.
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The group of atoms is called a carboxyl group or carboxyl.
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Organic acids containing one carboxyl group in the molecule are monophonic. General formula These acids rcón.

Carboxylic acids containing two carboxyl groups are called dibasic. These include, for example, oxal and amber acid.

There are substantial carboxylic acids containing more than two carboxyl groups. These include, for example, three-axis citric acid. Depending on the nature of the hydrocarbon radical, carboxylic acids are divided into limiting, unforeseen, aromatic.

Limit, or saturated, carboxylic acids are, for example, propane (propionic) acid or already familiar succinic acid.

Obviously, limiting carboxylic acids do not contain p- Communications in a hydrocarbon radical.

In molecules of unsaturated carboxylic acids, the carboxyl group is associated with an unsaturated, unsaturated hydrocarbon radical, for example, in acrylic (propnas) molecules, CH2 \u003d CH-coo or oleic CH3- (CH2) 7-CH \u003d CH- (CH2) 7-coxy and other acids.

As can be seen from the benzoic acid formula, it is aromatic, as it contains an aromatic (benzene molecule) ring.

Nomenclature and isomeria

General principles for the formation of carboxylic acid names, like other organic compounds, we have already considered. Let us dwell on the nomenclature of single and two-axis carboxylic acids. The name of the carboxylic acid is formed from the name of the corresponding alkane (alkane with the same number of carbon atoms in the molecule) with the addition of suffixes, the end, and the words of the acid. The numbering of carbon atoms begins with a carboxyl group. For example:

Many acids have historically established, or trivial, titles (Table 6).

After first acquaintance with diverse and interesting peace Organic acids consider more detail the limiting monosular carboxylic acids.

It is clear that the composition of these acids will be reflected in general formula with N 2N O2, or with N 2N +1 coon, or RCon.

Physical properties of limiting monosular carboxylic acids

Lower acids, i.e. acids with relatively small molecular weight containing in a molecule up to four carbon atoms - liquids with a characteristic sharp smell (remember the smell acetic acid). Acids containing from 4 to 9 carbon atoms - viscous oily liquids with an unpleasant odor; containing more than 9 carbon atoms in the molecule - solids that do not dissolve in water. The boiling points of limit mono-zero carboxylic acids increase with increasing the number of carbon atoms in the molecule and, therefore, with increasing relative molecular weight. For example, the boiling point of formic acid is equal to 101 ° C, acetic - 118 ° C, propionova - 141 ° C.

The simplest carboxylic acid is antson, having a small relative molecular weight (46), under normal conditions is a liquid with a boiling point of 100.8 ° C. At the same time, Bhutan (Mr (C4N10) \u003d 58) under the same conditions gaseous and has a boiling point -0.5 ° C. This is a mismatch of boiling and relative temperatures molecular weight It is explained by the formation of carboxylic acid dimers, in which two acid molecules are linked by two hydrogen bonds. The occurrence of hydrogen bonds becomes clear when considering the structure of carboxylic acid molecules.

Molecules of marginal monoxide carboxylic acids contain a polar group of atoms - carboxyl (think about the polarity of this functional group) and almost non-polar hydrocarbon radical. The carboxyl group is attracted by water molecules, forming hydrogen bonds with them.

The formic and acetic acid is soluble in water unlimited. Obviously, with an increase in the number of atoms in a hydrocarbon radical, the solubility of carboxylic acids is reduced.

Knowing the composition and structure of carboxylic acid molecules, it will not be easy for us to understand and explain the chemical properties of these substances.

Chemical properties

The general properties characteristic of class of acids (both organic and inorganic) are due to the presence of a hydroxyl group in molecules containing a strongly polar bond between hydrogen atoms and oxygen. These properties are well known for you. Consider them again on the example of organic acids soluble in water.

1. Dissociation to form hydrogen cations and anions of the acid residue. More accurately, this process describes the equation that takes into account the participation of water molecules in it.

The equilibrium of the dissociation of carboxylic acids is shifted to the left, the overwhelming majority of them are weak electrolytes. Nevertheless, an acidic taste, for example, formic and acetic acids, is due to dissociation on hydrogen cations and anions of acidic residues.

