Aqueous solution of phenol formula. Phenol: properties and production technology. Application in medicine and other industries

Included in medications

R.02.A.A.19 Phenol

I.A50-A64.A63.0 Anogenital (venereal) warts

VIII.H65-H75.H66 Purulent and unspecified otitis media

XII.L00-L08.L01 Impetigo

XII.L00-L08.L02 Skin abscess, furuncle and carbuncle

XII.L00-L08.L03 Phlegmon

XII.L00-L08.L08.0 Pyoderma

XII.L60-L75.L73.8 Other specified diseases of follicles

XII.L60-L75.L73.9 Disease of hair follicles, unspecified

XXI.Z20-Z29.Z29.8 Other specified preventive measures

All phenols are toxic and highly dangerous for humans. But all over the world they are produced and used by millions of tons per year.

When ingested, these substances can cause severe poisoning. Therefore, let's find out in which industries phenol is used, how it enters the human body, about its toxic properties and signs of poisoning by it, about first aid and treatment.

Characterization of phenols

Phenol has the appearance of colorless crystals, which, rapidly oxidized in air, acquire a pink color. The sharp specific smell of phenol is similar to the smell of gouache.

It is sparingly soluble in water (1:20). It dissolves well in alcohol, alkalis, acetone, oils. But at temperatures above 700 ° C, it dissolves in water in any ratio. It becomes volatile with water vapor. Easily adsorbed by products.

Phenols include:

• chlorophenol;
• cresol;
• lysol;
• creosote;
• butylphenol;
• resorcinol;
• pyrocatechin;
• hydroquinone and others.

The use of phenols

Any person has the opportunity to encounter and even get phenol poisoning in Everyday life given its widespread use. Where is it applied?

Phenol toxicity

Phenol has a hazard class II - a highly hazardous substance. It can enter the body through the mucous membranes, respiratory organs and skin, and is excreted through the kidneys and lungs.

A solution of phenol, as well as its dust and vapors, cause irritation and chemical burns of the skin, eyes, mucous membranes of the respiratory tract. Phenol vapor poisoning can impair function nervous system up to paralysis of the respiratory center.

When it comes into contact with the skin, the substance is quickly absorbed even through its intact areas. After a few minutes, the toxic effect on the brain begins. The lethal dose of phenol when taken internally for an adult ranges from 1 g to 10 g, and for children - from 0.05 g to 0.5 g.

The toxic effect on all cells occurs as a result of a change in the structure of protein molecules with a change in their properties and precipitation of cellular proteins. As a result, necrosis (necrosis) of tissues may develop.

Phenols also have a pronounced toxic effect on the kidneys. They destroy red blood cells, have an allergenic effect on the body, cause dermatitis and other allergic reactions.

Causes of poisoning

Phenol poisoning can occur for the following reasons:

Symptoms of phenol poisoning

Poisoning is acute and chronic. Signs of acute phenol poisoning can occur when the toxic substance enters through the mouth, Airways or by skin contact.

Acute inhalation phenol poisoning is manifested by the following symptoms:

If the substance gets on the skin, first there is a pronounced pallor and wrinkling on the affected area of ​​the skin, and then redness, blistering, followed by the development of necrosis. The appearance of numbness or tingling, the absence of pain at first, can cause delayed medical attention.

With extensive lesions, a severe degree of poisoning develops with fever, respiratory, circulatory and nervous system disorders.

When phenol enters the body, the characteristic manifestations of poisoning are:

When the liver is damaged, jaundice develops. The cessation of urination indicates kidney damage. When concentrated solutions or large doses of a substance enter the body, death occurs already on the first day.

Chronic poisoning is characterized by:

First aid and treatment

In case of phenol poisoning (even with the manifestation of minor symptoms), treatment must be carried out correctly from the very first minutes so as not to harm the victim.

What to do in case of acute phenol poisoning? Urgently call an ambulance, as delay in emergency care and treatment is unacceptable!

In case of phenol poisoning, first aid must be provided before the arrival of paramedics.

In all cases of phenol poisoning, treatment is carried out in the toxicology department. Treatment may include:

To avoid poisoning with phenol, you should strictly observe the safety precautions when working with it and ensure the proper storage of funds at home. In the event of poisoning, only immediate medical attention can save a life.

The names of phenols are made taking into account the fact that the trivial name "phenol" is preserved for the parent structure according to the rules of IUPAC. The numbering of the carbon atoms of the benzene ring starts from the atom directly bonded to the hydroxyl group (if it is the highest function), and continues in such a sequence that the existing substituents learn the smallest numbers.

