Surfactants reduce. Detergent surfactant. Surfactants. Natural and synthetic. Their advantages and disadvantages

Surfactants, having wetting, emulsifying and washing ability, are widely used in industry and, as a result of this, are contained in the wastewater of the corresponding industries. [...]

Surfactants or detergents are widely used in industry and in everyday life as detergents. When they get into the water bodies with sewage, they cause foaming, worsen the organoleptic properties of water, disrupt the oxygen metabolism, toxic effect on the fauna. [...]

SURFACE-ACTIVE SUBSTANCES (SAS) - substances that can accumulate on the interface (phase), lowering its free energy (surface tension). Surfactants are used in industry (for example, during flotation), they are part of detergents (detergents), varnishes and paints, pesticides, food products. Once in water bodies, surfactants strongly change the properties of the environment and adversely affect life processes. SURFACE WATERS - land waters permanently or temporarily on the earth's surface in a liquid (rivers and temporary streams, lakes, reservoirs, swamps) or solid (glaciers and snow) conditions. [...]

Surfactants and petroleum products are among the most common environmental pollutants. The annual volume of these wastes at only 35 engineering enterprises of Ufa amounts to more than 11,000 m3 per year of spent coolant, 10,000 m3 per year of irrigated oil products, 600 m3 per year of spent surfactants and washing solutions. [...]

DETERGENT CENTERS (MS) - powders, pastes and liquid solutions used for washing clothes. Modern M.S. consist of several components, including detergent (soap, surfactant - surfactant), bleach, water glass and washing soda. As part of M.S. An important role was played by phosphates, which, when released into water bodies with domestic sewage, caused eutrophication of water bodies. Currently developed recipes for phosphate-free MS. Modern M.S. can be used in any water, regardless of its hardness, and for washing different fabrics. However, the contents of M.S. in domestic wastewater creates many problems in their treatment and limits the use of sewage sludge (dry residue after treatment) as fertilizers. Currently, work continues on the creation of MS, minimally polluting the environment. [...]

Surfactants are compounds that, under certain conditions and at certain concentrations, can alter the degree of water wettability of the surfaces of various solids. This is the basis for the use of surfactants in many industries and especially in everyday life as detergents and cleaning agents. [...]

Non-ionic detergents - derivatives of polyoxyethylenes - are one of the active parts of some synthetic detergents. They can be found in domestic wastewater or in wastewater of various industries. Nonionic substances, like anionic detergents, enter surface waters from wastewater. [...]

Organic substances present in the circulating water (in the undissolved and dissolved state), under the same conditions, inhibit the formation of CaCO3 deposits. We can assume that organic substances, being in a colloidal state and, as it were, enveloping the CaCO3 crystal nuclei, to some extent impede their growth and deposition on the walls of refrigerators; surface-active substances (detergents) play a similar role. [...]

DETERGENT (S) - surface-active synthetic substances used in industry and everyday life as detergents and emulsifiers. They serve as one of the main chemical pollutants of water bodies, because they are difficult to decompose by microorganisms, upset the oxygen balance, and adversely affect living organisms. [...]

Synthetic surfactants (SAS) - a group of chemical compounds whose presence in wastewater especially threatens the sanitary condition of water bodies and dramatically affects the operation of treatment facilities. Surfactants appear in wastewater as a result of their widespread use in household and industrial applications as detergents, as well as wetting, emulsifying, leveling, and disinfecting preparations. The most widely used surfactants are in the oil and textile industries. In household detergents, the content of active agent (SAS) reaches 20-30%. [...]

Synthetic detergents are available in powder, liquid and paste form. [...]

Synthetic detergents (SMS), the surface-active basis of which are usually anionic detergents (alkylbenzenesulfonates, etc.), have found wide application in production and everyday life. To increase the activity of detergents, intracomplex compounds, usually sodium tripolyphosphate, are introduced into their composition. Up to 80-85% of surface-active substances (surfactants) are used for the manufacture of synthetic detergents. The use of these products inevitably leads to their entry into wastewater. Pollution of these water bodies, especially in areas with pronounced turbulence, causes intense foaming. There are cases when thick foam with a layer of up to 3 m covered the surface of the river on an area of ​​thousands of square meters. [...]

Actually, all surfactants - both used for the production of herbicides and those used in the manufacture of detergents as detergents - are surfactants. Surfactants that enhance the action of herbicides are only those substances that, when added to preparations during their production or to working solutions, increase their biological activity before use. The name surfactants is borrowed from English-language special literature (surface active agents). In German literature, these substances are called tensides; both terms are used in Hungary. [...]

Schwartz, Perry, Birch, Surfactants and Detergents, IL, 1960. [...]

The composition of organic substances in industrial wastewater of modern production is extremely diverse - these are aromatic hydrocarbons, oil products, phenols, oils, resins, amine products, pyridine bases, fatty acids, surface-active compounds of synthetic detergents, and many others. Despite the fact that the main components of various organic pollutants are the same elements (mainly carbon, hydrogen, oxygen and nitrogen), the degree. the harmfulness of an organic compound depends on the form of presence, i.e., the combination, of these elements in water. Therefore, to obtain a complete sanitary-hygienic characteristic of water quality, one needs to know the content of certain organic substances in the water. Using modern methods of chemical analysis, including spectrographic, it is theoretically possible to determine any combination of elements of organic substances in water, but in practice when analyzing natural and waste waters this is done due to the variety of organic compounds in these waters, as well as due to the complexity and cumbersomeness of many analyzes. The content of individual organic substances - pollutants - is established by analysis, as noted above, only in cases where there are assumptions about the presence of these substances in water. [...]

Surfactants mean substances that are part of detergents. This is one or more groups of surface-active agents and several binding components. The former reduce the surface tension of the liquid in which they dissolve and form a stable emulsion or suspension with particles of removed impurities. Binding components reduce water hardness due to the formation of an alkaline solution with water, in which the washing properties of surface-active groups are especially effective. [...]

