LABORATORY EXPERIMENTS ON THE TOPIC: "GENETIC LINK BETWEEN HYDROCARBONS, ALCOHOLS, ALDEHYDES AND ACIDS"

Limit hydrocarbons

Of the saturated hydrocarbons, methane is studied in detail in the school as a substance that is the simplest in composition and structure, the most accessible for practical familiarization and of great national economic importance as a chemical raw material and fuel.

Experiments with the first substance studied in organic chemistry should be carried out in sufficient quantity and with special care in methodological terms, since they should show new aspects of the experiment in the study of organic chemistry. Here, empirically, it will be possible to establish the composition and molecular formula of a substance, which is the first step in determining the structural formulas of organic compounds.

METHANE.

The order of experiments with methane may be different. Basically, it will be determined by whether the teacher starts the topic with obtaining methane and then sets up experiments to study its properties using the substance obtained in the lesson, or uses pre-prepared methane in order to clearly follow the sequence of studying questions - first consider the physical properties of the substance, then the chemical properties, the application of the substance, and finally the production of it. In the latter case, the experience of obtaining methane will be presented only at the end of the topic.

The first way of studying the topic and, consequently, constructing an experiment is more methodologically complicated, but more economical in time. The second method will require more time, but it is methodologically simpler and, moreover, valuable in that it will allow in conclusion to repeat and consolidate the knowledge of the basic experiments with the substance when it is received in the lesson.

When studying methane, there is no particular need for laboratory experiments. In essence, they could be reduced here only to obtaining methane and burning it. But getting methane from sodium acetate and burning it can easily be shown on a demonstration table.

It would be more expedient after studying the entire topic "Hydrocarbons" to deliver a special practical lesson. In this lesson, students will replicate the experience of making methane and be able to verify that methane does not decolorize bromine water and potassium permanganate solution.

Obtaining methane in the laboratory. The most convenient laboratory method for producing methane is the interaction of sodium acetate with soda lime.

The interaction of salts of carboxylic acids with alkali is a common method for obtaining hydrocarbons. The reaction in general form is represented by the equation:

if R = CH 3, then methane is formed.

Since caustic soda is a hygroscopic substance, and the presence of moisture interferes with the successful completion of the reaction, calcium oxide is added to it. A mixture of caustic soda with calcium oxide is called soda lime.

A fairly strong heating is required for the reaction to proceed successfully, however, excessive overheating of the mixture leads to side processes and the production of undesirable products, such as acetone:

Sodium acetate must be dehydrated prior to testing. Soda lime should also be calcined before preparing the mixture. If there is no ready-made soda lime, it is prepared as follows. In an iron or porcelain cup, well-calcined crushed lime CaO is poured over with half the amount of a saturated aqueous solution of alkali NaOH. The mixture is evaporated to dryness, calcined and crushed. Substances are stored in a desiccator.

To demonstrate the production of methane, it is best to use a small flask with an outlet tube, and for a practical lesson, a test tube (Fig. 1 and 2).

Assemble the device as shown in Fig. 1 or 2. An alkali solution is poured into a wash bottle to trap impurities (Fig. I). A mixture of sodium acetate and soda lime is placed in a reaction flask or test tube. To do this, finely divided substances are thoroughly mixed in a volume ratio of 1:3, i.e. with a considerable excess of lime to cause the sodium acetate to react as completely as possible.

Rice.

The flask is heated with a burner through an asbestos mesh, and the test tube on a naked flame. Methane is collected in a test tube according to the method of water displacement. To check the purity of the resulting gas, the test tube is removed from the water and the gas is ignited without turning over.

Since it is not advisable to interrupt the process of obtaining methane, and it is impossible to complete all other experiments while the reaction is in progress, it is recommended to collect gas for subsequent experiments in several cylinders (test tubes) or in a gasometer.

The filled cylinders are left for a while in the bath or they are closed under water with a glass plate (cork) and placed upside down on the table.

Methane is lighter than air. To get acquainted with the physical properties of methane, the teacher demonstrates a cylinder with the collected gas. Students observe that methane is a colorless gas. The collection of methane by the method of displacement of water suggests that this gas is apparently insoluble in water. The teacher confirms this conclusion.

On the scales, two identical flasks of the largest possible capacity are balanced. One of the flasks is suspended upside down (Fig. 3). Methane from the device is passed into this flask for some time. The scales are going up. Lest students think that the change in weight is due to the pressure of the jet of gas on the bottom of the flask, pay attention to the fact that the imbalance remains even after the passage of methane is stopped.

