Cl 2 at vol. T - yellow-green gas with a sharp suffocating odor, heavier than air - 2.5 times, slightly soluble in water (~ 6.5 g / l); X. R. in nonpolar organic solvents. It is found free only in volcanic gases.

How to get

Based on the process of oxidation of anions Cl -

2Cl - - 2e - = Cl 2 0

Industrial

Electrolysis of aqueous solutions of chlorides, more often - NaCl:

2NaCl + 2H 2 O \u003d Cl 2 + 2NaOH + H 2

Laboratory

Oxidation conc. HCI various oxidizing agents:

4HCI + MnO 2 \u003d Cl 2 + MpCl 2 + 2H 2 O

16HCl + 2KMnO 4 \u003d 5Cl 2 + 2MnCl 2 + 2KCl + 8H 2 O

6HCl + KClO 3 \u003d ZCl 2 + KCl + 3H 2 O

14HCl + K 2 Cr 2 O 7 \u003d 3Cl 2 + 2CrCl 3 + 2KCl + 7H 2 O

Chemical properties

Chlorine is a very strong oxidizing agent. Oxidizes metals, non-metals and complex substances, while turning into very stable anions Cl -:

Cl 2 0 + 2e - \u003d 2Cl -

Reactions with metals

Active metals in an atmosphere of dry chlorine gas ignite and burn; in this case, metal chlorides are formed.

Cl 2 + 2Na = 2NaCl

3Cl 2 + 2Fe = 2FeCl 3

Inactive metals are more easily oxidized by wet chlorine or its aqueous solutions:

Cl 2 + Cu \u003d CuCl 2

3Cl 2 + 2Au = 2AuCl 3

Reactions with non-metals

Chlorine does not directly interact only with O 2, N 2, C. Reactions proceed with other non-metals under various conditions.

Non-metal halides are formed. The most important is the reaction of interaction with hydrogen.

Cl 2 + H 2 \u003d 2HC1

Cl 2 + 2S (melt) = S 2 Cl 2

ЗCl 2 + 2Р = 2РCl 3 (or РCl 5 - in excess of Cl 2)

2Cl 2 + Si = SiCl 4

3Cl 2 + I 2 \u003d 2ICl 3

Displacement of free non-metals (Br 2, I 2, N 2, S) from their compounds

Cl 2 + 2KBr = Br 2 + 2KCl

Cl 2 + 2KI \u003d I 2 + 2KCl

Cl 2 + 2HI \u003d I 2 + 2HCl

Cl 2 + H 2 S \u003d S + 2HCl

ZCl 2 + 2NH 3 \u003d N 2 + 6HCl

Disproportionation of chlorine in water and aqueous solutions of alkalis

As a result of self-oxidation-self-healing, some chlorine atoms are converted into Cl - anions, while others in a positive oxidation state are part of the ClO - or ClO 3 - anions.

Cl 2 + H 2 O \u003d HCl + HClO hypochlorous to-ta

Cl 2 + 2KOH \u003d KCl + KClO + H 2 O

3Cl 2 + 6KOH = 5KCl + KClO 3 + 3H 2 O

3Cl 2 + 2Ca (OH) 2 \u003d CaCl 2 + Ca (ClO) 2 + 2H 2 O

These reactions are important because they lead to the production of oxygen compounds of chlorine:

KClO 3 and Ca (ClO) 2 - hypochlorites; KClO 3 - potassium chlorate (bertolet salt).

Interaction of chlorine with organic substances

a) substitution of hydrogen atoms in OB molecules

b) attachment of Cl 2 molecules at the point of breaking of multiple carbon-carbon bonds

H 2 C \u003d CH 2 + Cl 2 → ClH 2 C-CH 2 Cl 1,2-dichloroethane

HC≡CH + 2Cl 2 → Cl 2 HC-CHCl 2 1,1,2,2-tetrachloroethane

Hydrogen chloride and hydrochloric acid

Hydrogen chloride gas

Physical and chemical properties

HCl - hydrogen chloride. At rev. T - colorless. gas with a pungent odor, liquefies quite easily (mp. -114°С, bp. -85°С). Anhydrous HCl, both in gaseous and liquid states, is non-conductive, chemically inert with respect to metals, metal oxides and hydroxides, and also to many other substances. This means that in the absence of water, hydrogen chloride does not exhibit acidic properties. Only at very high temperatures does gaseous HCl react with metals, even such inactive ones as Cu and Ag.
The reducing properties of the chloride anion in HCl also manifest themselves to a small extent: it is oxidized by fluorine at vol. T, and also at high T (600°C) in the presence of catalysts, it reversibly reacts with oxygen:

2HCl + F 2 \u003d Cl 2 + 2HF

4HCl + O 2 \u003d 2Cl 2 + 2H 2 O

Gaseous HCl is widely used in organic synthesis (hydrochlorination reactions).

How to get

1. Synthesis from simple substances:

H 2 + Cl 2 \u003d 2HCl

2. Formed as a by-product during hydrocarbon chlorination:

R-H + Cl 2 = R-Cl + HCl

3. In the laboratory, they receive the action of conc. H 2 SO 4 for chlorides:

H 2 SO 4 (conc.) + NaCl \u003d 2HCl + NaHSO 4 (with low heating)

H 2 SO 4 (conc.) + 2NaCl \u003d 2HCl + Na 2 SO 4 (with very strong heating)

An aqueous solution of HCl is a strong acid (hydrochloric, or hydrochloric)

HCl is very soluble in water: at vol. T in 1 l of H 2 O dissolves ~ 450 l of gas (dissolution is accompanied by the release of a significant amount of heat). A saturated solution has a mass fraction of HCl equal to 36-37%. This solution has a very pungent, suffocating odor.

