Control Work (90 minutes). Laboratory work: Receiving methane and experiments with it D

ethanol by Winkler, has a number of disadvantages: multiple

distillation, the product is contaminated with ammonia resulting from

hydrolysis of calcium nitride, which is contained as an impurity in calcium metal.

e) Calcium carbide is an effective desiccant, but pollutes

alcohol with acetylene and other products. At present, neither metallic calcium nor its carbide is used for the absolute deposition of ethanol.

f) Anhydrous copper sulfate is advantageous in that its intensity

blue color can be judged on the quality of the original alcohol and the end

absolute process. However, it is also currently

are practically not used.

g) Azeotropic distillation of a mixture of alcohol - benzene, used for

obtaining absolute alcohol on a technical scale, was also developed for laboratory conditions. However, practically this

The method has not been widely adopted.

h) Chloride spike was used to dehydrate 95°

ethanol in the gas phase. This method was obtained 99.8% ethanol.

From the resulting solution, calcium chloride is easily regenerated.

i) Anhydrous calcium sulfate has also been proposed for drying ethanol. However, it is a relatively weak desiccant and is unsuitable for

for complete dehydration of alcohol. In addition, prn great content

water forms a dihydrate, which is difficult to remove from the flask.

Ethyl alcohol is often used as a solvent in the catalytic hydrogenation of various substances. In this case, usually the presence of a small amount of water does not matter, but it is essential to remove substances that poison the catalyst. Pure 95% ethyl alcohol contains very few of these substances, and it is usually sufficient to distill it in a device with thin sections. At the same time, thin sections are thoroughly cleaned and not lubricated, and the first part of the distillate is discarded. Even more efficient is the distillation of alcohol over a small amount of Raney nickel.

11.3. "-Propyl alcohol

“-Propyl alcohol (bp. 973) forms an azeotropic mixture with water, boiling at 88 ° and containing 71% propyl alcohol. It is miscible with water in any ratio. For its drainage, calcium oxide is used, and for final dehydration, calcium hydride is used. With a low water content, dehydration can be carried out using sodium proplate prepared by dissolving sodium metal in propyl alcohol.

11.4. Isopropyl alcohol

Has so bale. 82.4°, forms an azeotropic mixture with water, bp. 80° containing 87.4% isopropyl alcohol. It is miscible with water in all respects. With a high water content, isopropyl alcohol is first dried with sodium carbonate or potash and finally absolute with calcium chloride. With a small water content, calcium oxide is a good desiccant, which reduces the water content to 0.1%; for final dehydration, distillation over anhydrous copper sulfate is recommended. In addition, for drying isopropyl alcohol, you can use all the methods mentioned above for ethyl alcohol.

11.5. Butyl alcohols

“-Butyl alcohol (bp. 118 °) with water forms an azeotropic mixture with bp. 93°, containing 58% "-butyl alcohol.

Isobutyl alcohol (bp. 108 °) gives an azeotropic mixture with water with bp. 90° containing 67% isobutyl alcohol.

emop-butyl alcohol (bp 99.5°) forms an azeotropic mixture with water, bp 87.5° containing 73% emop-butyl alcohol.

/rzpem-Butyl alcohol (bp 82.5°) forms an azeotropic mixture with water, boiling at 80° and containing 88% mpem-butyl alcohol.

The first three of the listed alcohols are limitedly miscible with water, and in most cases fractional distillation is sufficient for their drying. Of the chemical desiccants, calcium oxide, barium oxide, magnesium oxide, or the corresponding sodium alcoholate, obtained by dissolving sodium in this alcohol, can be used.

mpem-butyl alcohol, on the other hand, is miscible with water in all proportions. This is a very valuable solvent, characterized by a significant dissolving power with high resistance to oxidizing agents, halogens, etc. With a high water content, tert-butyl alcohol is preliminarily dried with calcium chloride. Small amounts of water are removed with calcium oxide or metallic sodium. The high solidification temperature of tert-butyl alcohol (25.7 °) makes it possible to purify it by fractional crystallization.

11.6. Higher aliphatic alcohols

For alcohols of this type, only physical constants are given below. The main method of their purification is distillation, for example with the addition of conventional desiccants (calcium oxide, barium oxide, etc.).

Isoamyl alcohol (bp 132e) forms an azeotropic mixture with water, boiling at 95°C and containing 41% alcohol.

Optically active amyl alcohol, bp 128°.

n-Hexyl alcohol (bp 157.5°) forms an azeotropic mixture with water, boiling at 98° and containing 20% ​​alcohol.

2-Ethylbutanol-1 (b.p. 146°) image

TASKS OF THE SCHOOL STAGE OF THE ALL-RUSSIAN OLYMPIAD FOR SCHOOLCHILDREN IN CHEMISTRY

2014/15 ACADEMIC YEAR

NYAGAN KHMAO-YUGRA TYUMEN REGION

Grade 11

Part 1.

When completing the tasks of this part, from the proposed answers, select one

The nucleus of an iron atom contains:

a) 26 protons and 30 neutrons; b) 26 protons and 26 electrons;

c) 30 neutrons and 26 electrons; d) 26 protons and 26 electrons.

2. Corpuscular-wave dualism is possessed by:

a) protons; b) neutrons; c) electrons; d) all answers are correct.

3. What type of orbital is available at any energy level:

a) s; b) p; c) d; d) f.

4. The Ca 2+ ion corresponds to the electronic formula: a) 1s 2 2s 2 2p 6 3s 2 3p 6;

b) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 ; c) 1s 2 2s 2 2p 6 ; d) there is no correct answer.

5. The ionic nature of the bond is most pronounced in the compound:

a) CCl 4 ; b) SiO 2 ; c) CaBr 2 ; d) NH3.

6. By combining atoms of the same chemical element, a bond is formed:

a) ionic; b) covalent polar; c) covalent non-polar; d) hydrogen.

7. In which molecule is the oxidation state of the element equal to zero, and the valency is equal to one?

a) O 2 ; b) CaC 2 ; c) Cl 2 ; d) CO.

8. Substances with hardness, refractoriness, good solubility in water, as a rule, have a crystal lattice:

a) molecular; b) nuclear; c) ionic; d) metal.