After the scales are again brought into equilibrium (for this, the bottle with methane is turned upside down for a while), for comparison and more convincing conclusions, methane is passed into the flask normally standing on the scales. The balance of the scales is not disturbed.

Having shown that methane is lighter than air, the teacher reports how much a liter of methane weighs under normal conditions. This information will be needed later in the derivation of the molecular formula of the substance.

Combustion of methane. Following a consideration of the physical properties of methane, the question of what is the molecular formula of methane can be raised. The teacher informs that in order to clarify this issue, it will be necessary to first familiarize oneself with one of the chemical properties of methane - combustion.

Combustion of methane can be shown in two ways.

1. A glass cylinder (capacity, for example, 250 ml) filled with methane is placed on the table, a plate is removed from it or the cork is opened and the gas is immediately ignited with a splinter. As the methane burns, the flame descends into the cylinder.

In order for the flame to keep all the time above the cylinder and be clearly visible to students, water can be gradually poured into the cylinder with burning methane, thereby displacing the gas outward (Fig. 4).

2. Methane is ignited directly at the outlet tube of the device for obtaining gas or gasometer (in both cases, a check for purity is obligatory!). The size of the flame is controlled by the heating intensity in the first case and by the height of the displacing liquid column in the second case. If methane is purified from impurities, it burns with an almost colorless flame. To eliminate some of the luminosity of the flame (yellow color) due to sodium salts in the glass of the tube, a metal tip can be attached to the end of the tube.

ALDEHYDES AND KETONES

In the study of aldehydes, students are experimentally introduced to the stepwise nature of the oxidation of organic substances, to the chemistry of important production processes, and to the principle of obtaining synthetic resins.

In order for students to understand the place of aldehydes in the series of hydrocarbon oxidation products, when compiling chemical equations, one should not avoid using the names and formulas of acids into which aldehydes are converted. The formulas of acids may be given dogmatically in advance; in the future, students will receive experimental justification for them.

In the study of aldehydes, most of the experiments are carried out with formaldehyde as the substance most accessible to the school and of great industrial importance. In accordance with this, formaldehyde is given the main place in this chapter. For acetaldehyde, only production reactions are considered. Ketones are not specifically taught in school; therefore, only one representative of them is taken here - acetone, and experiments with it are given mainly for extracurricular work of students.

FORMALDEHYDE (METHANAL)

It is advisable to build a plan for studying this substance so that immediately after becoming familiar with the physical properties of aldehydes, students learn how to obtain it, then chemical properties, etc. A slightly earlier acquaintance with the methods of obtaining aldehyde will make it possible further, when studying the chemical properties (oxidation reactions), to consider aldehydes as a link in the hydrocarbon oxidation chain.

Formalin can be used as a sample when getting acquainted with the properties of formaldehyde. This should immediately ensure that students clearly understand the difference between formalin and formaldehyde.

The smell of formaldehyde. Of the physical properties of formaldehyde, familiarization with the smell is the most accessible in practice. For this purpose, test tubes with 0.5-1 ml of formalin are distributed to student tables. Once the students are familiar with the smell, the formalin can be collected and used for further experiments. Familiarization with the smell of formalin will enable students to detect this substance in other experiments.

Flammability of formaldehyde. The formalin is heated in a test tube and the vapors released are ignited; they burn with an almost colorless flame. The flame can be seen if you set fire to a splinter or a piece of paper in it. The experiment is carried out in a fume hood.

Obtaining formaldehyde. Since, before getting acquainted with the chemical properties, formaldehyde can only be detected by smell, the first experience of obtaining it should be done in the form of laboratory work.

1. Pour a few drops of methanol into a test tube. In the flame of a burner, a small piece of copper mesh rolled into a tube or a spiral of copper wire is heated and quickly lowered into methanol.

When calcined, copper oxidizes and becomes covered with a black coating of copper oxide, in alcohol it is restored again and turns red:

A strong odor of aldehyde is detected. If the oxidation process is repeated 2-3 times, then a significant concentration of formaldehyde can be obtained and the solution can be used for subsequent experiments.

2. In addition to copper oxide, other oxidizing agents familiar to students can be used to obtain formaldehyde.

To a weak solution of potassium permanganate in a demonstration tube, add 0.5 ml of methanol, and the mixture is heated to boiling. The smell of formaldehyde appears, and the purple color of the permanganate disappears.