It is obvious that the presence in the carboxylic acids of "acidic" hydrogen in molecules, i.e. hydrogen of the carboxyl group, caused other characteristic properties.

2. Interaction with metals facing the electrochemical row of voltages to hydrogen. So, iron restores hydrogen from acetic acid:

2SH3-coo + Fe -\u003e (CHGCOO) 2fe + H2

3. Interaction with the main oxides to form salt and water:

2R-coxy + saa -\u003e (R-souo) 2s + H20

4. Interaction with metals hydroxides to form salt and water (neutralization reaction):

R-coo + NaOH -\u003e R-Coona + H20 3R-coo + sa (OH) 2 -\u003e (R-souo) 2s + 2N20

5. Interaction with sheals of weaker acids, with the formation of the latter. Thus, acetic acid displaces the stearin of sodium stearate and coal from potassium carbonate.

6. The interaction of carboxylic acids with alcohols with the formation of esters is already known to you by the reaction of eTE-robes (one of the most important reactions characteristic of carboxylic acids). The interaction of carboxylic acids with alcohols is catalyzed by hydrogen cations.

The esterification reaction is reversible. Equilibrium shifts towards the formation of ester in the presence of water-based means and removing the ether from the reaction mixture.

In the reaction, inverse esterification, which is called the hydrolysis of the ester (the interaction of ester with water), acid and alcohol are formed. It is obvious that reacting with carboxylic acids, i.e., multiatomic alcohols, such as glycerin, can be reacting with esterification.

DCA carboxylic acids (except for formic), along with a carboxyl group, contain a hydrocarbon residue in molecules. Of course, this cannot but affect the properties of acids, which are determined by the nature of the hydrocarbon residue.

7. Reactions of attachment across multiple communication - inteadaneous carboxylic acids are entering into them; For example, hydrogen attachment reaction is hydrogenation. When hydrogenation of oleic acid, an extreme steaaric acid is formed.

Unfoluble carboxylic acids, like other unsaturated compounds, attach halogens for dual communication. So, for example, acrylic acid discolores bromine water.

8. Reactions of substitution (with halogen) - limit carboxylic acids are capable of entering it; For example, in the interaction of acetic acid with chlorine, various chlorine derivatives can be obtained:

With halogenation of carboxylic acids containing more than one carbon atom in the hydrocarbon residue, it is possible to form products with different positions of halogen in the molecule. If the reaction is flowing through a free radical mechanism, any hydrogen atoms in the hydrocarbon residue may be replaced. If the reaction is carried out in the presence of small amounts of red phosphorus, it goes selectively - hydrogen is not replaced only in but- Position (at the nearest to the functional group of carbon atom) in the acid molecule. The reasons for such selectivity you will learn when studying chemistry in a higher educational institution.

Carboxylic acids form various functional derivatives when replacing the hydroxyl group. During the hydrolysis of these derivatives, carboxylic acid is again formed.

Carboxylic acid chloranhydride can be obtained by an acid of phosphorus chloride (III) or thionyl chloride (SOSL 2). Anhydrides of carboxylic acids are obtained by the interaction of chlorine anhydrides with carboxylic acid salts. The esters are formed as a result of esterification of carboxylic acids with alcohols. Esterification is catalyzed by inorganic acids.

This reaction initiates the protonation of the carboxyl group - the interaction of the hydrogen cation (proton) with a vapor electronic pair of an oxygen atom. The protonation of the carboxyl group entails an increase in a positive charge on the carbon atom in it:

Methods for getting

Carboxylic acids can be obtained by oxidation primary alcohol and aldehydes.

Aromatic carboxylic acids are formed during the oxidation of benzene homologues.

Hydrolysis of various carboxylic acid derivatives also leads to acids. So, with hydrolysis of the ester, alcohol and carboxylic acid are formed. As mentioned above, the response of esterification and hydrolysis coded by acid is reversible. The hydrolysis of the ester under the action of an aqueous alkali solution proceeds irreversibly, in this case, it is not formed from the ester, and its salt is formed. In the hydrolysis of nitriles, amides are first form, which are then converted into acid. Carboxylic acids are formed when the interaction of magnesium-organic compounds with carbon oxide (IV).

