Sulfur and its compounds are among the most important classes of pesticides.
Sulfur - solid yellow color. There are crystalline and amorphous varieties. Sulfur does not dissolve in water, it dissolves well in carbon disulfide, aniline, phenol, benzene, gasoline, and poorly in alcohol and chloroform. At elevated temperatures it combines with oxygen, metals and many non-metals. Available in the form of 80-90% wetting powder, 70-75% colloidal sulfur, and ground sulfur.
Ground sulfur does not dissolve in water and is poorly wetted by it.
Colloidal sulfur It is well wetted with water and, when shaken or stirred, creates persistent cloudy suspensions. Evaporates weakly and slowly.
Produced and transported in metal and wooden barrels; and also in paper bags treated with a waterproof substance. When stored in loose containers, colloidal sulfur dries out, turning into lumps, and then mixes very poorly with water.
In livestock farming, colloidal sulfur is used to combat psoroptosis in cattle by spraying animals with a 3% aqueous suspension with a consumption of 3-4 liters per animal, twice, with an interval of 7-10 days.
Sulfur is low toxic. Acute poisoning when working with it is excluded. However, prolonged inhalation may cause respiratory problems.
Sulfur cuttings- molten sulfur turned into a cylindrical shape. Lit. When 1.4 g is burned, 1 liter of sulfur dioxide is obtained. The antiparasitic effect of sulfur is due to the formation of sulfur dioxide, hydrogen sulfide, oxygen, in the presence of moisture, alkalis and organic compounds. In concentrations of 5-8%, sulfur has a softening, keratoplastic, anti-inflammatory effect and a weak anti-itch, and in high concentrations, due to the formation of sulfuric and sulfurous acids, irritating, drying and keratolytic effects develop. Sulfur cuttings are used to treat animals suffering from scabies, trichophytosis, microsporia, furunculosis, seborrhea, eczema, dermatitis in the form of 10-30% purified sulfur ointment or 5-10 and 20% precipitated sulfur ointment, as well as in the form of liniments and dusts.
To treat scabies, use sulfur ointment (sulfur 6 parts, green soap - 8, potassium carbonate - 1 and petroleum jelly - 10 parts).
Purified sulfur- sulfur, free from all impurities, is produced in powder in carefully closed containers. Purified sulfur has an antiparasitic and antidote effect against many poisonings. It is used in all cases as cutting sulfur.
Sulfur precipitated- purified from many impurities. Lit. When burned, sulfur dioxide is formed, which has antiparasitic and insecticidal effects. Pharmacodynamics and mechanism of action are the same as those of cutting sulfur. Available in powder form, in well-closed jars.
Sodium sulfate- a sulfur-containing substance with an antiparasitic effect. The mechanism of action is the formation of sulfur dioxide and sulfur during the interaction of sodium thiosulfate molecules with a molecule of acids or acid salts, as a result of which the redox processes in the parasites sharply change.
It is produced in powder form, which must be stored in a well-closed container.
Demos- an acaricidal drug, which includes sulfur and auxiliary components. This is a light brown liniment with a weak specific odor. The drug is produced in glass or plastic bottles with a capacity of 10, 15 and 20 ml. Store demos at a temperature of 0-25°C in a place protected from light. Shelf life - 2 years from the date of manufacture.
Demos is active against sarcoptoid mites - the causative agents of psoroptic mange in rabbits, otodectic mange in carnivores, notoedrosis in cats, as well as against the causative agent of demodicosis in dogs.
The drug has low toxicity for warm-blooded animals, it does not have an irritating or sensitizing effect.
When treating animals with ear scabies, first thoroughly clean the auricles from scabs with a swab soaked in camphor alcohol, then inject 1.5-3.0 ml of demos into the auricle using a pipette and lightly massage the auricle at the base. If other parts of the body are affected, the drug is rubbed into the affected areas using a cotton gauze swab at the rate of 0.1-0.3 cm of adjacent healthy skin.
Animals with large areas of skin lesions are treated in 2 doses, with an interval of 1 day, applying the drug first to one half and then to the other half of the affected surface of the body.
Plison(diphenyl disulfide), C12H10S2. Obtained by mixing coal oil 22-42%, diphenyl sulfide 6-10%, emulsifier OP-7 (rosin) or OP-10 (neonol) - 15-20% and water up to 100%. Diphenyl disulfide is produced as a by-product in the production of coal-tar phenols.
Plizon is a homogeneous, dark-colored oily liquid. The aqueous emulsion of this drug is stable for 4 hours at room temperature. The drug is low-toxic; when applied cutaneously, the LD50 is 12,500 mg/kg. 0.5% plison emulsion (therapeutic concentration) is well tolerated by sheep and is not accompanied by changes in the morphological picture of the blood. Plizone 2% causes a decrease in the activity of cholinesterase and alkaline phosphatase on the first day after purchase, without the manifestation of clinical signs of toxicosis.
Plizon, according to research by O.D. Yanyshevsky et al., is excreted from the internal organs and tissues of sheep treated with a 0.5% emulsion after 40 days, and from fat after 65. In animals treated with a 0.25% plison emulsion, diphenyl disulfide was absent in the internal organs and tissues after 20 days. It persists on sheep wool for up to 5 months in an amount of 15.1 mg/kg. It is not excreted in the milk of suckling ewes.