2-3 ml of a saturated solution of potassium bichromate K 2 Cr 2 O 7 and the same volume of concentrated sulfuric acid are poured into a test tube. Add methanol dropwise and warm the mixture very carefully (point the tube opening to the side!). Further, the reaction proceeds with the release of heat. The yellow color of the chromium mixture disappears and the green color of chromium sulfate appears.

The reaction equation with students can not be disassembled. As in the previous case, they are only informed that potassium bichromate oxidizes methyl alcohol to aldehyde, while turning into a salt of trivalent chromium Cr 2 (SO 4) 3.

The interaction of formaldehyde with silver oxide(reaction of a silver mirror). This experience should be demonstrated to students in such a way that it simultaneously serves as an instruction for the subsequent practical lesson.

Obtaining phenol-formaldehyde resins. The bulk of formaldehyde obtained in industry is used for the synthesis of phenol-formaldehyde and other resins necessary for the production of plastics. The production of phenol-formaldehyde resins is based on the polycondensation reaction.

The most accessible in school conditions is the synthesis of phenol-formaldehyde resin. By this time, students are already familiar with both starting materials for producing resin - phenol and formaldehyde; the experience is relatively uncomplicated and proceeds smoothly; The chemistry of the process is not particularly difficult for students if it is depicted as follows:

Depending on the quantitative ratio of phenol and formaldehyde, as well as on the catalyst used (acidic or alkaline), novolac or resole resin can be obtained. The first of them is thermoplastic and has the linear structure given above. The second is thermosetting, since its linear molecules contain free alcohol groups - CH 2 OH, capable of reacting with mobile hydrogen atoms of other molecules, resulting in a three-dimensional structure.

ACETEC ALDEHYDE (ETHANAL)

After a detailed acquaintance with the properties of formaldehyde in this section of the topic, experiments related to the production of acetaldehyde are of greatest importance. These experiments can be designed to: a) show that all aldehydes can be obtained by oxidation of the corresponding monohydric alcohols, b) show how the structure of aldehydes can be experimentally substantiated, c) introduce the chemistry of the industrial method for obtaining acetaldehyde according to Kuchsrov.

Preparation of acetaldehyde by oxidation of ethanol. Copper (II) oxide can be taken as an oxidizing agent for alcohol. The reaction proceeds similarly to the oxidation of methanol:

• 1. Not more than 0.5 ml of ethyl alcohol is poured into a test tube and a red-hot copper wire is immersed. The odor of acetaldehyde, reminiscent of fruit, is detected and the reduction of copper is observed. If alcohol is oxidized 2-3 times, each time heating copper until copper oxide is formed, then, having collected the solutions obtained by students in test tubes, it will be possible to use aldehyde for experiments with it.
• 2. 5 g of crushed potassium dichromate K2Cr2O7 is placed in a small flask with a drain tube, 20 ml of dilute sulfuric acid (1:5) and then 4 ml of ethyl alcohol are poured. A refrigerator is attached to the flask and heated on a small flame through an asbestos mesh. The receiver for the distillate is placed in ice water or snow. A little water is poured into the receiver and the end of the refrigerator is lowered into the water. This is done in order to reduce the volatilization of acetaldehyde vapors (bp 21 °C). Together with ethanol, a certain amount of water, unreacted alcohol, formed acetic acid and other by-products of the reaction are distilled into the receiver. However, it is not necessary to isolate pure acetaldehyde, since the resulting product gives good performance in the usual reactions of aldehydes. The presence of aldehyde is determined by smell and by the reaction of a silver mirror.

Students' attention is drawn to the color change in the flask. The green color of the resulting chromium sulfate (III) Cr 2 (SO 4) 3 becomes especially distinct if the contents of the flask are diluted with water after the experiment. It is noted that the change in the color of potassium bichromate occurred due to the oxidation of alcohol by it.

Obtaining acetaldehyde by hydration of acetylene. The remarkable discovery of the Russian chemist M.G. Kucherov - the addition of water to acetylene in the presence of mercury salts formed the basis of a widespread industrial method for producing acetaldehyde.

Despite the great importance and accessibility for the school, this method is rarely demonstrated in chemistry classes.

In industry, the process is carried out by passing acetylene into water containing divalent mercury salts and sulfuric acid at a temperature of 70°C. The acetaldehyde formed under these conditions is distilled off and condensed, after which it enters special towers for oxidation into acetic acid. Acetylene is obtained from calcium carbide in the usual way and purified from impurities.