Separate representatives of carboxylic acids and their meaning

Formic (methane) Nson acid - a liquid with a sharp odor and a boiling point of 100.8 ° C, well soluble in water. Formic acid poisonous, when hitting the skin, causes burns! The staggering liquid released by ants contains this acid. Formic acid has a disinfectant property and therefore finds its use in the food, leather and pharmaceutical industry, medicine. It is also used when painting fabrics and paper.

Acetic (etch) acid CH3Cone is a colorless liquid with a characteristic sharp smell, mixed with water in any respect. Aqueous solutions of acetic acid go on sale under the name of vinegar (3-5% solution) and acetic essence (70-80% solution) and are widely used in the food industry. Acetic acid - a good solvent of many organic substances And therefore is used with dye, in leather production, in the paint industry. In addition, acetic acid is a raw material to obtain many technically important organic compounds: for example, it is based on substances used to combat weeds - herbicides.

Acetic acid is the main component of the wine vinegar, whose characteristic smell is determined by it. It is an ethanol oxidation product and is formed from it when storing wine in air.

The most important representatives of the highest limit mono-abnormal acids are palmitic C15H31Son and stearic acid C17N35Cone. In contrast to lower acids, these substances are solid, poorly soluble in water.

However, their salts are stearats and palmitates are well soluble and have detergent, so they are also called soaps. It is clear that these substances are produced on a large scale.

From unsaturated higher carboxylic acids the greatest value It has oleic acid C17n333Son, or (CH2) 7Con. This is an oil-based liquid without taste and smell. Widespread use in the technique find its salts.

The simplest representative of the two-axis carboxylic acids is the oxalic (ethadial) acid noso-coxy, which is found in many plants, for example, in sorvele and sourness. Sorrelic acid is a colorless crystalline substance, soluble in water well. It is used when polishing metals, in the woodworking and leather industry.

1. Unfoluble elaidin acid C17H33Son is a trans-isomer of oleic acid. Make the structural formula of this substance.

2. Make the equation of the hydrogenation reaction of oleic acid. Name the product of this reaction.

3. Make the equation of the reaction of the combustion of stearic acid. What volume of oxygen and air (n. Y.) Will be required for incineration of 568 g of stearic acid?

4. Mix solid fatty acids - Palmitic and stearinova - called Stearin (it is from it that the stearin candles make). What air volume (n. Y.) Is required for burning a two-gram stearin candle, if stearin contains equal masses palmitic and stearic acids? What volume carbon dioxide (n. y.) And the mass of water is formed at the same time?

5. Decide the previous problem, provided that the candle contains equal amounts (the same number of moles) stearin and palmitic acids.

6. To remove rust spots, they are treated with acetic acid solution. Make molecular and ionic equations of the reactions occurring at the same time, given that the rust contains oxide and iron hydroxide (III) - FE2O3 and Fe (OH) 3. Why such stains are not removed by water? Why do they disappear when treating a solution of acid?

7. The food (drinking) soda of MANS03 is added to the bezing dough, pre-"quenched" with acetic acid. Do this reaction at home and make its equation, knowing that coalic acid is weaker than acetic. Explain the formation of foam.

8. Knowing that chlorine is more electrone negotiable than carbon, position the following acids: acetic, propionic, chloroacetic, dichloroacetic and trichloroacetic acids in order of amplification of acidic properties. Justify your result.

9. What can be explained that formic acid enters the "silver mirror" reaction? Make the equation of this reaction. What gas can stand out at the same time?

10. In the interaction of 3 g of a limiting monosular carbo-new acid with an excess of magnesium, 560 ml (n. Y.) Hydrogen was separated. Determine the acid formula.

11. Give the reaction equations with which you can describe the chemical properties of acetic acid. Name the products of these reactions.

12. Suggest a simple laboratory method, with which you can recognize propane and acrylic acids.

13. Make the equation of the reaction of the preparation of methyl formate - ester of methanol and formic acid. In what conditions should this reaction be carried out?

14. Make the structural formulas of the substances having the composition of C3N602. What classes of substances can they be attributed? Give the equations of reactions characteristic of each of them.

15. The substance A - isomer of acetic acid is not dissolved in water, but it may be subjected to hydrolysis. What is the structural formula of substance or? Name the products of its hydrolysis.