9. Which of the elements can form an acidic oxide?

a) strontium; b) manganese; c) calcium; d) magnesium.

10. The number of substances to which the names correspond: formic aldehyde, formaldehyde, methanal, ethanal, acetaldehyde, acetaldehyde, is equal to:

a) 6; b) 4; in 2; d) 1.

11. The highest oxide of a chemical element with the serial number 25 refers to oxides:

a) main; b) acidic; c) amphoteric; d) non-salt-forming.

12. For the production of Christmas decorations in the industry, a chemical reaction is used:

a) Zinin reaction; b) Kucherov's reaction; c) "silver mirror" reaction; d) nitration reaction;

For each correct answer, the participant receives 1 point.

Part 2.

Solve problems, give full detailed solutions.

Task 1.

When interacting with water, 27.4 g of a divalent metal releases 4.48 liters (N.O.) of gas. To the resulting solution, the mass of which is equal to 800 g, was added 200 g of a 10% sodium sulfate solution, and a precipitate formed. What metal are we talking about? What is the mass of the resulting precipitate? What are the mass fractions of substances in the resulting solution?

Task 2.

Salt is composed of 26.53% potassium, 35.37% chromium, 38.1% oxygen. Determine the formula of the salt and calculate its mass spent on interaction with an excess of hydrochloric acid, if chromium chloride (lll) was formed and 13.4 liters of chlorine (n.o.) were released.

Task 3.

Calcium carbide was used to dehydrate ethanol. Determine the mass of calcium carbide that must be added to alcohol with a volume of 150 ml with a density of 0.8 g / ml, containing 96% ethanol to obtain anhydrous alcohol?

Task 4.

Add the equation, equalize using the electron balance method, determine the oxidizing agent and reducing agent:

KNO 2 + KMnO 4 + H 2 SO 4 → KNO 3 + ....

A task 5.

The diagram shows the transformations of X.

X + SO 2 → S + H 2 O

Suggest X and write down the equations of the transformations carried out.

Answers to tasks. Grade 11.

Part 1 answers.

Total: 12 points.

Part 2 answers.

Task 1.

The condition of the problem corresponds to the reaction equations:

Me + 2H 2 O \u003d Me (OH) 2 + H 2, - 0,5 points

Me(OH) 2 + Na 2 SO 4 = MeSO 4 ↓ + 2NaOH - 0,5 points

Calculate the amount of gas (H 2): 4.48 / 22.4 \u003d 0.2 (mol) - 0.5 points

N (Me) \u003d n (H 2) \u003d 0.2 mol; hence the atomic mass of the metal is: m(Me)/n(Me)=27.4/0.2=137 g/mol. The metal of interest is barium. - 1 point

Let's calculate the amount of substance Ba(OH) 2 ; n (Ba (OH) 2) \u003d n (H 2) \u003d 0.2 mol. - 0.5 points

Calculate m (Na 2 SO 4) \u003d w (Na 2 SO 4) * m (solution) / 100; m (Na 2 SO 4) \u003d 10 * 200 / 100 \u003d 20g, - 0,5 b

calculate n (Na 2 SO 4) \u003d m (Na 2 SO 4) / M (Na 2 SO 4) \u003d 20/142 \u003d 0.14 (mol). 0.5 points

From here: n (Ba (OH) 2) \u003d n (Na 2 SO 4) \u003d 0.14 mol, i.e. sodium sulfate fully reacts in the reaction. – 1 point

We calculate the amount of sediment substance: n (BaSO 4) \u003d 0.14 mol.

The solution contains NaOH: nNaoH \u003d 2 * 0, 14 \u003d 0.28 mol; the amount of remaining Ba (OH) 2 \u003d 0.2-0.14 \u003d 0.06 (mol). - 1 point

Sediment mass: m (BaSO 4) \u003d n (BaSO 4) * M (BaSO 4) \u003d 0.14 * 233 \u003d 32.62 (g).

Mass fraction of NaOH in solution: m(NaOH)*100/800= 0.28*40*100/800=1.4% -0.5 points

W(Ba(OH) 2)=0.06*171*100/800=1.3% - 0.5 points.

Total: 6 points

Task 2 Let us determine the atomic ratio of elements in salt K x Cr y O z:

x:y:z = 26.53/39: 35.37/52: 38.1/16 = 0.68:0.68:2.38 = 1:1:3.5 = 2:2:7 - 0.5 points

the desired salt is potassium dichromate - K 2 Cr 2 O 7. - 0.5 points

Salt reacts with hydrochloric acid according to the equation:

K 2 Cr 2 O 7 + 14 HCl \u003d 2KCl + 2CrCl 3 + 3Cl 2 + 7H 2 O - 1 point

Let's calculate the amount of chlorine substance: n (Cl 2) \u003d V / V m \u003d 13.4 / 22.4 \u003d 0.6 (mol) - 0,5

points

Let's calculate the amount of potassium dichromate substance: n (K 2 Cr 2 O 7) \u003d 1/3 n (Cl 2) \u003d 0.6: 3 \u003d 0.2 (mol). Hence, m (K 2 Cr 2 O 7) \u003d n (K 2 Cr 2 O 7) * M (K 2 Cr 2 O 7) \u003d 0.2 * 294 \u003d 58.8 (g). - 0.5 points

Thus, the mass of salt consumed is 58.8 grams.

Total: 3 points

Task 3.

Calculate the mass of alcohol m=V*density; m (C 2 H 5 OH) \u003d 150 * 0.8 \u003d 120 (g). - 0.5 points

Let's calculate the mass of water in alcohol: m (H 2 O) \u003d w (H 2 O) * m (solution) / 100 \u003d 4 * 120/100 \u003d 4.8 (g). - 0.5 points

Let's calculate the amount of water substance: n (H 2 O) \u003d m (H 2 O): M (H 2 O) \u003d 4.8: 18 \u003d 0.27 (mol). - 0.5 points

According to the condition of the problem, water reacts with calcium carbide:

CaC 2 +2 H 2 O \u003d Ca (OH) 2 ↓ + C 2 H 2 - 0.5 points

n (CaC 2) \u003d 1/2 n (H 2 O) \u003d 0, 27/2 mol \u003d 0.135 mol - 0.5 points

calculate the mass of calcium carbide: m (CaC 2) \u003d n (CaC 2) * M (CaC 2) \u003d 0.27 * 64 \u003d 17.28 (g) - 0.5 points.

therefore, 17.28 grams of calcium carbide will be required.