The need to purify acetylene and maintain the temperature in the reaction vessel, on the one hand, and the uncertainty in obtaining the desired product, on the other, usually reduce interest in this experiment. Meanwhile, the experiment can be carried out quite simply and reliably both in a simplified form and under conditions approaching industrial ones.

1. An experiment that, to a certain extent, reflects the conditions for carrying out the reaction in production and makes it possible to obtain a sufficiently concentrated solution of aldehyde, can be carried out in the device shown in fig. 29.

The first stage is the production of acetylene. Pieces of calcium carbide are placed in the flask and water or a saturated solution of common salt is slowly added from the dropping funnel. The pinning speed is adjusted so that a steady flow of acetylene is established, approximately one bubble per 1-2 s. Purification of acetylene is carried out in a washer with a solution of copper sulfate:

CuSO 4 + H 2 S H 2 SO 4

After purification, the gas is passed into a flask with a catalyst solution (15–20 ml of water, 6–7 ml of conc. sulfuric acid and about 0.5 g of mercury (II) oxide. The flask, where acetylene is hydrated, is heated with a burner (alcohol) , and the resulting acetaldehyde in gaseous form enters test tubes with water, where it is absorbed.

After 5--7 minutes in a test tube, it is possible to obtain a solution of ethanal of a significant concentration. To complete the experiment, first stop the water supply to the calcium carbide, then disconnect the device and, without any additional distillation of the aldehyde from the reaction flask, use the resulting solutions in test tubes for the corresponding experiments.

2. In the most simplified form, the reaction of M.G. Kucherov can be carried out as follows.

In a small round-bottom flask, 30 ml of water and 15 ml of conc. sulfuric acid. The mixture is cooled and a little (on the tip of a spatula) mercury oxide (II) is added to it. The mixture is heated carefully through an asbestos mesh to a boil, while mercury oxide is converted into mercury (II) sulfate.

Option 1

1. Write the reaction equations that can be used to carry out the following transformations: methane → chloromethane → methanol → formaldehyde → formic acid. Specify the reaction conditions.

2. Write the structural formula of a substance of the composition C₃H₆O₂, if it is known that its aqueous solution changes the color of methyl orange to red, with chlorine this substance forms the compound C₃H₅ClO₂, and when its sodium salt is heated with sodium hydroxide, ethane is formed. Name the substance.

3. Calculate the mass of the substance (in grams) and the amount of substance (in moles) of each product during the following transformations: bromoethane → ethanol → ethanoic acid. Bromoethane was taken with a mass of 218 g.

Option 2

1. Write the reaction equations that can be used to carry out the following transformations: acetylene → ethylene → ethanol → acetaldehyde → acetic acid. Specify the reaction conditions.

2. Write the structural formula of a substance of the composition C₄H₈O, if it is known that it interacts with copper (II) hydroxide and forms 2-methylpropanoic acid upon oxidation. Name this substance.

3. Calculate the mass of the substance (in grams) and the amount of substance (in moles) of each product during the following transformations: propane → 2-chloropropane → propanol-2. Propane was taken with a mass of 22 g.

Option 3

1. Write the reaction equations that can be used to carry out the following transformations: methane → acetylene → acetaldehyde → ethyl alcohol → ethanoic acid. Specify the reaction conditions.

2. Write the structural formula of a substance of the composition C₅H₁₀O, if it is known that it adds hydrogen in the presence of a catalyst, and when heated with freshly prepared copper (II) hydroxide, it forms a red precipitate. Name this substance.

3. Calculate the mass of the substance (in grams) and the amount of substance (in moles) of each product during the following transformations: benzene → chlorobenzene → phenol. Benzene was taken with a mass of 156 g.

Option 4

1. Write the reaction equations that can be used to carry out the following transformations: methane → formaldehyde → methanol → formic acid → carbonic acid. Specify the reaction conditions.

2. Write the structural formula of a substance of the composition C₂H₆O₂, if it is known that it interacts with sodium to release hydrogen, and forms a bright blue substance with copper (II) hydroxide. Name this substance.

3. Calculate the mass of the substance (in grams) and the amount of substance (in moles) of each product during the following transformations: chloromethane → methanol → methanoic acid. Chloromethane was taken with a mass of 202 g.