16. Make the structural formulas of the following substances:

a) methyl acetate;
b) oxalic acid;
c) formic acid;
d) dichlorofacial acid;
e) magnesium acetate;
e) ethyl acetate;
g) ethyl formate;
h) acrylic acid.

17 * A sample of a maximum single-axis organic acid weighing 3.7 g was neutralized with an aqueous solution of sodium bicarbonate. When transmitted gas separated through lime water was obtained 5.0 g of sediment. What acid was taken and what is the volume of the separated gas?

Carboxylic acids in nature

Carboxylic acids are very often found in nature. They are contained in fruits and plants. They are present in the needles, sweat, urine and cluster juice. You know, it turns out that the bulk of acids form esters that have smells. So the smell of lactic acid, which is contained in the sweat of a person, attracts mosquitoes, they feel pretty much to the considerable distance. Therefore, no matter how much you tried to drive off the annoying mosquito, he still feels good sacrifice. In addition to human sweat, lactic acid is contained in salt cucumbers and sauerkraut.

And female monkeys to attract the male, it highlights acetic and propionic acid. Sensitive, dog nose is able to hear the smell of oil acid, which has a concentration of 10-18 g / cm3.

Many species of plants are able to distinguish with acetic and oil acid. And some weighing plants use this and highlighting substances, eliminate their competitors, suppressing their growth, and sometimes causing their death.

Indians used acid. To destroy the enemy, they watched the arrows with a deadly poison, which turned out to be derived from acetic acid.

And then a natural question arises, is acid hazards for human health? After all, orange acid is widely common in nature, which is contained in sorvele, oranges, currants and raspberries, for some reason, did not find applications in the food industry. It turns out that there is oxalic acid in two hundred times stronger than acetic acid, and it is capable of even eroding, and its salts, accumulating in the human body, to form stones.

Acids were widely used in all spheres of human life. They are used in medicine, cosmetology, food industry, agriculture and used for household needs.

For medical purposes, organic acids such as dairy, wine, ascorbic. Probably, each of you used to strengthen the body vitamin C is just an ascorbic acid. It not only helps strengthen the immune system, but also has the ability to remove carcinogens and toxins from the body. Milk acid is used for migration, as it has high hygroscopicity. But the wine acid acts as a light laxative, as an antidote, with alkalis poisoning and as a component necessary for the preparation of plasma during blood transfusion.

But fans of cosmetic procedures, you should know that contained in citrus fruits, fruit acids, favorably affect the skin, as penetrating deep into the skin, they are able to speed up the skin renewal process. In addition, the smell of citrus is a toning effect on the nervous system.

Have you noticed that such berries like cranberries and a lingonberry are stored for a long time and remain fresh. Do you know why? It turns out that they contain benzoic acid, which is an excellent preservative.

But in agriculture, amber acid was widely used, since it can be increased by the yield of cultivated plants. It is also capable of stimulating the growth of plants and accelerate their development.

1. Carboxylic acids - these are oxygen-containing organically substances whose molecules contain one or more carboxyl groups

(-S ooh. ), connected to a carbon radical or a hydrogen atom.

The carboxyl group contains two functional groups - carbonyl\u003e C \u003d O and hydroxyl -OH, directly related to each other:

2. Classification

A) by the number of carboxyl groups in the molecule

B) by the nature of the hydrocarbon radical

3. Isomeria and nomenclature

I. . Structural

A) the isomerism of the carbon skeleton (starting with C 4 )

B) interclasses with estersR - CO - O - R 1 (starting with C 2)

For example: for 3N 6 o 2

CH 3 -CH 2 -COOH propionic acid

FROM H 3 -CO -OCH 3 Acetic Acid Methyl Ether

II. . Spatial

A) optical

For example:

B) cis - trans - isomeripal of non-precious acids

Example:

4. Nomenclature of carboxylic acids

Systematic acid names are given by the name of the corresponding hydrocarbon with the addition of suffix -com And words acid.

To indicate the position of the substituent (or radical), the numbering of the carbon chain is starting from the carbon atom of the carboxyl group. For example, a branched carbon chain connection (CH 3) 2 CH-CH 2 -COOH is called 3-methylbutan acid. For organic acids, trivial names are also widely used, which usually reflect the natural source, where these connections were first discovered.