HCl molecules in water almost completely decompose into ions, i.e., an aqueous solution of HCl is a strong acid.

Chemical properties of hydrochloric acid

1. HCl dissolved in water exhibits all the general properties of acids due to the presence of H + ions

HCl → H + + Cl -

Interaction:

a) with metals (up to H):

2HCl 2 + Zn \u003d ZnCl 2 + H 2

b) with basic and amphoteric oxides:

2HCl + CuO \u003d CuCl 2 + H 2 O

6HCl + Al 2 O 3 \u003d 2AlCl 3 + ZN 2 O

c) with bases and amphoteric hydroxides:

2HCl + Ca (OH) 2 \u003d CaCl 2 + 2H 2 O

3HCl + Al(OH) 3 \u003d AlCl 3 + ZN 2 O

d) with salts of weaker acids:

2HCl + CaCO 3 \u003d CaCl 2 + CO 2 + H 3 O

HCl + C 6 H 5 ONa \u003d C 6 H 5 OH + NaCl

e) with ammonia:

HCl + NH 3 \u003d NH 4 Cl

Reactions with strong oxidizing agents F 2 , MnO 2 , KMnO 4 , KClO 3 , K 2 Cr 2 O 7 . Anion Cl - is oxidized to free halogen:

2Cl - - 2e - = Cl 2 0

For reaction equations, see "Getting Chlorine". OVR between hydrochloric and nitric acids is of particular importance:

Reactions with organic compounds

Interaction:

a) with amines (as organic bases)

R-NH 2 + HCl → + Cl -

b) with amino acids (as amphoteric compounds)

Oxides and oxoacids of chlorine

Acid oxides

acids

salt

Chemical properties

1. All oxoacids of chlorine and their salts are strong oxidizers.

2. Almost all compounds decompose when heated due to intramolecular oxidation-reduction or disproportionation.

Bleaching powder

Chlorine (whitewash) lime - a mixture of hypochlorite and calcium chloride, has a bleaching and disinfecting effect. Sometimes it is considered as an example of a mixed salt, which simultaneously contains anions of two acids:

Javel water

Aqueous solution of chloride and potassium hapochlorite KCl + KClO + H 2 O

In 1774, Carl Scheele, a chemist from Sweden, first obtained chlorine, but it was believed that this was not a separate element, but a type of hydrochloric acid (calorizator). Elemental chlorine was obtained at the beginning of the 19th century by G. Davy, who decomposed table salt into chlorine and sodium by electrolysis.

Chlorine (from the Greek χλωρός - green) is an element of the XVII group of the periodic table of chemical elements of D.I. Mendeleev, has an atomic number of 17 and an atomic mass of 35.452. The accepted designation Cl (from the Latin Chlorum).

Being in nature

Chlorine is the most common halogen in the earth's crust, most often in the form of two isotopes. Due to its chemical activity, it is found only in the form of compounds of many minerals.

Chlorine is a poisonous yellow-green gas with a pungent odor and a sweetish taste. It was chlorine that, after its discovery, was proposed to be called halogen, it is included in the group of the same name as one of the most chemically active non-metals.

Daily requirement for chlorine

Normally, a healthy adult should receive 4-6 g of chlorine per day, the need for it increases with active physical exertion or hot weather (with increased sweating). Usually, the body receives the daily norm from food with a balanced diet.

The main supplier of chlorine to the body is table salt - especially if it is not subjected to heat treatment, so it is better to salt already prepared dishes. Also contain chlorine, seafood, meat, and, and,.

Interaction with others

The acid-base and water balance of the body is regulated by chlorine.

Signs of a lack of chlorine

The lack of chlorine is caused by processes that lead to dehydration of the body - severe sweating in the heat or during physical exertion, vomiting, diarrhea and some diseases of the urinary system. Signs of a lack of chlorine are lethargy and drowsiness, muscle weakness, pronounced dry mouth, loss of taste, lack of appetite.

Signs of excess chlorine

Signs of excess chlorine in the body are: increased blood pressure, dry cough, pain in the head and chest, pain in the eyes, watery eyes, disorders of the gastrointestinal tract. As a rule, an excess of chlorine can be caused by drinking ordinary tap water, which goes through the process of disinfection with chlorine and occurs in workers in industries that are directly related to the use of chlorine.

Chlorine in the human body:

• regulates water and acid-base balance,
• removes fluid and salts from the body in the process of osmoregulation,
• stimulates normal digestion,
• normalizes the state of erythrocytes,
• cleanses the liver of fat.

The main use of chlorine is the chemical industry, where it is used to produce polyvinyl chloride, polystyrene foam, packaging materials, as well as chemical warfare agents and fertilizers for plants. Disinfection of drinking water with chlorine is practically the only available way to purify water.

Chlorine, one might say, is already a constant companion of our daily life. Rarely in which house will there not be household products based on the disinfecting effect of this element. But at the same time, it is very dangerous for humans! Chlorine can enter the body through the mucous membrane of the respiratory system, digestive tract, and skin. You can poison them both at home and on vacation - in many pools, water parks, it is the main means of water purification. The effect of chlorine on the human body is sharply negative, it can cause serious dysfunction and even death. Therefore, everyone needs to be aware of the symptoms of poisoning, first aid methods.

