What is acetone? The formula of this ketone is considered in the school course of chemistry. But far from everyone have an idea of \u200b\u200bhow dangerous smell of this connection and what properties is this organic matter.
Features acetone
Technical acetone is the most common solvent used in modern construction. Since this compound has a low level of toxicity, it is also used in the pharmaceutical and food industry.
Technical acetone is used as chemical raw materials in the production of numerous organic compounds.
Doctors consider it a narcotic substance. When inhaling concentrated steams of acetone, serious poisoning and the defeat of the central nervous system. This compound presents a serious threat to the younger generation. Toxicomes that use acetone pairs in order to cause an euphoria state, risk hard. Doctors fear not only for the physical health of children, but also for their mental state.
The dose of 60 ml is considered deadly. If a significant amount of ketone comes into the body, the loss of consciousness comes, and after 8-12 hours - death.
Physical properties
This compound is for normal conditions Located in a liquid state, does not have color, has a specific odor. Acetone, the formula of which has the form of CH3Snos3, has hygroscopic properties. This compound in unlimited quantities is mixed with water, ethyl alcohol, methanol, chloroform. He has a low melting point.
Features of use
Currently, the scope of acetone is quite wide. It is rightfully considered one of the most sought-after products used in the creation and production of paints and varnishes, in the finishing works, the chemical industry, construction. All in more acetone is used to degrease the fur and wool, removal of wax lubricating oils. That is what organic We use painters and plasters in their professional activities.
How to preserve acetone whose formula CH3SH33? In order to protect this volatile substance from negative impact Ultraviolet rays, it is placed in plastic, glass, metal bottles away from UV.
The room where the location of a significant amount of acetone is assumed, it is necessary to systematically ventilate and install high-quality ventilation.
Features of chemical properties
The name of this compound received from the Latin word "acetum", meaning in translation "vinegar". The fact is that the chemical formula of the C3H6O acetone appeared much later than the substance itself was synthesized. It was obtained from acetates, and then used for the manufacture of ice synthetic acetic acid.
Andreas Libavius \u200b\u200bis considered the primary compound. At the end of the 16th century, by dry distillation, lead acetate, he managed to get a substance chemical composition which was deciphered only in the 1930s of the XIX century.
Acetone, the formula of which CH3COSN3, until the beginning of the 20th century was obtained by coking wood. After increasing demand during the First World War, new synthesis methods began to appear for this organic compound.
Acetone (GOST 2768-84) is a technical fluid. By chemical activity, this compound is one of the most reactive in the ketone class. Under the influence of alkalishes, adole condensation is observed, as a result of which diacetone alcohol is formed.
When pyrolysis is obtained from it. Acetoncyanidanegidrine is formed in the reaction with cyanorodum. For propanone, the substitution of hydrogen atoms on halogen, which occurs at elevated temperature (or in the presence of a catalyst).
Methods for getting
Currently, the main amount of oxygen-containing compound is obtained from propacted. Technical acetone (GOST 2768-84) must have certain physical and operational characteristics.
The kumol method consists of three stages and implies the production of acetone from benzene. First, by its alkylation with propenas, the cumul is obtained, then the resulting product is oxidized to hydroperoxide and split it under the influence of sulfuric acid to acetone and phenol.
In addition, this carbonyl compound is obtained by catalytic oxidation of isopropanol at a temperature of about 600 degrees Celsius. Metal silver, copper, platinum, nickel protrude as accelerators of the process.
Among the classical technologies for the production of acetone, the reaction of the direct oxidation of the propnation is of particular interest. This process is carried out at elevated pressure and presence as a catalyst for chloride of a bivalent palladium.
You can also get acetone by fermentation of starch under the influence of clostridium acetobutylicum bacteria. In addition to ketone, Banolol will be present among the reaction products. Among the disadvantages of this option to obtain acetone, we note a non-essential percentage.
Conclusion
Propanone is a typical representative of carbonyl compounds. Consumers are familiar with it as a solvent and degreaser. It is indispensable in the manufacture of varnishes, drugs, explosives. It is acetone that enters the composition of the cinema glue, is a means for cleaning surfaces from the mounting foam and superclaud, the tool of washing of injection engines and a method for increasing the octane number of fuel, etc.
n16.DOC.
Chapter 7.. Purpose of vapors, phase temperatureTransitions, surface tension
Information about the pressure of the vapor of pure liquids and solutions, their boiling and hardening temperatures (melting), as well as surface tension is necessary for calculating various technological processes: evaporation and condensation, evaporation and drying, distillation and rectification, etc.