Some mono-axial acids

For polypic acids apply suffixes -Dile, -tritis etc.

For example:

HOOC-COOH - etanova (oxal) acid;

HOOC-CH 2 -COOH - propandic (malonic) acid.

Limit mono-abnormal carboxylic acids

C N H. 2 N. +1 - CooolorC N H. 2 N.O. 2

Homologic series

The structure of the carboxyl group

The carboxyl group combines two functional groups - carbonyl\u003e C \u003d O and hydroxyl -OH, mutually affecting each other:

The acid properties of carboxylic acids are due to the displacement of electron density to carbonyl oxygen and caused by this additional (compared to alcohols) of the polarization of the O-N communication.
In an aqueous solution, carboxylic acids dissociate on ions:

Water solubility and high boiling points acids are due to the formation of intermolecular hydrogen bonds.

With an increase in the molecular weight solubility of acids in water decreases.

Physical properties of marginal monoxide acids

The lower members of this series under normal conditions are liquids with a characteristic acute odor. For example, the etching (acetic) acid has a typical "acetic" smell. Anhydrous acetic acid at room temperature is a liquid; At 17 ° C, it freezes, turning into a west substance, which got the name "Ice" acetic acid. The average representatives of this homologous series are viscous, "oil" liquids; Starting with C 10 - solids.

Back forward

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Objectives:

• Education:
  • bring up accuracy in recordings in notebooks;
  • teach to maintain the purity and accuracy of the workplace;
  • educate the ability to communicate in the team;
  • awareness of students of what a significant role is played by carboxylic acids in a person's life;
  • formation of ideological knowledge: show causal relationships when considering the structure, properties, application of these substances; The transition of quantitative changes to qualitative when considering the homologous series of acids and change them physical properties With increasing mass.
• Development:
  • be able to formulate the determination of limit carboxylic acids;
  • be able to make names of class representatives;
  • be able to find isomers and homologs from the list of proposed substances;
  • be able to make equations chemical reactionsreflecting the chemical properties of carboxylic acids.
• Education:
  • form an idea of \u200b\u200bcarboxylic acids as a class of organic compounds;
  • study the nomenclature and isomerism of limit carboxylic acids, as well as their classification;
  • explore the homologous series of limit carboxylic acids;
  • study the structure of carboxylic acids;
  • consider the properties of carboxylic acids and their use.

Equipment and reagents: acetic acid, formic acid, universal lactium paper, methyl orange, water extract, copper wire, iron hydroxide (III), sodium bicarbonate, silver nitrate, ammonia alcohol (for the preparation of ammonia silver oxide solution), potassium permanganate solution; holder of tubes, matches, alcohol, test tubes; Demo posters, demonstration preparations (eggs Kinder surprise), multimedia tools, videopyte (solubility of carboxylic acids in water, interaction of acetic acid with metals), natural objects (lemonade, ketchup), frontal work sheet (LFR) ( Attachment 1 ).

Methods:vite-visual, laboratory experiment, group work.

Methodology:traditional lesson, studying new.

DURING THE CLASSES

- Good day!

"Any substance - from the simplest to the most difficult - has three different, but interrelated parties are a property, composition, structure."

V.M. Kedrov

One of the leading ideas of the science of chemistry is the dependence of the properties of substances from their composition and structure, to study and confirm that we have to be reached.
Today's lesson is devoted to a special class of organic compounds. What? Junk in the past.
From ancient times, people grown grapes and poisoned the grape juice. When stored juice roamed, wine was obtained. If the wine skelted, vinegar formed. Hence the origin of the word "vinegar" - from the Greek "Oksos" - sour. (Demonstration of the drawing "Table Vinegar").
People began to use vinegar almost 3000 years ago. In antiquity, vinegar was the only dietary acid. Later, an important "additive" appeared to various culinary products - citric acid ... It was first highlighted from the juice of immature lemons.
To give food sour taste, sorrel leaves, rhubarb, lemon juice, oily berries (Demonstration of drawings). Of course, no one thought that an acidic taste in all cases is due to the presence of connections of the same class. What? (Acids) . Organic acids, which are called carbon.
The composition of cranberries, lingers, blueberries and honey include benzoic acid. It is widely used in the food industry as a preservative (E210) in the manufacture of beverages and ketchups (Demonstration of Lemonade and Ketchup).
Many insects forming families or simply "communities" (termites, ants, wasps, bees) are produced in the body with special chemicals with which they are notifying their hazard tribesmen. For example, red-haired ants have a pheromone anxiety - formic acid, which simultaneously serves as their weapon.
Formic acid is also found in some plants, in particular in Zhugoy Nature.