Topic 1. Theoretical Foundations of Organic Chemistry (4 hours)

Formation of organic chemistry as a science. organic substances. Organic chemistry. Theory of the structure of organic compounds A. M. Butlerova. Carbon skeleton. Radicals. functional groups. homologous series. Homologs.
Structural isomerism. Nomenclature. Significance of the theory of the structure of organic compounds.
Electronic nature of chemical bonds in organic compounds. Methods for breaking bonds in molecules of organic substances. Electrophiles. Nucleophiles.
Classification of organic compounds.
Demonstrations. Acquaintance with samples of organic substances and materials. Models of molecules of organic substances. Solubility of organic substances in water and non-aqueous solvents. Melting, charring and combustion of organic substances.

HYDROCARBONS (23 h)

Topic 2 Limit hydrocarbons (alkanes) (7 hours)

Electronic and spatial structure of alkanes. homologous series. Nomenclature and isomerism. Physical and chemical properties of alkanes. substitution reaction. Receipt and the use of alkanes.
Cycloalkanes. Structure of molecules, homologous series. Finding in nature. Physical and chemical properties.
Demos. Explosion of a mixture of methane and air. The ratio of alkanes to acids, alkalis, potassium permanganate solution and bromine water.
Laboratory experiments. Making models of hydrocarbon molecules and

halogen derivatives.
Practical work. Qualitative determination of carbon, hydrogen and chlorine in organic substances.
Calculation tasks. Finding the molecular formula of an organic compound by weight (volume) of combustion products.

Topic 3. Unsaturated hydrocarbons (6 hours)

Alkenes. Electronic and spatial structure of alkenes. homologous series. Nomenclature. Isomerism: carbon chain, multiple bond positions, cis-, trans- isomerism. Chemical properties: oxidation reaction, addition, polymerization. Markovnikov's rule. Preparation and use of alkenes.
Alkadienes. Structure. Properties, application. natural rubber.
Alkynes. Electronic and spatial structure of acetylene. Homologues and isomers. Nomenclature. Physical and chemical properties. Addition and substitution reactions. Receipt. Application.
Demos. Obtaining acetylene by the carbide method. The interaction of acetylene with a solution of potassium permanganate and bromine water. Burning acetylene. Decomposition of rubber during heating and testing of decomposition products.
Practical work. Obtaining ethylene and studying its properties.

Topic 4. Aromatic hydrocarbons (arenes) (4 hours)

Arenas. Electronic and spatial structure of benzene. Isomerism and nomenclature. Physical and chemical properties of benzene. Benzene homologues. Peculiarities of chemical properties of benzene homologues on the example of toluene. Genetic relationship of aromatic hydrocarbons with other classes of hydrocarbons.
Demos. Benzene as a solvent, benzene combustion. The ratio of benzene to bromine water and potassium permanganate solution. Toluene oxidation.

Topic 5. Natural sources of hydrocarbons (6 hours)

Natural gas. Associated petroleum gases. Oil and oil products. physical properties. Ways of oil refining. Distillation. Thermal and catalytic cracking. Coke production.
Laboratory experiments. Familiarization with samples of refined products.
Calculation tasks.

OXYGEN-CONTAINING ORGANIC COMPOUNDS (25 h)

Topic 6. Alcohols and phenols (6 hours)

Monohydric saturated alcohols. Structure of molecules, functional group. Hydrogen bond. Isomerism and nomenclature. Properties of methanol (ethanol), production and application. The physiological effect of alcohols on the human body. Genetic relationship of monohydric saturated alcohols with hydrocarbons.
polyhydric alcohols. Ethylene glycol, glycerin. Properties, application.
Phenols. The structure of the phenol molecule. Mutual influence of atoms in a molecule on the example of a phenol molecule. properties of phenol. Toxicity of phenol and its compounds. The use of phenol.
Demos. Interaction of phenol with bromine water and sodium hydroxide solution.
Laboratory experiments. Dissolution of glycerin in water. Reaction of glycerol with copper(II) hydroxide.
Calculation tasks. Calculations according to chemical equations, provided that one of the reactants is given in excess.

Topic 7. Aldehydes, ketones (3 hours)

Aldehydes. The structure of the formaldehyde molecule. functional group. Isomerism and nomenclature. properties of aldehydes. Formaldehyde and acetaldehyde: production and application.
Acetone is a representative of ketones. The structure of the molecule. Application.
Demos. Interaction of methanal (ethanal) with an ammonia solution of silver(I) oxide and copper(II) hydroxide. Dissolution in acetone of various organic substances.
Laboratory experiments. Preparation of ethanol by oxidation of ethanol. Oxidation of methanal (ethanal) with an ammonia solution of silver(I) oxide. Oxidation of methanal (ethanal) with copper(II) hydroxide.

