GLYCEROL, propanetriol (1, 2, 3), α, β, γ-trioxypropane, trihydric alcohol CH 2 OH CHOH CH 2 OH. Glycerol is extremely common in nature, where it occurs as esters - glycerides. In animal organisms, glycerol is also found in the form of lecithins - esters of glycerophosphoric acid. In addition, glycerin is a normal component of wine, as it is formed during the fermentation of grape sugar.
Pure glycerin is a syrupy, thick liquid of sweet taste, odorless, neutral reaction, D 4 20 = 1.2604. With prolonged strong cooling, it solidifies into crystals of the rhombic system, melting at 17-20 °. Glycerin is very hygroscopic. It is miscible with water and alcohol in all respects and dissolves inorganic salts; in ether and chloroform insoluble. At normal pressure it boils at 290° with little decomposition, but under reduced pressure and with water vapor it is distilled without decomposing; boiling point at 50 mm 205°, at 0.05 mm 115-116°. Anhydrous glycerin sublimates already at 100-150°.
When heated rapidly, it loses water and forms heavy fumes with the smell of acrolein, burning with a blue flame; with careful oxidation, glycerol gives aldehyde - glycerose CH 2 OH · CHOH · SON; upon further oxidation (by the action of HNO 3) it gives acids: glyceric CH 2 OH CHOH COOH, oxalic COOH COOH, glycolic CH 2 OH COOH and glyoxylic COOH COOH. Glycerin easily reacts with inorganic acids; so, with phosphoric acid glycerol forms glycerinophosphorus acid CH 2 OH·CH(OH)·CH 2 O·RO(OH) 2 ; heated with borax, glycerin gives glycerinoborate, which is used in medicine as an antiseptic. Under the action of metals, glycerin gives glycerates, b. including a crystalline compound. The action of hydrohalic acids or other halogen compounds on glycerol produces mono-, di- and trihalohydrins glycerin; the action of halohydrins of alcohols on glycerates produces mixed esters of glycerol - liquids resembling ethers of monohydric alcohols in properties. Like glycols, glycerol, losing water, gives an anhydride - glycide
Glycerol homologues, trihydric alcohols, so-called. glycerols, little studied; some are obtained artificially and are thick non-crystallizing liquids of sweet taste, highly soluble in water and alcohol.
Synthetic methods for obtaining glycerol are of no technical importance. In the technique, glycerin is obtained by splitting fats (saponification). The breakdown of fat is the decomposition of glyceride into free fatty acid and glycerin according to the equation:
There are many ways to split; the most important are: 1) autoclave method, 2) Twitchell method, 3) Krebitz method and 4) enzymatic. The Twitchell method is the most widely used, and then the autoclave method. In the USSR, in addition to the autoclave method, another method is used, which is some modification of the Twitchell method - splitting by means of "contact".
1. Splitting in autoclaves is carried out as follows: purified fat with water and 1-2% lime is heated in an autoclave (up to 150-180 °), equipped with a tube reaching almost to the bottom (Fig. 1), at 8-12 atm pressure.
With this treatment, fats break down, forming calcium salts of fatty acids (soap) and glycerol in aqueous solution - glycerin water- according to the equation:
The splitting operation lasts 6-8 hours, after which the reaction mixture is somewhat cooled and released from the autoclave. Due to the pressure remaining in the autoclave, the liquid rises through the tube, and first comes glycerin water, which is collected in a separate receiver and left to settle. Settling is very slow, especially if the fat taken for saponification was poorly purified. When impurities float to the surface, they are separated, and the solution is subjected to further processing to extract glycerol from it. Recently, magnesia or superheated steam in the presence of zinc oxide and zinc dust has been used instead of lime. For 2500 kg of fat, take 15 kg of zinc oxide, 7 kg of zinc dust and 500 liters of water. These changes make it possible to conduct splitting at a lower pressure (6-7 atm) and obtain glycerol with less loss. In Russia before the war of 1914-18. the splitting of fats was carried out almost exclusively in soap and stearin factories. True, in some places (in Moscow, Lodz, Warsaw) there were fat-splitting plants that produced glycerin for the textile industry, but their production was insignificant. In Western Europe, the fat-splitting business is very widespread: in addition to obtaining glycerin at soap and stearin factories as a by-product, there are a large number of special fat-splitting plants that extract glycerin from fats.
2. The Twitchell method (acid) is a modification of the old method of splitting fats with sulfuric acid, in which sulfuric acid plays the role of an emulsifier and at the same time enters into chemical interaction with glycerides of unsaturated acids and glycerin, giving sulfonic acids, which decompose when boiled back to sulfuric acid, fatty acids and glycerol. The Twitchell method is based on the emulsifying effect of the reagent proposed by him (a mixture of fatty aromatic sulfonic acids) - Twitchell's reagent. In the state of emulsion, the fat presents a huge surface to the splitting action of water, as a result of which the reaction is so accelerated that it becomes possible to carry out splitting without using an autoclave. The splitter - Petrov's "contact", which has now replaced Twitchell's reagent (and others like it), is a 40% aqueous solution of sulfonic acids of the cyclic series of the general formula: C n H 2n–9 SO 3 H and C n H 2 n–11 SO 3 H. Work on this method is carried out as follows. arr.: the fat is placed in a boiler equipped with a stirrer, heated to 50 ° and with strong shaking, 1.5% sulfuric acid 60 ° V is added to it (to destroy protein and other impurities). Then the mixture is diluted with water (20%), a decomposer (0.5-1.25%) is added and boiled. After 24 hours, usually 85% of the fat is broken down. The mass is allowed to settle, the glycerin water is separated and subjected to further processing to isolate glycerol. The autoclave method gives good exits and product quality, but its equipment is expensive. The Twitchel installation is cheaper, but wears out more quickly; the yields are smaller and the product is of inferior quality.
3. The Krebitz method (alkaline), used in soap making, is also based on increasing the reactive surface of the fat. This is achieved by vigorously stirring the fat with milk of lime (0.5-3% alkali is enough to split the fat) while simultaneously passing a jet of steam into the mixture. Then the mixture is left for 12 hours. During this time, saponification ends. It turns out lime soap in the form of a porous brittle mass, and glycerin goes into solution. Since a significant proportion of glycerin is captured by soap, the soap is crushed, washed hot water, and the wash water is added to the main solution of glycerol.
4. The breakdown of fats enzymatically occurs through the use of special (lipolytic) enzymes found in the seeds of some plants, mainly. arr. castor beans (Ricinus communis). For this purpose, after removing the oil, crushed castor bean seeds are triturated with weak sulfuric acid until an emulsion is formed (inactive parts are separated by centrifugation). This emulsion ("ferment milk") is used directly for splitting, which at a temperature of 30-40 ° ends in 2-3 days: fatty acids are separated, and 40-50% glycerol remains in the solution. At first, great hopes were placed on the enzymatic method, but in practice there were many difficulties, due to which, despite the improvements made by the works of Wilstatter, Goyer, Nicloux and others, it was not widely used. During the war of 1914-18, due to the need for large quantities of glycerin and the lack of fats, attention was paid in many countries to the possibility of recycling soap production waste. Solutions obtained after salting out soap, the so-called. soap liquors containing 5-10% glycerol were simply poured out by many factories; a lot of glycerin also remained in the so-called. adhesive soaps. So. arr. a significant part of the glycerin extracted from fats was lost unproductively. Therefore, in Germany in 1914, a ban on the production of glutinous soaps followed, and soap liquors began to be bought up by large factories to extract glycerin from them.