To remove surfactant detergent residues, the glass vessels are rinsed with a mixture of 9 parts of methanol or ethanol and 1 part of concentrated HC1. [...]

Despite the excellent washing ability, organic solvents cannot always clean the surface of the product from dirt of mineral origin. Therefore, in necessary cases, as well as when fatty layers have poor adhesion to the product material, cheaper and safer water-washing solutions and suspensions based on surfactants, soda, soaps, etc. are used [...]

The function of detergents as surface-active substances is to remove dirt from the fibers of the material and keep it in the washing solution. Since this property is suppressed by calcium and magnesium ions, to neutralize the action of the latter, they add a “phosphate detergent component”, which improves the detergent action of the detergent. [...]

Surfactants are widely used in industry and in everyday life as detergents. [...]

The use of synthetic surface-active detergents that replace soap is becoming increasingly common in industry and in everyday life. Currently, the most widely used are OP-7, OP-Yu, sulfanol and non-calcium, which are oil refining products, and Novosti powder (gardinol), which is produced from sperm whale fat. There are no ways to extract these substances from wastewater. [...]

The intended purpose of surfactants as detergents determines the ingress of almost the entire volume of their products into wastewater, which, in turn, can pollute surface water bodies, groundwater, and soil. Chemical and physico-chemical methods of wastewater treatment do not solve the problem of combating water pollution with surface-active substances, since when using these methods, surfactants, as a rule, only concentrate or partially decompose, but do not decompose completely to CO2, H20 and other simple products. The complete destruction of detergents is carried out by microorganisms, on the basis of which all biological methods of water purification are based. However, the treatment of wastewater from surfactants by conventional biological methods is difficult, since many of these substances are relatively resistant to microbial decomposition and pass through treatment plants without changing. At the same time, surfactants disrupt their work due to the high ability to foam, reducing the sedimentation rate of activated sludge. Spreading of the foam by the wind creates an epidemiological danger, as pathogenic bacteria, in particular pathogens of intestinal infections, spread along with the foam. The number of bacteria in ponds during foaming very increases due to the fact that extremely favorable trophic conditions are created in the foam. A small amount (0.2-0.4 mg / l surfactant) gives an unpleasant taste and smell to drinking water. The formation of foam on the surface of water bodies violates the oxygen regime and causes mass death of the flora and fauna that inhabit them. The monograph of E. A. Mozhaev is devoted to the study of the sanitary-hygienic aspects of surfactant water pollution, which presents data on their impact on water quality, self-cleaning ability of water bodies, the human and animal organisms.

TENZIDES (syn. Synthetic surfactants - SAS, T.) - chemical compounds that concentrate on the surface of two environments, for example, water and air. T. improve the wettability of surfaces and easily penetrate between dirt particles and the materials on which they are located. T. is the most important ingredient in detergents (washing powders and pastes) and cleaning products. The most famous T. is soap, which has been used by mankind for 5,000 years. T. adversely affect the skin, dissolving fats, slowly degrade in the environment and toxic to many inhabitants of aquatic ecosystems. At present, T. are being developed, which are rapidly destroyed in water and therefore less hazardous to the environment. [...]

Organic solvents are widely used as degreasing and detergent solutions: alcohols, gasoline, kerosene, and various compositions based on products of petrochemical synthesis. Their use in a production environment is associated with a certain degree of explosion and fire hazard; systematic work in an atmosphere saturated with vapors of such substances adversely affects the health of workers. Due to the emergence of a wide range of surfactants, non-combustible and non-toxic, the consumption of organic solvents for degreasing has decreased. However, there were problems associated with the disposal of waste solutions. Drain them in the sewers dramatically increases the degree of pollution of wastewater and the cost of their treatment. [...]

Additional organic substances entering, for example, in open surface water bodies during the processes of technogenesis, cause their eutrophication, i.e. enrichment with nutrients (Fig. 1.5.4). As a result, the algae become overgrown with water, which, after their withering away, consumes large amounts of oxygen. The emerging sapropel leads to the shallowing of the reservoir, its gradual transformation into a swamp with the active release of biogas. Eutrophication is promoted by the drift of nitrates leached from fertilizers, or phosphates from detergents (detergents) into water bodies. [...]

As emulsifiers, synthetic surfactants are most widely used in the production of synthetic rubber, rubber, plastics, polymers, synthetic resins. With their help, the polymerization of vinyl halides, acetates, ketones, esters, thioesters and their mixtures. Alkyl sulfates of polyhydric alcohols are also an aid in the coloring and filling of rubber and plastics. Many surfactants are used to stabilize adhesives, suspend solid and water-insoluble insecticides, are used in the leather, pharmaceutical and perfume industries, in addition they have become an indispensable detergent. [...]

Anionic and nonionic surfactants are part of detergents. [...]

SOAP (M) is the most traditional surfactant (surfactant), which improves the wettability of the surface with a solution, enhances the electrostatic repulsion between particles of dirt and detergent and increases the emulsifying and suspensive capacity of water. [...]

In recent years, synthetic detergent preparations MJI, Labomid, MC, etc. have become common. Preparations ML-51 and ML-52 are a mixture of surfactants with electrolytes: sodium salts of silicic and phosphoric acids. These drugs are available in the form of powder or granules of white and light yellow color. The drug ML-51 is used for jet cleaning of sediments with a solution concentration in water of 10-20 g / l, the drug ML-52 is used for cleaning parts by boiling out resinous sediments at a concentration of 25 - 35 g / l with a solution temperature of 70-80 ° C. The washing ability of ML drugs is 2-3 times higher than solutions based on caustic soda. [...]

Synthetic detergents, which are based on surface-active substances and alkaline salts (Labo-mead 101,203, Temp-1 OOD, etc.), are widely used in cleaning. When using synthetic detergents, a soda ash spray is released as a cleaning solution. Specific emissions of pollutants when washing parts and assemblies are given in Table. 7. [...]