Total: 3 points

Task 4.

5K +1 N +3 O 2 -2 +2K +1 Mn +7 O 4 -2 +3 H +1 2 S +6 O 4 -2 = 5K +1 N +5 O 3 -2 + K 2 S + 6 O 4 -2 + 2Mn +2 S +6 O 4 -2 + 3H +1 2 O -2

N +3 - 2e - = N +5 5 reducing agent, oxidation

Mn +7 + 5e - = Mn +2 2 oxidizer, reduction

Total: 3 points

Task 5.

2H 2 S + 3O 2 \u003d 2H 2 O + 2SO 2

H 2 S + Br 2 \u003d 2HBr + S ↓

H 2 S + 2KOH \u003d K 2 S + 2H 2 O (H 2 S + KOH \u003d KHS + H 2 O)

H 2 S + 2FeCl 3 \u003d 2FeCl 2 + 2HCl + S ↓

2H 2 S + SO 2 \u003d 3S ↓ + 2H 2 O

For each correctly written equation - 2 points.

Total: 10 points.

TOTAL: for the correct performance of all work - 37 points

Tasks prepared by: Yakunina L.B., MBOU "Secondary School No. 2"

The present invention relates to a method for producing absolute ethyl alcohol, which can be used in the chemical, electronic and pharmaceutical industries. The method includes supplying raw alcohol or a water-alcohol solution to a preliminary dehydration column operating under vacuum to obtain a distillate, which is sent to the final dehydration column operating at excess pressure, where absolute alcohol is taken in the form of a bottom liquid, and the distillate is taken in the form of a return the flow is sent to the pre-absolute column. At the same time, the rectification process on the preliminary absolute absolute pressure is carried out at an absolute pressure of 8.0-13.3 kPa to obtain a distillate with an alcohol content of 98.2-98.9 vol.%, and the rectification process on the final absolute absolute pressure is carried out at an absolute pressure of 0, 1-0.5 MPa and the alcohol content in the return flow of 96.5-97.2 vol.%. The proposed method makes it possible to obtain a high quality target product using an improved process flow diagram. 1 tab., 1 ill., 2 pr.

The invention relates to the alcohol industry, namely the production of dehydrated ethyl alcohol (absolute), and can be used in the chemical, electronic, pharmaceutical industries.

Known methods of dehydration of ethyl alcohol, based both on the use of chemical methods and various processes, such as extraction, adsorption, azeotropic and extractive distillation, pervaporation.

One of the ways to obtain absolute ethyl alcohol is to obtain anhydrous ethyl alcohol by separating mixtures in a complex of distillation columns operating under different pressures. The basis of this method is the change in the content of ethyl alcohol in the azeotropic mixture of ethanol - water, depending on the pressure.

To obtain dehydrated ethyl alcohol, a possible technological scheme of a two-column installation is presented (S.V. Lvov. Some issues of rectification of binary and multicomponent mixtures. M.: Publishing house of the Academy of Sciences of the USSR, 1960, p. 13). In the first column, operating at atmospheric pressure, from the initial ethanol-poor mixture, water is obtained as the bottom product and a mixture close to the azeotrope in composition, i.e. 90 mol.% ethyl alcohol and 10 mol.% water. The latter is pumped by a pump into the second distillation column operating at a pressure of 75 atm (7.6 MPa), where a mixture close in composition to an azeotropic mixture containing 70 mol.% ethanol and 30 mol.% water will be distilled as the top product, which is again sent for enrichment to the first column, and almost anhydrous alcohol will be obtained as the bottom product.

A known flowsheet for the production of bioethanol used as fuel ethanol, including a dehydration scheme consisting of two columns (N.Arifeen, R.Wang, I.K.Kookos, C.Webb, A.A.Koutinas. Process design and optimization of novel wheat- based continuous bioethanol production system Biotechnol Prog 2007, 23, 1394-1403). The first column, operating at a pressure of 1 bar (0.1 MPa), is supplied with an initial mixture containing 40 mol.% ethyl alcohol, where a distillate containing 89.75 mol.% ethyl alcohol is taken, and the bottom liquid is water containing ethyl alcohol. alcohol 1.09 mol.%. The distillate from the first column is sent to the second column, operating at a pressure of 10 bar (1.0 MPa), on which dehydrated ethanol containing 99.0 mol.% ethanol and a distillate containing 84.95% are taken in the form of bottom liquid. molar ethyl alcohol, which is returned to the first column.

A known method of dehydration of alcohol (US patent No. 1676700, B01D, publ. 07/10/1928), including the concentration of an aqueous solution of ethyl alcohol containing less than 95.6% ethanol, fractional distillation at an absolute pressure of not more than 6 inch Hg (20.3 kPa) with the selection of a distillate containing more than 95.6% ethanol, and fractional distillation of this distillate at a pressure of at least 100 psi (0.69 MPa), followed by removal of the dehydrated residue and obtaining a distillate containing less than 95.6% ethanol, which with an aqueous solution of ethyl alcohol is fed to distillation under vacuum.

A known method of obtaining dehydrated alcohol from fermented wort containing 8-10 vol.% alcohol (French patent No. 2461751, B01D 3/00, publ. 06.02.1981). The fermented wort, preheated in a heat exchanger, is fed to the first distillation column operating at a residual pressure of 190 mm Hg (25.3 kPa) at the head. Alcohol with a concentration of 97.4 wt.%, is taken and sent by means of a pump through the recuperator to a distillation column, which operates at a pressure of 7 bar (0.7 MPa). At this pressure, the alcohol content in the alcohol-water azeotrope is 93.6 wt.%; therefore, the feed of this column can be considered as a pseudo-binary mixture, consisting of 40.6 wt. % anhydrous alcohol (heavy part). Absolute alcohol is taken from the base of the second column and cooled. Azeotropic mixture with 10% absolute alcohol is removed from the head of the second column and returned to the first column. The vapors separated in the head of the second column are compressed to 7-8 bar (0.7-0.8 MPa) by a compressor driven by a steam turbine. Compressed alcohol vapors are condensed in the heat exchanger, heating the second column. The output of dehydrated alcohol is about 97% based on the alcohol in the feedstock.