Over the past 10 years, much attention has been paid to the method of obtaining glycerol by fermentation. Pasteur also found that during alcoholic fermentation of sugar, not a large number of glycerin (about 3%). Konstein (Konnstein) and Ludeke (Ludecke) by adding to the fermenting mixture of sodium sulfite Na 2 SO 3 increased the yield of glycerol to 36.7%. During the war, this method was used in America (Porto Rico) and in Western Europe to obtain glycerin from molasses (waste from sugar beet production), and with it more than 1 million kg of glycerin was extracted. In Germany, glycerin obtained by fermentation is called protol (Protol) or fermentol (Fermentol).
Glycerin solutions obtained in one way or another are highly diluted and contaminated; to isolate glycerin from them, they are treated with various chemical reagents (calcium is removed with oxalic acid, magnesium with lime water, zinc with barium carbonate), and then evaporated in open vessels (Fig. 2) or in vacuum apparatuses of various designs.
Of particular difficulty is the purification and evaporation of soap liquors, since they are heavily contaminated with colloidal solutions of soap and mineral salts. According to the Domier C ° method, 0.5% lime is first added to the solution, and then it is evaporated until the salts begin to crystallize. The alkalis formed in this process lather the resinous substances in the solution, and the soap collects in the form of foam on the surface, entraining the rest of the impurities with it. AT the latest ways after neutralization, soap liquors are treated with aluminum or iron sulfate, filtered to separate settled impurities, and the slightly acidic filtrate is neutralized with soda mixed with paper pulp. The latter adsorbs the remnants of contaminants, after which the solutions are filtered and evaporated in special vacuum apparatus equipped with a reservoir for collecting precipitated salts. By evaporation of glycerin water, crude glycerin is obtained, which has a dark color and contains a significant amount of inorganic salts. This technical grade glycerin is either sold directly or further refined. For this purpose, a solution of glycerin is passed through a series of filters filled with calcined bone charcoal, so that the glycerin passes first through the used charcoal, and finally through fresh charcoal (countercurrent principle). The whole battery of filters is heated up to 80° by steam passed between the walls of the filter lining. The method gives good results, but its application is limited due to the high cost, slowness of filtration and the need for periodic regeneration of bone charcoal. An easier method is heating with bleaching powders (animal charcoal, carborafine, etc.), but it gives worse results.
To obtain pure glycerol, one has to resort to distillation (the method of obtaining pure glycerol by crystallization is currently left as unprofitable in Western Europe). Distillation is carried out in copper or iron cauldrons using superheated steam and vacuum. This speeds up the process, saves fuel and improves the quality of the resulting products, since lowering the distillation temperature prevents the possibility of decomposition of glycerin from overheating, and glycerin is obtained almost anhydrous. Distillation plants of different companies differ from each other in details, but in general they are designed according to the same principle. According to Ruymbeke and Jollins (Fig. 3), the steam, before entering the distillation cube A, passes through the coil (c) located in the heating cube E, where steam is admitted from the steam boiler through the pipe (f).
Due to the wide diameter of the coil (c), the steam passing through it (from the pipe d with a smaller diameter) expands, cooling at the same time, but is immediately heated again to its original temperature by the steam surrounding the coil. Expanded and heated steam enters the distillation cube A, up to 1/3 of the volume filled with crude glycerin; through a perforated pipe (b) steam is introduced into the distilled mass; the distillate is condensed in condenser B, from where it passes into vessel C, where it is collected. This technique simultaneously avoids both the cooling of the steam during its expansion in the distillation cube itself, and the decomposition of glycerin due to overheating, which took place in previous installations, where the steam first passed through a superheater. In FIG. 4 shows a modern installation of distillation apparatuses from Feld and Forstman.
Crude glycerin is loaded into kettle B so that it fills no more than 1/3 of its volume. Let steam into superheater U to heat the serpentine and at the same time into pot still B to raise the temperature of the glycerin. Steam is then admitted into the serpentine and, when it expands and heats up, it is passed into the distillation cube. Vigorous distillation begins immediately. The glycerin is carried away with the steam and condenses in the condenser system G, while the vapor is carried further into a special water condenser K and is also condensed. The work takes place in a vacuum. From the point of view of fuel economy, the Marx & Rawolle multiplication plant in New York is interesting, where the same jet of steam is extremely expediently utilized.
Glycerin is commercially available in various purity grades. The following varieties are distinguished: 1) twice distilled, chemically pure glycerin- Glycerinum purissimum albissimum, 30° or 28° Ve; 2) G. Album - too pure product, but once distilled; 3) dynamite glycerine- distilled and the highest degree pure product; slightly yellow, 28° B; specific gravity 1.261-1.263; 4) refined glycerin- not subjected to distillation, but only clarified, there are two varieties: white and yellow, 28 ° and 30 ° V; 5) crude, unrefined glycerin (technical): a) from soap lye and b) saponification(obtained by autoclave).
Glycerin is widely used in many branches of industry and technology. Large quantities of glycerin are used to make nitroglycerin and dynamite. Glycerin is used to protect various products from drying out: in the soap industry, in the tanning of leather, in the tobacco industry, etc. Its preservative properties make it possible to use it in the canning industry and to preserve anatomical and botanical preparations. Glycerin is also used as a lubricant for the lubrication of various mechanisms: clocks, pumps, refrigeration and ice machines. It is then applied to hydraulic presses and railway brakes. In the textile industry, it is used in calico printing for various finishes. Significant amounts of glycerin are used for printing masses, glycerin gelatin, copy ink, parchment and binding paper; in pharmaceutical industry- for various cosmetics and medicines(glucosal, glycerophosphates); in the paint industry - for the preparation of some dyes (alizarin blue, benzanthrone dyes). The worst grades of glycerin are used for shoe waxes. The residue after distillation of glycerol is used as an insulating material in the manufacture of electrical cables.