Phosphates are ingredients of many synthetic surfactants (surfactants) (see below) used as detergents and fertilizers. With sewage, they enter the soil, rocks and groundwater, causing various contaminants. The harmful effects of phosphates on soils and groundwater also consist in stimulating the development of cyanobacteria, the "flowering" of water bodies (Ch. 2). [...]

Surfactants that reduce the surface tension of water have a negative impact on living organisms in water. Conventional soaps are anionic type surfactants. Surfactants are widely used as stabilizers for disperse systems (emulsions, suspensions), dispersants, film formers and detergents. [...]

DETERGENTS (from the Latin. - wash) - Chemical compounds that reduce the surface tension of water and are used as detergents and emulsifiers. Especially widespread synthetic surface-active substances (detergents), included in the composition of detergents and cleaning products (for them introduced a new concept abroad - tensides). Diverse use (for washing dishes, fabrics, cars, for personal hygiene) has led to an ever-increasing transfer of them to household and industrial wastewater. In agriculture, surfactants are used to emulsify pesticides, so they fall into the soil and groundwater. [...]

It should be pointed out that with the advent of synthetic surface-active substances (surfactants) in household waters and an increase in the content of phosphorus compounds (as a result of the use of detergents for washing), irrigation of the drainage areas with meadow waste waters is used as an after-treatment of household wastewater. . An example of such solutions are the English sewage treatment plants Norton Green and Lengley Mill with a capacity of 2,000 and 1,600 m3 / day, respectively. The actual load at these stations is 0.16-OD m3 / (m2-day). To ensure the necessary aeration of the soil, irrigation is carried out periodically - intermittently, not more than 6 times per day. Such a method allowed to reduce the surfactant concentration in biologically treated wastewater from 2.5 to 1 mg / l at station Lengley Mill and thereby increase the total effect of removing surfactant from 90 to 95.9%. [...]

In some cases, attention was drawn to the visible effects caused by detergents, which have recently become widely used in a number of countries for domestic, commercial and industrial purposes. Thus, the total amount of such substances in the main river basins increased by a few milligrams per liter, especially due to droughts. Surfactants were found in the drinking water produced by such water systems. One of the problems arising from the presence of detergents in the water of the main river basins is the problem of foam. In Germany, the Necker River acquired bad glory due to the pollution of its water with foam. Due to the extreme diversity of commercially available detergents, there is currently insufficient information regarding their damaging properties; experiments were carried out only to determine the specific ¡radicals of surface-active compounds. [...]

Detergents - detergent synthetic surface-active substances (detergents) enter the reservoirs with communal and partially industrial waters. These are high-molecular organic compounds obtained by the sulfonation of various oils, hydrocarbons, high-molecular alcohols and other substances of petroleum origin. The composition of detergents includes 20-40% surfactants and 60-80% of various additives. [...]

Dirty glass is poorly moistened with ordinary water, so without the use of special detergents to carry out an effective washing process is impossible. The recipe of detergents includes caustic soda (sodium hydroxide), soda ash (sodium carbonate, sodium carbonate), trisodium phosphate, water glass (sodium silicate), sulfates, sodium metasilicate, surfactants and other substances in various combinations and concentrations. Thus, the concentration of caustic soda can be in the range of 0.65-3%, surfactants 0.2-0.4%, trisodium phosphate 0.3-1.5%, etc. [...]

A very dangerous kind of pollution characteristic of urban sewage is detergents, or synthetic surface-active substances (surfactants), which are strong toxicants that are resistant to the processes of biological decomposition. They are widely used in everyday life and many industries as detergents, emulsifiers, foaming agents. In economically developed countries, the concentration of surfactants in wastewater reaches 5-15 mg / l. Waters are poorly cleaned from detergents and up to 50-60% of their initial amount is discharged into reservoirs. Practically, the concentration of these substances in urban sewage averages 4-6 mg / l, and in river waters - 0.3-1.0 and even 1.5 mg / l, although the maximum permissible concentration of surfactants in natural waters should not exceed 0 , 3 mg / l. [...]

In the presentation of this section, we follow. In addition to petroleum products, synthetic surfactants are found in coastal waters. In industry and everyday life, a large number of detergents used as detergents, foam and emulsion stabilizers, retardants, etc. are used. Getting into the ocean with sewage, they also participate in the formation of surface-active films. [...]

In the waste waters of textile enterprises, the production of chemical fibers and a number of others there are impurities of various detergents, dispersants, as well as industrial wastes with significant surface activity, especially in a neutral or slightly alkaline environment. These impurities reduce surface tension, increase foam stability, which facilitates its removal from flotation units. Thus, flotation turns out to be an effective complex method for removing suspended solids, emulsions and dissolved surfactants of various structures from wastewater (if the latter effect is the main purpose of wastewater treatment, then in this case it is not about flotation, but about foam concentration of dissolved substances ). It should be borne in mind that the flotation treatment of water also causes the oxidation of a number of toxic substances or their blowing. Due to this, the general sanitary-hygienic effect of water purification in flotation machines is incomparably higher than the effect of water sedimentation even with the use of coagulants, especially since the introduction of the latter or sorbents directly into the floated water is also often very effective. [...]

The result of measuring electrical conductivity is also influenced by the contamination of electrodes, especially when analyzing wastewater containing surfactants: fats, resins, oils, etc. The results of measurements in such cases are questionable. After the measurement is completed, the contaminated electrodes should be washed first with a solution of a suitable solvent selected according to the type of contamination, then with an alcohol or solution of a synthetic detergent, and then thoroughly washed with distilled water. Determination of the electrical conductivity of samples, the analysis of which may show the influence of interfering conditions, is carried out, as a rule, using electrodes with a shiny surface. [...]