The above technological schemes for the production of anhydrous ethyl alcohol using distillation columns operating under pressure require the use of high-pressure steam or other high-temperature heat carriers to ensure the specified parameters of the rectification process on high-pressure columns, which increases the consumption of heat and energy resources, as well as the creation of separation complexes using devices different functional action, which complicates the technological scheme of production.

The purpose of the present invention is to improve the method of dehydration of alcohol, improve the quality of the target product.

This goal is achieved in that the method for producing absolute ethyl alcohol includes the supply of raw alcohol or a water-alcohol solution to a preliminary absolute absolute column operating under vacuum to obtain a distillate, which is sent to the final absolute absolute column operating at excess pressure, on which absolute alcohol is taken in the form of a bottom liquid, and the distillate in the form of a return flow is sent to the column of preliminary dehydration. At the same time, the rectification process on the preliminary absolute absolute pressure is carried out at an absolute pressure of 8.0-13.3 kPa to obtain a distillate with an alcohol content of 98.2-98.9 vol.%, and the rectification process on the final absolute absolute pressure is carried out at an absolute pressure of 0, 1-0.5 MPa and the alcohol content in the return flow of 96.5-97.2 vol.%.

The proposed method allows to significantly simplify the technological scheme of alcohol dehydration, namely, to abandon complex equipment for mechanical vapor recompression. The process is carried out at a lower pressure, which reduces the requirements for the characteristics of heat carriers, makes it easy to implement this method at distilleries using water vapor of 0.6 MPa in the industrial cycle, and guarantee the production of absolute ethyl alcohol with a strength of 99.5-99.95 vol. %.

The method of obtaining absolute ethyl alcohol is carried out at the installation, the scheme of which is shown in the drawing, as follows.

The feedstock (alcohol with a strength of 95 vol.% or a water-alcohol solution with a strength of 40 vol.%) is taken into collection 1. From collection 1, raw materials are fed through line 2 into column 3 to the top of the first or second (counting from the bottom) side of column 3 due to pressure difference in collector 1 (atmospheric) and in column 3 (vacuum). On column 3, alcohol is pre-absoluted under vacuum at an absolute pressure of 8.0-13.3 kPa. Column 3 has 5 drawers filled with a regular packing of metal mesh, equipped with a dephlegmator 4 and a condenser 5, cooled by water at a temperature of 5-7°C. Column 3 is heated through an external boiler 6 with steam. Vapors coming from column 3 are condensed in dephlegmator 4 and condenser 5 and return in the form of phlegm through reflux collector 7 to the upper side of column 3. Non-condensable vapors and gases from condenser 5 enter the vacuum collector (not shown in the diagram). The distillate, which is partially anhydrous alcohol with a strength of 98.2-98.9 vol.%, is taken from the reflux collector 7 through the barometric tube 8 into the collection 9, which is under atmospheric pressure. The bottom liquid of column 3 (lutheran water) is discharged into an evacuated collector 10.

From collection 9, partially dehydrated alcohol is pumped by pump 11 along line 12 through heater 13 into column 14 to the top of the second or third (counting from the bottom) side of column 14. In heater 13, which is heated by steam, partially dehydrated alcohol is heated to a temperature of 95-100 ° FROM. On the column 14 is the final absolute absolute alcohol at an absolute pressure of 0.1-0.5 MPa. Column 14 has 5 drawers filled with a regular packing of metal mesh, equipped with a dephlegmator 15, cooled by water. Column 14 is heated through an external boiler 16 with steam. Vapors coming from column 14 are condensed in dephlegmator 15 and return in the form of phlegm through reflux collector 17 to the upper side of column 14. Air line 18 from dephlegmator 15 is equipped with a safety valve (not shown in the diagram). The distillate of column 14, which is return alcohol with a strength of 96.5-97.2 vol.%, is taken from the reflux collector 17 and sent through the refrigerator 19, in which it is cooled with water to 30 ° C, along line 20 to column 3 to the top of the second (counting bottom) side of column 3 due to the pressure difference in columns 3 and 14. The bottom liquid of column 14, which is absolute alcohol with a strength of 99.5-99.95 vol.%, is discharged through the refrigerator 21, cooled by water, into the collection 22 due to the pressure difference in column 14 (excess) and in collection 22 (atmospheric).

The operating modes of distillation columns and the quality of the obtained absolute ethyl alcohol according to the proposed method are presented in the table.

A method for producing absolute ethyl alcohol, which includes supplying raw alcohol or a water-alcohol solution to a preliminary absolute absolute column operating under vacuum to obtain a distillate, which is sent to a final absolute absolute column operating at excess pressure, on which absolute alcohol is taken in the form of a bottom liquid, and the distillate in the form of a return flow is sent to the preliminary absoluteization column, characterized in that the rectification process on the preliminary absoluteization column is carried out at an absolute pressure of 8.0-13.3 KPa to obtain a distillate with an alcohol content of 98.2-98.9 vol.% , and the process of distillation on the column of the final absolute is carried out at an absolute pressure of 0.1-0.5 MPa and the alcohol content in the return stream of 96.5-97.2 vol.%.

original mixture. Answer: volume fraction 40%; mass fraction 38.4%.

17.28. The composition of the hydrocarbon is expressed by the formula C3 H4. For the hydrogenation of this hydrocarbon weighing 5 g to the limit compound, hydrogen was consumed in a volume of 2.8 liters (normal conditions). Determine the structural formula of a hydrocarbon and name it. Answer: cyclopropene.

18. AROMATIC HYDROCARBONS 18.1. Compose the structural formulas of isomers that correspond to the formula

C8 H10 and containing an aromatic ring.