Lepran- a sulfur-containing product from the processing of benzothiophene coal tar. The liquid is dark brown in color with the smell of coal oil. When mixed with water, lepran forms a stable light brown emulsion. The drug consists of benzothiophene - 10-14%, coal oil 57-64, emulsifier 25-30 and water up to 100%. Lepran is low toxic, its LD50 when buying sheep is 14250 mg/kg. The cumulation coefficient is more than 5.28, which indicates weak cumulative properties, does not have allergenic and irritating to the skin and mucous membrane properties. When treating sheep (one-time purchase) with 2% leprane emulsion (0.22% DDV), according to research by B.A. Timofeev, the drug does not have mutagenic properties, does not change hematological parameters of phosphatase, veterinary and sanitary indicators of the quality of sheep meat. 50 days after treatment, benzothiophene is not detected in the organs and tissues of sheep, the meat is suitable for release and sale for food purposes. Benzothiophene is not excreted in milk; the drug can be used to treat pregnant and lactating sheep.
In cases of poisoning of animals with sulfur-containing drugs, activated carbon, burnt magnesia, and a laxative are used internally.
Characteristics of chemical element No. 16 (Sulfur)
1. History of the discovery of the element.
2.Distribution of the element in nature.
3.Physical properties.
4. Chemical properties.
5.Receipt.
6.Application.
History of the discovery of the element. Sulfur (English Sulfur, French Sufre, German Schwefel) in its native state, as well as in the form of sulfur compounds, has been known since ancient times. Man probably became familiar with the smell of burning sulfur, the suffocating effect of sulfur dioxide and the disgusting smell of hydrogen sulfide back in prehistoric times. It was because of these properties that sulfur was used by priests as part of sacred incense during religious rites. Sulfur was considered the work of superhuman beings from the world of spirits or underground gods. A very long time ago, sulfur began to be used as part of various flammable mixtures for military purposes. Homer already described “sulphurous fumes,” the deadly effect of burning sulfur emissions. Sulfur was probably part of the “Greek fire” that terrified opponents. Around the 8th century The Chinese began to use it in pyrotechnic mixtures, in particular, in mixtures such as gunpowder. The flammability of sulfur, the ease with which it combines with metals to form sulfides (for example, on the surface of pieces of metal), explains why it was considered the "principle of flammability" and mandatory integral part metal ores. Presbyter Theophilus (11th century) describes a method of oxidative roasting of copper sulfide ore, probably known back in ancient Egypt. During the period of Arab alchemy, the mercury-sulfur theory of the composition of metals arose, according to which sulfur was revered as an essential component (father) of all metals. Later it became one of the three principles of alchemists, and later the “principle of flammability” became the basis of the theory of phlogiston. The elemental nature of sulfur was established by Lavoisier in his combustion experiments. With the introduction of gunpowder in Europe, the development of natural sulfur mining began, as well as the development of a method for producing it from pyrites; the latter was common in ancient Rus'. It was first described in literature by Agricola. Origin of Lat. Sulfur unclear. It is believed that this name was borrowed from the Greeks. In the literature of the alchemical period, sulfur often appears under various secret names. In Ruland one can find, for example, the names Zarnec (explanation of “egg with fire”), Thucios (living sulfur), Terra foetida, spiritus foetens, Scorith, Pater, etc. The Old Russian name “sulfur” has been used for a very long time. It meant various flammable and foul-smelling substances, resins, physiological secretions (earwax, etc.). Apparently, this name comes from the Sanskrit sira (light yellow). The word “gray” is associated with it, that is, of an indefinite color, which, in particular, refers to resins. The second Old Russian name for sulfur - bogey (flammable sulfur) - also contains the concept of not only flammability, but also a bad odor. As philologists explain, German. Schwefel has the Sanskrit root swep (to sleep, Anglo-Saxon sweblan - to kill), which may be related to the poisonous properties of sulfur dioxide.(3)
Distribution of the element in nature. Sulfur is widely distributed in nature. It makes up 0.05% of the mass of the earth's crust. In a free state (native sulfur) it is found in large quantities in Italy (the islands of Sicily) and the USA. Deposits of native sulfur are found in the Volga region, in the states of Central Asia, in the Crimea and other areas.
Sulfur often occurs in compounds with other elements. Its most important natural compounds are metal sulfides: FeS 2- iron pyrite, or pyrite; ZnS- zinc blende; PbS- lead shine; HgS- cinnabar, etc., as well as sulfuric acid salts (crystalline hydrates): CaSO 4H 2H 2 O- plaster, Na 2 SO 4 H 10H 2 O- Glauber's salt, MgSO 4 H 7H 2 O- bitter salt, etc.(2)
Physical properties. Sulfur is a hard, brittle, yellow substance. It is practically insoluble in water, but dissolves well in carbon disulfide, aniline and some other solvents. Conducts heat and electricity poorly. Sulfur forms several allotropic modifications- sulfur rhombic, monoclinic, plastic. The most stable modification is rhombic sulfur; all other modifications spontaneously transform into it after some time.
At 444.6 °C, sulfur boils, forming dark brown vapors. If they are quickly cooled, a fine powder consisting of tiny sulfur crystals is obtained, called sulfur color.
Natural sulfur consists of a mixture of four stable isotopes:
Melting point, °C 112.8. Boiling point, °C 444.6
Chemical properties. Sulfur can donate its electrons when interacting with stronger oxidizing agents:
In these reactions, sulfur is the reducing agent. It must be emphasized that sulfur oxide(VI) can only be formed in the presence Pt or V2O5 and high blood pressure .