- Guys, specify theme lesson. (Carboxylic acids). Record the number and theme of the lesson.

Exploring the infusions obtained from the roots and leaves of different plants, by the end of the 18th century Karl Shelele allocated wine, lemon, apple, gallopal, oxalic acid.

- Today's lesson is devoted to one of the class of organic compounds - carboxylic acids. Inorganic acids you studied.

- What purpose do we put in today's lesson? (Determine, have carboxylic acid properties of inorganic, examining their composition and structure).

Show formulas of some carboxylic acids(Appendix 2. ).

- What do you see in their structure? (One or more groups).
- Mentally "dismembering" an unknown functional group into two.
- Which of the studied groups can be detected in its composition? (Hydro xy and carbonile). Hence the name - carboxylgroup.
- And now try to formulate the definition of carboxylic acids.

Carboxylic acids - Organic substances whose molecules contain one or more carboxyl groups connected to a hydrocarbon radical.
It is quite obvious that it is impossible to get acquainted with all acids. Therefore, we turn to their classification.

- Looking at the formulas of acids, classify them into groups of different criteria.
- What criteria can you divide them? (By the nature of the hydrocarbon radical, basicity).

(Work student at the board).

Carboxylic acids (by the nature of the hydrocarbon radical)
Limit (saturated)	Unforeseen (unsaturated)	Aromatic

Remember the classification of inorganic acids.
What is understood by the basicity of inorganic acids? (The number of hydrogen atoms capable of replacing metal).
It is also true for organic acids.

Carboxylic acids (basicity)
Monasular	Dubious	Multiment

So, carboxylic acids are extreme, unsaturated and aromatic, as well as monasonde, dual-mine and multipoint.
In today's lesson we will study monoxide Limit Carboxylic Acid.
The variety of carboxylic acids, as well as all organic compounds, provide two important phenomena.
What are these phenomena? (Isomeria and homology).
Word the definition of homologues. (Homologists are substances that have the same qualitative composition, but different quantitative composition (differ in one or more groups -CH 2), have a similar structure, and therefore similar properties.
You have a leaflets that you enter into your notebooks ( Appendix 3. ). The first column recorded the first members of the homologous row of carboxylic acids and some of the most common others. In the second you will enter their systematic name (Independently followed by checking). The third, fourth and fifth columns are already filled.
And now we will call carboxylic acids by systematic nomenclature. Recall the rules of the nomenclature of organic compounds on the example:

In the systematic nomenclature of carboxylic acids use the end -Offic acid. If carboxyl groups are several, then use consoles di-, three-, tetra etc. Most often, historically emerged names are used for carboxylic acids associated in most cases with the name of their natural sources. Therefore, in order to further navigate the nomenclature of organic compounds, the names of the simplest monasone acids should be remembered.
The first representative is formic acid. It has only one carbon atom. What hydrocaritus corresponds to him? (Methane) . So how will the carboxylic acid be called? (Methane acid) . We write the name.

We called only one phenomenon that provides a variety of aldehydes. And now, look . (I show the children of 3 chocolate eggs Kinder surprise). Outwardly, they are absolutely the same. We also have three absolutely identical molecular formulas of substances. (3 posters closed in advance on the board on the board). I open them(Appendix 4. ).
But it is known that these are 3 different substances. What is the reason? What phenomenon is it connected with? (With the phenomenon of isomeria).
That's how an externally chocolate eggs are the same, inside contain completely different toys and these substances have the same molecular formulas, but a different structure.
Word the definition of isomers. (Isomers are substances that have the same quality and quantitative composition, but a different structure).
Make a substance with a molecular formula C 4 H 8 O 2 isomers. (Work at the board).