Recently, during wastewater treatment, there was a problem with foam. This is due to the use in the industry and in everyday life of synthetic detergents. The presence of small amounts of surfactants in wastewater causes the formation of a stable foam in the aeration tanks and a significant decrease in the sedimentation rate of suspended solids. In some cases, it is enough to contain 5 mg / l of synthetic detergents in wastewater to create a problem of foaming. [...]

As an example, we present data on the evaluation of the dynamic characteristics of the CTS of wastewater treatment at the bleaching plant of the dyeing and finishing production of a textile enterprise from anion-active surfactants, which are widely used in the technology of finishing fabrics as wetting and washing preparations. The change in the concentration of surfactants in the wastewater of such production depending on the time of work is illustrated in Fig. 3.1. Based on the correlation analysis of changes in the composition of wastewater at the inlet to the CTS, the autocorrelation function is presented, shown in Fig. 3.2. [...]

The lack of soda solutions is a relatively high corrosive ability, which sufficiently limits their use. The emergence in recent years of a wide range of surfactants with excellent detergents, naturally squeezed soda solutions from industrial applications. Especially valuable was the use of detergent compositions based on surface-active substances when cleaning products, equipment and containers from high-molecular compounds (epoxy resins, polydieneurethane rubbers, mixtures based on them, etc.). [...]

Hydromonitor - washing machine, which is supplied with washing fluid under pressure of 0.8-1.2 MPa. The washing liquid washes the inner surface of the tank with the help of the washing machine hoses. Hot (45-70 ° С) aqueous solution of the ML-2 detergent preparation, the concentration of which is 0.15-0.35%, is used as the washing liquid. The washing preparation is a composition of synthetic surfactants with the addition of electrolytes. [...]

Among other methods of combating "harmful resin" in the production of cellulose, it should be noted that it is advisable to clean the cooking acid from cymol, pre-steam the chips in the boiler in order to remove the turpentine part of the resin, thoroughly wash the cooked pulp with warm water and separate it from the liquor, treat the cooked pulp -active substances with resin separation by flotation, alkaline extraction of the resin from cellulose in multi-stage bleaching followed by washing of the cellulose and processing it with non-ionic erhnostno-active compounds and polyphosphates. Finally, it is necessary to note the separation from the cellulose on the resin separator of the fine fraction of fibers (3-4% of the total amount of cellulose) containing the main amount of resin.

Hydromonitors are used for chemical-mechanical cleaning, but solutions of various preparations are used as working fluid, therefore hydrodynamic and thermal effects of a jet of liquid on residual contamination are accompanied by physicochemical processes that facilitate the removal of these contaminants. As reagents used a variety of substances, the choice of which depends on the chemical composition of residual contaminants and liquid in the tank. For example, if the contaminants contain free organic acids, washing is carried out with alkaline solutions, since the interaction of these substances produces soaps emulsifying both inorganic and organic contaminants. In the presence of resinous hydrocarbon deposits in the tank, organic solvents are sometimes used, but their use is associated with an increased fire hazard. Widely used detergents containing surfactants that have a high dispersing ability in relation to contaminants of various chemical composition. There are a number of complex compositions of detergent solutions, which include, along with surfactants, the addition of alkaline solutions or organic solvents. In the case of the use of surfactants when washing tanks for aviation fuel, you should ensure that they are completely removed from the tank after washing, since even minor additives of these substances to the fuel can significantly impair the efficiency of its purification from free water. In fig. 6 shows a diagram of the washing of a vertical tank using a set of equipment for mechanical cleaning of tanks (OMZR). [...]

According to the internal structure of the particles, micellar colloids are separated into a separate group, they are also called semi-colloids. They are formed from organic long-chain molecules with diphilic properties: that is, the non-polar radical interacts better with organic (non-polar) liquids, and the polar part of the molecule (carboxyl and other groups) interacts better with polar water molecules. Micelles are formed due to intermolecular dispersion forces, which are manifested during the contact of non-polar parts of molecules. The formation of such colloids is characteristic of aqueous sols of detergents (for example, C17Hz5C001Ma soap) and some organic dyes with large molecules. This group includes synthetic surfactants.

Surface-active substances (surfactants) are chemical compounds that, while concentrating on the interface, cause a decrease in surface tension.

The main quantitative characteristic of surfactants is surface activity - the ability of a substance to reduce surface tension at the interface is the derivative of surface tension with respect to surfactant concentration when C tends to zero. However, surfactant has a limit of solubility (the so-called critical micelle concentration or CMC), with which when the surfactant is added to the solution, the concentration at the interface remains constant, but at the same time the self-organization of the surfactant molecules in the bulk solution (micelle formation or aggregation) occurs. As a result of this aggregation, so-called micelles are formed. A distinctive feature of micelle formation is the clouding of the surfactant solution. Aqueous solutions of surfactants, when micelle formation also acquire a bluish tint (gelatinous tint) due to the refraction of light by micelles.

Typical surfactants are organic compounds of diphilic structure, that is, containing atomic groups in a molecule, which differ greatly in the intensity of interaction with the environment (in the most practically important case, water). So, in the surfactant molecules there is one or several hydrocarbon radicals that make up the oleo or lipophilic part (it’s also the hydrophobic part of the molecule), and one or more polar groups, the hydrophilic part. Oleophilic (hydrophobic) groups weakly interacting with water determine the tendency of a molecule to transition from an aqueous (polar) medium to a hydrocarbon (nonpolar) medium. Hydrophilic groups, on the contrary, keep the molecule in a polar medium or, if the surfactant molecule is in a hydrocarbon fluid, determine its desire to transition to a polar medium. Thus, the surface activity of surfactants dissolved in non-polar liquids is due to hydrophilic groups, and dissolved in water by hydrophobic radicals.