7.1. Poor pressure
One of the most simple equations for determining the pressure of a saturated pair of pure fluid depending on temperature 
Is Antoine equation:
, (7.1)
Where BUT, IN, FROM - constant characteristic of individual substances. The values \u200b\u200bof constant for some substances are given in Table. 7.1.
If two boiling temperatures are known at appropriate pressures, then taking FROM \u003d 230, you can determine constant BUT and IN By jointly solving the following equations:
; (7.2)
. (7.3)
Equation (7.1) quite satisfactorily corresponds to experimental data in a wide range of temperatures between the melting point and 
\u003d 0.85 (i.e. 
\u003d 0.85). The greatest accuracy is the equation in cases where all three constants can be calculated on the basis of experimental data. The accuracy of the calculation by equations (7.2) and (7.3) is significantly reduced by 
250 k, and for high-polar compounds at 0.65.
Changing the pressure of the steam of the substance depending on the temperature can be determined by the comparison method (according to the rule of the linearity), based on the known pressures of the reference fluid. If two temperatures of the liquid substance are known at the appropriate saturated steam pressures, you can use the equation
, (7.4)
Where 
and 
- Pressures of a saturated pair of two liquids BUT and IN at the same temperature 
; 
and 
- Pressures of a saturated pair of these liquids at temperatures 
; FROM - constant.
Table 7.1. Pressure vapors of some substances depending
from temperature
The table shows the values \u200b\u200bof the constant BUT, IN and FROM Antoine equations:, where - the pressure of a saturated couple, mm Hg.st. (1 mm Hg \u003d 133.3 PA); T. - Temperature, K.
| Name of substance | Temperature interval, about with | BUT | IN | FROM |
||
| from | before |
|||||
| Nitrogen | N 2. | –221 | –210,1 | 7,65894 | 359,093 | 0 |
| Nitrogen dioxide | N 2 O 4 (NO 2) | –71,7 | –11,2 | 12,65 | 2750 | 0 |
| –11,2 | 103 | 8,82 | 1746 | 0 |
||
| Nitrogen oxide | No. | –200 | –161 | 10,048 | 851,8 | 0 |
| –164 | –148 | 8,440 | 681,1 | 0 |
||
| Acrylamide | C 3N 5 ON | 7 | 77 | 12,34 | 4321 | 0 |
| 77 | 137 | 9,341 | 3250 | 0 |
||
| Acrolein | C 3N 4 O | –3 | 140 | 7,655 | 1558 | 0 |
| Ammonia | NH 3. | –97 | –78 | 10,0059 | 1630,7 | 0 |
| Aniline | C 6 H 5 NH 2 | 15 | 90 | 7,63851 | 1913,8 | –53,15 |
| 90 | 250 | 7,24179 | 1675,3 | –73,15 |
||
| Argon | AR | –208 | –189,4 | 7,5344 | 403,91 | 0 |
| –189,2 | –183 | 6,9605 | 356,52 | 0 |
||
| Acetylene | C 2 H 2 | –180 | –81,8 | 8,7371 | 1084,9 | –4,3 |
| –81,8 | 35,3 | 7,5716 | 925,59 | 9,9 |
||
| Acetone | C 3 H 6 O | –59,4 | 56,5 | 8,20 | 1750 | 0 |
| Benzene | C 6 H 6 | –20 | 5,5 | 6,48898 | 902,28 | –95,05 |
| 5,5 | 160 | 6,91210 | 1214,64 | –51,95 |
||
| Bromine | Br 2 | 8,6 | 110 | 7,175 | 1233 | –43,15 |
| Hydrogen bromide | HBR | –99 | –87,5 | 8,306 | 1103 | 0 |
| –87,5 | –67 | 7,517 | 956,5 | 0 |
||
Continuation of table. 7.1
| Name of substance | Chemical formula | Temperature interval, about with | BUT | IN | FROM |