Chlorine - what is this substance

Chlorine is a yellowish gaseous element. It has a sharp specific odor - In gaseous form, as well as in chemical forms, which imply its active state, it is dangerous, toxic to humans.

Chlorine is 2.5 times heavier than air, so in the event of a leak it will spread along ravines, the spaces of the first floors, and along the floor of the room. When inhaled, the victim may develop one of the forms of poisoning. We will talk about this further.

Symptoms of poisoning

Both prolonged inhalation of vapors and other exposure to the substance are very dangerous. Since it is active, the effect of chlorine on the human body manifests itself quickly. The toxic element affects the eyes, mucous membranes and skin to a greater extent.

Poisoning can be both acute and chronic. However, in any case, with untimely assistance, a fatal outcome threatens!

Symptoms of poisoning with chlorine vapor can be different - depending on the specifics of the case, the duration of exposure and other factors. For convenience, we have delimited the signs in the table.

Degree of poisoning	Symptoms
Light. The safest - passes on its own, on average, in three days.	Irritation, redness of the mucous membranes, skin.
Average. Requires medical attention and comprehensive treatment!	Violation of the heart rhythm, suffocation, pain in the chest, lack of air, profuse lacrimation, dry cough, burning sensation on the mucous membranes. The most dangerous symptom-consequence is pulmonary edema.
Heavy. Resuscitation measures are needed - death can occur in 5-30 minutes!	Dizziness, thirst, convulsions, loss of consciousness.
Lightning. Unfortunately, in most cases, help is useless - death occurs almost instantly.	Convulsions, swelling of the veins on the face and neck, respiratory failure, cardiac arrest.
Chronic. A consequence of frequent work with a substance that contains chlorine.	Cough, convulsions, chronic diseases of the respiratory system, frequent headaches, depression, apathy, cases of loss of consciousness are not uncommon.

This is the effect of chlorine on the human body. Let's talk about where you can get poisoned by its poisonous fumes and how to provide first aid in this case.

Poisoning at work

Chlorine gas is used in many industries. You may well get a chronic form of poisoning if you work in the following industries:

• Chemical industry.
• Textile factory.
• pharmaceutical industry.

Vacation poisoning

Although many are aware of the effect of chlorine on the human body (of course, in large volumes), not all saunas, swimming pools, and entertainment water complexes strictly monitor the use of such a budget disinfectant. But its dosage is very easy to accidentally exceed. Hence the chlorine poisoning of visitors, which happens quite often in our time.

How to notice that during your visit the dose of the element in the pool water is exceeded? Very simple - you will feel a strong specific smell of the substance.

What happens if you often visit the pool, where they violate the instructions for using Dez-chlor? Visitors should be wary of constant dry skin, brittle nails and hair. In addition, swimming in highly chlorinated water, you risk getting mild element poisoning. It manifests itself with the following symptoms:

• cough;
• vomit;
• nausea;
• in rare cases, inflammation of the lungs occurs.

Poisoning at home

Poisoning can also threaten you at home if you have violated the instructions for using Dez-Chlor. A chronic form of poisoning is also common. It develops if the housewife often uses the following means to clean up:

• Bleachers.
• Preparations designed to combat mold.
• Tablets, washing liquids, which contain this element.
• Powders, solutions for general disinfection of the premises.

Effects of chlorine on the body

The constant impact of even small doses of chlorine (the state of aggregation can be any) on the human body threatens people with the following:

• Pharyngitis.
• Laryngitis.
• Bronchitis (in acute or chronic form).
• Various diseases of the skin.
• Sinusitis.
• Pneumosclerosis.
• Tracheitis.
• Visual impairment.

If you have noticed one of the ailments listed above, provided that you have been constantly or once (cases of visiting the pool also applies here) were exposed to chlorine vapor, then this is a reason to contact a specialist as soon as possible! The doctor will prescribe a comprehensive diagnosis to study the nature of the disease. After studying its results, then he will prescribe treatment.

First aid for poisoning

Chlorine is a gas that is very dangerous to inhale, especially in large volumes! With an average, severe form of poisoning, the victim should immediately receive first aid:

1. Whatever the state of the person, do not panic. You should first of all pull yourself together, and then calm him down.
2. Remove the victim to fresh air or to a ventilated area free of chlorine fumes.
3. Call an ambulance as soon as possible.
4. Make sure that the person is warm and comfortable - cover him with a blanket, blanket or sheet.
5. Make sure that he breathes easily and freely - remove tight clothing, jewelry from the neck.

Medical care for poisoning

Before the arrival of the ambulance team, you can help the victim yourself, using a number of household and medical preparations:

• Prepare a 2% baking soda solution. Rinse the victim's eyes, nose, and mouth with this liquid.
• Put vaseline or olive oil in his eyes.
• If a person complains of pain, pain in the eyes, then in this case, a 0.5% dicaine solution would be best. 2-3 drops for each eye.
• For prevention, an eye ointment is also applied - synthomycin (0.5%), sulfanilic (10%).
• Albucid (30%), zinc sulfate solution (0.1%) can be used as a substitute for eye ointment. These drugs are instilled into the victim twice a day.
• Intramuscular, intravenous injection. "Prednisolone" - 60 mg (intravenously or intramuscularly), "Hydrocortisone" - 125 mg (intramuscularly).