Examples By the type of hydrophilic groups, surfactants are divided into ionic, or ionic, and non-ionic, or nonionic. Ionic surfactants dissociate in water into ions, some of which have adsorption (surface) activity, while others (counterions) are adsorptionally inactive. If anions are adsorption active, surfactants are called anionic, or anionic, in the opposite case - cationic, or cation-active. Anionic surfactants - organic acids and their salts, cationic - bases, usually amines of various degrees of substitution, and their salts. Some surfactants contain both acidic and basic groups. Depending on the conditions, they exhibit the properties of either anionic or cationic surfactants; therefore, they are called amphoteric, or ampholytic, surfactants.

Ionogenic surfactants.

Anionic substances make up the majority of global production of surfactants. This group of detergents is the most incompatible with dirt, and it is precisely it that is most criticized by soap-fouls. Anionic and cryptoanionic compounds (acetyl peptides, lauryl– and laureth sulfates of sodium, potassium, magnesium or ammonium) better than all other surfactant groups remove dirt from contact surfaces. Therefore, no effective cleanser can do without them.

People learned to make this group of washing substances earlier than others (remember the passage about the ashes, which the ancient sages sprinkled their heads on). As progress progressed, anionic toxides were boiled from proteins and fats, alkalized (sodium hydrolization) with the help of ash (the most popular alkaline natural raw materials are the ash of the tree Salasola soda) and other alkaline compounds. Coconut, palm, rapeseed, soybean oil, lard oil, spermaceti, butter from cow and goat milk are used as raw materials for anionic and cryptanionic surfactants.

The outstanding purifying qualities of anionic toxoids are explained by the structure of their molecules, which consist of two parts - hydrophilic (water-loving) and, conversely, hydrophobic.

The former allow them to dissolve in water (or polar solvents) and completely wash it off from the skin, and the latter in contact with non-polar substances (hydrocarbons, resins, urea, dust, fats, oils). During washing with shampoo or soap, hydrophobic "jaws" bind trapped particles of dirt, placing them in the center of the micelle (a hollow ball formed by a number of molecules, the hydrophilic "tails" of which are directed outwards, and inwards - the hydrophobic "heads").

Fast, full-fledged, high-quality evacuation of dirt from the surface of the skin and its appendages, foaming, bactericidal (eliminating gram-positive microorganisms) and bacteriostatic, lipolytic (dissolving the oxidized fat secretion of the sebaceous glands and tar-mineral contamination of the skin) action.

Industrial surfactants of this type can be divided into the following. main groups: carboxylic to-you and their salts (soaps), alkyl sulfates (sulfonic esters), alkyl sulfonates and alkyl aryl sulfonates, other products.

In the production of soaps and many ionic and non-ionic soap-like surfactants, carboxylic to-you, obtained by hydrolysis from vegetable and animal fats, and synthetic fatty to-you. Pitch and fatty to-you of tall oil - a by-product of cellulose production - pitch to-you rosin among which abietinovy ​​prevails have industrial value also.

The most important as surfactants from monocarboxylic salts are t-soaps (sodium, potassium and ammonium) fatty-tones of ROOH, where R is a saturated or unsaturated normal aliphatic radical with 12-18 carbon atoms, and soaps (sodium, less often potassium) resin kt. Practical importance also dicarboxylic to-you, for example. alkenylsucate obtained in the industrial condensation of unsaturated hydrocarbons with maleic anhydride.

Alkyl sulfates are usually synthesized by sulfoesterification of higher fatty alcohols or α-olefins, followed by neutralization of primary or secondary alkyl sulfuric acids, respectively.

Alkylaryl Sulfonates, Ch. arr. mono- and dialkylbenzene sulfonates, as well as mono- and dialkylnaphthalene sulfonates make up the majority of synthetic anionic surfactants.

Alkylsulfonates are usually obtained from saturated C12-C18 hydrocarbons of normal structure, which are sulfochlorinated or sulfo-oxidized, followed by saponification or neutralization of the product.

Cationic IIAV.

Cationic tensides are compounds that dissociate (dissolve) in an aqueous solution to form cations (positively charged molecules).

Quaternary ammonium bases, are polysaccharides derived from dairy products, lanolin, potatoes, corn, sugar cane, beets, sunflower.

By virtue of their positive charge, cationic tensides attract negatively charged hair and horny scales of the epidermis, accelerating their wetting, fix valuable medicinal components contained in a cosmetic preparation on their surface, and also have a bradykinase effect (eliminate irritation, itching, burning, swelling). They capture and hold negatively charged particles, kill gram-negative bacteria.

Cationic detergents are valuable components of cosmetic products (shampoos, balms, conditioners): they activate foam formation, increase the productivity of skin and hair oxygen exchange, emulsify oil and aromatic substances in an aqueous solution, have a bactericidal effect, eliminate the residual electrical charge on the hair after washing (antistatic effect ), provide easy combing, styling and increase the efficiency of therapeutic components on the skin and hair.

They can be divided into the following. main groups: amines of various degrees of substitution and quaternary ammonium bases, other nitrogen-containing bases (guanidine, hydrosines, heterocyclic compounds, etc.), quaternary phosphonium and tertiary sulfonium bases.

The raw materials for cationic surfactants of economic importance are amines derived from fatty alcohols and alcohols, alkhalides, as well as alkylphenols. Quaternary ammonium salts are synthesized from the corresponding long-chain halide alkyls by reaction with tertiary amines, from amines by chloroalkylation or by other routes from synthetic alcohols, phenols and phenolic mixtures.

Greater importance as cationic surfactants and as starting materials in the synthesis of non-ionic surfactants (see below) are not only mono-, but also diamines, polyamines and their derivatives.

Amphoteric surfactants

Manufacturers of high-quality cosmetics in order to soften the effect of the best, i.e. anionic cleansing ingredients (in particular, so that anionic surfactants do not damage the lipid complex of the lipid mantle) and at the same time not reduce even one iota of the cleansing activity of the preparation, they must be introduced into the SOAP formula, which is being washed. Amphoteric and non-ionic detergents neutralize the acid reaction of anions, promote their rapid decomposition, while increasing the density and reducing the "airiness" (diameter) of foam bubbles.