Monosubstituted phenol derivatives, such as methylphenol (cresol), can exist in the form of three structural isomers - ortho-, meta- and para-cresols.

physical properties.

Phenols are mostly crystalline substances(-cresol - liquid) at room temperature. They have a characteristic odor, are rather poorly soluble in water, but dissolve well in aqueous solutions of alkalis (see below). Phenols form strong hydrogen bonds and have fairly high boiling points.

Ways to get.

1. Obtaining from halobenzenes. When chlorobenzene and sodium hydroxide are heated under pressure, sodium phenolate is obtained, upon further treatment of which with acid, phenol is formed:

2. Obtaining from aromatic sulfonic acids (see reaction 3 in the section " Chemical properties benzene”, § 21). The reaction is carried out by fusing sulfonic acids with alkalis. Initially formed phenoxides are treated with strong acids to obtain free phenols. The method is usually used to obtain polyhydric phenols:

Chemical properties.

In phenols, the p-orbital of the oxygen atom forms a single system with the aromatic ring. Due to this interaction, the electron density at the oxygen atom decreases, and in the benzene ring it increases. Polarity O-N connections increases, and the hydrogen of the OH group becomes more reactive and is easily replaced by a metal even under the action of alkalis (unlike saturated monohydric alcohols).

In addition, as a result of such mutual influence in the phenol molecule, the reactivity of the benzene ring in the ortho and cara positions in electrophilic substitution reactions (halogenation, nitration, polycondensation, etc.) increases:

1. Acid properties phenols are manifested in reactions with alkalis (the old name "carbolic acid" has been preserved):

Phenol, however, is a very weak acid. When carbon dioxide or sulfur dioxide is passed through a solution of phenolates, phenol is released - such a reaction proves that phenol is a weaker acid than carbonic and sulfurous:

The acid properties of phenols are weakened by the introduction of substituents of the first kind into the ring and are enhanced by the introduction of substituents of the second kind.

2. Formation of esters. Unlike alcohols, phenols do not form esters when exposed to carboxylic acids; for this, acid chlorides are used:

3. Halogenation. When acting on phenol bromine water(compare with the conditions for the bromination of benzene - § 21) a precipitate of 2,4,6-tribromophenol is formed:

This is a qualitative reaction for the detection of phenol.

4. Nitration. Under the action of 20% nitric acid, phenol is easily converted into a mixture of ortho- and para-nitrophenols. If phenol is nitrated with concentrated nitric acid, then 2,4,6-trinitrophenol is formed - a strong acid (picric).

5. Oxidation. Phenols are easily oxidized even under the action of atmospheric oxygen.

So, when standing in air, phenol gradually turns into a pinkish-red color. In the vigorous oxidation of phenol with a chromium mixture, quinone is the main oxidation product. Dihydric phenols are oxidized even more easily. When hydroquinone is oxidized, quinone is formed:

Phenols - organic compounds that can harm a person and affect his health. Despite this, the production of this substance in the world is increasing every year.

Characterization of phenols

The physical properties of phenol: their shape resembles crystals, which tend to oxidize in air, becoming covered with a pink color, has a specific smell, similar to the smell of gouache. The maximum allowable concentration (MAC) of phenol in the air is 4 mg/m³, in natural waters - 0.001.

This substance is perfectly soluble in alcohol, oils, acetone. In water, phenol dissolves gradually, in a ratio of 1/20 if the water temperature reaches +700 ° C. In polluted natural waters, its content can reach tens and even hundreds of micrograms per 1 liter.

Carbolic acid is a 2-5% solution of phenol, it is an excellent antiseptic that can destroy pathogenic microbes and bacteria. Carbolic acid is used in the manufacture of many pharmaceuticals.

Synthetic technical phenol is used as a raw material for the production of caprolactam, adipic acid, aniline, alkylphenol, hydroquinone. In terms of the number of OH groups, phenols and alcohols are similar in structure, but phenol is a stronger acid.