Prevention

Knowing how dangerous chlorine is, what substance has an effect on the human body, it is best to take care of reducing or eliminating its negative impact on your body in advance. This can be achieved in the following ways:

• Compliance with sanitary standards in the workplace.
• Regular medical examinations.
• The use of protective equipment when working with chlorine-containing drugs at home or at work - the same respirator, tight protective rubber gloves.
• Compliance with safety regulations when working with the substance in an industrial environment.

Working with chlorine always requires caution, both on an industrial scale and in households. You know how to diagnose yourself for signs of substance poisoning. Assistance to the victim must be provided immediately!

In the west of Flanders lies a tiny town. Nevertheless, its name is known throughout the world and will long remain in the memory of mankind as a symbol of one of the greatest crimes against humanity. This town is Ypres. Crecy (in the Battle of Crecy in 1346 the English troops used firearms for the first time in Europe.) - Ypres - Hiroshima - milestones on the way to turning the war into a giant destruction machine.

At the beginning of 1915, the so-called Ypres ledge formed on the western front line. The allied Anglo-French troops northeast of Ypres wedged into the territory comma of the German army. The German command decided to launch a counterattack and level the front line. On the morning of April 22, when a flat northeast blew, the Germans began an unusual preparation for the offensive - they carried out the first gas attack in the history of wars. On the Ypres sector of the front, 6,000 cylinders of chlorine were simultaneously opened. Within five minutes, a huge, weighing 180 tons, poisonous yellow-green cloud formed, which slowly moved towards the enemy's trenches.

Nobody expected this. The troops of the French and British were preparing for an attack, for artillery shelling, the soldiers dug in securely, but in front of the destructive chlorine cloud they were absolutely unarmed. The deadly gas penetrated into all the cracks, into all the shelters. The results of the first chemical attack (and the first violation of the 1907 Hague Convention on the Non-Use of Poisonous Substances!) were stunning - chlorine struck about 15,000 people, and about 5,000 died. And all this - in order to level the front line 6 km long! Two months later, the Germans launched a chlorine attack on the eastern front as well. And two years later, Ypres increased its notoriety. During a heavy battle on July 12, 1917, a poisonous substance, later called mustard gas, was used for the first time in the area of ​​\u200b\u200bthis city. Mustard is a derivative of chlorine, dichlorodiethyl sulfide.

We recalled these episodes of history, connected with one small town and one chemical element, in order to show how dangerous element No. 17 can be in the hands of militant madmen. This is the darkest page in the history of chlorine.

But it would be completely wrong to see in chlorine only a poisonous substance and a raw material for the production of other poisonous substances...

History of chlorine

The history of elemental chlorine is relatively short, dating back to 1774. The history of chlorine compounds is as old as the world. Suffice it to recall that sodium chloride is table salt. And, apparently, even in prehistoric times, the ability of salt to preserve meat and fish was noticed.

The most ancient archaeological finds - evidence of the use of salt by humans date back to about 3...4 millennium BC. And the most ancient description of the extraction of rock salt is found in the writings of the Greek historian Herodotus (V century BC). Herodotus describes the mining of rock salt in Libya. In the oasis of Sinah in the center of the Libyan desert was the famous temple of the god Ammon-Ra. That is why Libya was called "Ammonia", and the first name of rock salt was "sal ammoniacum". Later, starting around the thirteenth century. AD, this name was assigned to ammonium chloride.

Pliny the Elder's Natural History describes a method for separating gold from base metals by calcining with salt and clay. And one of the first descriptions of the purification of sodium chloride is found in the writings of the great Arab physician and alchemist Jabir ibn Hayyan (in European spelling - Geber).

It is very likely that alchemists also encountered elemental chlorine, since in the countries of the East already in the 9th, and in Europe in the 13th century. "royal vodka" was known - a mixture of hydrochloric and nitric acids. The book Hortus Medicinae by the Dutchman Van Helmont, published in 1668, says that when ammonium chloride and nitric acid are heated together, a certain gas is obtained. Based on the description, this gas is very similar to chlorine.

Chlorine was first described in detail by the Swedish chemist Scheele in his treatise on pyrolusite. By heating the mineral pyrolusite with hydrochloric acid, Scheele noticed the smell characteristic of aqua regia, collected and studied the yellow-green gas that gave rise to this smell, and studied its interaction with certain substances. Scheele was the first to discover the effect of chlorine on gold and cinnabar (in the latter case, sublimate is formed) and the bleaching properties of chlorine.

Scheele did not consider the newly discovered gas to be a simple substance and called it "dephlogistinated hydrochloric acid". In modern terms, Scheele, and after him other scientists of that time, believed that the new gas was hydrochloric acid oxide.

Somewhat later, Bertholet and Lavoisier suggested that this gas be considered an oxide of some new element, murium. For three and a half decades, chemists have unsuccessfully tried to isolate the unknown murium.

A supporter of "murium oxide" was at first also Davy, who in 1807 decomposed table salt with an electric current into the alkali metal sodium and yellow-green gas. However, three years later, after many fruitless attempts to obtain muria, Davy came to the conclusion that the gas discovered by Scheele was a simple substance, an element, and called it chloric gas or chlorine (from the Greek χλωροζ - yellow-green). And three years later, Gay-Lussac gave the new element a shorter name - chlorine. True, back in 1811, the German chemist Schweiger proposed another name for chlorine - “halogen” (literally it translates as salt), but this name did not take root at first, and later became common for a whole group of elements, which includes chlorine.