Amphoteric surfactants are one of the most expensive ingredients lathering basis. They are obtained by squeezing, extraction, infusion, rectification and oxidation of natural raw materials (both vegetable and animal). The most well-known raw material sources of amphoteric surfactants, namely cocoamphoacetate, lactate, alpha-amino acids, pectins, waxes, are soapstone, algae, apple fruit pulp, root crops (beets, carrots, Jerusalem artichoke), palm oil, dairy products, lanolin.

Even elementary knowledge of chemistry gives rise to doubts about the possibility of combining cationic and anionic surfactants in a single formula, since oppositely charged substances, pairwise attracted to each other, reduce their affinity for water (precipitate), and, naturally, purifying activity decreases. Only due to amphoteric detergents, this problem was resolved: these surfactants, due to their ability to easily give and attach an electron pair, exhibit both acidic and basic properties depending on the reaction of the medium in which they are located (so in an alkaline medium they become anions, and in acid - cations).

properties of amphoteric surfactants

Amphoteric detergents protect the skin and hair from dryness and irritation, restore the stratum corneum of the epidermis and hair keratin, soften, increase the elasticity of the connective tissue, make the hair silky, and the foam of the lathering substance has a creamy texture.

Obtained from anionic by introducing amino groups into them or from cationic by introducing acidic groups.

Such compounds, for example, RNHCH2CH2COONa, are obtained by reacting a primary amine and methyl acrylate with subsequent saponification of the ester group with an alkali.

Induced amphoteric surfactants are produced in small quantities, and their consumption expands slowly.

Nonionic surfactants

Compounds that dissolve in water without the formation of ions are called non-ionic. Their group is represented by polyglycolic and polyglycolic esters of fatty alcohols (for example, disubstituted - Disodium Laurethsulfosuccinate - a fluid fluid consisting of citric acid and fatty alcohols). Non-ionic surfactants are obtained by oxyethylation of vegetable oils (castor, wheat, flax, sesame, cocoa, calendula, parsley, rice, St. John's wort). Non-ionic surfactants exist only in liquid or pasty form, and therefore cannot be contained in solid detergents (soap, powders).

Aqueous solutions of esters of fatty acids are dispersion micelle solution, which is often called “smart soap”, because it emulsifies dirt and grease, removing them from the surface of the skin and hair, without damaging the protective mantle.

Properties of non-ionic surfactants

This type of surfactant adds to the detergent softness, safety, environmental friendliness (biodegradability of non-ionic detergents is 100%). They stabilize soap suds, have soft thickener properties, have a bradykinase and polishing effect, restoring the outer layers of the epidermis and hair, and contribute to enhancing the effect of therapeutic additives of the cleansing drug.

This is the most promising and fast-growing class of surfactants. Not less than 80-90% of such surfactants are obtained by adding ethylene oxide to alcohols, alkyl phenols, carboxylic acids, amines, and other compounds with reactive hydrogen atoms. Polyoxyacrylate alkylphenol ethers are the most numerous and widespread group of nonionic surfactants, including more than a hundred trade names, the most well-known drugs OP-4, OP-7 and OP-10. Typical raw materials are octyl, ionyl and dodecylphenols; cr. In addition, cresols, cresol-to-that, β-naphthol, etc. are used. If an individual alkylphenol is taken in the reaction, the finished product is a mixture of surfactants of the total fi rly RC6H4O (CH2O) mH, where t is the degree of hydroxyethylation, depending on the molar ratio of the initial components.

All surfactant. can be divided into two categories according to the type of systems they form when interacting with a solvent medium. One category includes micelle-forming surfactants. in., to the other - not forming micelles. In solutions of micelle-forming surfactants in. above the critical micelle concentration (CCM), colloidal particles (micelles) consisting of tens or hundreds of molecules (ions) arise. The micelles reversibly decompose into individual molecules or ions when the solution is diluted (more precisely, the colloidal dispersion) to a concentration below CCM.

Thus, solutions of micelle-forming surfactants. occupy an intermediate position between the true (molecular) and colloidal solutions, so they are often called semi-colloid systems. The micelle-forming surfactants include all detergents, emulsifiers, wetting agents, dispersants, etc.

Surface activity is conveniently assessed by the greatest decrease in surface tension divided by the corresponding concentration - CMC in the case of micelle-forming surfactants. Surface activity is inversely proportional to CMC:

The formation of micelles occurs in a narrow concentration range, which becomes narrower and more defined as the hydrophobic radicals lengthen.

The simplest micelles of typical semi-colloid surfactants, for example. salts of fatty acids, at concentrations not exceeding CMC, have a spheroidal shape.

With an increase in the surfactant concentration of anisometric micelles, it is accompanied by a sharp increase in structural viscosity, which in some cases leads to gelation, ie complete loss of fluidity.

Action detergents. Soap has been known for thousands of years, but only relatively recently chemists have understood why it has detergent properties. The mechanism for removing dirt is essentially the same for soap and synthetic detergents. Consider it on the example of table salt, ordinary soap and sodium alkyl benzene sulfonate, one of the first synthetic detergents.

When dissolved in water, salt dissociates into positively charged sodium ions and negatively charged chloride ions. Soap, i.e. Sodium (I) stearate, substances similar to it, as well as sodium alkylbenzenesulfonate (II) behave in a similar way: they form positively charged sodium ions, but their negative ions, unlike chloride ion, consist of about fifty atoms.