18.4. Make up the reaction equations with which you can carry out transformations:

methane → X → benzene

Name the substance X. Specify the conditions for the reactions to take place. Answer: X is acetylene.

18.5. Dehydrogenation of ethylbenzene weighing 4.24 g gave styrene. The yield of the reaction product was 75%. What mass of a solution of bromine in carbon tetrachloride can be discolored by the resulting styrene if the mass fraction of bromine in the solution is 4%?

18.6. What volume of hydrogen, measured under normal conditions, is formed during the cyclization and dehydrogenation of m-hexane with a volume of 200 ml and a density of 0.66 g/ml? The reaction proceeds with a yield of 65%. Answer: 89.4 liters.

18.7. What volume of air, measured under normal conditions, will be required for the complete combustion of 1,4-dimethylbenzene weighing 5.3 g? The volume fraction of oxygen in the air is 21%. Answer: 56 liters.

18.8. When burning a homologue of benzene weighing 0.92 g in oxygen, carbon monoxide (IV) was obtained, which was passed through an excess of calcium hydroxide solution. In this case, a precipitate was formed weighing 7 g. Determine the formula of the hydrocarbon and name it. Answer: C7 H8

18.9. An aromatic hydrocarbon, which is a homologue of benzene, weighing 5.3 g was burned, obtaining carbon monoxide (IV) with a volume of 8.96 l (normal conditions). Determine the formula for the hydrocarbon. How many isomers can this hydrocarbon have among benzene homologues? Write the structural formulas of these isomers. Answer: C8 H10; 4 isomeric homologues of benzene.

18.10. From acetylene with a volume of 3.36 liters (normal conditions) we obtained

benzene with a volume of 2.5 ml. Determine the yield of the product if the density of benzene is 0.88 g/ml. Answer: 56.4%.

18.11. When benzene was brominated in the presence of iron (III) bromide, hydrogen bromide was obtained, which was passed through an excess of silver nitrate solution. In this case, a precipitate with a mass of 7.52 g was formed. Calculate the mass of the resulting product of benzene bromination and name this product. Answer: 6.28 g; bromobenzene.

18.12. Benzene, obtained by dehydrogenation of piclohexane with a volume of 151 ml and a density of 0.779 g/ml, was subjected to chlorination under illumination. A chlorine derivative with a mass of 300 g was formed. Determine the yield of the reaction product. Answer: 73.6%.

18.13. A mixture of benzene and cyclohexene weighing 4.39 g discolors bromine water weighing 125 g with a mass fraction of bromine of 3.2%. What mass of water is formed when the same mixture of mass 10 g is burned in oxygen?

18.14. A mixture of benzene and styrene of a certain mass discolors bromine water weighing 500 g with a mass fraction of bromine of 3.2%. When burning a mixture of the same mass, carbon monoxide (IV) was released with a volume of 44.8 liters (normal conditions). Determine the mass fractions of benzene and styrene in the mixture. Answer: 60% benzene; 40% styrene.

19. ALCOHOLS AND PHENOLS

Nomenclature, properties and production of alcohols and phenols

19.4. How many isomeric alcohols can chloropropanol C3 H6 CIOH have? Write the structural formulas of isomers and name them according to substitutional nomenclature. Answer: 5 isomers.

19.5. How many phenols can be isomeric to 2-methyl-6-chlorophenol? Write the structural formulas of these phenols and name them. Answer: 12 isomeric phenols (excluding 2-methyl-6-chlorophenol).

19.6. How many isomeric tertiary alcohols can have the composition C6 H13 OH? Write the formulas of these alcohols and name them according to the substitutional nomenclature. Answer: three alcohols.

19.11. Three tubes contain butanol-1, ethylene glycol and a solution of phenol in benzene. What chemical reactions can be used to distinguish between these substances? Write the equations for the corresponding reactions.

19.12. Three test tubes without inscriptions contain liquids: n-propanol, 1-chlorobutane and glycerin. What chemical reactions can be used to distinguish between these substances? Write the equations for these reactions.

Calculations by reaction equations involving saturated monohydric alcohols

19.14. What mass of sodium propylate can be obtained by reacting propanol-1 weighing 15 g with sodium weighing 9.2 g?

19.15. During the interaction of butanol-1 with an excess of metallic sodium, hydrogen was released, which under normal conditions occupies a volume of 2.8 liters. What amount of butanol-1 reacted? Answer: 0.25 mol.

19.16. Methanol was heated with an excess of potassium bromide and sulfuric acid in an amount of 0.5 mol of substance, bromomethane was obtained with a mass of 38 g. Determine the yield of bromomethane. Answer: 80%.

19.17. During the dehydration of propanol-2, propylene was obtained, which discolored bromine water weighing 200 g. The mass fraction of bromine in bromine water is 3.2%. Determine the mass of propanol-2 taken for the reaction.

Answer: 2.4 g.

19.18. When saturated monohydric alcohol with a mass of 12 g was heated with concentrated sulfuric acid, an alkene with a mass of 6.3 g was formed. The product yield was 75%. Determine the formula of the original alcohol.

19.19. Determine the formula of the limiting monohydric alcohol if, when dehydrating a sample with a volume of 37 ml and a density of 1.4 g / ml, an alkene with a mass of 39.2 g was obtained. Answer: C4 H9 OH.

19.20. Sodium weighing 12 g was placed in ethanol with a volume of 23 ml and a density of 0.8 g/ml. The mass fraction of water in ethanol is 5%. What volume of hydrogen will be released in this case? Calculate the volume under normal conditions.

19.21. What mass of metallic sodium will react with a solution of propanol-1 weighing 200 g, the mass fraction of water in which is 10%? What volume of hydrogen, measured under normal conditions, will be released in this reaction? Answer: 94.5 g Na; 46 g H2.

19.22. What mass of calcium carbide must be added to alcohol with a volume of 150 ml and a density of 0.8 g / ml to obtain absolute (anhydrous) alcohol,

if the mass fraction of ethanol in alcohol is 96%? What mass of absolute alcohol will be obtained in this case? Answer: 8.53 g CaC2; 115.2 g absolute alcohol.