When interacting with metals, sulfur exhibits oxidative properties:
Sulfur reacts with most metals when heated, but in the reaction with mercury the interaction occurs already at room temperature. This circumstance is used in laboratories to remove spilled mercury, the vapors of which are a strong poison.(3)
Some examples of sulfur compounds.
Hydrogen sulfide . When sulfur is heated with hydrogen, a reversible reaction occurs with a very small yield of hydrogen sulfide H 2 S. Usually H 2 S is obtained by the action of dilute acids on sulfides:
This reaction is often carried out in a Kipp apparatus.
Hydrogen sulfide - typical reducing agent. It burns in oxygen. A solution of hydrogen sulfide in water is a very weak hydrosulfide acid, which dissociates stepwise and mainly in the first step:
Hydrogen sulfide acid, like hydrogen sulfide, is a typical reducing agent.
Hydrogen sulfide acid is oxidized not only by strong oxidizing agents, such as chlorine, but also by weaker ones, such as sulfurous acid H 2 SO 3 or ferric ions:
Sulfides. For example, Na 2 S is sodium sulfide, NaHS is sodium hydrosulfide.
Hydrosulfides are almost all highly soluble in water. Sulfides of alkali and alkaline earth metals are also soluble in water, while other metals are practically insoluble or slightly soluble; some of them do not dissolve in dilute acids. Therefore, such sulfides can be easily obtained by passing hydrogen sulfide through salts of the corresponding metal.
Some sulfides have a characteristic color: CuS And PbS- black, CdS- yellow, ZnS- white, MnS- pink, SnS- brown, Sb 2 S 3- orange, etc. Qualitative analysis of cations is based on the different solubility of sulfides and the different colors of many of them. (4)
Sulfur(IV) oxide. Sulfur (IV) oxide, or sulfur dioxide, under normal conditions is a colorless gas with a pungent, suffocating odor. When cooled to -10° C, it liquefies into a colorless liquid. In liquid form, it is stored in steel cylinders.
SO 2 is formed when sulfur is burned in oxygen or when sulfides are roasted. It is highly soluble in water (40 volumes in 1 volume of water at 20 °C).
Sulfur(VI) oxide. SO 3 - sulfuric acid anhydride - a substance with t pl = 16.8 °C and t bp = 44.8 °C. Sulfur (VI) oxide, or sulfur trioxide, is a colorless liquid that solidifies at temperatures below 17° C into a solid crystalline mass. Sulfur oxide (VI) has all the properties of acidic oxides. It is an intermediate product in the production of sulfuric acid.
Sulfur oxide (VI) is obtained by oxidation of SO 2 with oxygen only in the presence of a catalyst:
The need to use a catalyst in this reversible reaction is due to the fact that a good yield of SO 3 (i.e., a shift of the equilibrium to the right) can only be obtained by lowering the temperature, but at low temperatures the reaction rate drops very significantly.
The SO3 molecule has the shape of a triangle, in the center of which is a sulfur atom:
This structure is due to the mutual repulsion of bonding electron pairs. The sulfur atom provided all six outer electrons for their formation.
Sulfuric acid. Sulfur (VI) oxide combines vigorously with water to form sulfuric acid:
SO 3 dissolves very well in 100% sulfuric acid. A solution of 80z in such an acid is called oleum.
Salts of sulfuric acid. Sulfuric acid, being dibasic, forms two series of salts: middle ones, called sulfates , and sour, called hydrosulfates . Sulfates are formed when an acid is completely neutralized by an alkali (for one mole of acid there are two moles of alkali), and hydrosulfates are formed when there is a lack of alkali (for one mole of acid there is one mole of alkali):
Many salts of sulfuric acid are of great practical importance.(2)
Receipt. Native sulfur contains foreign substances, which are separated by using the ability of sulfur to easily melt. However, sulfur obtained by smelting from ore (lumpy sulfur) usually contains many more impurities. Further purification is carried out by distillation in refining furnaces, where the sulfur is heated to boiling. Sulfur vapor enters a brick-lined chamber. Initially, while the chamber is cold, the sulfur directly turns into a solid state and is deposited on the walls in the form of a light yellow powder ( sulfur color). When the chamber is heated above 120°C, the vapor condenses into a liquid, which is released from the chamber into molds, where it hardens into sticks. The sulfur obtained in this way is called Cherenkova .
An important source of sulfur is iron pyrite FeS 2, also called pyrite, and polymetallic ores containing sulfur compounds of copper, zinc and other non-ferrous metals. Some sulfur (gas sulfur) is obtained from gases produced during the coking and gasification of coal.(4)
Application. About half of annual sulfur consumption goes into the production of industrial chemicals such as sulfuric acid, sulfur dioxide and carbon disulfide (carbon disulfide). In addition, sulfur is widely used in the production of insecticides, matches, fertilizers, explosives, paper, polymers, paints and dyes, and in the vulcanization of rubber. The leading place in sulfur production is occupied by the USA, CIS countries and Canada.
Sulfur is found in the bodies of animals and plants, as it is part of protein molecules. Organic sulfur compounds are found in oil.(3)
Literature.