Topic 8. Carboxylic acids (6 hours)

Monobasic limiting carboxylic acids. The structure of molecules. functional group. Isomerism and nomenclature. properties of carboxylic acids. esterification reaction. Obtaining carboxylic acids and application.
Brief information about unsaturated carboxylic acids.
Genetic relationship of carboxylic acids with other classes of organic compounds.
Practical work
Preparation and properties of carboxylic acids.
Solving experimental problems for the recognition of organic substances.

Topic 9. Complex ethers. Fats (3 hours)

Esters: properties, production, application. Fats. The structure of fats. Fats in nature. Properties. Application.
Detergents. Rules for the safe handling of household chemicals.
Laboratory experiments. Solubility of fats, proof of their unsaturated nature, saponification of fats. Comparison of the properties of soap and synthetic detergents. Acquaintance with samples of detergents. Study of their composition and instructions for use.

Topic 10. Carbohydrates (7 hours)

Glucose. The structure of the molecule. Optical (mirror) isomerism. Fructose is an isomer of glucose. properties of glucose. Application. Sucrose. The structure of the molecule. Properties, application.
Starch and cellulose are representatives of natural polymers. Polycondensation reaction. Physical and chemical properties. Finding in nature. Application. Acetate fibre.
Laboratory experiments. Interaction of glucose with copper(II) hydroxide. Interaction of glucose with an ammonia solution of silver(I) oxide. The interaction of sucrose with calcium hydroxide. Interaction of starch with iodine. hydrolysis of starch. Acquaintance with samples of natural and artificial fibers.
Practical work. Solving experimental problems for the production and recognition of organic substances.

Topic 11. Amines and amino acids (3 hours)

Amines. The structure of molecules. Amino group. Physical and chemical properties. The structure of the aniline molecule. Mutual influence of atoms in a molecule on the example of an aniline molecule. properties of aniline. Application.
Amino acids. Isomerism and nomenclature. Properties. Amino acids as amphoteric organic compounds. Application. Genetic relationship of amino acids with other classes of organic compounds.

Topic 12. Proteins (4 hours)

Squirrels- natural polymers. Composition and structure. Physical and chemical properties. The transformation of proteins in the body. Advances in the study and synthesis of proteins.
The concept of nitrogen-containing heterocyclic compounds. Pyridine. Pyrrole. Pyrimidine and purine bases. Nucleic acids: composition, structure.
Chemistry and human health. Medicines. Problems associated with the use of drugs.
Demos. Fabric dyeing with aniline dye. Proof of the presence of functional groups in amino acid solutions.
Laboratory experiments. Color reactions for proteins (biuret and xantoprotein reactions).

HIGH MOLECULAR COMPOUNDS (7 hours)

Topic 13. Synthetic polymers (7 hours)

The concept of macromolecular compounds. Polymers obtained in polymerization reactions. The structure of molecules. Stereoneregular and stereoregular structure of polymers. Polyethylene. Polypropylene. Thermoplasticity. Polymers obtained in polycondensation reactions. Phenol-formaldehyde resins. thermosetting.
Synthetic rubbers. Structure, properties, obtaining and application.
Synthetic fibres. Kapron. Lavsan.
Generalization of knowledge on the course of organic chemistry. Organic chemistry, man and nature.
Demos. Samples of plastics, synthetic rubbers
and synthetic fibers.
Laboratory experiments. Study of the properties of thermoplastic polymers. Determination of chlorine in polyvinyl chloride. Study of the properties of synthetic fibers.
Practical work. Recognition of plastics and fibers.
Calculation tasks. Determination of the mass or volume fraction of the yield of the reaction product from the theoretically possible.

Grade 11
70 h/year (2 h/week; 7 h reserve time)

These are derivatives of hydrocarbons in which one hydrogen atom is replaced by a hydroxy group. The general formula of alcohols is C&H 2 n +1 Oh.

Classification of monohydric alcohols.

Depending on the location where IS HE- group, distinguish:

Primary alcohols:

Secondary alcohols:

Tertiary alcohols:

.

Isomerism of monohydric alcohols.

For monohydric alcohols characteristic isomerism of the carbon skeleton and isomerism of the position of the hydroxy group.

Physical properties of monohydric alcohols.

The reaction proceeds according to Markovnikov's rule, therefore, only primary alcohol can be obtained from primary alkenes.