The annual world production of glycerin exceeds 72,000 tons. In Russia in 1912 it reached 5,000 tons, with 30-40% of the total production exported to Germany, France and America. Interrupted by the war and the conditions of the blockade, the export of glycerin from the USSR resumed in 1926/27. The total production of glycerin in the USSR, according to the data of 1925/26, was 3.5 thousand tons, and in 1926/27 in the 3rd quarter alone it reached 896.5 tons for technical glycerin and for chemical and dynamite glycerin 487.1 tons
Glycerol(chem., Glyc é rine fr., glycerin German and English) C 2 H 3 O 2 \u003d C 2 H 5 (OH) 2 - discovered in 1779 by Scheele, who noticed that when boiling olive oil with glen, in addition to the lead plaster (lead soap, i.e., the lead salt of fatty acids), a sweet, syrupy liquid is also obtained; in the same way, Scheele then obtained glycerin from oils: almond, linseed, rapeseed, cow and pork fat. The almost correct percentage (elementary) composition of Glycerin is given by Chevrel (1813), who proved that both the vegetable oils mentioned above and animal fats (see) can be considered chemically acid esters Glycerin, and thus correctly identified the alcoholic nature of Glycerin (see and). This view was finally confirmed by experiments (1853 and 1854), which artificially obtained fats by heating Glycerin with fatty acids; esters with one, two and three equivalents of the taken acid (depending on the conditions of the experiment) established the triatomicity of Glycerol (see below). In addition to fats, glycerin is always (in a free state) in wine (from 0.978% to 1.667% -), since it is formed during the alcoholic fermentation of sugar (up to 3% of sugar taken - Pasteur) and in a very small amount in vodka ( Morin). Synthetically, Glycerin was obtained by Würz from tribromohydrin Glycerin, in turn formed by the action of bromine on allyl iodide (see); Friedel and Silva - from trichlorohydrin obtained by the interaction of iodine chloride with propylene chloride, and since the latter was prepared by them by adding chlorine to propylene obtained from isopropyl alcohol, Glycerin can be synthesized based on the elements. Glycerin is obtained, finally, by the oxidation of allyl alcohol with a manganese-potassium salt. (E. Wagner - see). For technical extraction of Glycerin, see acc. article. Pure Glycerin is a thick, syrupy liquid with a sweet taste; it does not solidify during short-term cooling to -40 ° C, although it noticeably thickens; with prolonged cooling to 0 °, under certain conditions that are not fully elucidated, pure glycerin can, however, crystallize, forming rhombic crystals that spread in air, melting point cat. + 17°С (according to Genninger), + 20°С (according to Nietzsche) and + 22.6°С (according to Kraut). Oud. weight Glycerin - d 15/4 = 1.2637; (Mendeleev, 1861, see below), d 20/4 = 1.2590 (Brühl et al.); Glycerin is optically inactive; refractive index for a line ß hydrogen = 1.478 (Brühl); = 0.612 (Winckelmann). Glycerin is miscible in all respects with water and alcohol, but almost insoluble in sulfuric ether and chloroform. Glycerin is able to dissolve in a significant amount, calcium, strontium and barium oxides, potassium sulfate, sodium sulfate, copper sulfate and many other salts; in its presence, ferric chloride is not precipitated by caustic alkali. Under reduced pressure, or with water vapor, Glycerin distills unchanged; under ordinary pressure, it boils at + 20 ° C (Mendeleev); presence mineral salts, especially substances that can take away water, such as, for example, acidic sulfuric potassium salt, phosphoric anhydride - causes decomposition of glycerin, accompanied by the loss of water and the formation of acrolein -
C 3 H 8 O 3 - 2H 2 O \u003d C 3 H 4 O
- (Redtenbacher, Gayter and Cartmel), always observed when natural fats are heated (burnt fat owes its smell to acrolein), which easily distinguishes the latter from mineral oils. With careful oxidation (the action of atmospheric oxygen in the presence of platinum black - Grimaud, or bromine vapor on lead glycerate - Fischer and Tafel) Glycerin gives aldehyde - glycerose CH 2 (OH).CH (OH).SON (see and) and together with her dihydroxyacetone CH 2 (OH).CO.CH 2 (OH) (Fischer). obtained by the action nitric acid s on Glycerin, but besides it, as products of further oxidation, the following are formed: glyceric- CH 2 (OH).CH (OH).COOH, oxalic - COOH.COOH, formic - H.COOH, glycolic - CH 2 (OH).COOH and glyoxylic - CHO.COOH acids; at the same time, the appearance of hydrocyanic acid (Przhibytek) is observed, the formation of which explains the production, in addition to the substances mentioned, also grape (Heinz) and mesotartaric acids (Przhibytek, see):
CH 2 (OH).CH(OH).SON + HCN \u003d CH 2 (OH).CH(OH).CH(OH).CN
CH 2 (OH). CH (OH). CH (OH). CH + 2H 2 O + O 2 \u003d COOH. CH (OH). CH (OH). COOH + NH 3.
When oxidized with a manganese-potassium salt, Glycerin can be obtained tartaric acid. COOH.CH(OH).COOH (Zadtler, Przybytek, and Bizzari), but under the action of an excess of an oxidizing agent, the reaction proceeds according to the equation:
C 3 H 3 O 3 + C 2 H 2 O 4 (oxalic acid) + CO 2 + 3H 2 O
(Wanklin and Fox - a method for the quantitative determination of Glycerin). When heated with solid caustic potassium, Glycerin gives acrylic acid (Redtenbacher), when melted with it, its decomposition products: formic and acetic acids (Dumas and Stas). Like wine alcohol, Glycerin easily reacts with inorganic acids; the resulting products in terms of chemical nature fully correspond to those obtained under the same conditions from ethyl alcohol; yes, gives glycerin-sulfur acid - CH 2 (OH). CH (OH). CH 2 .O.SO 2 .OH (obtained by Peluz by dissolving one part of Glycerin in 2 parts of sulfuric acid), a complete analog of sulphuric acid. CH 3 CH 2 O.SO 2 .OH; besides it, two more acids are possible for Glycerin, namely: CH 2 (OH).CH (OSO 2 OH).CH 2 (OSO 2 OH) and CH 2 (OSO 2 OH).CH (OSO 2 OH).CH 2 (OSO 2 OH); both obtained by Clesson: the latter under the action of the first sulfuric acid chloride. - SO 2 (OH) Cl on Glycerin, and the first - when acting on glycerin trisulfur sour water. With phosphoric acid. Glycerin forms glycerinophosphorus sour - CH 2 (OH). CH (OH). CH 2 O. PO (OH) 2, of which esters are especially remarkable lecithins - substances found in the brain, in egg yolk, in spermatozoa, in yeast, spores, etc., and which, when heated with barite water, decompose into (oleic, palmitic, stearic, etc.), glycerinophosphoric acid and neurin (see) and therefore, they probably represent the esters of the glycerin-phosphorus salt of neurin of composition - CH 2 (OR "). CH (OR"). CH 2 O.PO (OH) [O.N (CH 3) 3 .C 2 H 4 (OH) ], where R" is a fatty acid residue. Heated with borax, Glycerin gives a derivative of boric glyceric acid. (glycerinoborate), having an acidic reaction and having a fairly extensive use in pharmacy as an antiseptic. (esters of nitric acid - see; esters of fatty and other organic acids, see Fats and below on the structure of Glycerin). For Glycerin, numerous are known, which are obtained for the most part either by the action of hydrohalic acids or phosphorus halides on Glycerin; phosphorus iodide gives, however, not triiodhydrin, as one might expect, but a substance containing less than two iodine atoms - namely allyl iodide -
CH 2: CH.CH 2 J \u003d CH 2 J.CHJ.CH 2 J. - J 2 \u003d C 3 H 2 J
(Bertelo and Lucas), a liquid boiling at 100 - 102 °, forming under the action hydrogen iodide secondary propyl iodide:
CH 2: CH.CHJ + 2HJ = CH 2 .CHJ. CH 3 + J 2,
and under the action of bromine - tribromohydrin Glycerol
CH 2: CH.CH 2 J + 2Br 2 \u003d CH 2 Br.CHBr.CH 2 Br + JBr
(Wurtz). Like ordinary alcohol, which forms, Glycerin gives under the action of alkali metals or oxides of alkaline earth and heavy metals - glycerates, mostly crystalline, easily changeable compounds; monosodium glycerate C 3 H 7 O 2 (ONa), decomposing upon heating, forms CH 3 .CH (OH) in a significant amount. CH 2 (OH) (Belogubek, Lebish and Loos), simultaneously with which methyl, ethyl and normal propyl alcohols, hexylene, etc. (Fernbach). lead glycerate, mentioned above, is obtained by precipitating with ordinary alcohol a solution of lead oxide in boiling water. Glycerin whole line mixed esters Glycerin; these are all liquids boiling below Glycerin and resembling mixed esters of monohydric alcohols in properties. Like glycols, Glycerin is capable, by releasing water from one particle, to give ester-like anhydrides, of which glycide is known - CH 2 . CH.CH 2 (CH) - (allyl alcohol oxide -), obtained for the first time by Gegerfeld; Ganriot obtained glycide by the action of anhydrous barite on a solution of monochlorohydrin Glycerin in anhydrous ether; it is a mobile liquid, boiling at 157° - 160°, miscible in all respects with water, alcohol and ether, and quickly combined with water, forming back Glycerin, and at not enough water, - quite similar to polyethylene alcohols (see Glycols). glycide is (see). Glycerin dissolved in water, in the presence of chalk and casein, is able to ferment, forming ethyl alcohol, butyric acid and some