1. Directory of sulfuric acid.1971 A.I. Busev., L.N. Simonova (www.krugosvet.ru).
2. Basics general chemistry. M.: Chemistry, 1967. B.V.Nekrasov
3. Chemistry for those entering universities. 1993 G.P. Khomchenko
4. General and inorganic chemistry. 1981 N.S. Akhmetov.
Sulfur is a substance that has now been studied almost completely by humanity. In ancient times, it was considered mystical and was surrounded by secrets, legends and myths that arose due to people’s superstitious fear of everything unknown. However, many of the physical properties of sulfur were known to people even before Mendeleev placed the element in the periodic table and assigned it number 16. This substance was quite widely used back in the era of Homer, in addition, some information (conditionally reliable) about it can be found in New and Old Testaments.
It was quite difficult to systematize the information accumulated over centuries about a substance such as sulfur overnight. Many scientists did this, but D.I. Mendeleev was able to determine its belonging to the class. In the periodic table it is designated by number 16. Sulfur is located in the third period, the sixth group of the main subgroup, atomic mass - 32, density (under normal conditions) - 2070 kg/m 3.
Sulfur is found quite often in rocks of the earth's crust. In terms of availability and prevalence, it ranks 16th among all chemical elements. The structure of the sulfur atom allows this substance to be in pure form(in certain natural conditions). But in most cases it is part of various ores and forms sulfides and sulfates in compounds. Its most common connections are with metals: cinnabar, zinc blende (sphalerite). Magnesium, calcium, and sodium sulfates are present in the World Ocean. To date, more than 200 names of minerals have been identified. The second group in terms of mass fraction of content is gypsum, kieserite, and Glauber's salt. Sulfur is part of protein molecules, i.e. it is found in animal bodies. Organic compounds are very widely represented: oil, gases and natural coal. The main source of the formation of sulfur and its derivatives are volcanic eruptions, but human activity (industrial, economic) has accelerated and enriched this process. A significant amount of this substance is accumulated in groundwater, clay, gypsum, at the bottom of lakes and seas, in oil, natural gas and coal, in salt marshes and in ocean waters. The circulation of sulfur in the biosphere occurs with the help of microorganisms, and this is also facilitated by moisture that evaporates from the surface of a vast expanse of water, falls in the form of precipitation and goes back into the seas and oceans with waste streams from rivers.
During the development of alchemy, there were several names used to designate the modern chemical element sulfur. What substance was meant by them is not entirely clear; perhaps it was about compounds, ore or sulfur dioxide. In the periodic table, sulfur is designated by the symbol S (Sulfur). This Latin name does not have a clear origin; it was probably borrowed from the ancient Greek language, and it can be translated as “burning.” The term used in Russian has very ancient roots. The word “sulfur” was used to describe unpleasant-smelling mixtures. There is also a version about the origin of the name from the color of the substance: “light yellow”, “gray”, i.e. not defined. This is what all resins were called. The second name for the substance, not used in modern times, is “bogey”. It also defines the concepts of flammability and bad odor. Philologists have concluded that this word contains a Sanskrit root for “to kill,” which is probably related to the properties of sulfur dioxide.
Depending on the allotropic modification, the bonds within the element vary. It is customary to distinguish three types of lattice (stable chain of atoms) formed: rhombic, plastic, monoclinic. The color and physical properties of the substance sulfur depend on the modification. The most stable and common are cyclic compounds S8. It is this type of chain that is characteristic of crystalline sulfur, a brittle substance with a yellowish tint. Plastic and monoclinic modifications are unstable and spontaneously transform into a cyclic structure some time after production. Sulfur formula in in this case contains the character S 4 or S 6 . Under normal conditions, a stable compound is a rhombic chain: during heating, the substance passes into a liquid state of aggregation, then thickens. Gradual cooling forms needle-shaped crystals of monoclinic sulfur, which are dark yellow in color. When a molten substance interacts with cold water, a plastic allotropic modification is formed, which has a structure similar to rubber, consists of several polymer chains, and has a dirty yellow (dark) color. The most common description of sulfur is as a solid yellow substance that does not interact with water, remaining on its surface. Organic compounds can be used as a solvent: turpentine, carbon disulfide, etc. Sulfur as a simple substance under normal conditions has the following thermodynamic properties:
During the heating process, the number of sulfur atoms in the molecule decreases. At 300 o C, it is a fairly actively moving liquid; to obtain vapor, the temperature is increased to 450 o C. Monatomic sulfur can be obtained by heating the substance to 1760 o C (S 8 - S 6 - S 4 - S 2 - S). This substance is a poor conductor of electric current and heat, which is widely used in its application.
Sulfur reacts with all metals, resulting in the formation of sulfides. In most cases for chemical reaction a catalyst is needed, which is heat. Under normal conditions (room temperature), the connection occurs only with mercury. This property is used to neutralize its vapors, which are formed as a result of the interaction of metal droplets with oxygen. The element does not interact with platinum, iridium, and gold. are fire hazardous compounds that burn quite intensely when ignited. Sulfur purified in open air reacts with oxygen. This compound is characterized by the formation of a colorless gas (sulfur dioxide) and combustion. A reversible reaction of interaction with hydrogen occurs when heated (by analogy with carbon and silicon), the resulting gases are called hydrogen sulfide, carbon disulfide. Like all other elements of group VI of the periodic table, sulfur interacts in a sealed tube with halogens (fluorine, bromine, chlorine, phosphorus). At room temperature, the reaction is only possible with fluorine. Sulfur chloride is the substance most widely used in chemical industry. It does not interact with water and acid solutions; compounds with alkali are reversible - they are formed under the influence of a catalyst. Many existing acids and salts are formed as a result of the combination (temperature is a prerequisite) of sulfur with oxygen and hydrogen.
