First of all, you should call a team of doctors, and then take first aid measures.

Therapy:

• If potassium cyanide is ingested through the mouth, you need to flush the stomach with plenty of water.
• In case of vapor poisoning, a person needs to provide him with access fresh air, unfasten the squeezing clothing on it.
• If a poisonous substance has got on things, then they must be removed from the poisoned person so that the poison does not penetrate inside.
• In the absence of consciousness and respiratory activity, resuscitation measures must be taken.

In a medical institution, doctors prescribe the necessary tests, and then therapy. Be sure to use an antidote to neutralize the action of potassium cyanide. There are several types of drugs that can make such potassium safer.

Kinds:

• glucose,
• sodium thiosulfate,
• drugs (nitroglycerin, methylene blue).

Doctors use the remedy that is most suitable in each particular case. If help is provided quickly and on time, then, as a rule, a person can be saved. In severe poisoning, the recovery process is quite long.

Prevention and consequences

Potassium cyanide poisoning adversely affects the entire human body. In the future, various health disorders may occur, chronic diseases may worsen. The most severe consequence is death. However, this can be avoided if the person is helped in time.

To avoid the occurrence of intoxication, people involved in the production of potassium cyanide must follow safety precautions. Do not try to get potassium yourself at home, the result can be unpredictable.

Potassium cyanide is a substance that poses a serious danger to humans. Knowing how the poison works, you should be careful when working with it, and if poisoning occurs, help the person very quickly.

Video: top 10 most dangerous poisons for humans