other products (Bertelo, Bechamp). Under the influence of fermentation caused by the development of Bacilus subtilis (Cohn), it forms mainly ethyl alcohol (Fitz), and under the influence of Butyl-Bacilus, it gives normal (see) - CH 3 .CH 2 .CH 2 .CH 2 (OH) ( Fitz) and - CH 2 (OH). CH 2 .CH 2 (OH) (Freund, see Glycols). Structure Glycerin, as a two-primary secondary alcohol - C 3 H 8 O 3 \u003d CH 2 (OH). CH (OH). CH 2 (OH) is derived on the basis of the following considerations. It was mentioned above that Chevreul was the first to point out the chemical proximity of fats and esters of organic acids. “Indeed,” says Berthelot (1854), “in fats, neutral compounds, the properties of acids are massaged in exactly the same way as in esters, which are formed, with the release of water elements, during the interaction of acids with alcohols; both classes of compounds regenerate acids and alcohols, fixing back the elements of water, or under the influence of alkalis, or acids, or water ( the reaction is going on quickly at + 220 ° C and slowly at ordinary temp.), with the only difference being that esters and alcohols are obtained from esters, and glycerin and glycerol are obtained from fats; under the action of ammonia, both fats and esters produce acid amides. Even more convincingly, the chemical equivalence of alcohol (ordinary) and Glycerin is proved by the fact that by heating (complex) esters of alcohol with Glycerin, one can, under certain conditions, obtain fats (hence, displace alcohol from the taken ether), conversely, by heating fats with alcohol, one can obtain ether alcohol (and isolate Glycerol in a free state), and this, in addition to any hypotheses, convinces of a complete analogy in the constitution of fats and esters. But if, in terms of chemical nature, Glycerin approaches alcohol, then, on the other hand, the formulas of the compounds it forms with acids and the existence of several neutral products for Glycerin and the taken acid establish a profound difference between it and alcohol: the latter gives with acids only one series of neutral compounds, and for Glycerin, three different series are known, of which only one of the formulas corresponds to alcohol esters, since it is formed by the interaction of one particle of acid with one particle of Glycerin, when one particle of water is isolated [Bertelo uses the old atomic weights (H = 1, O \u003d 8) and therefore says 2, 4 and 6 equivalents of water, instead of one, two and three particles of water], the second row is formed by the interaction of one particle of Glycerin with two particles of acid in the isolation of 2 particles [Bertelo uses the old atomic weights (H \u003d 1, O \u003d 8) and therefore says 2, 4 and 6 equivalents of water, instead of one, two and three particles of water] water, and, finally, the third, identical with natural fats, formed by the interaction of one particle of Glycerin with three particles of acid, when 3 particles are isolated [Bertelo uses the old atomic weights (H = 1, O = 8) and therefore says 2, 4 and 6 equivalents of water, instead of one, two and three particles of water] water ... These facts show that Glycerin is related to alcohol, as it is related to nitric acid, "or, as Wurtz (1855) says: "They show that Glycerin is a trihydric alcohol, i.e., it is a compound formed through the substitution of a glyceryl (C 3 H 5) radical for three hydrogen atoms in three particles of water. The correctness of such a representation was proved by Wurtz himself, both by the synthesis of Glycerol (see above) and by the preparation of dihydric glycols-alcohols (see Glycols), and this played a large role in clarifying correct presentation about the atomicity of organic radicals (see). "If ethyl (C 2 H 5)," says Wurtz in an article on glycols (1859), "capable of combining with 1 equivalent of chlorine, replaces 1 equivalent of hydrogen [For example, in water, forming: H.O.H - water, C 2 H 5 .О.Н - alcohol, the reaction is carried out by means of double decomposition: C 2 H 5 Cl (Br, J, chloride, bromide, ethyl iodide) + KOH (caustic potash) = C 2 H 5 OH + KCl (Br, J, chloride, bromide, potassium iodide)], then ethylene C 2 H 4 , which combines directly with two equivalents of chlorine, like, for example, tin, can replace 2 equivalents of hydrogen. Ethylene is a diatomic radical, and is a diatomic chlorine. When the latter (obtained synthetically) enters into an exchange decomposition with a silver salt, the radical remains intact and takes the place of 3 equivalents of silver. This is what theoretical interest my work; he proved that an organic group, combined with 2 equivalents of chlorine or bromine, can, leaving them, replace 2 equivalents of silver. This fact, in my opinion, is new and important. I have tried to generalize it, not only by introducing into the circle of research other bromures similar to ethylene bromide, but also by proving that a radical combined with 3 bromine atoms can replace 3 equivalents of silver; this is clear from the experience of the transformation of allyl iodide into Glycerol. Allyl, monoatomic in allyl iodide, becomes triatomic by absorbing three bromine atoms and turning into allyl tribromide; and, reacted with 3 particles of silver acetate, it replaces three equivalents of silver. Thanks to these observations, the doctrine of polyatomic radicals, which was an indefinite hypothesis without the support of experimental data, finally entered the field of exact knowledge. "First structural formula Glycerin was proposed by Cooper (1858), namely C 3 H 8 O 3 = CH(OH) 2 .CH 2 .CH 2 (OH); A. M. soon pointed out that another formula is also possible - CH 2 (OH). CH (OH). CH 2 (OH) - now generally accepted. Therefore, the primacy of two aqueous residues (hydroxyls) of Glycerin is proved by the preparation of trimethylene glycol CH 2 (OH).CH 2 .CH 2 (OH) and tartronic acid COOH.CH(OH).COOH from it, and the secondary hydroxyl is clear from the fact that monochlorohydrin Glycerin under the action of sodium amalgam gives (Buff) propylene glycol:
CH 2 Cl.CH (OH).CH 2 (OH) + H 2 \u003d CH 2.CH (OH).CH 2 (OH) + HCl.
The same formula leads to the preparation of Glycerin by the oxidation of allyl alcohol
CH 3: CH.CH 2 (OH) + H 2 O + O \u003d CH 2 (OH). CH (OH). CH 2 (OH)
and the formation under the action of phosphorus iodide on glyceric acid (the structure of which has been proven completely independently - see Glycerin acid) - ß iodopropionic acid -
CH 2 (OH). CH (OH). COOH + 3HJ \u003d CH 2 J.CH 2. COOH + 2H 2 O + J 2.
It is impossible not to notice, moreover, that this is the only possible formula that satisfies the legality of a-Kekule, according to which no more than one hydroxyl can be found in polyhydric alcohols at one carbon atom (see Mesoxalic acid and).
A. I. Gorbov.Δ.
Glycerol(technical). Glycerin is of great and extensive importance in technology. By treating with a mixture of fuming nitric and strong sulfuric acids, it is converted into an ester of nitric acid C 3 H 5 (NO 3) 2, called nitroglycerin, which has extremely strong explosive properties and therefore is part of various explosives, especially dynamite (see), which are great application in various fields of industry, especially in mining. In addition, glycerin is used due to its hygroscopic properties as an additive to such substances that need to be protected from drying out: hence its extensive use in soap production from adding it to soap, the latter does not dry for a long time and remains soft. For the same purpose, it is added to sculptural clay, and for the same reason, it is wetted in solution in some cases of leather during tanning. Further, it is used to flavor wine, beer, vinegar, liqueurs, and various preserves, to which it imparts a sweet taste and prevents description. A large amount of it is used for the preparation of various cosmetics, the lubrication of machine parts (especially watches), the preparation of mordants for certain paints, etc. The total Glycerin extends in Europe up to 3,500,000 pd. per year [Including from Russia 101.6 thousand pd., in the amount of 435.9 thousand rubles. (1889)], and half of this amount goes to the preparation of dynamite. Glycerin is obtained in technology exclusively as a by-product of the decomposition of natural fats and oils, produced in stearin in soap factories. Natural fats (see), representing glycerides or glycerol esters of various fatty acids, under certain conditions are able to decompose with m Glycerin and free fatty acids, which have long been widely used in industry as a material for making candles and soap. The mentioned decomposition in technology is carried out in three ways: by alkaline washing of fats, by the action of sulfuric acid on them, and by decomposition with superheated water vapor. All of these methods have the same importance. fat washing is done as follows. In a special, hermetically sealed cylindrical copper cauldron, the so-called autoclave (Fig. 1), 2000 kg of fat (lamb or beef lard or palm oil), 1000 kg of water and lime milk are added, so that it accounts for from 2 - 3% lime in relation to the amount of fat taken, i.e. 40 - 60 kg per given proportion.