"Personal card" of chlorine

To the question, what is chlorine, you can give at least a dozen answers. First, it is a halogen; secondly, one of the strongest oxidizing agents; thirdly, an extremely poisonous gas; fourthly, the most important product of the basic chemical industry; fifthly, raw materials for the production of plastics and pesticides, rubber and artificial fibers, dyes and medicines; sixth, the substance with which titanium and silicon, glycerin and fluoroplast are obtained; seventh, a means for purifying drinking water and bleaching fabrics ...

This listing could be continued.

Under normal conditions, elemental chlorine is a rather heavy yellow-green gas with a pungent characteristic odor. The atomic weight of chlorine is 35.453, and the molecular weight is 70.906, because the chlorine molecule is diatomic. One liter of gaseous chlorine under normal conditions (temperature 0 ° C and pressure 760 mmHg) weighs 3.214 g. When cooled to a temperature of -34.05 ° C, chlorine condenses into a yellow liquid (density 1.56 g / cm hardens at a temperature of -101.6°C. Under increased pressure, chlorine can be liquidized at higher temperatures up to +144°C. Chlorine is highly soluble in dichloroethane and some other chlorine-containing organic solvents.

Element number 17 is very active - it directly connects with almost all elements of the periodic system. Therefore, in nature, it occurs only in the form of compounds. The most common minerals containing chlorine, halite NaCI, sylvinite KCl NaCl, bischofite MgCl 2 6H 2 O, carnallite KCl MgCl 2 6H 2 O, kainite KCl MgSO 4 3H 2 O. This is their first of all "wine ” (or “merit”) that the chlorine content in the earth’s crust is 0.20% by weight. For non-ferrous metallurgy, some relatively rare chlorine-containing minerals are very important, for example, horn silver AgCl.

In terms of electrical conductivity, liquid chlorine ranks among the strongest insulators: it conducts current almost a billion times worse than distilled water, and 10 22 times worse than silver.

The speed of sound in chlorine is about one and a half times less than in air.

And finally - about the isotopes of chlorine.

Now nine isotopes of this element are known, but only two are found in nature - chlorine-35 and chlorine-37. The first is about three times more than the second.

The remaining seven isotopes were obtained artificially. The shortest-lived of them - 32 Cl has a half-life of 0.306 seconds, and the longest-lived - 36 Cl - 310 thousand years.

How is chlorine obtained?

The first thing you notice when you get to the chlorine plant is the numerous power lines. Chlorine production consumes a lot of electricity - it is needed in order to decompose natural chlorine compounds.

Naturally, the main chlorine raw material is rock salt. If the chlorine plant is located near the river, then the salt is delivered not by rail, but by barges - it's more economical. Salt is an inexpensive product, but a lot of it is consumed: to get a ton of chlorine, you need about 1.7 ... 1.8 tons of salt.

Salt goes to warehouses. Three-six-month stocks of raw materials are stored here - chlorine production, as a rule, is large-tonnage.

Salt is crushed and dissolved in warm water. This brine is pumped through the pipeline to the cleaning shop, where in huge tanks, the height of a three-story house, the brine is cleaned from impurities of calcium and magnesium salts and clarified (allowed to settle). A pure concentrated solution of sodium chloride is pumped to the main chlorine production shop - to the electrolysis shop.

In an aqueous solution, salt molecules are converted into Na + and Cl - ions. The Cl ion differs from the chlorine atom only in that it has one extra electron. This means that in order to obtain elemental chlorine, it is necessary to tear off this extra electron. This happens in the cell on a positively charged electrode (anode). Electrons seem to be “sucked off” from it: 2Cl - → Cl 2 + 2 ē . The anodes are made of graphite, because any metal (except platinum and its analogues), taking away excess electrons from chlorine ions, quickly corrodes and collapses.

There are two types of technological design of chlorine production: diaphragm and mercury. In the first case, a perforated iron sheet serves as the cathode, and the cathode and anode spaces of the cell are separated by an asbestos diaphragm. On the iron cathode, hydrogen ions are discharged and an aqueous solution of caustic soda is formed. If mercury is used as a cathode, then sodium ions are discharged on it and sodium amalgam is formed, which is then decomposed by water. Hydrogen and caustic soda are obtained. In this case, a separating diaphragm is not needed, and the alkali is more concentrated than in diaphragm electrolyzers.

So, the production of chlorine is simultaneously the production of caustic soda and hydrogen.

Hydrogen is removed through metal pipes, and chlorine through glass or ceramic pipes. Freshly prepared chlorine is saturated with water vapor and is therefore particularly aggressive. Subsequently, it is first cooled with cold water in high towers lined with ceramic tiles from the inside and filled with ceramic nozzles (the so-called Raschig rings), and then dried with concentrated sulfuric acid. It is the only chlorine desiccant and one of the few liquids that chlorine interacts with.

Dry chlorine is no longer so aggressive, it does not destroy, for example, steel equipment.

Chlorine is usually transported in a liquid state in railway tanks or cylinders under pressure up to 10 atm.