The structure of the sulfur atom allows the element to act as an oxidizing and reducing agent, and during a chemical reaction to have different valencies. This is due to the distribution of electrons across levels. The nucleus of an atom has a charge of +16 at atomic mass 32 (16 protons and neutrons), radius - 127 pm. The sulfur diagram (electronic) is as follows: S+16)2)8)6; in a calm state - 1S 2 2S 2 2P 6 3S 2 3P 4. At the third level, the sulfur atom has five unoccupied orbitals, so the valence in its compounds varies within the following limits: -2, +2, +4, +6, which depend on the degree of its excitation.
The amount of sulfur produced increases annually. This is due to a fairly wide range of its applications, which is constantly growing due to technological breakthroughs and more thorough research of already known chemical elements. In nature, sulfur is found in native form and is part of a large number of ores. Depending on this, they apply various ways her prey. Stratiform deposits are common in the USA, Iraq, the middle Volga region and the Carpathian region. They are the most profitable in percentage terms; they extract from 50 to 60% of sulfur. Carbonate and sulfate rocks lie in huge layers, reaching tens of meters in depth and several hundreds in length. Salt dome fields are typical for regions of intensive oil production. The largest deposits include the Gulf of Mexico zone, which is being developed in parallel by the USA, Chile and Mexico. The most modern, recently formed deposits are volcanic deposits. Their origin is associated with tectonic faults in the earth's crust and the action of volcanoes. Accordingly, these deposits are located in the Pacific Ocean. Japan and Russia are actively developing these zones. On the territory of Eurasia, deposits of native sulfur are more common, which has sufficient ancient origin and is predominantly located in the surface layers. The Ural Mountains, Volga region, Lviv region are developed deposits that are being developed until today. World sulfur production is more than 50 million tons per year, with 30% coming from nuggets, 33% from gas and oil products, 14% from processing industrial emissions, 16% from sulfides, 6% from sulfates.
Depending on the depth of occurrence of the sulfur-containing ore, various methods its extraction and further processing. The physical properties of sulfur come to the fore, regardless of the extraction method, bringing the safety of the process to the forefront. As a rule, deposits of this substance are accompanied by a large accumulation of toxic gases, and cases of spontaneous combustion cannot be ruled out. Surface ore layers are removed in layers using excavators - this method is the least dangerous (subject to all technological requirements). Purified sulfur is obtained as a result of its further processing at appropriate enterprises, where it is delivered from quarries. Methods of purification and enrichment are varied: thermal, centrifugal, filtration, steam-water, extraction.
It is much more difficult to extract sulfur, which is contained in underground layers. The mine method - due to the release of accompanying gas - is practically inaccessible, so the Hermann Frasch method has been used quite successfully since 1895. It is most productive when developing rich deposits and provides significant savings in transportation costs and costs for further processing of ore, since it involves the release of pure substance. The installation principle is simple: ore layers containing sulfur are treated with hot water, which is supplied through a pipe. Inside it there are two more cylindrical separate vessels, which are designed to supply gas and output the finished product. Due to the low melting point, sulfur with a small amount of impurities comes to the surface under pressure.
The main consumer of sulfur is the chemical industry, which cannot exist without acids based on this element. Textile, oil refining, food, pulp, and mining production segments cannot do without this substance. The formula of sulfur makes it possible to use its compounds for the manufacture of explosives, matches, rubber, cosmetics, medicines, etc. In agriculture, the substance we are considering is part of soil fertilizers (increases the percentage of absorbed phosphorus) and poisons that are used to treat seeds from various pests.
Purified sulfur is used to produce dyes and luminous compounds. By the degree of extraction, processing and use of this element one can judge the industrial potential of the entire state. Majority the latest developments in many knowledge-intensive sectors of the economy is based on the use of sulfur and its compounds. It is difficult to assess the full potential of the use of this chemical element, which has been used by humanity since ancient times and continues to actively participate in the technological evolutionary process.