19.23. From technical calcium carbide weighing 4 g, under the action of excess water, a gas with a volume of 1.12 liters (normal conditions) can be obtained. What mass of technical carbide must be taken to obtain ethanol weighing 19.6 g, the mass fraction of water in which is 6%? Answer: 32

19.24. During the catalytic dehydration of ethanol weighing 1.84 g, a gas was obtained, which reacted with bromine contained in a chloroform solution weighing 50 g. The mass fraction of bromine in this solution is 8%. Determine the yield of the alcohol dehydration product, if the yield in the bromination reaction is quantitative. Answer: 62.5%.

19.25. Limiting monohydric alcohol weighing 30 g interacts with an excess of metallic sodium, forming hydrogen, the volume of which under normal conditions was 5.6 liters. Determine the formula for alcohol. Answer:

C3 H7 OH.

19.26. In the production of synthetic rubber according to the Lebedev method, ethanol is used as a feedstock, the vapors of which are passed over the catalyst, obtaining butadiene-1,3, hydrogen and water. What mass of butadiene-1,3 can be obtained from alcohol with a volume of 230 liters and a density of 0.8 kg / l, if the mass fraction of ethanol in alcohol is 95%? Note that the product yield is 60%. Answer: 61.56 kg.

19.27. Methanol is produced by the interaction of carbon monoxide (II) with hydrogen. Carbon monoxide (II) with a volume of 2 m3 and hydrogen with a volume of 5 m3 were taken for the reaction (volumes are reduced to normal conditions). The result was methanol weighing 2.04 kg. Determine the yield of the product. Answer:

19.28. What mass of metallic sodium and absolute ethanol must be taken to obtain an ethanol solution weighing 200 g, in which the mass fraction of sodium ethoxide is 10.2%?

19.29. Determine the mass fraction of sodium alcoholate in its alcohol solution obtained as a result of the reaction between sodium metal weighing 2.3 g and absolute ethanol with a volume of 50 ml and a density of 0.79 g / ml.

Answer: 16.3%.

19.30. From propanol-2 weighing 24 g, 2-bromopropane was obtained, which was used to obtain 2,3-dimethylbutane. What mass of dimethylbutane was formed if the yield of products at each stage of the synthesis was

60%? Answer: 6.2g.

19.31. The interaction of butanol-2 weighing 7.4 g with an excess of hydrobromic acid gave a bromo derivative, from which 3,4-dimethylhexane weighing 3.99 g was synthesized. Determine the yield of the reaction product. Answer: 70%.

19.32. Dehydration of the saturated monohydric alcohol yielded an alkene of a symmetrical structure with an unbranched chain weighing 8.4 g, which interacts with bromine weighing 24 g. Determine the structural formula of the initial alcohol and name it. Answer: butanol-2.

19.33. When saturated monohydric alcohol is heated with concentrated hydrobromic acid, a compound is formed, the mass fraction of bromine in which is 73.4%. Determine the formula of the original alcohol. Answer: C2 H5 OH.

19.34. What volume of hydrogen, measured under normal conditions, can be obtained by reacting metallic sodium weighing 1.6 g with a mixture of methanol and ethanol weighing 2.48 g? The mass fraction of methanol in the mixture is 25.8%, ethanol - 74.2%. Answer: 672 ml.

Calculations using reaction equations involving phenols

19.35. What mass of sodium phenolate can be obtained by reacting phenol with a mass of 4.7 g with a solution of sodium hydroxide with a volume of 4.97 ml and a density of 1.38 g/ml? The mass fraction of sodium hydroxide in solution is 35%. Answer: 5.8 g.

19.36. When reacting a solution of phenol in benzene weighing 200 g with an excess of bromine water, a bromine derivative weighing 66.2 g was obtained. Determine the mass fraction of phenol in the solution. Answer: 9.4%.

19.37. There is a mixture of phenol with ethanol. An excess of metallic sodium was added to one half of the mixture, producing 672 ml of hydrogen (normal conditions). An excess of bromine solution was added to the other half of the mixture, and a precipitate of 6.62 g was formed. Determine the mass fractions of phenol and ethanol in the mixture.

19.38. A 50 ml solution with a mass fraction of sodium hydroxide of 18% and a density of 1.2 g/ml was used to neutralize the mixture of phenol with ethanol. The same mass of the mixture reacted with sodium metal weighing 9.2 g. Determine the mass fractions of phenol and ethanol in the mixture. Answer: phenol

80.9%; ethanol 19.1%. 20. ALDEHYDES

20.1. Write the structural formulas of the following aldehydes: 2-methylpentanal, 2,3-dimethylbutanal, hexanal.

20.4. What amount of formaldehyde substance is contained in a solution with a volume of 3 or a density of 1.06 g / ml, the mass fraction of CH2O in which is equal to

twenty%? Answer: 21.2 mol.

20.5. What volume of formaldehyde must be dissolved in 300 g of water to obtain formalin with a mass fraction of formaldehyde of 40%? Calculate the volume under normal conditions. What mass of formalin will be obtained? Answer: CH2 O with a volume of 149.3 liters; formalin weighing 500 g.

20.6. In the interaction of ethanol weighing 13.8 g with copper (II) oxide weighing 28 g, aldehyde was obtained, the mass of which was 9.24 g. Determine the yield of the reaction product. Answer: 70%.

20.7. In industry, apetaldehyde is obtained by the Kucherov method. What mass of acetaldehyde can be obtained based on commercial calcium carbide weighing 500 kg, the mass fraction of impurities in which is 10.4%? The output of acetaldehyde 75%. Answer: 231 kg.

20.8. During the catalytic hydrogenation of formaldehyde, an alcohol was obtained, upon interaction of which with an excess of metallic sodium, hydrogen was formed with a volume of 8.96 liters (normal conditions). The yield of products at each stage of the synthesis was 80%. Determine the initial mass of formaldehyde. Answer: 37.5 g.

20.9. What mass of silver will be obtained as a result of the "silver mirror" reaction if an aqueous solution weighing 50 g with a mass fraction of propanal of 11.6% is added to an excess of ammonia solution of silver oxide.