2. Hydrolysis of alkyl halides under the influence of aqueous solutions of alkalis:

If the heating is weak, then intramolecular dehydration occurs, resulting in the formation of ethers:

B) Alcohols can react with hydrogen halides, with tertiary alcohols reacting very quickly, while primary and secondary alcohols react slowly:

The use of monohydric alcohols.

Alcohols They are mainly used in industrial organic synthesis, in the food industry, in medicine and pharmacy.

Lesson topic:

“Representatives of unsaturated carboxylic acids. Relationship between hydrocarbons, alcohols, aldehydes and acids"

The purpose of the lesson: To systematize and deepen students' knowledge of functional groups, homology using the example of limiting monobasic carboxylic acids. To consolidate the ability of students to designate the distribution of electron density in the molecules of specific carboxylic acids. Highlight the common chemical properties of acids in inorganic and organic chemistry. Emphasize the unity of substances. Development of skills for independent application of knowledge when considering unsaturated carboxylic acids. When revealing a genetic connection, show the diversity of organic substances, the transition from a simpler structure to a more complex one, the transition of quantitative changes to qualitative ones, the formation of a dialectical-materialistic worldview.

Equipment: Films for codoscope.

1. Model of HCOOH, CH molecules 3 COOH.

2. "Hydrogen bond"

3. "Comparison of acids HCOOH and CH 3 COOH, CH 3 COOH and CH 2 ClCOOH "

4. "Spatial isomers of unsaturated acid C 17 H 33 COOH"

Solutions: CH 3 COOH, Na 2 C0 3 ; NaOH; phenolphthalein; stearic acid C17H35COOH, oleic acid C 17 N 33 COOH, crystalline salt sodium acetate - CH 3 COONa, soap, aspirin, acetate fiber, film, (CH3COO) 2 Pb, latex.

Lesson methods: Conversation, frontal individual survey, use of cards, films for a codoscope, demonstration of visual aids, conducting experiments.

Lesson plan:

1. Generalization of knowledge about carboxylic acids.

2. Physical properties, the presence in nature of limiting monobasic carboxylic acids.

3. Chemical properties of limiting monobasic carboxylic acids.

4. Obtaining limiting monobasic carboxylic acids.

5. The use of formic acid, acetic and higher limiting monobasic acids.

6. Acquaintance with unsaturated carboxylic acids, their properties, application.

7. Genetic relationship between hydrocarbons, alcohols, aldehydes, carboxylic acids.

Lesson progress: (introductory word)

Today we continue talking about carboxylic acids, substances that are so diverse in their structure. Their fields of application are interesting and multifaceted.

We have only to introduce a radical multiple bond, and we will get acquainted with unsaturated monobasic carboxylic acids. So, the purpose of our lesson is to consolidate, improve knowledge about acids, oxidation products of hydrocarbons, alcohols, aldehydes, on our own, using all the accumulated knowledge and ability to predict the properties of unsaturated acids.

I call 6 students to the board who work on cards.

No. 1. "Chemical properties of carboxylic acids"

No. 2. "Special properties of carboxylic acids"

No. 3. "Specific Properties of Formic Acid"

No. 4. "Methods for obtaining formic acid"

No. 5. "Methods for the production of acetic acid"

No. 6. “Obtaining stearic acid in the laboratory and according to the method of N.M. Emanuel"

At the same time, I am conducting a face-to-face survey.

Questions for the class:

1. What compounds are called carboxylic acids?

2. How are carboxylic acids classified?

3. What is the general formula for limiting monobasic carboxylic acids? Name the representatives of the homologous series, give them names?

4. Finding acids in nature (showing the formulas of lactic, citric, oxalic acids).

I add: even acids are found in nature in the form of animal and vegetable fats, in oils, and also in wax (ie, in the form of esters). These acids have been discovered for a long time. In peanut butter - arachidic acid C 19 N 39 COOH, in palm - palmitic C 15 H 31 COOH.

But odd acids with a large number of carbon atoms are not usually found in nature, they are obtained synthetically and are called Greek numerals.

5. Physical properties of carboxylic acids?

We listen to the answers of students who worked at the board on cards. After explaining the chemical properties of carboxylic acids by them, attention is focused on the commonality of organic acids and the features in the manifestation of properties in organic acids - as substances of a more complex structure.

We carry out experiments specific to inorganic and organic acids. (Experiments were carried out by students on a demonstration table).

