SULPHURIC ACID (H 2 SO 4 ) — the strong dibasic acid which is widely applied as a reactant in biochemical, clinicodiagnostic, sanitary and hygienic and other laboratories. In a human body and animals derivative S. to. participate in the neutralization of toxic connections happening in liver (see). Genetically caused insufficiency of the nek-ry enzymes participating in exchange of ethers C. to. in an organism, is the reason of serious hereditary diseases (see. Glikozidoza ). Nek-ry salts C. to. use in medicine as pharmaceuticals, S. sometimes concentrated to. apply as a caustic (see. Caustics ). Page to. represents considerable professional harm for the persons contacting to it in a process of manufacture of mineral fertilizers, smoke-generating and explosive substances and also in the oil, metal-working, textile, tanning industry, etc.
Anhydrous 100% sulfuric to - that represents a colorless oily liquid, edges stiffens in the form of crystalline mass at +10,37 °. At 279,6 ° (760 mm of mercury.) sulfuric to - that boils with decomposition (with release of sulfur trioxide) before education constant boiling mixture (see), the chamois containing 98,3% to - you and 1,7% of water. This mix boils at 338,8 °. Sulfuric to - that mixes up with water and trioxide are gray (see) — colorless easily mobile liquid (SO 3 ) — in any relations. With strengthening of aqueous solutions of S. to. temperature of boiling increases, reaching a maximum (338,8 °) at concentration of 98,3%.
At addition of water to S. to. heat, quantity to-rogo on 1 mol is generated to - you is proportional to number of moths of the added water. Therefore to mix S. to. with water it is necessary carefully: it is impossible to pour in water in to at all - that!
Page to. actively absorbs water vapor in this connection it is often used for drainage of gases or in exsiccators. This property C. to. the carbonization of many organic matters, especially speaks carbohydrates (see) at action on them the concentrated S. to. (in composition of carbohydrates oxygen and hydrogen are included in the same ratio, as well as into a water molecule).
Structure of a molecule C. to. corresponds to a formula
The concentrated S. to. — a vigorous oxidizer, it oxidizes HI and HBr (but not HCl) to free iodine and bromine, carbon — to carbon dioxide gas (CO2, carbon dioxide), sulfur — to SO2 sulfur dioxide. The diluted S. to. oxidizes at the expense of an ion of H+ therefore it reacts only with those metals, to-rye among activity cost (electrochemical series) to hydrogen, e.g.: Zn +> H2SO4 ZnSO4 + H2. The concentrated S. to. oxidizes at the expense of sulfur (IV). It the metals standing among activity to silver inclusive are oxidized. At interaction with low-active metals, napr, with copper, S. to. it is recovered to sulfur dioxide: Cu + 2H2SO4 —> CuSO4 + SO2 + H2O. At interaction with more active metals both SO2, and elemental sulfur can be products of recovery or hydrogen sulfide (see).
Solution of sulfur trioxide in S. to. call an oleum. It is widely applied to purification of oil products, by productions of nek-ry dyes, etc. In an oleum a part of the molecules SO3 connects to S. to., at the same time it is formed two-sulfuric, or disulphuric, to - that H2S2O7: SO3 + H2SO4 <-> H2S2O7.
During the cooling of an oleum two-sulfuric to - that is allocated in the form of colourless crystals. Salts two-sulfuric to - you — disulphates, or pyrosulphates, receive heating of hydrosulphates, e.g.: 2KHSO4 —> K2S2O7 + H2O. During the heating higher than temperature of melting pyrosulphates decay, passing into sulfates: K2S2O7 SO3 + K2SO4.
At electrolysis of 50% of solution the chamois to - you on the cathode discharges ions of H+, and on the anode — HSO 4 - , to-rye, losing the charges, connect in pairs and form peroxotwo-sulfuric, or persulphuric, to - that H2S2O8: 2HSO4 - -> H2S2O8 + 2e. A structure persulphuric to - you correspond to a formula
As well as all peroxides (see), persulphuric to - that has strong oxidizing properties. Its salts — persulphates — use for whitening, disinfection of fabrics, as oxidizers in a lab. to practice, etc.
The industry releases several grades of S. to. The most part of the made S. to. has concentration from 91 to 94% and density of 1,825 — 1,84 g/cm3.