Answer: 21.6

20.10. Acetylene with a volume of 280 ml (normal conditions) was used to obtain acetaldehyde, the yield of which was 80%. What mass of metal can be obtained by adding all the resulting aldehyde,

to an excess of ammonia solution of silver oxide? Answer: 2.16 g.

20.11. To an aqueous solution weighing 4 g with a mass fraction of some aldehyde 22% was added an excess of ammonia solution of silver oxide. In this case, a precipitate was formed weighing 4.32 g. Determine the formula of the starting aldehyde.

20.12. During the oxidation of alcohol vapor weighing 2.3 g over an excess of copper (II) oxide, aldehyde and copper weighing 3.2 g were obtained. Which aldehyde was obtained? Determine the mass of aldehyde if its yield was 75%. Answer: 1.65 g of acetaldehyde.

20.13. The mass fractions of carbon, hydrogen and oxygen in the aldehyde are 62.1%, 10.3% and 27.6%, respectively. What volume of hydrogen will be required to hydrogenate this aldehyde weighing 14.5 g to alcohol? Calculate the volume under normal conditions. Answer: 5.6 liters.

20.14. One of the industrial methods for obtaining aldehydes is heating alkenes with carbon monoxide (II) and hydrogen at elevated pressure in the presence of a catalyst. For such a reaction, propylene with a volume of 140 liters (normal conditions) and an excess of other substances were taken. What mass of butanal and 2-methylpropanal will be obtained if the result is a mixture of these aldehydes, in which the mass fraction of butanal is 60%? Answer: 270 g of butanal and 180 g of 2-methylpropanal.

20.15. During the oxidation of some oxygen-containing organic substance weighing 1.8 g with an ammonia solution of silver oxide, silver was obtained weighing 5.4 g. Which organic substance was subjected to oxidation? Answer: butanal.

20.16. From calcium carbide weighing 7.5 g, containing impurities (the mass fraction of impurities is 4%), acetylene was obtained, which was converted into aldehyde by the Kucherov reaction. What mass of silver will be released during the interaction of all the resulting aldehyde with an ammonia solution of silver oxide? Answer: 24.3

20.17. The oxidation of ethanol gave the aldehyde in 80% yield. When the same mass of ethanol interacted with metallic sodium, hydrogen was released, occupying a volume of 2.8 liters under normal conditions (yield - quantitative). Determine the mass of aldehyde formed in the first reaction. Answer: 8.8 g.

20.18. What mass of formalin with a mass fraction of formaldehyde of 40% can be formed if aldehyde obtained by catalytic oxidation of methane with a volume of 336 liters (normal conditions) with atmospheric oxygen is used? The yield of products in the oxidation reaction is 60%.

20.19. What mass of a solution with a mass fraction of acetaldehyde of 20% is formed if the aldehyde was obtained with a yield of 75% from acetylene with a volume of 6.72 liters (normal conditions) by the Kucherov reaction? Answer: 49.5 g.

20.20. When burning aldehyde weighing 0.9 g, carbon monoxide (IV) was formed, which reacted with a solution of sodium hydroxide with a volume of 16.4 ml and a density of 1.22 g / ml to form an average salt. The mass fraction of sodium hydroxide in this solution is 20%. Determine the formula of the burned aldehyde. How many isomeric aldehydes can fit this formula? Write their structural formulas. Answer: butanal; 2 isomeric aldehydes.

21. CARBOXY ACIDS Nomenclature, chemical properties and preparation of carboxylic acids

21.2. Write the structural formulas of the following acids: 2-methylpropanoic acid, 2,3,4-trichlorobutanoic acid, 3,4-dimethylheptanoic acid.

21.3. How many isomeric carboxylic acids can correspond to the formula C5 H10 O2? Write the structural formulas of these isomers. Answer: 4 isomers.

21.4. Three unlabeled tubes contain the following substances: ethanol, formic acid, acetic acid. What chemical methods can be used to distinguish between these substances?

21.5. Four test tubes contain the following substances: propionic acid, formaldehyde solution, phenol solution in benzene, methanol. What chemical reactions can be used to distinguish between these substances?

21.6. How many isomeric monobasic carboxylic acids can correspond to the formula C6 H12 O2;? Write the structural formulas of these acids and name them according to substitutional nomenclature. Answer: 8 isomeric acids.

Calculation tasks

21.11. What volume of vinegar essence with a density of 1.070 g / ml should be taken to prepare table vinegar with a volume of 200 ml and a density of 1.007 g / ml? The mass fraction of acetic acid in vinegar essence is 80%, in vinegar -6%.

21.12. What masses of solutions of acetic acid with a mass fraction of CH3 COOH 90 and 10% must be taken to obtain a solution weighing 200 g with a mass fraction of acid 40%? Answer: a solution with a mass fraction of 90% - 75

G; 10% - 125 g.

21.13. The laboratory has a solution with a volume of 300 ml with a mass fraction of acetic acid of 70% and a density of 1.07 g/ml. What volume of water with a density of 1 g / ml should be added to the existing solution to obtain a solution with a mass fraction of acid of 30%? Ignore the change in volume when mixing the solution and water. Answer: 428 ml. 236

21.14. Ammonia with a volume of 4.48 liters was passed through a solution of acetic acid weighing 150 g (normal conditions). Determine the mass fraction of CH3 COOH in the resulting solution, if the mass fraction of acid in the initial solution was 20%.

21.15. Sodium hydroxide weighing 20 g was added to a solution weighing 300 g with a mass fraction of acetic acid of 30%. What volume of a solution with a mass fraction of potassium hydroxide of 25% will be required to neutralize the solution obtained after adding sodium hydroxide? The density of the KOH solution is 1.24 g/ml. Answer: 180.6 ml.

21.16. Sodium bicarbonate was placed into a solution weighing 370 g with a mass fraction of propionic acid of 60%. As a result of the reaction, a gas with a volume of 11.2 liters was formed (normal conditions). Determine the mass fraction of propionic acid in the resulting solution. Answer: 47.4%.

