Use of potassium and its compounds. Potassium is a metal of great biogenic importance. Interaction with others

Potassium is an interesting and controversial element. It is involved in many vital processes of the body and is actively used in medicine, electroplating, electronics and agriculture. It is part of a poison known since ancient times - potassium cyanide(hydrocyanic acid). This metal is considered common, but doctors say that every fifth person is deficient in the trace element. Potassium cannot be found in a free state in nature, only in combination with other substances. According to average estimates, 2.4% of our planet consists of potassium.

General characteristics of potassium

In the periodic table, potassium occupies the 19th position and is designated by the symbol K. It is a soft and very active alkali metal. On Earth, potassium is found in other minerals (mica, kainite, feldspar, etc.) and salts. In terms of prevalence, it ranks 5th among metals and 7th among chemical elements. Potassium deposits are located in Canada, Belarus and Russia.

According to their own chemical properties potassium resembles sodium, but is more active. People knew about some of the properties of potassium back in the 20th century. It was used as a fertilizer, and potash (a composition of potassium sulfate and chloride, carbonate and soda) was considered an excellent detergent. To obtain it, wood or straw was burned, then mixed with water and evaporated.

Potassium as separate element was isolated in 1807 by the English chemist Humphry Davy, who conducted experiments with caustic potassium. During electrolysis, a metal was released, and the chemist named it potassium. In 1809, the name was changed on the initiative of L.V. Gilterta. He suggested the name “potassium” (from the Arabic word “al-kali”, that is, “potash”).

Potassium melts easily and quickly oxidizes when exposed to oxygen. Original form– metal with crystal structure, painted silver-white. When burning, the flames turn purple-pink. When reacting with water, a fire or explosion occurs, it is chemically active and is considered a strong reducing agent. Requires special conditions storage Most often, pure potassium is poured with a layer of kerosene. In this form it can stand without losing its properties.

Potassium is actively used in agriculture for the production of fertilizers (along with phosphorus and nitrogen). When it is deficient, photosynthesis is disrupted in plants and leaves die. Potassium salts are actively used in electronics. Liquid alloys are used in nuclear power plants and as coolants for closed systems. The alloy of potassium, cesium and sodium has the lowest melting point - 78 degrees Celsius.

Potassium enters the human body with food and water. Absorption of the metal occurs in the intestines and is excreted in the urine. It does not accumulate in the body, so it is needed constantly.

Benefits of potassium for the human body

The role of potassium in the human body is:

• Improves oxygen exchange, increases brain activity.
• Regular consumption of potassium-containing foods is an excellent disease prevention of cardio-vascular system. Potassium reduces arterial pressure and normalizes heart rate, strengthens blood vessels.
• Has a beneficial effect on muscle tissue. Potassium helps maintain muscle tone and recover after intense exercise. Prevents the appearance aching pain and seizures.
• Participates in the processing of glucose, provides correct abbreviation muscle fibers.
• Maintains fluid balance and intracellular pressure. It is part of all fluids of the human body.
• Improves the functions of the urinary system, prevents the deposition of waste and fluid stagnation.
• Works closely with magnesium, helping to maintain its optimal concentration (magnesium is extremely important for protecting the heart).
• Normalizes the body's energy balance.
• Actively used to treat diseases nervous system: stabilizes the condition, helps avoid depression and breakdowns. Relieves fatigue syndrome.
• Strengthens bones. For their health, they need not only calcium and fluoride, but also minerals, including potassium. This macronutrient protects against the onset of osteoporosis.
• Improves metabolic processes. Potassium helps the body break down and absorb certain elements. If you're on a diet and still don't lose weight, make sure you're getting enough potassium in your diet.

Main sources of potassium

Sources of potassium are conventionally divided into four groups:

• Low content (up to 100 mg per 100 grams of product).
• Average level (content 150-250 mg per 100g).
• High content (250-390 mg).
• Very saturated (about 400 mg).

Plant sources of potassium (Table 1):

• Dried fruits.
• Cereals (buckwheat, oats, millet).
• Vegetables (tomatoes, beets, carrots, pumpkin, spinach, cucumbers, lettuce, radishes, zucchini, cabbage).
• Legumes (soybeans, peas, beans).
• Berries (lingonberries, grapes, currants, cranberries, blackberries, viburnum, blueberries).
• Fruits (bananas, citrus fruits, apples, melon, apricots, etc.).
• Nuts (almonds, peanuts, pine, hazelnuts).
• Mushrooms (ceps, champignons, chanterelles, boletus, etc.).