Application in medicine and other industries

The scope of phenol, due to its danger and toxicity, is limited. To reduce the danger, it is used in small quantities, mixed with other components. The substance is actively used by manufacturers of the following industries:

• Medicine: used as a good antiseptic, disinfectant against fungal infections, inflammation of the middle ear. He is also involved in the production medicines(Aspirin), in genetic engineering;
• In cosmetology: phenol peeling. Apply phenol formaldehyde for the manufacture of cosmetic products;
• Oil refining industry: cleaning of residual oil raw materials;
• Agriculture: various fertilizers for pest and weed control. It is also used as an antiseptic preparation for the disinfection of animal skins;
• Food industry - for food preservation;
• Chemical industry: production of cleaning and disinfecting agents, epoxy resins, plastics, in the manufacture of dyes.

Why is phenol dangerous?

This substance is dangerous and toxic, its hazard class is the second. It enters the body through the mucous membranes and skin, after which it is transported to the internal organs:

• The ingestion of one gram of phenol in the human body leads to death. Less than one gram is enough for a child's body. Regardless of the state of phenol formaldehyde, for a person it is a colossal harm that affects health;
• Liquid phenol or in the form of vapor (gaseous) can cause burns or allergic reactions, and also causes tissue necrosis (as a result of changes in protein molecules).
• In addition, they impair blood circulation in the body, destroy red blood cells, and provoke the occurrence of dermatitis.

In order to avoid the occurrence of severe consequences of phenol formaldehyde on the body, you need to know the causes of poisoning and how to deal with it.

Causes of poisoning

Poisoning occurs for the following reasons:

1. The use of phenol-containing drugs, the expiration date of which has expired;
2. Ignorance of the composition of the medicine, use without a "prescription";
3. Phenol poisoning upon contact with toys (most often found in toys made in China, although other manufacturers sin this.
4. Excessive dosages.

If adults are inadvertently exposed to phenol, then children suffer because adults put drugs in easily accessible places, and sometimes even left them open.

Symptoms of poisoning

Phenol poisoning is divided into acute and chronic.

Acute poisoning occurs when the substance comes into contact with the skin, ingested or by inhalation of vapors. At home, it is very difficult to get poisoned by vapors, it happens much more often in enterprises. One breath is enough to observe the following symptoms:

• Persistent cough caused by lung irritation;
• Excessive excitability;
• severe pain in the head;
• Weakness and aches in the body.

The above health problems may be the reason for hospitalization.

Signs of phenol poisoning in contact with the skin:

• The damaged area of ​​the skin becomes white;
• Skin transformation, manifestation of wrinkles and folds;
• After a while, the skin turns red;
• Bubbles are inflated;
• Burning and tingling.

If the chemical is ingested, the following symptoms may occur:

• Bad breath;
• The appearance of spots in the oral cavity;
• Sore throat, internal organs;
• Feeling unwell, vomiting;
• increased sweating;
• Change in color of urine.

At high doses of carbolic acid, a lethal outcome is possible.

In the case of a constant, but small effect of a substance on the body, chronic poisoning develops, which is accompanied by:

• Weakness and body aches;
• Bad sleep;
• severe headache;
• Lack of appetite;
• Bad mood.

First aid for phenol poisoning

If phenol poisoning is suspected, immediate medical attention should be sought. medical care. It is impossible to remove the substance from the body on its own, but it is quite possible to provide first aid.

1. Remove the victim to fresh air;
2. If the concentration of the substance in the stomach is large, it is worth taking the sorbent, drinking plenty of water;
3. In case of internal poisoning, rinse your mouth thoroughly with water (milk) for 5 to 10 minutes, after which you spit it out;
4. Damaged skin should be washed with water;
5. Do not leave the shower until the ambulance arrives, thoroughly wash all affected areas of the body.

Full treatment and diagnosis is carried out only under the supervision of a physician. Poison should be removed using vitamin B1, ethanol (topically), as well as procedures such as tracheotomy and intubation.

Prevention

The main rule that must be followed in order not to get poisoned is to avoid contact with the substance when working with phenol-containing components. It is recommended to use protective equipment (gloves, masks, suits and respirators).

Do not buy drugs that contain phenol formaldehyde, if possible, take analog and alternative drugs (it’s easier to spend a little than risk your health), if you have any at home, store them in places that are hard to reach for children.

For cosmetic purposes, I use phenol formaldehyde as a phenol peel, but it can show its allergic effect, so you should think about the advisability of such a procedure.

The figure shows the relationship various methods phenol production, and in the table under the same numbers their technical and economic indicators are given (in% relative to the sulfonate method).

Rice. 1.1. Phenol Production Methods

Table 1.3

Thus, from an economic point of view, the cumene process that is most in demand at the present time is the most expedient. The industrial processes that have been used at one time or another to produce phenol are briefly described below.