In Russia, the production of chlorine was first organized as early as 1880 at the Bondyuzhsky plant. Chlorine was then obtained in principle in the same way that Scheele had obtained it in his time - by reacting hydrochloric acid with pyrolusite. All chlorine produced was used to produce bleach. In 1900, for the first time in Russia, a workshop for the electrolytic production of chlorine was put into operation at the Donsoda plant. The capacity of this workshop was only 6 thousand tons per year. In 1917, all chlorine plants in Russia produced 12,000 tons of chlorine. And in 1965, about 1 million tons of chlorine were produced in the USSR ...

One of many

All the variety of practical applications of chlorine can be expressed without much stretch in one phrase: chlorine is necessary for the production of chlorine products, i.e. substances containing “bound” chlorine. But speaking of these same chlorine products, you can’t get off with one phrase. They are very different - both in properties and in purpose.

The limited volume of our article does not allow us to talk about all the compounds of chlorine, but without a story about at least some of the substances that require chlorine, our “portrait” of element No. 17 would be incomplete and unconvincing.

Take, for example, organochlorine insecticides - substances that kill harmful insects, but are safe for plants. A significant part of the produced chlorine is spent on obtaining plant protection products.

One of the most important insecticides is hexachlorocyclohexane (often referred to as hexachlorane). This substance was first synthesized back in 1825 by Faraday, but found practical application only after more than 100 years - in the 30s of our century.

Now hexachlorane is obtained by chlorinating benzene. Like hydrogen, benzene reacts very slowly with chlorine in the dark (and in the absence of catalysts), but in bright light, the benzene chlorination reaction (C 6 H 6 + 3Cl 2 → C 6 H 6 Cl 6) proceeds quite quickly.

Hexachloran, like many other insecticides, is used in the form of dusts with fillers (talc, kaolin), or in the form of suspensions and emulsions, or, finally, in the form of aerosols. Hexachloran is especially effective in seed dressing and in pest control of vegetable and fruit crops. The consumption of hexachlorane is only 1...3 kg per hectare, the economic effect of its use is 10...15 times higher than the costs. Unfortunately, hexachlorane is not harmless to humans...

PVC

If you ask any student to list the plastics known to him, he will be one of the first to name polyvinyl chloride (otherwise, vinyl plastic). From the point of view of a chemist, PVC (as polyvinyl chloride is often referred to in the literature) is a polymer in the molecule of which hydrogen and chlorine atoms are strung on a chain of carbon atoms:

There may be several thousand links in this chain.

And from a consumer point of view, PVC is insulation for wires and raincoats, linoleum and gramophone records, protective varnishes and packaging materials, chemical equipment and foam plastics, toys and instrument parts.

Polyvinyl chloride is formed during the polymerization of vinyl chloride, which is most often obtained by treating acetylene with hydrogen chloride: HC ≡ CH + HCl → CH 2 = CHCl. There is another way to obtain vinyl chloride - thermal cracking of dichloroethane.

CH 2 Cl - CH 2 Cl → CH 2 \u003d CHCl + HCl. Of interest is the combination of these two methods, when HCl is used in the production of vinyl chloride by the acetylene method, which is released during the cracking of dichloroethane.

Vinyl chloride is a colorless gas with a pleasant, somewhat heady, ethereal odor that polymerizes easily. To obtain a polymer, liquid vinyl chloride is injected under pressure into warm water, where it is crushed into tiny droplets. So that they do not merge, a little gelatin or polyvinyl alcohol is added to the water, and in order for the polymerization reaction to develop, the polymerization initiator, benzoyl peroxide, is also introduced there. After a few hours, the droplets harden and a suspension of the polymer in water is formed. The polymer powder is separated on a filter or centrifuge.

Polymerization usually occurs at a temperature of 40 to 60°C, and the lower the polymerization temperature, the longer the resulting polymer molecules...

We talked about only two substances, for which element No. 17 is required. Only about two out of many hundreds. There are many such examples. And they all say that chlorine is not only a poisonous and dangerous gas, but a very important, very useful element.

Elementary calculation

When chlorine is obtained by electrolysis of a sodium chloride solution, hydrogen and sodium hydroxide are simultaneously obtained: 2NACl + 2H 2 O \u003d H 2 + Cl 2 + 2NaOH. Of course, hydrogen is a very important chemical product, but there are cheaper and more convenient ways to produce this substance, such as the conversion of natural gas ... But caustic soda is obtained almost exclusively by electrolysis of sodium chloride solutions - other methods account for less than 10%. Since the production of chlorine and NaOH are completely interrelated (as follows from the reaction equation, the production of one gram-molecule - 71 g of chlorine - is invariably accompanied by the production of two gram-molecules - 80 g of electrolytic alkali), knowing the productivity of the workshop (or plant, or state) in terms of alkali , you can easily calculate how much chlorine it produces. Each ton of NaOH is "accompanied" by 890 kg of chlorine.

Oh, and lube!

Concentrated sulfuric acid is practically the only liquid that does not interact with chlorine. Therefore, for compressing and pumping chlorine, factories use pumps in which sulfuric acid plays the role of a working fluid and at the same time a lubricant.