Animal sources of potassium (Table 1):

• Fish (cod, tuna, mackerel, etc.), seafood.
• Dairy products (kefir, milk, hard cheese, cottage cheese, butter).
• Liver.
• Poultry, beef, lamb.
• Eggs.

Table 1. Potassium content in foods

Expert advice. Potassium evaporates easily from food when high temperatures and interaction with liquids. Potassium deficiency peaks in winter when people consume limited quantity fresh vegetables and fruits

• Minimal heat treatment.
• Prepare food in small quantity water.
• Eat more fresh fruits and vegetables.
• Ideally, dishes should be baked, not overcooked and not stewed for a long time.

Potassium mixture recipe. You will need 300g of dried apricots, raisins, prunes, figs, 1 cup of walnuts, 1 cup of honey (preferably fresh), 2 lemons. Grind the lemons in a meat grinder, finely chop the nuts. Mix with dried fruits and honey, store in a cool, dark place. Eat a heaped teaspoon three times a day 1.5 hours after meals. The potassium norm for humans is given in Table 2.

Table 2. Daily norm potassium

Interaction with other elements

What you need to know about potassium:

• Combines well with sodium and magnesium. Potassium promotes the absorption of magnesium and the excretion of sodium.
• It is better absorbed if you take vitamin B6 at the same time.
• Potassium absorption is prevented by alcohol-containing drinks, caffeine, and sugar.
• Some medications Triamterene, Sulfamethoxazole, as well as inhibitors and potassium-containing salts can artificially increase potassium in the blood.
• Table salt consumed in large doses can cause potassium deficiency.
• Some heart medications and diuretics remove potassium from the body.
• Rubidium, cesium, and thallium are considered antagonists and can also displace potassium from the body.

Deficiency and excess of potassium in the body

Potassium deficiency is common and there are a number of reasons for this:

• Unbalanced diet.
• Disorders of metabolic processes in the body.
• Diseases of the digestive organs, kidneys.
• Dehydration of the body due to taking medications, poisoning, etc.
• Overload of the nervous system.
• Excessive intake of micro- and macroelements into the body, displacing potassium.
• Abuse of coffee, alcohol and sweets.

Potassium deficiency manifests itself as follows:

• Immunity decreases.
• Feels like constant fatigue and frequent muscle cramps.
• Chronic exhaustion.
• Frequent urination.
• Deterioration of the condition of hair, skin (becomes dry) and nails.
• Hypertension.
• Increased heart rate and breathing.
• The appearance of ulcers and erosions on the mucous membranes.
• Diseases of the reproductive system.
• Swelling of the limbs and face.
• Problems with bowel movements.

In pregnant women, potassium deficiency is accompanied by nausea, muscle weakness, and persistent toxicosis.

In the future, hypokalemia can lead to arrhythmia and disruption of the body’s acid-base balance. The risk of developing diabetes and heart disease increases.

If alarming symptoms appear, contact a specialist. Simple tests and a cardiogram is often sufficient to make a diagnosis. Don't self-medicate

Excess potassium in the body may appear in the following cases:

• Abuse of potassium-containing drugs.
• Following a diet containing foods high in potassium.
• Violation of metabolic processes.
• Insulin deficiency.
• Kidney failure.
• Changes in hormonal levels (in particular, the sympathoadrenal system).

A single dose of 6 g of potassium can disrupt basic functions body, 14 g is considered lethal dose. So you need to approach the choice of products and medications responsibly. If the concentration of potassium in the blood exceeds 5 mmol/l, we can talk about hyperkalemia.

Symptoms of hyperkalemia:

• Increased excitability, anxiety, nervous state.
• Increased sweating.
  Muscle tremors, convulsions, and in severe cases, paralysis.
• Arrhythmia.
• Colic in the stomach and intestines.
• Increased blood sugar levels.
• Increased urine output.

A serious overdose of potassium can impair heart function. Potassium is deposited in the ligaments, causing muscle cramps and short-term paralysis. The risk of developing urolithiasis and diabetes increases.

Preparations with potassium

Potassium preparations are available in the following forms:

• Solutions and soluble tablets.
• Capsules.
• Coated tablets.