In S.'s industry to. receive oxidation of SO2 sulfur dioxide to trioxide with the subsequent its interaction with water. The most widespread way of receiving sulfur dioxide — roasting of iron pyrite: 4FeS2 + 11O2 -> 2Fe2O3 + 8SO2. The iron oxide (III) which is formed during the roasting of pyrite, a so-called roasted pyrite, can be used for receiving iron. Sulfur dioxide is received also, burning sulfur. In this case gas, free from harmful impurity and not needing cleaning is formed. A large amount of sulfur dioxide is received from so-called off-gases of nonferrous metallurgy, furnace gases which are formed in significant amounts at combustion of the black coal containing a lot of sulfur.
A contact method of receiving S. to. consists in oxygenation to sulfur dioxide at contact of these gases with the catalyst (most often vanadic V2O5 anhydride). Before implementation of a contact method widely used a nitrose method of receiving by a chamois to - you: SO2 + NO2 + H20 -> H2SO4 + NO; 2NO + O2 —> 2NO2 etc.
The most usable qualitative test on S. to. (on SO sulfate ion 4 2- ) education insoluble even in to-takh a white deposit of BaSO4 is at reactions with soluble salts of barium. Quantitatively S. to. determine by a neutralization test (see. Neutralizations method ), method polyarografiya (see), etc.
In metabolism at the person and animals ethers C. to. (organic sulfates) play an essential role, among them ethers C. are especially widely presented to. and glikozaminoglikan (see. Chondroitinsulphuric acids ) both ethers since and steroids. In cells, including and microbic, cholinesulphate and sulfate ascorbic to - you meet, and sulfoethers of phenols and other organic sulfates are found among the catabolits allocated with urine.
Hydrolysis of ethers C. to. in an organism catalyze numerous hydrolases of ethers a chamois to - you are (KFZ.1.6). Their value for a normal metabolism was shown during the studying of genetically caused disease — a mukopolisakharidoza of the III type (see. Sanfilippo disease ), to-ry it is characterized by excess allocation of a geparansulfat that is explained with obvious inborn insufficiency of enzyme of geparansulfat-sulphatase (see. Sulphatases ).
Sulphuric acid as professional harm
S. to. possesses the irritating and cauterizing action on mucous membranes of airways and lungs. S.'s aerosol to. sulfur dioxide possesses more expressed toxic action, than.
At working sulphuric acid workshops at non-compliance with safety regulationss and occupational health note diseases of a mucous membrane of an oral cavity, atrophic changes of a mucous membrane of upper respiratory tracts, bronchitis (see), pneumoscleroses (see), sometimes bronchial asthma (see). Observe also destruction of teeth, gastritises (see), peptic ulcer (see). There are c given about functional changes. N of page, diseases of a liver, cardiovascular system, etc. at hron. S.'s intoxications to.
At hit on S.'s skin to. causes the heavy burns (see) which are shown strong burning; if it to wash away water, S.'s action at once to. it can be limited to erubescence, otherwise to - that gets into depth of fabrics, the scab, and then a deep ulcer is formed, healing a cut comes to an end with formation of the flat hems or growths supporting edges of an ulcer. At the workers who are constantly dealing with the diluted S. to. (concentration within 3%), noted a loosening and an ulceration of skin on hands, hron. pustules about nails, paronychias (see), dermatitis (see). Treatment at hron. S.'s intoxications to. symptomatic.
Acute poisoning of S. to. it is shown by sharp irritation of upper respiratory tracts, difficulty of breath, a laryngospasm, burning in eyes; at S.'s concentration to. in air of 5 mg! m3 noted emergence of a bloody phlegm, vomiting also above (sometimes with impurity of blood), heavy bronchitis developed later and pneumonia (see). Usually in air along with S.'s aerosol to. a large amount of sulfur dioxide therefore intoxication caused by S. to contains., it is aggravated with action on an organism of this strong poison.
First aid and emergency treatment at acute poisoning with sulphuric acid
the Victim should be brought to fresh air immediately. At acute irritation of a mucous membrane of respiratory tracts inhalations of soda solution, careful steam inhalation of alcohol, ether, chloroform, and also 10% of solution of menthol in chloroform, warm drink are necessary (milk with soda and borzhomy). At cough — codeine, dionine, mustard plasters. Symptomatic further treatment.