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PROPERTIES OF SULFUR Sulfuric acid is one of the most important products of the chemical industry (producing alkalis, acids, salts, mineral fertilizers, chlorine). It is obtained mainly by contact or tower method according to the following principle: B The majority of the resulting acid is used for the production of mineral fertilizers (superphosphate, ammonium sulfate). Sulfuric acid serves feedstock for the production of salts and other acids, for the synthesis of organic substances, artificial fibers, for the purification of kerosene, petroleum oils, benzene, toluene, in the manufacture of paints, etching of ferrous metals, in the hydrometallurgy of uranium and some non-ferrous metals, for the production of detergents and medicines, such as electrolyte in lead batteries and as a desiccant. Thiosulfuric acid H2S2O3 structurally similar to sulfuric acid except for the replacement of one oxygen with a sulfur atom. The most important acid derivative is sodium thiosulfate Na 2 S 2 O 3 - colorless crystals formed by boiling sodium sulfite Na 2 SO 3 with sulfur color. Thiosulfate(or hyposulfite) sodium is used in photography as a fixative.Sulfonal(CH 3 ) 2 C (SO 2 C 2 H 5 ) 2 - a white crystalline substance, odorless, slightly soluble in water, is a narcotic and is used as a sedative and hypnotic.Hydrogen sulfide H 2 S (hydrogen sulfide) - colorless gas with a sharp unpleasant smell rotten eggs. It is slightly heavier than air (density 1.189 g/dm 3 ), easily liquefies into a colorless liquid and is highly soluble in water. A solution in water is a weak acid with a pH~ 4. Liquid hydrogen sulfide is used as a solvent. The solution and gas are widely used in qualitative analysis for the separation and determination of many metals. Inhalation of small amounts of hydrogen sulfide causes headache and nausea, large amounts or continuous inhalation of hydrogen sulfide causes paralysis nervous system, heart and lungs. Paralysis occurs unexpectedly, as a result of disruption of the vital functions of the body.Sulfur monochloride S 2 Cl 2 - a fuming, amber-colored oily liquid with a pungent odor, tearing and making breathing difficult. It smokes in moist air and decomposes with water, but is soluble in carbon disulfide. Sulfur monochloride is a good solvent for sulfur, iodine, metal halides and organic compounds. The monochloride is used for the vulcanization of rubber, in the production of printing ink and insecticides. Reaction with ethylene produces a volatile liquid known as mustard gas (ClC 2 H 4 ) 2 S is a toxic compound used as a chemical warfare agent with an irritating effect.Carbon disulfide CS 2 (carbon disulfide) - pale yellow liquid, toxic and flammable. C.S. 2 obtained by synthesis from elements in electric oven. The substance is insoluble in water, has a high refractive index, high vapor pressure, low boiling point (46° C). Carbon disulfide - effective solvent fats, oils, rubber and rubber - are widely used for the extraction of oils, in the production of artificial silk, varnishes, rubber adhesives and matches, the destruction of barn weevils and clothing moths, and for soil disinfection.see also CHEMICAL ELEMENTS. LITERATURE Sulfuric Acid Manufacturer's Handbook . M., 1971Busev A.I., Simonova L.N.Analytical chemistry of sulfur . M., 1975 |
FeS + 2HCl = H 2 S + FeCl 2
An unpleasant smell of rotten eggs emanates from the test tube - this disappears hydrogen sulfide. If you pass it through water, it will partially dissolve. A weak acid is formed, a solution of which is often called hydrogen sulfide water.
Extreme care must be taken when working with hydrogen sulfide, as the gas is almost as poisonous as hydrocyanic acid HCN. It causes paralysis of the respiratory tract and death if the concentration of hydrogen sulfide in the air is 1.2-2.8 mg/l. Therefore, experiments with hydrogen sulfide should be carried out only in the open air or under draft. Fortunately, the human olfactory organs sense hydrogen sulfide already at a concentration in the air of 0.0000001 mg/l. But with prolonged inhalation of hydrogen sulfide, paralysis of the olfactory nerve occurs, and here we can no longer rely on our sense of smell.
Chemically, hydrogen sulfide is detected using wet lead reagent paper. To obtain it, we moisten filter paper with a dilute solution of lead acetate or lead nitrate, dry it and cut it into strips 1 cm wide. ( Carefully! Lead salts are poisonous!)
Hydrogen sulfide reacts with lead ions, resulting in the formation of black lead sulfide:
Pb 2+ + S 2-- = PbS↓
We use other strips of prepared lead reagent paper for experiments with natural hydrogen sulfide - let's check presence of hydrogen sulfide in spoiled food products (meat, eggs) or examine the air above cesspool and in the stable.
We recommend obtaining hydrogen sulfide for experiments using the dry method, since in this case the gas flow can be easily adjusted and shut off at the right time. For this purpose, melt about 25 g of paraffin (candle residue) in a porcelain cup and mix 15 g of sulfur-colored melt with the melt. Then remove the burner and stir the mixture until it hardens. If we stop stirring early, the sulfur particles will be unevenly distributed in the hardening paraffin. Grind the solid mass and save it for further experiments.
When it is necessary to obtain hydrogen sulfide, we heat several pieces of a mixture of paraffin and sulfur in a test tube with a gas outlet tube to a temperature above 170 °C. As the temperature rises, the gas output increases, and if the burner is removed, it stops. During the reaction, paraffin hydrogen interacts with sulfur, resulting in the formation of hydrogen sulfide, and carbon remains in the test tube, for example: To examine the color of precipitated metal sulfides, let's pass hydrogen sulfide through solutions of various metal salts. Sulfides of manganese, zinc, cobalt, nickel and iron will precipitate if an alkaline environment is created in the solution (for example, by adding ammonium hydroxide). Sulfides of lead, copper, bismuth, cadmium, antimony and tin precipitate in the hydrochloric acid solution. Let's enter our observations into a table, which will be useful for further experiments. Having made a preliminary test for detonating gas, let’s ignite the hydrogen sulfide coming out of a glass tube drawn at the end. Hydrogen sulfide burns with a pale flame with a blue halo:
2H 2 S + 3O 2 = 2H 2 O + 2SO 2
As a result of combustion, sulfur(IV) oxide is produced - “sulfur dioxide”. It is easily identified by its pungent odor and the redness of wet blue litmus paper.
If there is insufficient access to oxygen, hydrogen sulfide is oxidized only to sulfur. Activated carbon catalytically accelerates this process. This method is often used for fine purification of industrial gases, the sulfur content of which should not exceed 25 g/m3:
2H 2 S + O 2 = 2H 2 O + 2S
It is not difficult to reproduce this process. The installation diagram is shown in the figure. The main thing is to pass air and hydrogen sulfide through the activated carbon in a ratio of 1:3. The coal will release yellow sulfur.