Other isomers can be made. Let's focus on this.
Take out what kinds of isomerism are characteristic of carboxylic acids. (Isomerism of the carbon skeleton (1 and 2) and interclace isomeria (for example, 1 and 4)).
What class of organic compounds is isomeric carboxylic acids? (With esters).
And now let's call 1 and 2 compounds by systematic nomenclature. (Work at the board).
Knowing the systematic name, one can make a structural formula. Make a formula 2-hydroxypropanotic acid. (Work at the board).

This acid has a trivial name - dairy - Accept active participation in vital processes . Back in the last century I.I. Mechnikov noted that the nutrition of the milk-eyed products oxidizes the intestine from the rotor microflora and contributes to longevity.
Let me remind you, the properties of the substance depend on their structure. Let us turn to the structure.

In carboxylic acid molecule r-Electrons atom ABOUT- Hydroxyl group interact with electrons π - Communication of the carbonyl group, resulting in polarity communication O-n, hardening π -Ob in the carbonyl group, decreases δ+ Atom charge FROM and increases partial δ+ Atom N.. This contributes to the formation of durable hydrogen bonds between carboxylic acid molecules.
In the homologous row of carboxylic acids, their strength falls with an increase in the hydrocarbon radical, so formic acid is the strongest of them. This is due to an increase in the positive induction effect of the alkyl substituent in the row -h\u003e -CH 3\u003e -C 2 H 5. Further elongation of the carbon chain does not have a noticeable influence on the magnitude + I.- Effect and, therefore, the power of acid:

The physical properties of carboxylic acids describe, after completing the No. 4 of the LFR. We find out how the physical properties of carboxylic acids in the homologous row change. Let's see the video character - the solubility of carboxylic acids in water.
Recall the properties of inorganic acids. (Student responses).
Acid properties of carboxylic acids are similar to the properties of weak inorganic acids. Inorganic acids are dissociated (soluble in water), change the color of the indicator (soluble in water), interact with metals in the electrochemical row of metals voltage to H 2, with amphoteric and main oxides, with bases, with salts of weaker acids.
Do the carboxylic acids possess these properties? Check.
We repeat the safety regulations when working with acids.
If the acids or alkalis and alkalis are shaken on the skin, they shake the visible drops and then wash off with a wide stream of cool water; It is forbidden to process the striking plot with a moistened tampon. Why?
Choose the correct answer.
When burning with acid, the skin must be treated with a solution:

The neutralization of hydrogen cations is caught with a pitch, since you can get chemical and thermal burns. For this purpose, a solution of soda, having an alkaline environment. Answer: 2

Walk out the experiments. (Work on groups with the writing of the corresponding reaction equations on the board).

Let's look at the rebus. . What acid will we work with?

One of the groups will explore special properties formic acid, After completing the number 7 of the LFR.

Move practical work and alleged students' responses - Appendix 5. .

The interaction of acetic acid with metals - video expects.

Will there be alcohols to interact with carboxylic acids? (Yes).

Such reactions are called reactions. esterification.

The esterification reaction is the reaction of the formation of esters in the interaction of acids and alcohols in the presence of a watering agent.
In accordance with the mechanism of flowing the response of esterification in the formation of a complex ether from an acid molecule, a hydroxyl group is cleaved, from the alcohol molecule - a hydroxyl hydrogen atom:

The use of carboxylic acids (slides).
- Let's summarize:
- What's new we learned in the lesson? What did you learn? What do you know?

(Brief replies of students).

- Word the conclusion about the properties of carboxylic acids. (Carboxylic acids have the properties of inorganic acids, show specific properties).
Soluble acids dissociate change the color of the indicator, carboxylic acids react with active metals with hydrogen release, react with basic and amphoteric oxides, bases, salts of weaker acids.

- Today we went through the way from the composition and structure of substances to predict their properties.

1. Word the definition of the concept of "carboxylic acids"?
2. What are the features of the classification of acids?
3. What types of isomerism are characteristic of them?
4. What are the features of carboxylic acid nomenclature?
5. What substances are carboxylic acids?
6. Where are the use of carboxylic acids?
7. In the food industry, acetic acid is used as a preservative and an acidity regulator under the code E-260. Write the structural formula of the previous homologue of this acid having the E-236 code. Name the substance on a systematic and trivial nomenclature.
8. Make the equation of the reaction of the interaction of acetic acid with bromine into the light; hydrogenation of acrylic acid; Propionic acid with methyl alcohol.