At strong S.'s hit to. on skin or mucous membranes it is necessary to wash out immediately struck surface as it is possible a large amount of cold running water within 10 — 15 min. if washing is made with lateness, it shall proceed not less than 40 — 60 min. It is necessary to stop washing after total disappearance of a smell of S. to. from the struck surface. Treatment — see. Burns, treatment .
Maximum allowable concentration of S. to. in air of a working zone of 1 mg/m3.
Occupational health by production of sulphuric acid
Basic processes by S.'s production to. preparation and transportation of floatation iron pyrite, the dosed giving it in the furnace, roasting, cooling and removal of a roasted pyrite, purification of kiln gas of dust, arsenic, selenium in electric precipitators and coppers utilizers, delivery of gas to processing, oxidation of sulfur dioxide in sulfur trioxide (S03 sulphuric anhydride) with the subsequent absorption of sulphuric anhydride are water or weak S. to.
Operations of preparation and transportation of floatation pyrite are followed by release of dust, especially at low humidity of raw materials, and also at absence or insufficiency of pylekupiruyushchy shelters and pyleudalyayushchy devices on nodes of an overload. Combustion of floatation pyrite depending on a type of the furnace happens at a temperature from 540 — 630 ° to 1000 — 1100 °. The heating of walls of the furnace, ogarkoudalyayushchy devices, coppers utilizers happening at the same time, etc. creates unfavorable conditions in oven departments of workshops, leads to temperature increase of air on platforms of oven departments and to irregularity of air temperatures at the different height of production rooms (see. Hot workshops ). Constant jobs at operation of modern furnaces are available only for ogarkoudalyayushchy devices and coppers utilizers therefore action of high temperature on workers at such furnaces has smaller value, than at service of hearth fungal furnaces of old designs. Besides, also hard physical work in the conditions of high temperature is excluded. Removal of a candle end from the furnace mechanically can lead to air pollution of the production room dust of a candle end, edges becomes especially toxic, adsorbing on itself dioxide and sulfur trioxide. Dust of a candle end after unloading from electric precipitators and thin purification of roaster gas is especially toxic (diameter of dust particles to 50 microns). Existence arsenic (see) in iron pyrite can become the reason of emergence in air of oven department of hydrogen arsenide.
Intake of sulfur dioxide in air of oven department is noted at disturbance of operation of furnaces and tightness of the equipment, and also during the unloading and transportation of a candle end. Emergence in air of an aerosol of S. to. perhaps as a result of oxidation of SO2 in SO3 during removal of a candle end, content of sulfur trioxide in kiln gas (5 — 7%) and receipts of an aerosol of S. to. with an induced air (because of pollution of the atmosphere of the factory platform).
At a tower way of production of S. to. (a nitrose method of receiving to - you) in premises of pumping and refrigerating compartments hit in air of nitrogen oxides and S.'s aerosol is possible to. Their concentration in air depends on degree of tightness of pumps, pipelines, etc.
Transition to the refrigerators which are completely closed irrigating and spiralnshche led to considerable decrease in receipt in air of pumping and refrigerating rooms of toxicants. S.'s production to. in the contact way more absolutely from the point of view of occupational health: at it there are no sources of release of nitrogen oxides and the maximum sealing of production is possible.
Production of the equipment and details for sulphuric acid production from steel and polymeric materials allowed to eliminate the danger of lead intoxications existing earlier during the works with lead pipes (soldering, change of their form), etc. Sulphuric acid workshops release into the surrounding atmosphere sulfur dioxide, S.'s aerosol to., and tower systems — nitrogen oxides. Concentration of these toxicants in air are subject to the considerable fluctuations depending on a number of factors: scheme and maintaining tekhnol. process, height of exhaust pipes, extent of cleaning of emissions, direction of wind, air humidity.
In S.'s production to. there is a considerable danger of chemical burns sulfuric and nitric to-tami (during the pouring to - you, its transportation, at repair of towers, refrigerators, fittings, etc.) therefore it is extremely important to fulfill strictly special requirements for control of observance of the accident prevention.
Content of sulfur dioxide and S.'s aerosol to. in air of workshops, as a rule, does not exceed maximum allowable concentration, but sometimes owing to temporary malfunctions or disturbances in tekhnol. process raises a little that can cause irritation of mucous membranes of upper respiratory tracts. Health of workers is influenced also by dust and unfavorable weather conditions in nek-ry workplaces.