21.17. What volume of a solution with a mass fraction of sodium hydroxide of 20% and a density of 1.22 g / ml will be required to neutralize a monobasic carboxylic acid with a mass of 14.8 g? The acid has a composition: carbon (mass fraction 48.65%), oxygen (43.24%), hydrogen (8.11%). Answer: 32.8

21.18. Determine the volume of methane that can be obtained by heating 50 g of acetic acid with an excess of sodium hydroxide. Consider that the mass fraction of water in the acid is 4%, and the gas yield is 75%. Volume

calculate under normal conditions. Answer: 13.44 liters.

21.19. What mass of stearic acid С17 H35 COOH can be obtained from liquid soap containing potassium stearate weighing 96.6 g? The acid yield is 75%. Answer: 63.9 g. 238

21.20. What mass of a solution with a mass fraction of acetic acid of 90% can be obtained by oxidizing butane with a volume of 56 liters (normal conditions) with atmospheric oxygen if the acid yield is 60%? Answer:

21.21. Acetic acid can be obtained in three successive steps using calcium carbide as the starting material. For the reaction, technical calcium carbide weighing 200 g was taken, the mass fraction of impurities in which is 12%. What mass of acid will be obtained if the yield of products at the first stage of synthesis is 80%, at the second - 75%, at the third - 80%. Answer: 79.2 g.

21.22. When passing chlorine into a solution with a mass fraction of acetic acid of 75%, chloroacetic acid was obtained. Determine its mass fraction in the solution, assuming that excess chlorine and hydrogen chloride are removed from the solution. Answer: 82.5%.

21.23. A 5 ml solution with a mass fraction of potassium hydroxide of 40% and a density of 1.4 g/ml was used to neutralize the limiting monobasic acid with a mass of 3.7 g. Determine the formula of the acid.

21.24. Determine the formula of the limiting monobasic carboxylic acid, if it is known that a solution of 15.75 ml with a mass fraction of sodium hydroxide of 25% and a density of 1.27 g / ml was used to neutralize a sample of 11 g. How many isomeric acids correspond to the found formula? Answer: C3 H7 COOH; two isomeric acids.

21.25. During the oxidation of formic acid, a gas was obtained, which was passed through an excess of calcium hydroxide solution. In this case, a precipitate was formed weighing 20 g. What mass of formic acid was taken for oxidation? Answer: 9.2g.

21.26. There is a solution of formic acid weighing 36.8 g. An excess of an oxidizing agent was added to the solution. The gas obtained as a result of oxidation was passed through an excess of barite water, resulting in a precipitate weighing 39.4 g. Determine the mass fraction of acid in the initial

Option 5

Alcohols and phenols.

1. For an alcohol of the composition C5H12O (I) and (II), under the action of PCl5, the corresponding monochlorine derivatives are obtained; upon dehydration of the latter, the same alkene 2-methyl-2-butene is obtained. Write the structural formulas of alcohols (I) and (II).

2. For what reason and under what conditions can monohydric alcohols react with each other? What substances are formed.

3. Why the first representatives of alcohols are liquid substances, give an explanation.

4. Make up the reaction equations in accordance with the scheme. Decipher unknown substances - give their structural formula and name.

5. For combustion of 50 ml of methanol (p=0.80 g/ml) air volume is required:

a) 150l b) 200l c) 250l d) 180l

6. For the complete neutralization of a mixture of phenol and acetic acid, 46.8 ml of a 20% by weight KOH solution with a density of 1.2 g / ml are required; when the same mixture interacts with bromine water, 33.1 g of a precipitate is formed. Determine the mass fractions of acetic and phenol in the initial mixture.

Control work 90 min.

Option - 10

1) Write the structural formulas of isomeric alcohols and ethers corresponding to the formula C3H8O. Name them.

2) To recognize ethanol and glycerin, use:

a) Hydrogen chloride

c) Acetic acid

d) Copper (II) hydroxide

Write an equation for the reaction.

3) Write the equation of chemical reactions that need to be carried out to obtain phenol from calcium carbide and indicate the conditions for their implementation.

4) Write the reaction equations with which you can carry out the following transformations:

Specify reaction conditions.

5) To 50 g of a 2.6% solution of phenol, bromine water was added until the end of the reaction. Determine what mass of 2% sodium hydroxide solution must be added to the reaction mixture to completely neutralize it. Write the reaction equation.

6) What mass of sodium phenolate can be obtained by reacting 4.7 g of phenol with a solution of sodium hydroxide with a volume of 4.97 ml (p = 1.38 g / ml)? The mass fraction of sodium hydroxide in solution is 35%.

Control work for 90 minutes

Option number 4

1. Write the reaction equations by which 1-propanol can be converted to 2-propanol.

2. match the formula of the substance and the method of its preparation:

3. Acid properties are most pronounced in:

1) phenol 2) methanol 3) ethanol 4) glycerin

5. When 13.8 g of ethanol was oxidized with copper (II) oxide weighing 28 g, 9.24 g of aldehyde was obtained with a practical yield:

A) 70% B) 75% C) 60% D) 85%

6. Calcium carbide was used to dehydrate ethanol, what is the mass (in grams) of calcium carbide that must be added to calcium alcohol with a volume of 150 ml with a density of p = 0.8 g / ml containing 96% ethanol to obtain anhydrous alcohol?

Control work 90 min.

Option 12

1. The presence of a functional group in alcohol molecules does not affect:

A) solubility in water B) boiling point

B) the structure of the hydrocarbon radical D) characteristic chemical properties

2. What are the chemical properties of a compound whose structural formula is CH2=CH-CH2OH? Confirm your answer by making the appropriate reaction equations. Specify the conditions for their implementation.

3. Two test tubes contain ethyl alcohol and ethylene glycol. How can these substances be distinguished?

4. Make up the reaction equations in accordance with the transformation schemes:

Calcium carbide → acetylene → benzene → chlorobenzene → phenol → trinitrophenol

Specify the reaction conditions.

5. Calculate the mass of ethylene glycol, which can be obtained from 200 g of an aqueous solution with a mass fraction of ethanol of 92%.

6. When 9 g of saturated monohydric alcohol was oxidized with copper (II) oxide, 9.6 g of copper was obtained. Determine the molecular formula of alcohol. Calculate the mass of aldehyde formed if its yield is 90%