|
| from | before |
|||||
| 1,3-Butadiene | C 4 H 6 | –66 | 46 | 6,85941 | 935,53 | –33,6 |
| 46 | 152 | 7,2971 | 1202,54 | 4,65 |
||
| n.-Butane | C 4 H 10 | –60 | 45 | 6,83029 | 945,9 | –33,15 |
| 45 | 152 | 7,39949 | 1299 | 15,95 |
||
| Butyl alcohol | C 4 H 10 O | 75 | 117,5 | 9,136 | 2443 | 0 |
| Vinilacetate | CH 3 Coch \u003d CH 2 | 0 | 72,5 | 8,091 | 1797,44 | 0 |
| Vinyl chloride | CH 2 \u003d CHCL | –100 | 20 | 6,49712 | 783,4 | –43,15 |
| –52,3 | 100 | 6,9459 | 926,215 | –31,55 |
||
| 50 | 156,5 | 10,7175 | 4927,2 | 378,85 |
||
| Water | H 2 O. | 0 | 100 | 8,07353 | 1733,3 | –39,31 |
| Hexane | C 6 H 1 4 | –60 | 110 | 6,87776 | 1171,53 | –48,78 |
| 110 | 234,7 | 7,31938 | 1483,1 | –7,25 |
||
| Heptane | C 7 H 1 6 | –60 | 130 | 6,90027 | 1266,87 | –56,39 |
| 130 | 267 | 7,3270 | 1581,7 | –15,55 |
||
| Dean | C 10 H 22 | 25 | 75 | 7,33883 | 1719,86 | –59,35 |
| 75 | 210 | 6,95367 | 1501,27 | –78,67 |
||
| Diisopropyl ether | C 6 H 1 4 O | 8 | 90 | 7,821 | 1791,2 | 0 |
| N, N-dimethylacetamide | From 4 N 9 ON | 0 | 44 | 7,71813 | 1745,8 | –38,15 |
| 44 | 170 | 7,1603 | 1447,7 | –63,15 |
||
| 1,4-dioxan | C 4 H 8 O 2 | 10 | 105 | 7,8642 | 1866,7 | 0 |
| 1.1-dichloroethane | C 2 H 4 Cl 2 | 0 | 30 | 7,909 | 1656 | 0 |
| 1,2-dichloroethane | C 2 H 4 Cl 2 | 6 | 161 | 7,18431 | 1358,5 | –41,15 |
| 161 | 288 | 7,6284 | 1730 | 9,85 |
||
| Diethyl ether | (C 2 H 5) 2 | –74 | 35 | 8,15 | 1619 | 0 |
| Isomaslane acid | C 4 H 8 O 2 | 30 | 155 | 8,819 | 2533 | 0 |
| Isoprene | C 5 H 8 | –50 | 84 | 6,90334 | 1081,0 | –38,48 |
| 84 | 202 | 7,33735 | 1374,92 | 2,19 |
||
| Isopropyl alcohol | C 3 H 8 O | –26,1 | 82,5 | 9,43 | 2325 | 0 |
| Iodide hydrogen | HI | –50 | –34 | 7,630 | 1127 | 0 |
| Krypton | Kr. | –207 | –158 | 7,330 | 7103 | 0 |
| Xenon | He. | –189 | –111 | 8,00 | 841,7 | 0 |
| n.-Xilol | C 8 H 10 | 25 | 45 | 7,32611 | 1635,74 | –41,75 |
| 45 | 190 | 6,99052 | 1453,43 | –57,84 |
||
| about-Xilol | C 8 H 10 | 25 | 50 | 7,35638 | 1671,8 | –42,15 |
| 50 | 200 | 6,99891 | 1474,68 | –59,46 |
||
Continuation of table. 7.1
| Name of substance | Chemical formula | Temperature interval, about with | BUT | IN | FROM |
|
| from | before |
|||||
| Oil Acid | C 4 H 8 O 2 | 80 | 165 | 9,010 | 2669 | 0 |
| Methane | CH 4. | –161 | –118 | 6,81554 | 437,08 | –0,49 |
| –118 | –82,1 | 7,31603 | 600,17 | 25,27 |
||
| Methylene chloride (dichloromethane) | CH 2 Cl 2 | –28 | 121 | 7,07138 | 1134,6 | –42,15 |
| 127 | 237 | 7,50819 | 1462,59 | 5,45 |
||
| Methyl alcohol | CH 4 O. | 7 | 153 | 8,349 | 1835 | 0 |
| -methylstyrene | C 9 H 10 | 15 | 70 | 7,26679 | 1680,13 | –53,55 |
| 70 | 220 | 6,92366 | 1486,88 | –71,15 |
||
| Methyl chloride | CH 3 Cl. | –80 | 40 | 6,99445 | 902,45 | –29,55 |
| 40 | 143,1 | 7,81148 | 1433,6 | 44,35 |
||
| Methyl ethyl ketone | C 4 H 8 O | –15 | 85 | 7,764 | 1725,0 | 0 |
| Formic acid | CH 2 O 2 | –5 | 8,2 | 12,486 | 3160 | 0 |
| 8,2 | 110 | 7,884 | 1860 | 0 |
||
| Neon | Ne | –268 | –253 | 7,0424 | 111,76 | 0 |
| Nitrobenzene | C 6 H 5 O 2 N | 15 | 108 | 7,55755 | 2026 | –48,15 |