The most common drugs:

• Asparkam. Contains 175 mg of potassium and magnesium aspartate. There are 20-50 tablets in a package. Often prescribed for diseases of the cardiovascular system.
• Potassium chloride. Available in tablets and ampoules (dosage 40 mg/ml), administered intravenously, referred to as “hot” injections. Tablets in dosages from 500 to 1500 mg.
• IonicKalium. Spray 60 ml, contains potassium ions. It is injected under the tongue, and the macroelement is absorbed into the mucous membrane without entering the digestive system.
• Potassium orotate. Contains 500 mg of potassium in each tablet, 10-50 pieces per pack.
• Panangin. Contains 45.2 mg of potassium and magnesium in high concentration. There is also a Forte form - 316 mg of potassium per tablet.
• Kudesan. Complex with potassium and magnesium. Contains 250 mg magnesium aspartate and 450 mg potassium aspartate. The complex is enriched with ubichon, which improves the immune system.

In medium dosages, potassium is included in vitamin-containing preparations: Vitrum (40 mg), Centrus (40 mg), Vitalux (40 mg), TeravitAntistress (80 mg).

For medicinal purposes, drugs with higher concentrations are used: Pamaton, Aspacard, Orocamag, Aspariginate, etc.

How to take potassium-containing medications:

• It is recommended to take vitamins and potassium tablets after meals.
• Do not chew tablets and capsules. The liquid form is most often injected under the tongue.
• Take the tablets big amount water.
• Add soluble drugs to water or juice and drink in small sips within 5 minutes.
• It is not recommended to administer the drug in ampoules yourself.

Not every person knows the features chemical reactions with potassium. We suggest you look at a few interesting experiments with this metal in the video below.

POTASSIUM (Latin Kalium), K, chemical element of group I short form (group 1 long form) periodic table; atomic number 19; atomic mass 39.0983; refers to alkali metals. Natural potassium consists of three isotopes: 39 K (93.2581%), 40 K (0.0117%; weakly radioactive, T 1/2 1.277 10 9 years, β-decay up to 40 Ca), 41 K (6.7302 %). Radioisotopes with mass numbers 32-54 have been artificially obtained.

Historical reference. Some potassium compounds were known in ancient times, for example, potassium carbonate K 2 CO 3 (the so-called plant alkali) was isolated from wood ash and used in making soap. Metallic potassium was first obtained by G. Davy in 1807 by electrolysis of wet solid hydroxide KOH and called it potassium (English potassium from English potash - the name of potassium carbonate). In 1809, the name “potassium” (from the Arabic al-kali - potash) was proposed. The name “potassium” has been preserved in Great Britain, the USA, France and other countries. In Russia, since 1840, the name “potassium” has been used, which is also adopted in Germany, Austria, and the Scandinavian countries.

Prevalence in nature. The potassium content in the earth's crust is 2.6% by weight. Potassium does not occur in a free state in nature. IN significant quantities potassium is found in nepheline and leucite silicates, feldspars (for example, orthoclase), micas (for example, muscovite). Own potassium minerals - sylvite, sylvinite, carnallite, kainite, langbeinite K 2 SO 4 ∙2MgSO 4 form large accumulations of natural potassium salts. As a result of the action of water and carbon dioxide, potassium turns into soluble compounds, which are partially carried into the seas and partially retained by the soil. Potassium salts are also found in the brine of salt lakes and underground brines.

Properties. External configuration electron shell potassium atom 4s 1; in compounds exhibits an oxidation state of +1; ionization energies K 0 →K + →K 2+ are respectively 4.3407 and 31.8196 eV; Pauling electronegativity 0.82; atomic radius 220 pm, ion radius K + 152 pm ( coordination number 6).

Potassium - silvery white soft metal; crystal cell cubic body-centered; t melt 63.38 °C, boil t 759 °C, density 856 kg/m 3 (20 °C); heat capacity 29.60 J/(mol K) at 298 K.

Potassium can be pressed and rolled, easily cut with a knife and retains its plasticity when used. low temperatures; Brinell hardness 0.4 MPa.