1) 2CH 3 COOH + Mg → (CH 3 COO) 2 Mg + H 2

2Н + Mg° → Mg + H2°

2) CH 3 COOH + NaOH → CH 3 COOHa + H 2 O

H + OH \u003d H 2 0

3) 2CH 3 COOH + Na 2 C0 3 → 2CH 3 COONa + C0 2 + H 2 O

2H + CO 3 → C0 2 + H 2 O.

(showing the crystalline salt CH 3 COOHa)

After the answers of all students at the blackboard, I propose to look at the model of HCOOH and CH molecules 3 COOH (designing film No. 1 through the overhead projector). Questions for the class:

• Where is formic acid used?

We listen to additions about the use of UNO.

What explains the increase in formic acid production in recent years?

My addition:

Disinfectant and "soothing" (distracting) agent - the so-called formic alcohol. This is not just a solution of formic acid in ethanol, its strength is sufficient to catalyze its own reaction with alcohol - esterification, to which acetic acid, for example, without the help of another, more powerful one, is incapable, i.e. we have an equilibrium composition of formic acid, ethanol and ethyl formate.

Formic acid is used in the production of solvents. The catalytic activity of HCOOH also plays a role in the production of natural rubber and is used to coagulate latex. It does not do without formic acid when dressing leather, here it serves as a catalyst for the hydrolysis of fats polluting the skin, and promotes tanning.

Another major advantage of formic acid is that over time it decomposes by itself, which means that any production associated with it is environmentally friendly. Formic acid can be used for pickling steel sheets, processing wood, the yield of wood pulp would increase one and a half times, and the problems of environmental pollution, inevitable with the traditional version of the technology that consumes mineral acids, could be largely eliminated.

Where is acetic acid used?

What are herbicides?

Write the structural formulas of some hybrids. (additional message).

Where are higher carboxylic acids used?

Designing film #2.

We consider where: (in alcohols, aldehydes, acids), a hydrogen bond is formed.

Designing film #3.

We analyze which acid is stronger:

HCOH and CH 3 COOH

CH 3 COOH and CH 3 C1COOH.

Consider unsaturated carboxylic acids. I call the student to the board. We write down the chain in which we get acquainted with two unsaturated acids:

CH 3 -CH 2 -COOH → CH 2 \u003d CH-COOH → CH 2 \u003d C - COOH

acrylic ‌‌ │

SNz

metalacrylic acid

Another student:

H 2

C I7 H 35 COOH → C 17 H zz COOH

oleic acid

Are there spatial isomers for: CH h - (CH 2) 7 -CH \u003d CH- (CH 2) 7 -COOH?

Show tape #4.

Oleic acid is a cis isomer, its molecular shape is as follows. That the forces of interaction between molecules are relatively small, and the substance turns out to be liquid. The molecules of the trans isomer are more elongated; they can adjoin each other more closely, the interaction forces between them are large and the substance turns out to be solid - this is ethanedioic acid.

CH s - (CH 2) 4 -CH \u003d CH-CH 2 -CH \u003d CH-(CH 2) 7 -COOH

Linoleic acid

What reactions are typical for unsaturated acids?

a) Students independently characterize the chemical properties. Making records:

How do acids react with alcohols?

CH 2 \u003d C-COOH + NOCH 3 ↔ CH 2 \u003d C - COOSH 3

│ │

CH 3 CH 3

b) As for unsaturated compounds, reactions of addition, polymerization, oxidation are characteristic. For example:

C 17 H sz COOH + H 2 → C 17 H 35 COOH

Oleic stearic

Oxidation of acids produces drying oils from linseed and hemp oil, which include oleic and linoleic acids in the form of esters.

Consider the genetic relationship between carbons and oxygen-containing organic compounds.

Designing film #5.

I set tasks for groups of students.

Task number 1. The country you live in is rich in coal, make a chain to get CH from COOH.

The correct answer is:

C + H 2 O + H 2 O + O 2

CaO → CaC 2 → C 2 H 2 → CH 3 COOH → CH 3 COOH

Task number 2. Based on oil, get CH3COOH.

Correct answer:

Oil → pyrolysis → C 2 H 4 → C 2 H 5 OH → CH 3 COOH or

Oil → C 4 H 10 → CH 3 COOH.

Passing from some substances to others, to more complex in structure, we confirm one of the laws of the dialectic of transition to qualitative ones, the unity and interrelation of inorganic and organic substances is again traced.

I evaluate students.

Homework.