| 108 | 300 | 7,08283 | 1722,2 | –74,15 |
||
| Nitromegetan | CH 3 O 2 N | 55 | 136 | 7,28050 | 1446,19 | –45,63 |
| Octane | C 8 H 18 | 15 | 40 | 7,47176 | 1641,52 | –38,65 |
| 40 | 155 | 6,92377 | 1355,23 | –63,63 |
||
| Pentane | C 5 H 12 | –30 | 120 | 6,87372 | 1075,82 | –39,79 |
| 120 | 196,6 | 7,47480 | 1520,66 | 23,94 |
||
| Propane | C 3 H 8 | –130 | 5 | 6,82973 | 813,2 | –25,15 |
| 5 | 96,8 | 7,67290 | 1096,9 | 47,39 |
||
| Propylene (Propen) | C 3 H 6 | –47,7 | 0,0 | 6,64808 | 712,19 | –36,35 |
| 0,0 | 91,4 | 7,57958 | 1220,33 | 36,65 |
||
| Propylene oxide | C 3 H 6 O | –74 | 35 | 6,96997 | 1065,27 | –46,87 |
| Propylene glycol | C 3N 8 O 2 | 80 | 130 | 9,5157 | 3039,0 | 0 |
| Propyl alcohol | C 3 H 8 O | –45 | –10 | 9,5180 | 2469,1 | 0 |
| Propionic acid | C 3N 6 O 2 | 20 | 140 | 8,715 | 2410 | 0 |
| Hydrogen sulfide | H 2 S. | –110 | –83 | 7,880 | 1080,6 | 0 |
| Seroublerod. | CS 2. | –74 | 46 | 7,66 | 1522 | 0 |
| Sulfur dioxide | SO 2. | –112 | –75,5 | 10,45 | 1850 | 0 |
| Sulfur trioxide () | SO 3. | –58 | 17 | 11,44 | 2680 | 0 |
| Sulfur trioxide () | SO 3. | –52,5 | 13,9 | 11,96 | 2860 | 0 |
| Tetrachloroethylene | C 2 CL 4 | 34 | 187 | 7,02003 | 1415,5 | –52,15 |
Ending table. 7.1
| Name of substance | Chemical formula | Temperature interval, about with | BUT | IN | FROM |
|
| from | before |
|||||
| Tiophenol. | C 6 H 6 S | 25 | 70 | 7,11854 | 1657,1 | –49,15 |
| 70 | 205 | 6,78419 | 1466,5 | –66,15 |
||
| Toluene | C 6 H 5 CH 3 | 20 | 200 | 6,95334 | 1343,94 | –53,77 |
| Trichlorethylene | C 2 HCL 3 | 7 | 155 | 7,02808 | 1315,0 | –43,15 |
| Carbon dioxide | CO 2. | –35 | –56,7 | 9,9082 | 1367,3 | 0 |
| Carbon oxide | CO | –218 | –211,7 | 8,3509 | 424,94 | 0 |
| Acetic acid | C 2 H 4 O 2 | 16,4 | 118 | 7,55716 | 1642,5 | –39,76 |
| Acetic anhydride | C 4 H 6 O 3 | 2 | 139 | 7,12165 | 1427,77 | –75,11 |
| Phenol | C 6 H 6 O | 0 | 40 | 11,5638 | 3586,36 | 0 |
| 41 | 93 | 7,86819 | 2011,4 | –51,15 |
||
| Fluorine | F 2. | –221,3 | –186,9 | 8,23 | 430,1 | 0 |
| Chlorine | Cl 2. | –154 | –103 | 9,950 | 1530 | 0 |
| Chlorobenzene. | From 6 H 5 SL | 0 | 40 | 7,49823 | 1654 | –40,85 |
| 40 | 200 | 6,94504 | 1413,12 | –57,15 |
||
| Hydrogen chloride | HCL | –158 | –110 | 8,4430 | 1023,1 | 0 |
| Chloroform | CHCL 3. | –15 | 135 | 6,90328 | 1163,0 | –46,15 |
| 135 | 263 | 7,3362 | 1458,0 | 2,85 |
||
| Cyclohexane | C 6 H 12 | –20 | 142 | 6,84498 | 1203,5 | –50,29 |
| 142 | 281 | 7,32217 | 1577,4 | 2,65 |
||
| Four chloride carbon | CCL 4. | –15 | 138 | 6,93390 | 1242,4 | –43,15 |
| 138 | 283 | 7,3703 | 1584 | 3,85 |
||
| Ethane | C 2 H 6 | –142 | –44 | 6,80266 | 636,4 | –17,15 |
| –44 | 32,3 | 7,6729 | 1096,9 | 47,39 |
||
| Ethylbenzene | C 8 H 10 | 20 | 45 | 7,32525 | 1628,0 | –42,45 |
| 45 | 190 | 6,95719 | 1424,26 | –59,94 |
||
| Ethylene | C 2 H 4 | –103,7 | –70 | 6,87477 | 624,24 | –13,14 |
| –70 | 9,5 | 7,2058 | 768,26 | 9,28 |
||
| Ethylene oxide | C 2 H 4 O | –91 | 10,5 | 7,2610 | 1115,10 | –29,01 |
| Ethylene glycol | C 2 H 6 O 2 | 25 | 90 | 8,863 | 2694,7 | 0 |