Potassium is a metal of high chemical activity (potassium is stored under a layer of gasoline, kerosene or mineral oil). At normal conditions potassium interacts with oxygen (oxide K 2 O, peroxide K 2 O 2 is formed, superoxide KO 2 is the main product), halogens (corresponding potassium halides), when heated - with sulfur (sulfide K 2 S), selenium (selenide K 2 Se ), tellurium (K 2 Te telluride), with phosphorus in a nitrogen atmosphere (phosphides K 3 P and K 2 P5), carbon (layered compounds of the composition KS 8 - KS 60), hydrogen (KN hydride). Potassium interacts with nitrogen only when exposed to electrical discharge(KN 3 azide and K 3 N nitride are formed in small quantities). Potassium reacts with some metals, forming intermetallic compounds or solid solutions(potassium alloys). Alloys with sodium, characterized by high chemical activity, are of greatest practical importance; obtained by alloying metals in an inert atmosphere or by the action of metallic sodium on KOH hydroxide or KCl chloride.

Metallic potassium is a strong reducing agent: it reacts vigorously (under normal conditions with explosion and ignition of the metal) with water (potassium hydroxide KOH is formed), reacts violently (sometimes with explosion) with acids (forms corresponding salts, for example, potassium dichromate, potassium nitrate, potassium permanganate, potassium phosphates, potassium cyanide), reduces the oxides of B, Si, Al, Ag, Bi, Co, Cr, Cu, Hg, Ni, Pb, Sn, Ti to elements; sulfates, sulfites, nitrates, nitrites, carbonates and phosphates of other metals - to oxides of the corresponding metals. Potassium metal dissolves slowly in liquid ammonia to form a dark blue solution with metallic conductivity; the dissolved metal gradually reacts with ammonia to form an amide: 2K + 2NH 3 = 2KNH 2 + H 2. Potassium interacts with various organic compounds: alcohols (alcoholates are formed, for example ethyl C 2 H 5 OK), acetylene (acetylenides KS≡CH and KS≡SK), alkyl halides (potassium alkyls, for example ethylpotassium C 2 H 5 K) and aryl halides (potassium aryls, for example phenylpotassium C 6 H 5 TO). Potassium metal initiates the polymerization reactions of alkenes and dienes. With N- and O-donor polycyclic ligands (crown ethers, cryptands and other ionophores), potassium forms complex compounds.

When working with potassium, it is necessary to take into account its high reactivity, including the ability to ignite upon contact with water. For safety reasons, you must use rubber gloves, safety glasses or a mask. Large amounts of potassium should be worked in special chambers in an inert atmosphere (argon, nitrogen). Potassium is used to extinguish fires table salt NaCl or soda ash Na 2 CO 3.

Biological role . Potassium is a biogenic element. Daily requirement person in potassium is about 2 g. In living organisms, potassium ions play an important role in the processes of regulation of metabolism, in particular, the transport of ions through cell membranes(see, for example, the article Ion pumps).

Receipt. In industry, potassium is obtained by reducing molten KOH hydroxide or KCl chloride with sodium metal in a countercurrent column, followed by condensation of potassium vapor. Promising vacuum-thermal methods potassium production based on the reduction of KCl chloride by heating with a mixture of aluminum or silicon with calcium oxide (6KCl + 2Al + 4CaO = 6K + 3CaCl 2 + CaO Al 2 O 3 or 4Kl + Si + 4CaO = 4K + 2CaCl 2 + 2CaO∙SiO 2), as well as a method based on the production of a potassium-lead alloy by electrolysis of K 2 CO 3 carbonate or KCl chloride with a molten lead cathode and subsequent distillation of the potassium alloy. The volume of global potassium production is about 28 tons/year (2004).

Application. Potassium metal is the material of electrodes in chemical sources current, catalyst in the processes of producing synthetic rubber. Various potassium compounds are widely used: peroxide K 2 O 2 and superoxide KO 2 - components of compositions for oxygen regeneration (on submarines, spaceships and in others indoors), KH hydride is a reducing agent in chemical synthesis, an alloy of potassium with sodium (10-60% Na by weight, liquid at room temperature) - coolant in nuclear reactors, a reducing agent in titanium production, a reagent for purifying gases from oxygen and water vapor; potassium salts are used as potassium fertilizers, components detergents. Complexes of potassium with ionophores are models for studying the transport of potassium ions across cell membranes. The radioisotope 42 K (T 1/2 12.36 h) is used as a radioactive tracer in chemistry, medicine and biology.

Lit.: Sodium and potassium. L., 1959; Stepin B. D., Tsvetkov A. A. Inorganic chemistry. M., 1994; Inorganic chemistry: chemistry of elements / Edited by Yu. D. Tretyakov. M., 2004. T. 2.