Activated carbon can be cleaned of sulfur by washing it in carbon disulfide. In technology, a solution of ammonium sulfide (NH 4) 2 S is most often used for this gap.
H 2 O + SO 2 = SO 2 * H 2 O
It kills germs and has a whitening effect. In breweries and wineries, barrels are fumigated with sulfur. Sulfur dioxide is also used to bleach wicker baskets, wet wool, straw, cotton and silk. Blueberry stains, for example, are removed if you keep the moistened, contaminated area in the “vapor” of burning sulfur for a long time.
Let's check the bleaching effect of sulfurous acid. To do this, put various colored objects (flowers, wet pieces of fabric, damp litmus paper, etc.) into the cylinder, where pieces of sulfur were burning for some time, close the cylinder well with a glass plate and wait for a while.
Anyone who has ever studied the atomic structure of elements knows that the sulfur atom has six so-called valence electrons in its outer orbit. Therefore, sulfur can be maximally hexavalent in compounds. This oxidation state corresponds to sulfur(VI) oxide with the formula SO 3. It is a sulfuric anhydride:
H 2 O + SO 3 = H 2 SO 4
When sulfur is burned under normal conditions, sulfur(IV) oxide is always produced. And if a certain amount of sulfur(VI) oxide is formed, then most often it immediately decomposes under the influence of heat into sulfur(IV) oxide and oxygen:
2SO3 = SO2 + O2
In the production of sulfuric acid, the main problem is the conversion of SO 2 to SO 3. For this purpose, two methods are currently used: chamber(or improved - tower) And contact. Fill a large vessel (500 ml round-bottomed flask) with sulfur oxide (IV) SO2, placing burning pieces of sulfur in it for a while or supplying gas from the apparatus where it is formed. Sulfur(IV) oxide can also be prepared relatively easily by dropping concentrated sulfuric acid into a concentrated solution of sodium sulfite Na 2 SO 3 . In this case, sulfuric acid, being stronger, will displace the weak acid from its salts. 
When the flask is filled with gas, close it with a stopper with three holes. In one, as shown in the figure, we insert a glass tube bent at a right angle, connected to the side outlet of the test tube, in which nitric oxide (IV) is formed by the interaction of pieces of copper and nitric acid:
4HNO 3 + Cu = Cu(NO 3) 2 + 2H 2 O + 2NO 2
The acid concentration should be about 60% (wt). Attention! NO 2 is a strong poison! Into another hole we will insert a glass tube connected to the test tube, through which water vapor will later flow.
In the third hole we insert a short piece of tube with a Bunsen valve - a short piece of rubber hose with a slot. First, let's create a strong influx of nitric oxide into the flask.
But there is no reaction yet. The flask contains a mixture of brown NO 2 and colorless SO 2.
As soon as we pass the water vapor, a change in color will indicate that the reaction has begun. Under the influence of water vapor, nitrogen oxide(IV) oxidizes sulfur oxide(IV) to sulfur oxide(VI), which immediately, interacting with water vapor, turns into sulfuric acid:
2NO 2 + 2SO 2 = 2NO + 2SO 3
2NO + O 2 = 2NO 2
Colorless condensate will collect at the bottom of the flask, and excess gas and vapor will escape through the Bunsen valve. Let's pour the colorless liquid from the flask into a test tube, check the acidic reaction with litmus paper and detect the sulfate ions SO 4 2 - of the resulting sulfuric acid by adding a solution of barium chloride. A thick white precipitate of barium sulfate will indicate to us successful implementation experience.
By this principle, but on a much larger scale, sulfuric acid is produced in technology. Previously, reaction chambers were lined with lead, as it is resistant to sulfuric acid vapor. Modern tower installations use ceramic-based reactors. But large quantity Sulfuric acid is now produced using the contact method. Various raw materials are used in the production of sulfuric acid. Pure sulfur began to be used in the GDR only recently. In most cases, enterprises produce sulfur(IV) oxide by roasting sulfide ores. In a rotary tube kiln or multi-deck kiln, pyrite reacts with atmospheric oxygen according to the following equation:
4FeS 2 + 11O 2 = 2Fe 2 O 3 + 8SO 2
The resulting iron(III) oxide is removed from the furnace in the form of scale and further processed in iron production plants.
Crush several pieces of pyrite in a mortar and place them in a refractory glass tube, which we close with a stopper with a hole. Then use a burner to heat the tube strongly, while simultaneously passing air through it using a rubber bulb. In order for the volatile dust from the roasting gas to settle, we will take it into an empty glass vessel, and from it into a second refractory tube, which contains a catalyst heated to 400-500 °C. 
In technology, vanadium(V) oxide V2O5 or sodium vanadate NaVO3 is most often used as a catalyst, and for this purpose we will use red iron(III) oxide Fe2O3. Apply finely ground iron oxide to glass wool, which we distribute in a tube in a layer 5 cm long. Heat the tube with the catalyst until it starts to become red hot. On the catalyst, sulfur(IV) oxide reacts with atmospheric oxygen; as a result, sulfur oxide (VI) is formed
2SO2 + O2 = 2SO3
Which we recognize by its ability to form fog in moist air. Collect SO 3 in an empty flask and, shaking vigorously, mix with a small amount of water. We will obtain sulfuric acid - we will prove its presence, as in the previous method.