| 90 | 130 | 9,7423 | 3193,6 | 0 |
||
| Ethanol | C 2 H 6 O | –20 | 120 | 6,2660 | 2196,5 | 0 |
| Ethyl chloride | C 2N 5 SL | –50 | 70 | 6,94914 | 1012,77 | –36,48 |
In determining the pressure linear of a saturated pair of water-soluble substances, water is used as a reference fluid, and in the case of organic compounds insoluble in water, they usually take hexane. The pressure values \u200b\u200bof a saturated pair of water depending on the temperature are given in Table. §.11. The dependence of the pressure of saturated steam from the temperature of the hexane is given in Fig. 7.1.
Fig. 7.1. The dependence of the pressure of a saturated pair of hexane from temperature
(1 mm Hg \u003d 133.3 PA)
Based on the relation (7.4), a nomogram is constructed to determine the pressure of a saturated steam depending on the temperature (see Fig. 7.2 and Table 7.2).
Over solutions, the pressure of a saturated pair of solvent is less than above a clean solvent. Moreover, the decrease in the pressure of the steam is greater than the above the concentration of the dissolved substance in the solution.
Allen.
6
1,2-dichloroethane
26
Propylene
4
Ammonia
49
Diethyl ether
15
Propionic
56
Aniline
40
Isoprene
14
acid
Acetylene
2
Iodbenzene.
39
Mercury
61
Acetone
51
m.-Krezol
44
Tetralin
42
Benzene
24
about-Krezol
41
Toluene
30
Bromboenzene.
35
m.-Xilol
34
Acetic acid
55
Bromistic ethyl
18
iO-Maslyana
57
Fluorbenzene.
27
-Bromnaftalin
46
acid
Chlorobenzene.
33
1,3-Butadiene
10
Methylamine
50
Chloride Vinyl
8
Butane
11
Methyl monosilane
3
Chloride methyl
7
-Butylene
9
Methyl alcohol
52
Chloride
19
-Butylene
12
Methyl formate
16
methylene
Butylene glycol
58
Naphthalene
43
Chloride ethyl
13
Water
54
-Naftol
47
Chloroform
21
Hexane
22
-Naftol
48
Four chloride
23
Heptane
28
Nitrobenzene
37
carbon
Glycerol
60
Octane
31*
Ethane
1
Dealin
38
32*
Ethyl acetate
25
Dean
36
Pentane
17
Ethylene glycol
59
Dioxan
29
Propane
5
Ethanol
53
Diphenyl
45
Ethyl formate
20
In practice, numerous solutions consisting of two or more well soluble in each other are widely used. The most simple are mixtures (solutions) consisting of two liquids - binary blends. Patterns found for such mixtures can also be used for more complex. Such binary mixtures include: benzene toluene, alcohol-ether, acetone-water, alcohol water, etc. In this case, both components are contained in the vapor phase. The pressure of a saturated pair of the mixture will be made from partial pressure of components. Since the transition of the solvent from the mixture into a vapor-shaped state expressed by its partial pressure is, the greater the greater the content of its molecules in the solution, Raul found that the "partial pressure of a saturated pair of solvent over the solution is equal to the product of a saturated steam pressure over a clean solvent at the same temperature On his molar share in solution ":
where 
- pressure of a saturated pair of solvent over the mixture; 
- Pressure of saturated steam over a clean solvent; N is a molar proportion of the solvent in the mixture.