Pseudonym of Friedrich Wöhler

Investigating the interaction of organic substances with chlorine, the French chemist of the XIX century. Jean Dumas made an amazing discovery: chlorine is able to replace hydrogen in the molecules of organic compounds. For example, during the chlorination of acetic acid, first one hydrogen of the methyl group is replaced by chlorine, then another, a third ... But the most striking thing was that the chemical properties of chloroacetic acids differed little from acetic acid itself. The class of reactions discovered by Dumas was completely inexplicable by the then dominant electrochemical hypothesis and the theory of Berzelius radicals (in the words of the French chemist Laurent, the discovery of chloroacetic acid was like a meteor that destroyed the entire old school). Berzelius, his students and followers vigorously disputed the correctness of Dumas' work. A mocking letter from the famous German chemist Friedrich Wöhler under the pseudonym S.C.H. appeared in the German journal Annalen der Chemie und Pharmacie. Windier (in German "Schwindler" means "liar", "deceiver"). It reported that the author was able to replace in fiber (C 6 H 10 O 5) and all carbon atoms. hydrogen and oxygen to chlorine, and the properties of fiber did not change. And what now in London they make warm girdles from cotton wool, consisting ... of pure chlorine.

Chlorine and water

Chlorine is visibly soluble in water. At 20°C, 2.3 volumes of chlorine dissolve in one volume of water. Aqueous solutions of chlorine (chlorine water) are yellow. But over time, especially when stored in the light, they gradually discolor. This is explained by the fact that dissolved chlorine partially interacts with water, hydrochloric and hypochlorous acids are formed: Cl 2 + H 2 O → HCl + HOCl. The latter is unstable and gradually decomposes into HCl and oxygen. Therefore, a solution of chlorine in water gradually turns into a solution of hydrochloric acid.

But at low temperatures, chlorine and water form a crystalline hydrate of an unusual composition - Cl 2 5 3 / 4 H 2 O. These greenish-yellow crystals (stable only at temperatures below 10 ° C) can be obtained by passing chlorine through ice water. The unusual formula is explained by the structure of the crystalline hydrate, and it is determined primarily by the structure of ice. In the crystal lattice of ice, H 2 O molecules can be arranged in such a way that regularly spaced voids appear between them. The elementary cubic cell contains 46 water molecules, between which there are eight microscopic voids. In these voids, chlorine molecules settle. The exact formula of chlorine hydrate should therefore be written as follows: 8Cl 2 46H 2 O.

Chlorine poisoning

The presence of about 0.0001% chlorine in the air irritates the mucous membranes. Constant exposure to such an atmosphere can lead to bronchial disease, sharply impairs appetite, and gives a greenish tint to the skin. If the chlorine content in the air is 0.1 ° / o, then acute poisoning can occur, the first sign of which is bouts of severe coughing. In case of chlorine poisoning, absolute rest is necessary; it is useful to inhale oxygen, or ammonia (sniffing ammonia), or vapors of alcohol with ether. According to existing sanitary standards, the content of chlorine in the air of industrial premises should not exceed 0.001 mg/l, i.e. 0.00003%.

Not only poison

"Everyone knows that wolves are greedy." That chlorine is poisonous, too. However, in small doses, poisonous chlorine can sometimes serve as an antidote. So, victims of hydrogen sulfide are given to sniff unstable bleach. Interacting, two poisons are mutually neutralized.

Chlorine analysis

To determine the chlorine content, an air sample is passed through absorbers with an acidified solution of potassium iodide. (Chlorine displaces iodine, the amount of the latter is easily determined by titration with a solution of Na 2 S 2 O 3). To determine the microquantities of chlorine in the air, a colorimetric method is often used, based on a sharp change in the color of certain compounds (benzidine, orthotoluidine, methyl orange) during their oxidation with chlorine. For example, a colorless acidified solution of benzidine turns yellow, and a neutral one turns blue. The color intensity is proportional to the amount of chlorine.

Chlorine is more than just bleach Should we be concerned about the presence of chlorine in the cleaners and detergents we use at home?
The answer is clear - Yes!
Whether chlorine is used alone or mixed with other chemicals, detergents containing it are harmful to health.
It is especially worth paying attention to the following:
 detergents used in dishwashers,
 bleaches,
 disinfectants,
 anti-mold products,
 toilet bowl cleaners.

In order not to indicate that the cleaning agent contains chlorine, they write that it contains sodium hypochlorite (sodium hypochlorite) or simply hypochlorite (hypochlorite). The fumes contained in high chlorine cleaners can cause lung irritation, which is especially dangerous for people with heart problems or respiratory problems such as asthma or emphysema. The risk is increased if detergents with chlorine are used in small, poorly ventilated areas such as bathrooms.
Chlorine is also a very caustic substance that can damage the skin and eyes. In 1990 in the USA, in clean air law, chlorine has been listed as a hazardous air pollutant, and exposure to chlorine in the workplace is regulated by federal law. Using detergents containing chlorine in dishwashers and washing machines can pollute the air in your home. Water in cars, which contains chlorine from detergents, releases it into the air through an evaporation process. And then we breathe polluted air.
Dishwashers are the biggest pollutants, releasing chemicals into the air as a vaporous mist when the machine door is opened. In washing machines, chlorine mixes with clothing dirt and produces toxic, chlorine-containing organic chemicals.
Chlorine is dangerous even when stored at home. In 1993, 40,000 cases of household chlorine poisoning were reported to the US poison control centers, far more than any other chemical element. Particularly dangerous are perfumed products containing chlorine and chlorine bleach products plus surfactants. Clogging the smell of chlorine with aromatic substances (in fact, it turns out that chlorine-containing preparations are pleasant to inhale), can lead to chlorine poisoning. Another danger lies in mixing products containing chlorine, whether intentionally or accidentally. These mixtures can produce chlorine gas and chloramines, toxic gases that severely damage lung tissue.