Are among recreational actions on sulphuric acid productions: full automation, mechanization of pouring, packaging and movement in workshops C. to., use of furnaces with a fluidized bed and furnaces of powdered roasting with mechanization of processes of loading of pyrite and removal of the cooled candle end (use of shnekogasi-tel, refrigerating and transport drums and pipes, and also methods of hydroremoval or vibrotransportation), automation of contact and tower systems, a continuity of process and tightness of the equipment, utilization of off-gases, correctly organized positive-pressure ventilation in workshops (see. Ventilation ).
In workshops installation of hydrants for bystry washing off to - you, got on skin or on clothes working is obligatory. Spilled to - that (melange) is neutralized the powder ML containing soda ash (60%), liquid glass (30%), sulphanole (10%) or other neutralized structures.
Carry industrial to necessary individual protection equipment gas masks (see), respirators (see), special clothes (see. Clothes special ), rubber footwear (see. Footwear, production ); rubber gloves, points (see. Points, protective ). Preliminary and periodic medical examinations are important (see. Medical examination ), especially surveys of the otorhinolaryngologist and stomatologist. Working in contact with S. to. receive special food.
At initial forms hron. S.'s intoxications to. the diseased can be temporarily transferred to other work which is not connected with the prof. vrednost (see. Professional harm ). At emergence of permanent disturbances of the state of health as a result hron. or an acute otravle-leniye of S. to. the diseased is discharged of work with S. to. also is subject to rational employment.
Sulphuric acid in the medicolegal relation
S.'s Poisonings to. in life most often have accidental character or meet in suicide attempts. S.'s hit to. on the person causes the disfiguring, long not beginning to live hems.
A lethal dose at hit by the concentrated S. to. in a stomach makes apprx. 5 ml. In this case at court. - a medical research of a corpse on skin around a mouth note brownish and gray-yellow burns. Mucous membrane of lips, mouth, throat, gullet dry, grayish-brown color. The wall of a stomach is thickened, gray-black color (owing to formation of decomposition products of hemoglobin), are possible its perforation. In an upper part of a small bowel the centers of a dry whitish-gray necrosis. In cases of bystry approach of death or S.'s removal to. at treatment morfol. changes are expressed to hl. obr. in a stomach. At approach of death in several days after S.'s reception to. note increase in a liver, kidneys, sites of bronchial pneumonia, flabbiness and dimness of a cardiac muscle, hypostasis of a brain. The mucous membrane of a gullet, a stomach, intestines of a nekroti-zirovan, with hemorrhages, are visible fibrinferments of blood vessels; the liver, a myocardium, cells of a brain dystrophic are changed, kidneys of a nekrotizirovana, at perforations note the phenomena of peritonitis.
At court. - a chemical research C. to. isolate from biol. material by means of dialysis. In dialyzate C. to. find qualitative test with solution of salt of barium. For free S.'s definition to. the studied dialyzate is overtaken in the presence of copper shaving. The emitted sulphurous anhydride is collected in the receiver with water solution of iodine in potassium iodide. Page to. find by means of reaction with salt of barium by training of an insoluble residue of fixed white. Quantitative definition of S. to. carry out by method of neutralization (see. Neutralizations method ).
Bibliography: Arkhipov A. S. and B about fluo in A. N. Pollution by toxicants of the air environment in production of sulphuric acid, the Gigabyte. and dignity., No. 9, page 12, 1962; Arkhipov A. S. and d river. About toxicity of dust in pylegazovy mixes (on the example of production of sulphuric acid), the Gigabyte. work and the prof. having got sick., L'v 5, page 5, 1981; Harmful substances in the industry, under the editorship of N. V. Lazarev and N. D. Ga-daskina, t. 3, page 67, L., 1977; Metz l of e r D. Biokhimiya, the lane with English, t. 2, page 139, M., 1980; The Guide to forensic medical examination of poisonings, under the editorship of R. V. Berezhny, etc., page 60, M., 1980; C in y l e in and E. A. and d river. About occupational diseases of a respiratory organs in sulfate productions, the Gigabyte. work and the prof. having got sick., No. 10, page 35, 1961; Sh in and y to about in and M. D. Toxicological chemistry, page 355, M., 1975; N about at And. Century of a. Trudinger P. A. The biochemistry of inorganic compounds of sulfur, L. — N. Y., 1970.
H. G. Budkovskaya; A. H. It is fighting, 3. I. Israelson (gigabyte.), E. 3. Bronstein (court.).