Fig. 2. A device for the decomposition of fats with superheated water vapor.
At this time, a continuous jet of superheated water vapor is let into the cube through a pipe m, what is the breakdown of fat. Mixture of water vapor, glycerin and fatty acids by tube n is removed from the cube and enters TO, consisting of a series of vertical tubes connected to each other. In the curved, lower end of each refrigerator tube there is a hole with a tap that communicates it with the receiver h, in which the vapors condensed in the refrigerator are collected. Closer to the apparatus, almost completely pure fatty acids are collected, and as they move away from it, along with water and Glycerin In the last receiver l there is already almost one water. Separated from the fatty acids, the aqueous liquid containing Glycerin is processed to isolate the latter.
The isolation of Glycerin from its aqueous solution, obtained by one or another method of decomposition of fat, is carried out in such a way that the solution is first subjected to thickening by evaporation, to a specific gravity of 1.12 - 1.22, best in vacuum apparatus, i.e. in void, for which, for example, the device shown in Fig. 3. Heating in it is carried out by steam entering through the pipe BUT, having plate-shaped extensions inside the boiler B, B, B increasing heating. The steam pipe can rotate around its axis, which further enhances evaporation. Air and water vapor are pumped out through a pipe WITH. Glycerin condensed in this way is impure and colored brown. To purify it, it is filtered through and subjected to a secondary distillation, which is carried out in copper cubes, best of all with superheated steam and, if possible, at a low temperature, not higher than 210 °, and for chemically pure Glycerin - even at 171 °. through charcoal and distillation is repeated several times until a product of the desired purity is obtained.
Glycerin, as mentioned above, is capable, under certain conditions, of crystallization. This property is often used for its purification (at the Sarg factory in Vienna and at the ova in Kazan). Several crystals of Glycerin previously obtained in solid form are introduced into the Glycerin solution cooled to 0 °. After some time, the liquid solidifies into a crystalline mass, which is placed in centrifuges (see) and in the latter the solid part is separated from the liquid.
Fig. 4. Boiler for thickening the impure aqueous solution of glycerin resulting from soap making.
Evaporating boiler a has a conical shape and consists of two parts: the boiler itself a and two tanks, separated from the boiler by a special partition, which can be pushed in and out at will, setting it in last case communication between the boiler and tanks. The purpose of the latter is that they collect the precipitate released during the evaporation of salts. When enough of the latter have collected, the valve of one of the tanks is closed, the tank is thus separated from the evaporation boiler and can be cleaned without interrupting the entire evaporation process, which is carried out partly by superheated steam. entering the boiler through a tube about, part of the bare fire, for which the cauldron a surrounded on the sides by a sand bath p, which is heated directly by flue gases obtained from the furnace b. The raw Glycerin obtained (remaining in the boiler), containing up to 10% more minerals, is subjected to distillation for purification. In some cases, it is pre-purified by shaking with petroleum ether, carbon disulfide, etc., to free it from various fatty and resinous impurities. such Glycerin is conducted somewhat differently from how it was described above. The cube is taken the same, ordinary; the difference exists only in the device of the refrigerator, which is made like those used in the distillation and rectification of alcohol. It consists of a column A, A.(Fig. 5), in which there are partitions - the so-called plates D D, punched with small (1/10 inch) holes.
Fig. 5. Column apparatus for separating water from glycerin during distillation.
Vapors of glycerine and water rising from below WITH, go up, condense on the mentioned plates and flow down the tubes D, to receivers D2, equipped with cranes D1. At the bottom of the column, on the nearest plates, almost pure Glycerin thickens, and on more distant ones - mixed with water. Such aqueous glycerin subjected to further distillation in the usual way. Obtained by the described methods, Glycerin goes on sale in various condition purity, which is why it is necessary to pay attention to the latter when buying it, since in many applications Glycerin requires a completely pure product. The following varieties are commonly found on sale: 1) raw Glycerin; 2) chemically pure Glycerin, which, however, often contains 6-10% water. It should not, when heated with sulfuric acid and alcohol, give any ethereal odor, and with acetic-lime salt - sediment; 3) dynamite Glycerine at 28°B. yellowish; it should be free from lime and give only a slightly noticeable turbidity with a solution of lapis; 4) white Glycerin, not containing lime, but less pure than the previous one; 5) Yellow Glycerin, also free of lime. in all these varieties of various foreign substances of organic origin is best recognized by using a solution of lead vinegar (basic acetic-lead salt), which in this case produces a more or less abundant precipitate in glycerin. If the latter is obtained - Glycerin is unsuitable for making dynamite. Of organic substances, fatty acids, fats and resins can be determined by shaking the test Glycerin with chloroform, which will extract all similar substances. Evaporating then the layer of chloroform separated from the glycerol, one can obtain the residue of these substances in solid form. The presence of lime is discovered by the fact that a solution of oxalo-ammonia salt is added to an aqueous solution of the tested Glycerin; if lime is found, a white precipitate is obtained. Yet in general minerals can be determined by burning a certain (5 g) amount. Glycerin substances will be in the balance. them in good varieties should not exceed 0.1%, at most 0.2. Good Glycerin should mix with alcohol, forming a completely transparent solution, should not turn black when heated with strong sulfuric acid, and when mixed with a 10% solution of lapis should not emit, even when standing (in a dark place), a black precipitate of reduced silver.
Wed S. Koppe, "Das Glycerin, seine Darstelung n. Anwendung" (1889). On the decomposition of fats, see works on the preparation of candles and soap with stearin.