You can also place the pyrite and catalyst, separated by glass wool, into one of the glass tubes. You can also work in a test tube with a side outlet. Let's put pyrite at the bottom of the test tube, a layer of glass wool on it, and then glass wool with a catalyst. We introduce air from above through a tube that should fit close to the catalyst. On the side branch we will attach a tube bent at an angle, which leads into the test tube.
If there is no pyrite, then in a test tube with a side outlet we will obtain sulfur(IV) oxide from sodium sulfite or hydrosulfite and sulfuric acid, and then pass the resulting gas over the catalyst along with a stream of air or oxygen. Chromium(III) oxide can also be used as a catalyst, which should be calcined in an iron crucible and finely crushed in a mortar. For the same purpose, you can soak a clay shard with a solution of iron(II) sulfate and then strongly calcinate it. In this case, a fine powder of iron(III) oxide is formed on the clay. If there are few metal sulfides (as, for example, in the German Democratic Republic), then the starting products for the production of sulfuric acid can be anhydrite CaSO 4 and gypsum CaSO 4 * 2H 2 O. The method for producing sulfur oxide (IV) from these products was developed by Müller and Kuehne 60 years ago.
Methods for producing sulfuric acid from anhydrite will continue to be important in the future, since sulfuric acid is the most common chemical product. Installations for producing sulfuric acid from gypsum, produced in the GDR, are known and valued on the world market.
Sulfates can be decomposed using high (up to 2000 °C) temperatures. Müller found that the decomposition temperature of calcium sulfate could be reduced to 1200 °C by adding finely ground coke. First, at 900 °C, coke reduces calcium sulfate to sulfide, which in turn, at a temperature of 1200 °C, reacts with undecomposed sulfate; this produces sulfur(IV) oxide and quicklime:
CaSO 4 + 3C = CaS + 2CO 2
CaS+ 3CaSO 4 = 4CaO + 4SO 2
It will be possible to decompose calcium sulfate in laboratory conditions only if appropriate high temperature. We will work with equipment similar to that which was used for firing pyrite, only we will take a porcelain or iron tube for combustion. We close the tube with plugs wrapped in asbestos fabric for thermal insulation. Insert a capillary into the hole in the first plug, and into the second - a simple glass tube, which we connect to a washing bottle half filled with water or a fuchsin solution.
Let's prepare the reaction mixture as follows. Crush and mortar 10 g of gypsum, 5 g of kaolin (sold in a pharmacy under the name "Bolus alba") and 1.5 g of active powdered carbon. Dry the mixture by heating it for some time at 200 °C in a porcelain cup. 
After cooling (preferably in a desiccator), add the mixture to the middle of the combustion tube. At the same time, pay attention to ensure that it does not fill the entire cross-section of the tube. Then we heat the tube strongly using two burners (one from below, the second obliquely from above) and, when the tube is heated, we pass a not too strong air flow through the entire system. Within 10 minutes, due to the formation of “sulfurous acid”, the fuchsin solution in the washing bottle will become discolored. Turn off the water jet pump and stop heating.
Get high temperature we can also if we wrap the porcelain tube as tightly as possible with a 750-1000 W heating coil (see picture). We connect the ends of the spiral with thick copper wire, which we also wrap around the tube many times, and then insulate it with porcelain beads and connect it to the plug. ( Be careful when working with 220 V voltage!) Naturally, a glass torch or blowtorch can also be useful as a heating source.
The technique works with a mixture of anhydrite, coke, clay, sand and pyrite cinder Fe2O3. A worm conveyor feeds the mixture into a 70-metre rotating tube kiln where the pulverized coal is burned. The temperature at the end of the furnace, at the combustion site, is approximately 1400 °C. At this temperature, the quicklime formed during the reaction is fused with clay, sand and pyrite cinder, resulting in cement clinker. The cooled clinker is ground and mixed with a few percent of gypsum. The resulting high-quality Portland cement goes on sale. With careful implementation and control of the process, from 100 tons of anhydrite (plus clay, sand, coke and pyrite cinder) you can get about 72 tons of sulfuric acid and 62 tons of cement clinker.
Sulfuric acid can also be obtained from kieserite (magnesium sulfate MgSO 4 *H 2 O), which is supplied in significant quantities by the salt mines of the GDR.
For the experiment, we will use the same setup as for the decomposition of gypsum, but this time we will take a tube made of refractory glass. We obtain the reaction mixture by calcining 5 g of magnesium sulfate in a porcelain bowl, and 0.5 g of active carbon in an iron crucible with a lid, and then mixing them and grinding them in a mortar to a dusty state. Transfer the mixture to a porcelain boat and place it in the reaction tube.
The white mass that will be obtained at the end of the experiment in the porcelain boat consists of magnesium oxide. In technology, it is processed into Sorel cement, which is the basis for the production of xylolite. The production of derivative products such as cement clinker and xylolite, which are important for the construction industry, makes the production of sulfuric acid from local raw materials particularly economical. Processing intermediate and by-products into valuable raw materials or final products is important principle chemical industry. Mix equal parts of magnesium oxide and sawdust with a solution of magnesium chloride and apply a layer of the resulting slurry about 1 cm thick to the substrate. After 24-48 hours the mass will harden like stone. It does not burn, it can be drilled, sawed and nailed. In the construction of houses, xylolite is used as a flooring material. Wood fiber, hardened without filling the gaps with Sorel cement (magnesium cement), pressed and glued into slabs, is used as a lightweight, heat- and sound-proof building material.