Equation (8.6) is the mathematical expression of the Raul law. To describe the behavior of a bat dissolved substance (the second component of the binary system), the same expression is used:
.
(8.7)
The total pressure of saturated vapor over the solution will be equal to (Dalton's law):
The dependence of the partial and overall pressure of the vapor of the mixture from its composition is shown in Fig. 8.3, where the pressure of saturated vapors is deposited on the ordinate axis, and the abscissa axis is the composition of the solution in molar fractions. At the same time, along the abscissa axis, the content of one substance (a) decreases from left to right from 1.0 to 0 molar fractions, and the content of the second component (B) simultaneously in the same direction increases from 0 to 1.0. With each specific composition, the general pressure of the saturated pair is equal to the amount of partial pressures. The total pressure of the mixture varies from the pressure of a saturated pair of one individual fluid 
before the pressure of a saturated pair of the second pure liquid 
.
Raoul and Dalton laws are often used to assess the fire hazard of mixtures of liquids.
Composition of the mixture, molar shares
Fig. 8.3 Diagram The composition of the solution - a saturated pair pressure
Typically, the composition of the steam phase does not coincide with the composition of the liquid phase and the steam phase is enriched with a more volatile component. This difference can be depicted and graphically (the schedule has the form of a similar graph in Fig. 8.4, only temperature and pressure on the ordinate is taken on the axis).
In diagrams representing the dependence of boiling temperatures from the composition (diagram boiling temperature Fig. 8.4), it is usually taken to build two curves, one of which binds these temperatures with the composition of the liquid phase, and the other with the composition of steam. The lower curve refers to the compositions of the liquid (fluid curve), and the upper - to the composition of the steam (steam curve).
The field concluded between two curves corresponds to a two-phase system. Any point in this field corresponds to the equilibrium of the two phases - the solution and saturated steam. The composition of the equilibrium phases is determined by the coordinates of the points lying on the intersection of isotherms passing through curves and this point.
At temperatures T 1 (at this pressure), a liquid solution of the composition X 1 will be boiled (point A 1 on the fluid curve), steam, equilibrium with this solution, has the composition X 2 (point B 1 on the steam curve).
Those. The liquids of the composition X 1 will correspond to the pairs of the composition X 2.
Based on expressions: 
,
,
,
,
the relationship between the composition of the liquid and steam phases can be expressed by the ratio:
.
(8.9)
Fig. 8.4. Diagram Compound temperature of boiling double mixtures.
The real pressure of a saturated pair of individual fluid at a given temperature is a characteristic value. There are practically no fluids that would have the same values \u200b\u200bof the saturated pair pressure at the same temperature. therefore 
always more or less 
. If a 
>
T. 
>
. The composition of the steam phase is enriched with component A. Studying solutions, D.P. Konovalov (1881) made a generalization that received the name of the first law of Konovalov.
In the double system of steam, compared with it in equilibrium fluid, relatively richer from the components, the addition of which increases the overall pressure of steam, i.e. lowers the boiling point of the mixture at this pressure.
The first Konovalov law is theoretical basis for separating liquid solutions to the original components by fractional distillation. For example, a system characterized by a point K consists of two equilibrium phases, the composition of which is determined by the points a and b: point A characterizes the composition of the saturated steam, point B is the composition of the solution.
According to graphics, it is possible to compare the compositions of steam and liquid phases for any point concluded in the plane between the curves.
Real solutions. Raul's law is not performed for real solutions. Deviation from the Raul law there are two types:
partial pressure of solutions greater pressures or volatility of the vapor of ideal solutions. The general pressure of steam is greater than an additive value. Such deviations are called positive, for example, for mixtures (Fig. 8.5 A, b) CH 3 COCH 3 -C 2 H 5 OH, CH 3 COCH 3 -CS 2, C 6 H 6 - CH 3 COCH 3, H 2 O- CH 3 OH, C 2 H 5 OH-CH 3 OCH 3, CCl 4 -C 6 H 6, etc.;
b.
Fig. 8.5. The dependence of the total and partial pressures of steam from the composition:
a - for mixtures with a positive deviation from the Raul law;
b - for mixtures with a negative deviation from the Raul law.
partial pressure of solutions is less than the pressure of the vapor of ideal solutions. The total pressure of the steam is less additive. Such deviations are called negative. For example, for the mixture: H 2 O-HNO 3; H 2 O-HCl; CHCl 3 - (CH 3) 2 CO; CHCl 3 -C 6 H 6, etc.