Soap (I) can be represented by the formula Na + and C17H35COO–, where 17 carbon atoms with hydrogen atoms attached to them are stretched into a winding chain. Sodium alkylbenzenesulfonate (Na + C12H25C6H4SO3–) has about the same number of carbon and hydrogen atoms. However, they are located not in the form of a winding chain, as in soap, but in the form of a branched structure. The significance of this distinction will become clear later. For the detergent action, it is important that the hydrocarbon portion of the negative ion is insoluble in water. However, it is soluble in fats and oils, and in fact it is thanks to fat that mud adheres to things; and if the surface is completely free of grease, dirt does not linger on it.

Negative ions (anions) of soap and alkyl benzene sulfonate tend to concentrate on the interface of water and fat. The water-soluble negatively charged end remains in the water, while the hydrocarbon portion is immersed in fat. In order for the interface to be the largest, the fat must be present in the form of the smallest droplets. The result is an emulsion - a suspension of droplets of fat (oil) in water (III).

If there is a film of fat on a solid surface, then upon contact with water containing detergent, the fat leaves the surface and passes into the water in the form of tiny droplets. The anions of soap and alkyl benzene sulfonate are at one end in water and the other in fat. The dirt held by the grease film is removed by rinsing. So in a simplified form, you can imagine the effect of detergents.

Any substance that tends to collect at the oil-water interface is called a surfactant. All surfactants are emulsifiers because they contribute to the formation of an oil-in-water emulsion, i.e. “Mixing” oil and water; they all have detergent properties and form a foam - because foam is like an emulsion of air bubbles in water. But not all of these properties are expressed in the same way. There are surfactants that form a lot of foam, but are mild detergents; there are those who barely foam, but are excellent detergents. Synthetic detergents are synthetic surfactants with particularly high detergency. In industry, the term "synthetic detergent", as a rule, means a composition comprising a surfactant component, bleach and other additives.

Soaps, alkyl benzene sulphonates and many other detergents, where the anion is soluble in fats, are called anionic. There are also surfactants in which the cation is fat soluble. They are called cationic. Typical cationic detergent, alkyl dimethyl benzyl ammonium (IV) chloride

is a quaternary ammonium salt containing nitrogen bound to four groups. The chloride anion always remains in the water, so it is called hydrophilic; hydrocarbon groups associated with positively charged nitrogen are lipophilic. One of these groups, C14H29, is similar to a long hydrocarbon chain in soap and alkyl benzene sulfonate, but it is attached to a positive ion. Such substances are called "reverse soaps." Some of the cationic detergents have a strong antimicrobial effect; They are used in the composition of detergents intended not only for washing, but also for disinfection. However, if they cause eye irritation, then when using them in aerosol formulations, this fact should be reflected in the instructions on the label.

Another type of detergent is non-ionic detergents. The fat soluble group in detergent (V) is a kind of fat soluble group in alkyl benzene sulfonates and soaps, and the residue is a long chain containing many oxygen atoms and a OH group at the end that are hydrophilic. Typically, non-ionic synthetic detergents exhibit high detergency, but weakly form foam.

Synthetic surfactants (Synthetic Surface-Active Substances) are an extensive group of compounds, different in structure, belonging to different classes. These substances are able to adsorb on the interface and, as a result, lower the surface energy (surface tension). Depending on the properties shown by synthetic surfactants when dissolved in water, they are divided into anionic substances (the anion is the active part), cationic (the cation is the active part of the molecules), ampholytic and non-ionic, which are not ionized at all.

It is no secret that the main active components of laundry detergents are surface-active substances (surfactants). In truth, these active chemical compounds, entering the body, destroy living cells by disrupting the most important biochemical processes.

The future for the synthetics? Apparently, yes. In confirmation of this, surfactants are being improved more and more, there are so-called non-ionic surfactants whose biodegradability reaches 100%. They are more effective at low temperatures, which is important for gentle washing modes. Since many artificial fibers do not withstand high temperatures. In addition, washing in colder water saves energy, which is more relevant with each passing day. Unfortunately, most non-ionic surfactants are liquid or pasty, and therefore are used in liquid and pasty detergents. Nonionic surfactants are introduced into powdered CMC in the form of additives of 2-6% wt. Important advantages of synthetic surfactants are that they do not form water-soluble calcium and magnesium salts. So, it is equally well washed both in soft and hard waters. The concentration of synthetic detergents even in soft water can be much lower than that of soaps derived from natural fats.

Probably from the products of household chemicals, we know most of all synthetic detergents. In 1970, for the first time in the world, synthetic detergents (SMS) produced more than regular natural soaps. Every year its production all decreases, while the release of SMS is constantly increasing.

For example, in our country, the dynamics of growth in the production of SMS can be displayed by the following data: in 1965 they produced 106 thousand tons, in 1970 -470 thousand tons, and in 1975 almost one million tons will be produced.

Why, then, does the production of natural, sound, soap, which faithfully served man for many years, fall so much? It turns out that he has many flaws.

First, soap, being a salt of a weak organic acid (more precisely, a salt formed by a mixture of three acids, palmitic, margarine and stearic) and a strong base, caustic soda, hydrolyzes in water (i.e., is split by it) into acid and alkali. The acid reacts with hardness salts and forms new, water-insoluble salts, which fall in the form of a sticky white mass onto clothes, hair, etc. This is not a very pleasant phenomenon well known to everyone who tried to wash or wash in hard water. .

Another product of hydrolysis - alkali - destroys the skin (defats it, leads to dryness and the formation of painful cracks) and reduces the strength of the fibers that make up various fabrics. Polyamide fibers (capron, nylon, perlon) are destroyed by soap especially intensively.

Secondly, soap is a relatively expensive product, since its production requires food raw materials - vegetable or animal fats.

There are other, less significant disadvantages of this until recently completely irreplaceable substance in everyday life.

Unlike natural soap, synthetic detergents have undoubted advantages: greater detergency, hygiene and cost effectiveness.

About 500 items of synthetic detergents, produced in the form of powders, granules, scales, pastes, liquids, are known on the international market.