Glycerol(method of definition). Glycerin opens easily only in aqueous solutions. typical reactions to it are: the characteristic smell of acrolein, which is formed by evaporating to dryness a solution with acidic potassium sulfate and then heating the residue (the evolved gases can be collected in water and the formation of acrolein can be proved using fuchsin-sulphurous acid [Staining in pink color colorless aqueous solutions of fuchsine-sulphurous acid, when the test substance is added, serves as a characteristic reaction for all monohydric aldehydes (Schiff and Caro), which makes it possible to distinguish them from ketones, which do not show this reaction. With the described test for Glycerin, staining appears rather slowly. reaching the highest brightness after 15-20 minutes of standing. The experiment is carried out in the cold, since the solution of fuchsin-sulphurous acid is colored by heating. Mannitol, glucose, starch, dextrin, gelatin, stearic and oleic acids do not give color, but the presence of carbon hydrates in Glycerin reduces the reaction, because the products formed when they are heated with acidic potassium sulphate salt interfere with the appearance of pink coloration, and in the case the presence of carbohydrates must begin with their removal (see below for the definition of Glycerol). When opening Glycerin in milk, casein, albumin and milk sugar are previously removed. (Kon)]; the appearance of a green color when a piece of borax moistened with a solution of Glycerin is introduced into the flame of the burner (the absence of ammonia salts must first be proven, or they must be removed) and carmine-red coloration when ammonia is added to a cooled solution of Glycerin, previously heated to 120 ° with sulfuric acid (Reichl). The quantitative content of Glycerol in aqueous solutions can be calculated based on the specific gravity or refractive index of the solution (see numerical data below); but for this it is necessary that the solution be known to be pure [According to the requirements of the German Pharmacopoeia, pure Glycerin should neither give a silver mirror nor be painted in yellow(within five minutes), at the following test: a solution of equal parts of Glycerin and aqueous ammonia is heated to a boil with constant stirring, then the flame is removed and a few drops are added ammonia solution silver nitrate; the test is mainly aimed at discovering the content of arsenic anhydride in glycerol, but it fails completely - even with a known content of several% As 2 O 3 - in the case of an excess of ammonia (Jaffe, Lutke). The presence of acrolein in Glycerin is more easily determined by the smell, or by pink coloration with a solution of fuchsin-sulphurous acid (Lutke), or by the formation of a brown (red) precipitate upon shaking with reagent a ( alkaline solution double salt of potassium iodide and mercury iodide); the precipitate formed with aldehydes differs from the precipitate given by the reagent with ammonia (see), in that it turns black with potassium cyanide, while the precipitate from ammonia disappears from the addition potassium cyanide, highly sensitive reaction (Krizmer)]. Of the methods for determining the content of Glycerin in sales samples, we note the following: and Pelle determine Glycerin in the form of nitroglycerin, for which the substance is treated with a mixture of concentrated nitric and sulfuric acids (Dickman advises adding dropwise a mixture of 5 parts of sulfuric acid at 66 ° B with 3 including nitric acid at 48 ° B.; sulfuric and nitric acids should not contain hydrochloric acid and nitric acid can be no more than 1% nitrous acid); the resulting nitroglycerin is washed with water, the part dissolved in the washings is extracted with ether, dried to constant weight on a water bath and weighed; 190 hours of nitroglycerin correspond to 100 hours. Glycerin The Moravsky method is safer, consisting in the fact that 1 hour . crude Glycerin is mixed with 25 hours of lead oxide, evaporated and dried to constant weight at 130 °. The weight gain of lead oxide corresponds to all non-volatile impurities contained in Glycerin and its residue C 3 H 6 O 2 ; the amount of non-volatile impurities is determined (approximately) by weighing Glycerol to a constant weight at 160 ° (Glycerol evaporates rather quickly at this temperature), subtracted from the weight gain of lead oxide and the difference is multiplied by 1.3429. The method is convenient, but its applicability is limited, since it gives good results only with fairly pure samples of Glycerin, containing, in addition to sodium chloride, only insignificant amounts of extraneous organic substances; when there is an admixture of sulfate salts, free alkalis or resinous substances, it is not possible to completely remove glycerin by heating at 16 0 ° and, moreover, it is impossible (without more complex devices) to avoid the absorption of carbon dioxide by caustic alkalis (Gener). According to Cantor, boil (for 1 hour) Glycerin (1 g) with acetic anhydride (7 g) and anhydrous sodium acetate salt (3 g) in a flask with a condenser placed back (otherwise losses occur due to the significant volatility of triacetin with water vapor ); then the solution is cooled; add 50 cu. see water; slightly heated to facilitate the dissolution of the settled oil; filtered off from the white flocculent precipitate, which contains most organic impurities Glycerin and can be very significant; cool again; averaged in the presence of a acetic acid weak solution caustic soda , avoiding its excess; saponify triacetin with a solution of caustic soda (approximately 10%) and titrate back its excess with normal hydrochloric acid, which accurately determines the titer of caustic soda used for saponification; the difference between both titrations represents the amount of hydrochloric acid used to saponify triacetin; 1 cu. cm normal hydrochloric acid corresponds to 0.03067 g Glycerol Due to the easy saponification of triacetin, even under strict observance of the above conditions, figures obtained by this method are mostly too low; it is completely inapplicable if the test solution contains less than 30% Glycerol (Gener). The simpler Bauman-Ditz method is quite similar in principle, consisting in the fact that a solution of Glycerin (about 0.1 g of Glycerin in 10 - 20 cubic cm of water) is shaken for 10 - 15 minutes with benzoyl chloride (5 cubic cm) and caustic sodium chloride (35 cubic cm 10% solution), the precipitate is triturated with an alkaline liquid (to completely remove benzoyl chloride) and, after a short standing, is collected on a filter dried at 100 ° C, washed with water and, finally, dried for 2 - 3 hours at 100 ° C 3.85 hours of the resulting mixture of di- and tribenzoate [This mixture melts, after recrystallization from ether, quite constantly at + 170 ° C and its formation under these conditions can also serve as a qualitative reaction to Glycerin When using a solution of caustic soda greater strength is obtained exclusively tribenzoate (Ditz, Panormov)]. answer 1 hour. Glycerin Other polyhydric alcohols and carbohydrates that can also give benzoyl chloride should be absent, or they must first be removed [In addition to the above methods, in which the first and last are the simplest, many others are described and recommended, consisting in oxidation Glycerin and quantitative determination of any of the resulting products]. This is especially important when determining the content of Glycerin in beer and wine, where they proceed as follows: 50 cubic meters. cm beer is evaporated to dryness with an admixture of sand and lime milk; the residue is finely ground, 50 cu. cm 96% alcohol, 75 cubic meters are added to the chilled extract. see absolute ether, which precipitates maltose and ; the filtrate is evaporated on a water bath; the residue is dried at 100 ° - 150 ° C, dissolved in 5 - 10 cu. cm of water and shaken with 2 - 3 cu. see benzoyl chloride and 7 hours 10% sodium hydroxide; then proceed as above. Wines are analyzed in the same way, with the only difference being that with fermented, sugar-poor white and red wines, 20 cu. cm of wine, the remainder is extracted 20 cu. cm 96% alcohol, after precipitation, 30 cubic meters are added. cm of anhydrous ether, filtered, the precipitate is washed with a mixture of alcohol (2 hours) with ether (3 hours) and the filtrate is evaporated on a water bath, and with sweet wines to 20 cu. cm of wine, in addition to lime milk, another 1 g of sand is added, and the amounts of alcohol and ether are doubled; for the final determination, take no more than 0.1 - 0.2 g of crude Glycerin, thus isolated. When determining the content of glycerin in fats, 65 hours of crystalline barium hydroxide are added to 100 hours of melted fat; the mass is carefully rubbed; add another 80 cubic meters to facilitate saponification. see 95% alcohol; then, when everything hardens, boil (for 1 hour) with 1 liter of water; the pounded precipitate of barite salts is washed two more times with water; all water extracts are acidified with sulfuric acid, evaporated by half; excess sulfuric acid is removed with barite carbonate; the filtrate is thickened to 50 cu. cm and finally the content of glycerin in it is determined by one of the methods described above.
BUT. I. Gorbov. Δ.