Positive deviations are observed in solutions in which heterogeneous molecules interact with a smaller force than homogeneous.
This facilitates the transition of molecules from the solution into the steam phase. Solutions with a positive deviation are formed with the absorption of heat, i.e. The heat of mixing clean components will be positive, the volume increases, a decrease in the association.
Negative deviations from the Raul law arise in solutions that have increased interaction of heterogeneous molecules, solvation, the formation of hydrogen bonds, the formation of chemical compounds. This makes it difficult to transition molecules from a solution to the gas phase.
Method for calculating the parameters of evaporation of combustible unheated liquids and liquefied hydrocarbon gases
I. 1 The intensity of evaporation W, kg / (C · m 2) are determined by reference and experimental data. For unheated above ambient temperatures, the LVZ, in the absence of data it is allowed to count W. By Formula 1)
W \u003d 10 -6 h p n, (and.1)
where H. - The coefficient received by Table and.1 depending on the speed and temperature of the air flow above the evaporation surface;
M - molar mass, g / mol;
p H - saturated pair pressure settlement temperature Fluid t p, determined by reference data, kPa.
Table and.1.
| Airflow speed indoors, m / s | The value of the coefficient H at a temperature of T, ° C, indoor air | ||||
| 10 | 15 | 20 | 30 | 35 | |
| 0,0 | 1,0 | 1,0 | 1,0 | 1,0 | 1,0 |
| 0,1 | 3,0 | 2,6 | 2,4 | 1,8 | 1,6 |
| 0,2 | 4,6 | 3,8 | 3,5 | 2,4 | 2,3 |
| 0,5 | 6,6 | 5,7 | 5,4 | 3,6 | 3,2 |
| 1,0 | 10,0 | 8,7 | 7,7 | 5,6 | 4,6 |
And.2 For liquefied hydrocarbon gases (SUG), in the absence of data, it is allowed to calculate the specific mass of the vapor of evaporating Sug M Sug, kg / m 2, according to Formula 1)
, (AND 2)
1) The formula is applicable at a temperature of the underlying surface from minus 50 to plus 40 ° C.
where M - Molar mass of Sug, kg / mol;
L is a molar heat of evaporation of SUG at the initial temperature of SUG T G, J / mol;
T 0 - the initial temperature of the material, on the surface of which the Sug is poured, corresponding to the estimated temperature T p, K;
T f - the initial temperature of Sug, K;
l TV - the coefficient of thermal conductivity of the material on the surface of which the Sug, W / (M · K) diffuses;
a - the effective coefficient of the temperature of the material, on the surface of which the SUG is poured, equal to 8.4 · 10 -8 m 2 / s;
t - the current time, with, taken equal to the time of complete evaporation of the SUG, but not more than 3600 s;
Reynolds number (n - air flow speed, m / s; d - Characteristic Size Sug, M;
u B is the kinematic viscosity of air at the estimated temperature T p, m 2 / s);
l B is the coefficient of thermal conductivity of air at the calculated temperature T p, W / (M · K).
Examples - calculation of the parameters of evaporation of combustible unheated liquids and liquefied hydrocarbon gases
1 Determine the mass of steam of acetone entering the room as a result of emergency depressurization of the device.
Data for calculation
In the room with a floor of Paul 50 m 2, a device with acetone with a maximum volume VP \u003d 3 m 3 was installed. Acetone enters the apparatus of gravity in the pipeline with a diameter d. \u003d 0.05 m with consumption q, equal to 2 · 10 -3 m 3 / s. Length of the pressure pipeline from the tank to the manual valve L 1 = 2 m. Length of the area of \u200b\u200bthe discharge pipeline with a diameter d \u003d 0.05 m from the tank to the manual valve L 2 is 1 m. The speed of the air flow and indoors with a working consumer ventilation is 0.2 m / s. The air temperature in the room T p \u003d 20 ° C. The density R acetone at a given temperature is 792 kg / m 3. The pressure of saturated steam of acetone P a at T p is 24.54 kPa.
The volume of acetone released from the pressure pipeline, V N.T.
where T is the estimated pipe of the pipeline, equal to 300 s (with manual disabling).
The volume of acetone released from the discharge pipeline V. from amount
The volume of acetone entered
V a \u003d v ap + v n.t + v from \u003d 3 + 6.04 · 10 -1 + 1.96 · 10 -3 \u003d 6,600 m 3.