Chlorine
Other names hypochlorite (hypochlorite), sodium hypochlorite (sodium hypochlorite), sodium dichloroisocyanurate (sodium dichloroisocyanurate), hydrogen chloride (hydrogen chloride), hydrochloric acid (hydrochloric acid). Chlorine began to be produced industrially in the early 20th century. It was used as a poisonous substance during the First World War.
Chlorine ranks first in the United States among the chemicals used to poison people at work and at home. Chlorine is a highly toxic substance that is produced using the energy-intensive process of seawater electrolysis. This manufacturing process also produces highly toxic by-products.
sodium hypochlorite, (known as bleach - 5% sodium hypochlorite solution) is a chemical precursor to chlorine and should be handled accordingly, as any use of it creates pure chlorine in the environment.
In addition to being highly toxic to living organisms, chlorine reacts with organic materials in the environment and produces other dangerous and carcinogenic toxins, including trihalomethanes (THMs), chloroform and organochlorines, a very dangerous class. components that cause disruption of the endocrine and immune systems. The most well known organochlorin is DIOXIN.
Products containing chlorine (or any of their derivatives or chemical precursors, including sodium hypochlorite) must be considered highly hazardous and unacceptable to use. Also, any other chemical containing "-chlor-" in its name, or known, as "bleach" are also harmful to use because they contain a highly toxic and environmentally damaging chlorine component. Chlorine and chlorine components are also one of the reasons for the disappearance of atmospheric ozone. Chlorine used in laundry damages both natural and synthetic fabrics.

Dioxin
Paper mill waste released into the environment after bleaching paper with chlorine contains dioxins, which do not decompose, which means that, over time, they accumulate in air, water and soil. Once they are there, they enter our food, and we are poisoned by the food we eat. Dioxins are now so widespread in the environment that they are found in the body of virtually every man, woman and child. Every American ingests 300 to 600 times the so-called "safe" dose daily. They accumulate in the body to a critical level, and then, their effects begin to manifest.
Dioxins are deadly. They are the most carcinogenic chemical elements known to science. According to the US Environmental Protection Agency (EPA), dioxins are 300,000 times more potent carcinogens than DDT, which was banned in the US in 1972. It is impossible to cover up or embellish the destructive effect of dioxins on people and the environment. Recent studies have confirmed that dioxins cause cancer, reproductive damage in adults, deformities and developmental problems in children, and immune system breakdown. Dioxins can cause these disorders in amounts hundreds of thousands of times smaller than most dangerous chemicals.

Organochlorins
Like dioxins, organochlorins are long-lived substances that easily spread in the surrounding space. Now, every person on the planet has these substances in his body. Scientists are very concerned about these chemicals because they believe that when organochlorin molecules enter the body, they mimic hormones, which are natural substances that our body produces in small amounts to regulate its many functions. Since organochlorin molecules are shaped like hormone molecules, they can enter cells and the results of this penetration are simply terrible.
These include lowering IQ, reduced fertility, genital deformities, breast cancer, prostate cancer, testicular cancer, sperm deterioration, immune system abnormalities through a process called endocrine disruption.
Studies have shown that dioxins and organochlorins cause birth defects, cancer, reproductive and developmental defects. Many scientists believe that recent reports of decreased sperm count in men living in industrialized countries are due to organochlorins. Similar problems arise in animals, due to environmental pollution with these substances. Many biologists believe that organochlorins are responsible for unusual mutations, sterility, impaired immune systems, and extinction of animal species from the Great Lakes to the North Sea.

What can you do to protect yourself from the effects of chlorine.
1. Buy unbleached paper products (napkins, toilet paper, kitchen paper, etc.).
Because bleached paper may contain dioxin and organochlorins, which can pass into any food or any person who comes into contact with them.
2. The U.S. Environmental Protection Agency (EPA) warns that bleached coffee filter papers can result in life-long dioxin poisoning that "exceeds acceptable limits." Purchase unbleached filters.
3. Using detergents containing chlorine in dishwashers or washing machines will pollute the air in your home.
The water in cars, which contains chlorine from detergents, releases the chlorine into the air through the evaporation process. Choose products that do not contain chlorine.

Non-Toxic Disinfectant Recipes
You know where the breeding ground for germs is in your bathroom. Not where you think, but in the sewer. What can be done about this? Studies at the Tufts Medical Center in New England have shown that disinfectants are not effective, but also lead to the emergence of more resistant types of bacteria. However, there is a great non-toxic remedy to get rid of bacteria in the bathroom or anywhere else.
1. Pour a cup or two of regular vinegar into the drain pipes. Vinegar - 80-99% destroys bacteria and viruses. Do this 1-2 times a week.
2. Prepare an antibacterial spray for toilet bowls, lids, doorknobs, light switches, cutting boards, etc. (wherever bacteria can grow).
Lavender has more pronounced antiseptic properties than phenol, which is used in the production of antibacterial agents.
Ingredients
1 cup of water; 1 teaspoon lavender oil; 10-15 grams of alcohol to dissolve the oil.
Pour alcohol into a spray bottle, add oil, shake the bottle, pour water. Spray the surface, leave for 15 minutes, then rinse, but you can not rinse.
Shelf life is not limited.

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