Specific gravity of aqueous solutions of glycerol. Pure Glycerin in liquid form at ordinary temperature is a thick, syrupy liquid that changes its external properties very little from the addition of water. But since the addition of water beats. weight decreases, then the content of Glycerin in the solution is most easily (when there are no other impurities) determined using the specific gravity [For the same purpose, the determination of the refractive index of light and the vapor pressure of Glycerin solutions is also used]. i, made by me in 1861 for anhydrous glycerin, are consistent with the later more detailed studies of W. Lenz (1880) and Gerlach (1884) and as a result [For details, see Mendeleev, "Investigation of aqueous solutions by specific weight"] we get the following table in which p means the content of Glycerol in percent by weight, s is the specific gravity at 15°C, counting water at 4° as 10,000 [in airless space], ds/dp there is a change (derivative) beats. weight with an increase in the content of Glycerin by 1% and ds/dt there is a change ud. weight as the temperature rises by 1°C.
| p = 0% | s = 9992 | ds/dp = 23.6 | ds/dt = - 1.5 |
| 10 | 10233 | 24,5 | -2,0 |
| 20 | 10473 | 25,3 | -2,2 |
| 30 | 10739 | 26,2 | -2,8 |
| 40 | 11005 | 27,0 | -3,5 |
| 50 | 11279 | 27,8 | -4,1 |
| 60 | 11562 | 28,7 | -4,6 |
| 70 | 11845 | 27,8 | -5,2 |
| 80 | 12118 | 26,9 | -5,4 |
| 90 | 12382 | 25,9 | -5,7 |
| 100 | 12637 | 25,0 | -5,7 |
Data for ud. weights are expressed with sufficient accuracy for practice by two parabolas:
From p \u003d 0 to p \u003d 63%: S \u003d 9992 + 23.65r + 0.0420r 2
From p \u003d 63% to p \u003d 100%: S \u003d 9671 + 34.33p - 0.0467r 2
The intermediate compound (p = 63.0% Glycerol) corresponds to the composition C 3 H 3 O 3 + 3H 2 O.
D. Mendeleev.
Glycerin or according to the international nomenclature propanetriol -1,2,3 - complex substance, which refers to polyhydric alcohols, or rather is trihydric alcohol, because has 3 hydroxyl groups - OH. The chemical properties of glycerin are similar to those of glycerol, but are more pronounced due to the fact that there are more hydroxyl groups and they influence each other.
Glycerin, like alcohols with one hydroxyl group, is highly soluble in water. This, one might say, is also a qualitative reaction to glycerol, since it dissolves in water in almost any ratio. This property is used in the production of antifreezes - liquids that do not freeze and cool the engines of cars and aircraft.
Glycerin also interacts with potassium permanganate. This is a qualitative reaction to glycerin, which is also called the Scheele volcano. To carry it out, it is necessary to add 1-2 drops of anhydrous glycerin to the potassium permanganate powder, which is poured in the form of a slide with a recess in a porcelain bowl. After a minute, the mixture spontaneously ignites. During the reaction, a large amount of heat is released, and hot particles of reaction products and water vapor fly apart. This reaction is redox.
Glycerin is hygroscopic, i.e. able to retain moisture. It is on this property that the following qualitative reaction to glycerol is based. It is carried out in a fume hood. To carry it out, pour about 1 cm3 of crystalline potassium hydrogen sulfate (KHSO4) into a clean, dry test tube. Add 1-2 drops of glycerin, then heating until a pungent odor appears. Potassium hydrogen sulfate acts here as a water-absorbing substance, which begins to manifest itself when heated. Glycerin, losing water, is converted into an unsaturated compound - acrolein, which has a sharp bad smell. C3H5(OH)3 - H2C=CH-CHO + 2 H2O.
The reaction of glycerol with copper hydroxide is qualitative and serves to determine not only glycerol, but also others. In order to carry it out, it is initially necessary to prepare a fresh solution of copper (II) hydroxide. To do this, we add to and get copper (II) hydroxide, which forms a blue precipitate. We add a few drops of glycerin to this test tube with a precipitate and notice that the precipitate has disappeared, and the solution has acquired a blue color.
The resulting complex is called copper alcoholate or glycerate. Qualitative reaction on glycerin with copper (II) hydroxide is used if glycerin is in pure form or in aqueous solution. To carry out such reactions in which glycerol is with impurities, it is necessary to pre-purify it from them.
Qualitative reactions to glycerin help to detect it in any environment. It is actively used to determine glycerin in foods, cosmetics, perfumes, medical preparations and antifreeze.
The test can not be done completely, but see, if possible, most of the questions. With uv. I.V.
Methods of knowledge in chemistry. Chemistry and Life ( open bank 2014)
Part A
1. What reagent detects chloride ion?
3. Ammonium salts can be detected using a substance whose formula is
5. Aqueous solutions of sulfuric and nitric acids can be distinguished using
7. Formula of propylene polymerization product
9. A substance that is non-toxic to humans is
11. The process of decomposition of oil hydrocarbons into more volatile substances is called
13. The chemical structure of butadiene rubber is expressed by the formula
15. A method of processing oil and oil products, in which don't happen
chemical reactions is
16. Under the action of an alcoholic solution of alkali on 2-chlorobutane, it is predominantly formed
17. The products of roasting pyrite FeS 2 are
19.Water displacement it is forbidden
collect
20. During alkaline hydrolysis of 1,2-dichloropropane,
21. An aqueous solution of potassium permanganate changes its color under the action of
The monomer for the production of polyethylene is
23. You can detect sulfate ion in a solution using
24. Aminoacetic acid can be obtained by reacting ammonia with
25.Environmentally friendly fuel is
35. Iron (III) hydroxide is formed by the action of alkali solutions on
36. Aniline from benzene can be distinguished using
38.Bromethane it is forbidden
get
interaction
39. Under the action of an aqueous solution of alkali on monobromoalkanes, predominantly formed
40. Under the action of a concentrated alcoholic solution of alkali on monobromoalkanes, when heated, they predominantly form
41. Has strong antiseptic properties
42. Acetylene in industry is obtained
43. Chloroprene rubber is obtained from
45. In the reaction scheme NaOH + X C 2 H 5 OH + NaCl with the substance " X" is an
46. Ethylene can be obtained by dehydration
The process of flavoring gasoline is called
48. The presence of Cu 2+ and SO 4 2– ions in a solution can be confirmed using solutions:
50.For industrial production methanol from synthesis gas is not
characteristic
51. What a reaction not used
in the production of sulfuric acid?