1. Sulfonate process was the first phenol process implemented on an industrial scale by BASF in 1899. This method is based on the sulfonation of benzene with sulfuric acid, followed by alkaline melting of the sulfonic acid. Despite the use of aggressive reagents and the formation a large number sodium sulfite waste, this method been used for almost 80 years. In the USA, this production was closed only in 1978.

2. In 1924, the Dow Chemical company developed a process for producing phenol, including the reaction of benzene chlorination and subsequent hydrolysis of monochlorobenzene ( catalytic hydrolysis process of halogenated benzenes ). An independently similar technology was developed by the German firm I.G. Farbenindustrie Co. Subsequently, the stage for obtaining monochlorobenzene and the stage for its hydrolysis were improved, and the process was called the "Raschig process". The total yield of phenol in two stages is 70-85%. This process has been the main method for producing phenol for several decades.

3. Cyclohexane process , developed by Scientific Design Co., is based on the oxidation of cyclohexane to a mixture of cyclohexanone and cyclohexanol, which is further dehydrogenated to form phenol. In the 1960s, Monsanto used this method for several years at one of its plants in Australia, but later switched it to the cumene method for producing phenol.

4. In 1961, Dow Chemical of Canada sold process through decomposition of benzoic acid , this is the only method for the synthesis of phenol based on the use of non-benzene raw materials. Both reactions proceed in the liquid phase. First reaction. toluene oxidation. was used in Germany already during World War II to produce benzoic acid. The reaction proceeds under rather mild conditions with a high yield. The second step is more difficult due to catalyst deactivation and low phenol selectivity. It is believed that carrying out this step in the gas phase can make the process more efficient. Currently, this method is used in practice, although its share in the world production of phenol is only about 5%.

5. The synthesis method by which today most of the phenol produced in the world is obtained - cumene process - opened by a group of Soviet chemists headed by Professor P. G. Sergeev in 1942. The method is based on oxidation aromatic hydrocarbon cumene (isopropylbenzene) with atmospheric oxygen, followed by decomposition of the resulting hydroperoxide diluted with sulfuric acid. In 1949, the world's first cumene plant was put into operation in the city of Dzerzhinsk, Gorky Region. Prior to this, hydroperoxides were considered to be unstable intermediate products of hydrocarbon oxidation. Even in laboratory practice, they were almost never used. In the West, the cumene method was developed in the late 1940s and is partly known as the Hock process, after a German scientist who later independently discovered the cumene route for the synthesis of phenol. On an industrial scale, this method was first used in the United States in the early 1950s. Since that time, for many decades, the cumene process has become a model of chemical technology throughout the world.

Despite the well-established technology and long operating experience, the cumene method has a number of disadvantages. First of all, this is the presence of an explosive intermediate compound (cumene hydroperoxide), as well as the multi-stage method, which requires increased capital costs and makes it difficult to achieve a high yield of phenol based on the initial benzene. So, with a useful product yield of 95% at each of the three stages, the final yield will be only 86%. Approximately this yield of phenol gives the cumene method at the present time. But the most important and fundamentally unremovable drawback of the cumene method is related to the fact that acetone is formed as a by-product. This circumstance, which was originally seen as a strength of the method, is becoming a more and more serious problem, since acetone does not find an equivalent market. In the 1990s, this problem became especially noticeable after the creation of new methods for the synthesis of methyl methacrylate by the oxidation of C4 hydrocarbons, which drastically reduced the need for acetone. The acuteness of the situation is evidenced by the fact that a technology has been developed in Japan that provides for the recycling of acetone. To this end, two more stages are added to the traditional cumene scheme, the hydrogenation of acetone to isopropyl alcohol and the dehydration of the latter to propylene. The resulting propylene is again returned to the benzene alkylation step. In 1992, Mitsui launched a large-scale production of phenol (200,000 tons/year) based on this five-stage cumene technology.

Rice. 1.2. Acetone recycling to propylene

Other similar modifications to the cumene method are also proposed that would mitigate the acetone problem. However, all of them lead to a significant complication of the technology and cannot be considered as a promising solution to the problem. Therefore, research focused on the search for new routes for the synthesis of phenol, which would be based on the direct oxidation of benzene, has acquired a particularly intensive character in the last decade. Work is carried out mainly in the following areas: oxidation with molecular oxygen, oxidation with monatomic oxygen donors and conjugated oxidation. Let us consider in more detail the directions of the search for new ways of synthesis of phenol.