Based on the fact that 1 l acetone is poured on 1 m 2 of the floor area, the calculated area of \u200b\u200bevaporation S p \u003d 3600 m 2 acetone will exceed the floor area of \u200b\u200bthe room. Consequently, the area of \u200b\u200bthe floor of the room is taken for the epiphany of acetone, equal to 50 m 2.
The intensity of evaporation is:
W is \u003d 10 -6 · 3.5 · 24.54 \u003d 0.655 · 10 -3 kg / (С · m 2).
Mass of acetone vapor formed during emergency depressurization of the device t, kg, will be equal
t \u003d 0.655 · 10 -3 · 50 · 3600 \u003d 117.9 kg.
2 Determine the mass of gaseous ethylene formed by evaporation of the scenic of liquefied ethylene in emergency depressurization of the tank.
Data for calculation
The isothermal reservoir of liquefied ethylene volume V I.R.E \u003d 10000 m 3 is mounted in concrete molding with a free area S OB \u003d 5184 m 2 and the height of the beading H OB \u003d 2.2 m. The degree of filling of the tank A \u003d 0.95.
Entering the liquefied ethylene pipeline to the tank is made from above, and the output of the removal pipeline is from below.
The diameter of the removal pipeline D TP \u003d 0.25 m. The length of the pipeline area from the tank to the automatic valve, the probability of which exceeds 10 -6 per year and the redundancy of its elements is not provided, L \u003d. 1 m. Maximum consumption of liquefied ethylene in the issuance mode G J.E \u003d 3,1944 kg / s. The density of liquefied ethylene R j.e at operating temperatures T EK \u003d 169.5 K is 568 kg / m 3. The density of the gaseous ethylene R G. T EK equal to 2,0204 kg / m 3. Molar mass liquefied ethylene M. J.E. = 28 · 10 -3 kg / mol. Moligic heat evaporation of liquefied ethylene L and CN. At T EC is 1.344 · 10 4 J / mol. The temperature of the concrete is equal to the maximum possible air temperature in the corresponding climatic zone T B \u003d 309 K. The coefficient of thermal conductivity of concrete l b \u003d 1.5W / (M · K). Coefficient of temperature of concrete but \u003d 8.4 · 10 -8 m 2 / s. The minimum airflow speed U min \u003d 0 m / s, and the maximum for this climatic zone U Max \u003d 5 m / s. The kinematic viscosity of the air N at the estimated air temperature for this climatic zone T p \u003d 36 ° C is 1.64 · 10 -5 m 2 / s. The thermal conductivity coefficient L at T p is 2.74 · 10 -2 W / (M · K).
When the isothermal tank is destroyed, the volume of liquefied ethylene will be
Free bulk volume V. about = 5184 · 2.2 \u003d 11404.8 m 3.
Due to the fact that V. J.E.< V об примем за площадь испарения S исп свободную площадь обвалования S об, равную 5184 м 2 .
Then the mass of the evaporating ethylene M I.E from the spiring area at the speed of the air flow U \u003d 5 m / s is calculated by the formula (and.2)
Mass M I.E with u \u003d 0 m / s will be 528039 kg.
The table shows the thermophysical properties of a pair of benzene C 6 H 6 at atmospheric pressure.
The values \u200b\u200bof the following properties are given: density, heat capacity, thermal conductivity coefficient, dynamic and kinematic viscosity, temperature, temperature, number of parandtl depending on temperature. Properties are given in the temperature range from.
According to the table, it can be seen that the density values \u200b\u200band the number of the prandtl with increasing the temperature of the gas can be reduced. Specific heat, thermal conductivity, viscosity and thermal duration when heating a pair of benzene increases their values.
It should be noted that the density of the benzene pair at a temperature of 300 K (27 ° C) is 3.04 kg / m 3, which is much lower than this indicator in liquid benzene (see).
Note: Be careful! The thermal conductivity in the table is indicated to the degree 10 3 do not forget to divide by 1000.
Thermal conductivity of a pair of benzene.
The table shows the thermal conductivity values \u200b\u200bof the benzene pair at atmospheric pressure depending on the temperature in the range from 325 to 450 K.
Note: Be careful! The thermal conductivity in the table is indicated to the degree 10 4. Do not forget to divide by 10,000.
The table shows the pressure values \u200b\u200bof a saturated pair of benzene in the temperature range from 280 to 560 K. It is obvious that when the benzene is heated, the pressure of its saturated vapor increases.
Sources:
1.
2.
3. Volkov A. I., Zharky I. M. Great chemical reference book. - M: Soviet school, 2005. - 608 p.