53. What process in the production of sulfuric acid is carried out in a contact apparatus?
54. During alkaline hydrolysis of 2-chlorobutane, predominantly formed
55. The reaction for the industrial production of methanol, the scheme of which is CO + H 2 CH 3 OH, is
56. For the production of sulfuric acid raw materials is not
58. The main product of the reaction of chloroethane with an excess of an aqueous solution of potassium hydroxide is
59. Violet coloration appears when acting on a protein
60. A bright blue solution is formed by the interaction of copper (II) hydroxide with
61. The monomer for producing polystyrene (- CH 2 - CH (C 6 H 5) -) n is
62. Explosive mixtures with air forms
63. Sodium chloride solution is used to detect ions
65. The monomer for producing artificial rubber according to the Lebedev method is
66. The monomer for producing polyvinyl chloride is
67. The apparatus for separating liquid products of production is
68. Butadiene-1,3 is obtained from
69.Basic natural source butane is
70. A qualitative reaction to formaldehyde is its interaction with
71. Proteins become yellow under the action of
73. The separation of oil into fractions is carried out in the process
75. Acetic acid it is forbidden
get
76. Propanol-1 is formed as a result of the reaction, the scheme of which
78. Methods for obtaining alkenes include:
79. Butanol-2 and potassium chloride are formed by interaction
80. The reaction with which you can determine the sulfate ion is:
82. A characteristic reaction for polyhydric alcohols is the interaction with
84. In a galvanized vessel it is forbidden
store solution
86. In the production of ammonia as a raw material is used
87. Explosive mixture with air forms
89. To obtain ammonia in industry, they use
90. Is it true the following judgments about the rules for handling substances?
A. In the laboratory you can not get acquainted with the smell of substances.
B. Lead salts are very poisonous.
91. Are the following judgments about the rules for handling substances correct?
A. In the laboratory, you can get acquainted with the smell and taste of substances.
B. Chlorine gas is highly toxic.
92. Are the following judgments about industrial methods for producing metals correct?
A. Pyrometallurgy is based on the process of recovering metals from ores at high temperatures.
B. In industry, carbon monoxide (II) and coke are used as reducing agents.
93. In the production of sulfuric acid at the stage of oxidation of SO 2 to increase the yield of the product
94. The reagent for polyhydric alcohols is
96. Each of the two substances enters into the “silver mirror” reaction:
97. Using the fluidized bed method in industry, they carry out
98. Pentanol-1 is formed as a result of the interaction
99. Natural polymer is
100. Pentanoic acid is formed as a result of interaction
101. Methane is the main component
103. In one stage, butane can be obtained from
104. Propanic acid is formed as a result of interaction
105. Are the following judgments about indicators correct?
A. Phenolphthalein changes color in acid solution.
B. Litmus can be used to detect both acids and bases.
106. Rubber is formed during polymerization
107. In the laboratory, acetic acid can be obtained by oxidation
108. A qualitative reaction to polyhydric alcohols is a reaction with
109.Main component natural gas is an
110. Potassium permanganate solution can be used to detect
111. The reactions of synthesis of macromolecular substances include
112. Sodium acetate, when heated with solid sodium hydroxide, forms
114. Cracking of petroleum products is carried out in order to obtain
115. When heating saturated monohydric alcohols with carboxylic acids formed in the presence of sulfuric acid
116. When acetaldehyde reacts with hydrogen, it forms
117. The industrial production of methanol is based on a chemical reaction, the equation of which
119. Are the following judgments about the production of ammonia correct?
A. In industry, ammonia is obtained by synthesis from simple substances.
B. The reaction of ammonia synthesis is exothermic.
120. Butanoic acid is formed as a result of interaction
121. Ammonia solution of silver oxide (I) is a reagent for
122. Are the following judgments about the methods of oil refining correct?
A. The methods of secondary oil refining include cracking processes: thermal and catalytic.
B. When catalytic cracking along with cleavage reactions, isomerization reactions of saturated hydrocarbons occur.
123. Freshly precipitated copper(II) hydroxide reacts with
124. Propanol-1 is formed as a result of interaction
125. Which of the listed ions is the least toxic?
127. A solution of potassium permanganate is decolorized by each of the two substances:
128. Butanoic acid can be obtained by interaction
129. Are the following judgments about the rules for handling substances correct?
A. Substances must not be tasted in the laboratory
B. Mercury salts should be handled with extreme care due to their toxicity.
130. Environmentally friendly fuels include
131.What alcohols it is forbidden
get hydration of alkenes?
132. To obtain acetylene in the laboratory, use
133. Butanol-1 is formed as a result of interaction
134. Are the following judgments about the rules for handling substances and equipment correct?
A. Thickened oil paint must not be heated over an open fire.
B. Spent organic matter it is forbidden to pour into the drain.
135. Polypropylene is obtained from propene as a result of the reaction
136. For the synthesis of butane in the laboratory, metallic sodium and
137. Esters are formed as a result of the reaction
139. The starting material for the production of butadiene rubber is
141. A polymer having the formula
receive from
142. Are the following judgments about the toxicity of substances and the rules of work in the laboratory correct?
A. The most toxic gases are oxygen and hydrogen.
143. At the last stage of the production of sulfuric acid, sulfur oxide (VI) is used to absorb
144. Are the following judgments about working with gases correct?
A. Carbon dioxide can be dried by passing it through concentrated sulfuric acid.
B. Solid calcium hydroxide can be used to dry the hydrogen chloride.
145. The "fluidized bed" method in the production of sulfuric acid is used in the process
146. When propylene is hydrated, it is predominantly formed
147. Are the following judgments about safety regulations correct?
A. When preparing acid solutions, carefully (in a thin stream) pour the acid into cold water, stirring the solution.
B. The dissolution of solid alkalis is best done in porcelain, and not in thick-walled glassware.
148. In the production of sulfuric acid, the catalyst is used at the stage
149. Butanol-2 is formed as a result of interaction
151. The method of "fluidized bed" is used in the production
152. Acetylene in the laboratory is obtained
153. Non-toxic is each of the two substances:
155. Butanol-2 can be obtained by interaction
156. Each of two gases is toxic:
158. Pentanoic acid is formed as a result of interaction
159. A solution containing ions can serve as a reagent for carbonate ions
161. Butanoic acid is formed as a result of interaction
162. The qualitative composition of barium chloride can be determined using solutions containing ions
164. A reagent for ammonium cations is a substance whose formula is
166. Phosphate ions in solution can be detected using a substance whose formula is
168. Acetic acid is formed during the interaction
170. Are the following judgments about scientific principles industrial synthesis of ammonia?
A. The synthesis of ammonia is carried out on the basis of the principle of circulation.
B. In industry, ammonia synthesis is carried out in a fluidized bed.
171. Calcium propionate is formed by interaction
172. Are the following judgments about the production of sulfuric acid in industry correct?
A. To absorb sulfur oxide (VI), use concentrated sulfuric acid.
B. Potassium hydroxide is used to dry sulfur oxide (IV).
C 3 H B (OH) E (Mol. wt. 92.06)
Qualitative reactions
1. When glycerin is heated with a double amount of potassium bisulfate KHS0 4 until a slight charring begins, the smell of acrolein is felt, which strongly irritates the mucous membranes and causes lacrimation. A paper moistened with Nessler's reagent, when immersed in the vapors of released acrolein, turns black (from released mercury):
2. The Deniger reaction is based on the oxidation of glycerol with bromine water to dihydroxyacetone:
Heat 0.1 g sample with 10 ml freshly prepared bromine water (0.3 ml bromine in 100 ml water) for 20 minutes and then remove the remaining bromine by boiling. The resulting dihydroxyacetone restores Nessler's reagent and Fehling's solution.
quantitation
1. Refractometric determination. The content of glycerol in aqueous solutions that do not contain other substances can be determined refractometrically from the refractive index using the appropriate table.
2. Acetin method. A sample of glycerol is acetylated to obtain acetic ester of glycerol - triacetin. By saponifying triacetin, the amount of spent alkali is determined and the amount of glycerol is calculated. In view of the fact that the acetylation of glycerol requires a particularly high quality acetic anhydride, which should contain only traces of free acetic acid prefer the determination of glycerol by the bichromate method.
3. Bichromate method of determination. Purified glycerin, which does not contain foreign oxidizable substances, is oxidized in an acidic environment with dichromate to carbon dioxide and water:
Using an excess of a titrated solution of potassium dichromate, determine the excess of the latter iodometrically:
The released iodine is titrated with sodium thiosulfate solution. For the technique of determination, see Meyer (1937).
4. More convenient for the determination of small amounts of glycerol is the method of oxidation with bromine (see above).
A weighed portion of a glycerin solution corresponding to 0.02-0.04 g of 100% glycerol is placed in a conical flask with a ground stopper. Acidic solutions are neutralized with 0.1 N. alkali solution in the presence of one drop of methyl orange solution. Then pour in 10 ml of 0.1% bromine water, moisten the stopper with a solution of potassium iodide and leave the reaction mixture alone for 15 minutes. Pour in 10 ml of a 10% potassium iodide solution, 50-100 ml of water and titrate with iodine 0.02 N. sodium thiosulfate solution in the presence of starch. At the same time put a blind experiment.
where a- the number of u,uz n. a solution of sodium thiosulfate in milliliters used for a blind experiment, b- the amount of the same solution in milliliters used in the determination, e- weight in milligrams.