The production of SMS gives a great economic effect. Experiments have shown that one ton of synthetic detergents replaces 1.8 tons of 40 ° / oh household soap, produced from valuable food raw materials. It is estimated that one ton of SMS saves 750 kg of vegetable fats for the food industry.

The use of SMS in the household can reduce labor costs for hand and machine washing by 15-20%. It is much better than using conventional soap, the strength and initial consumer properties of the fabric (whiteness, brightness of color, elasticity) remain.

I must say that SMS is not just for washing clothes. There are special products for washing and cleaning various household items, toilet synthetic soaps, hair washing products-shampoos, bath-washing additives, in which biostimulants are introduced that have a tonic effect on the body.

The main component of all these products is a synthetic surface-active substance (surfactant), whose role is the same as the organic salt in ordinary soap.

However, chemists have long known that an individual substance, no matter how versatile it is, cannot satisfy all the requirements for it. Small additives of other related substances help to find very useful qualities in this basic substance. That is why all modern SMS are not individual surfactants, but compositions, which may include bleaches, fragrances, foam regulators, biologically active substances and other components.

The second most important component of modern detergents are condensed, or polymeric, phosphates (polyphosphates). These substances have a number of useful properties: they form water-soluble complexes with metal ions present in the water, which prevents the possibility of the appearance of insoluble mineral salts that occur when washing with ordinary soap; increase the washing activity of surfactant; prevent the sedimentation of suspended particles of dirt on the washed surface; cheap in production.

All these properties of polyphosphates make it possible to reduce the content of the more expensive main component-surfactant in SMS.

As a rule, fragrance is a part of any synthetic detergent - a substance with a pleasant odor, which is transferred to the laundry when using SMS.

A substance called sodium carboxymethylcellulose is injected into almost all SMS. It is a high molecular weight synthetic product, soluble in water. Its main purpose is to be, along with phosphates, antiresorptive, that is, to prevent the sedimentation of dirt on already washed fibers.

Most of them have a number of advantages over soap, which has long been used for this purpose. For example, surfactants dissolve well and foam, even in hard water. Potassium and magnesium salts formed in hard water do not impair the detergent action of surfactants and do not form a white residue on the hair.

The main active ingredients of all washing powders, so-called. Surfactants (surface active substances) are extremely active chemical compounds. Possessing some chemical affinity with certain components of the cell membranes of humans and animals, surfactants, when ingested, accumulate on the cell membranes, covering their surface with a thin layer and at a certain concentration can cause disruption of the most important biochemical processes occurring in them, disrupt the function and integrity cells

In animal experiments, scientists found that surfactants significantly alter the intensity of redox reactions, affect the activity of a number of the most important enzymes, break down protein, carbohydrate and fat metabolism. Surfactant anions are especially aggressive in their actions. They can cause gross violations of the immune system, the development of allergies, damage to the brain, liver, kidneys, lungs. This is one of the reasons why strict restrictions on the use of a-surfactants (anionic surfactants) in detergent compositions are imposed in Western European countries. At best, their content should not exceed 2-7%. In the West, more than 10 years ago, they refused to use in everyday life powders containing phosphate additives. In the markets of Germany, Italy, Austria, Holland and Norway only non-phosphate detergents are sold. In Germany, the use of phosphate powders is prohibited by federal law. In other countries, such as France, Great Britain, Spain, according to government decisions, the content of phosphates in SMS is strictly regulated (no more than 12%).

The presence of phosphate additives in powders leads to a significant increase in the toxic properties of a-surfactant. On the one hand, these additives create conditions for more intense penetration of a-surfactant through intact skin, contribute to enhanced skin defatting, more active destruction of cell membranes, drastically reduce the barrier function of the skin. Surfactants penetrate the microvessels of the skin, are absorbed into the bloodstream and spread through the body. This leads to a change in the physicochemical properties of the blood itself and impaired immunity. A-surfactant has the ability to accumulate in organs. For example, 1.9% of the total amount of a-surfactant on unprotected skin settles in the brain, 0.6% in the liver, etc. They act like poisons: in the lungs they cause hyperemia, emphysema, damage the function of cells in the liver, which leads to an increase in cholesterol and increase the effects of atherosclerosis in the vessels of the heart and brain, disrupts the transmission of nerve impulses in the central and peripheral nervous systems.

But this does not exhaust the harmful effects of phosphates - they represent a greater threat to our environment. After washing, together with the wastewater, into the water bodies, phosphates are taken to act as fertilizer. The "harvest" of algae in water begins to grow by leaps and bounds. Algae, decomposing, emit in large quantities methane, ammonia, hydrogen sulfide, which destroy all life in water. The overgrowing of water bodies and the clogging of slow-flowing water leads to gross violations of the ecosystems of water bodies, deterioration of oxygen exchange in the hydrosphere and create difficulties in providing the population with drinking water. Also for this reason, in many countries, the use of phosphate SMS has been prohibited by law.

The traditional disadvantage of surfactants is stiffness, expressed in irritation of the skin, the appearance of dryness and discomfort after using a shampoo or shower gel.

The skin of the hands, in contact with the active chemical solutions of laundry detergents, become the main conductor of the penetration of hazardous chemical agents into the human body. A-surfactants actively penetrate even through intact skin of the hands and with the assistance of phosphates, enzymes and chlorine intensively disinfect it. Restoration of normal oiliness and moisture of the skin occurs no earlier than in 3-4 hours, and with repeated use due to the accumulation of a harmful effect, the lack of fatty skin covering is felt for two days. Barrier functions of the skin are reduced, and conditions are created for intensive penetration of not only a-surfactant into the body, but also any toxic compounds - bacteriological toxins, heavy metals, etc. After several washings with phosphate powders, skin inflammations often develop - dermatitis. The conveyor of pathological immune reactions starts.

Bibliography

Van Krevelen DV, Properties and chemical structure of polymers, trans. With English, M., 1976;

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