Homework: §30, LFR number 13, 14, 15.

Bibliography

1. Gabrielyan O.S. Chemistry / O.S. Gabrielyan, I.G. Ostrumova, S.A. Sweets. - M.: / Drop, 2011.
2. Kartzova A.A.Chemistry without formulas. - 3rd ed., Pererab. - St. Petersburg: Avalon, Classic ABC, 2005.
3. Martynenko B.V. Chemistry: Acids and bases: Handbook for students 8-11 cells. general education. institutions. - M.: Enlightenment, 2000.
4. Chemistry at school, 2008, № 5-80.
5. Chemistry at school, 2010, № 3-80.

Classification

a) on basicity (i.e. numeruclearboxyl groups in the molecule):

Monople (monocarbonic) RCOOH; eg:

CH 3 CH 2 CH 2 coxy;

Noo-CH 2 Propandic (Malonic) Acid

Three-axle (tricarboxylic) R (COOH) 3, etc.

b) on the structure of a hydrocarbon radical:

Aliphatic

limit; For example: CH 3 CH 2 coxy;

unforeseen; For example: CH 2 \u003d propanking (acrylic) acid

Alicyclic, for example:

Aromatic, for example:

Limit monocarboxylic acids

(single-axis saturated carboxylic acids) - carboxylic acids in which the saturated hydrocarbon radical is connected to one carboxyl group -COOH. All of them have the general formula C n H 2N + 1 COOH (n ≥ 0); or CNH 2N O 2 (n≥1)

Nomenclature

The systematic names of single-axis limit carboxylic acids are given by the name of the corresponding alkane with the addition of suffix and the blood of the acid.

1. NSOon methane (formic) acid

2. CH 3 Syon Equity (acetic) Acid

3. CH 3 CH 2 Syon propane (propionic) acid

Isomeria

The skeleton isomeria in the hydrocarbon radical manifests itself, starting with butanic acid, which has two isomers:

Interclative isomerism is manifested, starting with acetic acid:

CH 3 -COOH acetic acid;

H-COO-CH 3 methyl formate (Methyl ether of formic acid);

HO-CH 2 -COH Hydroxyetanal (hydroxyuxous aldehyde);

HO-CHO-CH 2 hydroxyethylene oxide.

Homologic series

Acid residues and acid radicals

Electronic structure of carboxylic acid molecules

The displacement of the electron density shown in the formula in the direction of the oxygen carbonyl atom determines the strong polarization of the O-H bond, as a result of which the separation of the hydrogen atom is facilitated in the form of a proton - in aqueous solutions Acid dissociation process occurs:

RCOOH ↔ RCOO - + H +

In carboxylate-ion (RCOO), there is a p, π-conjugation of a vapor pair of electrons of an oxygen atom of a hydroxyl group with p-clouds forming π communication, as a result, the π- communication is delocalizing and the uniform distribution of the negative charge between two oxygen atoms:

In this regard, for carboxylic acids, unlike the aldehydes, the reaction of the attachment is not characteristic.

Physical properties

The boiling points of acids are significantly higher than the boiling points of alcohols and aldehydes with the same number of carbon atoms, which is explained by the formation of cyclic and linear associates between acid molecules due to hydrogen bonds:

Chemical properties

I. Acid Properties

The strength of the acids decreases in the row:

Nson → CH 3 Soam → C 2 H 6 Cooh → ...

1. Neutralization reactions

CH 3 coam + Kon → CH 3 COI + H 2 O

2. Reactions with main oxides

2HCOOH + SAO → (NSOO) 2 sa + H 2 O

3. Reactions with metals

2CH 3 CH 2 Soam + 2NA → 2 SH 3 CH 2 Coona + H 2

4. Reactions with salts of weaker acids (including with carbonates and hydrocarbonates)

2CH 3 Soam + Na 2 CO 3 → 2CH 3 Coona + CO 2 + H 2 O

2NOsone + Mg (HCO 3) 2 → (NSOO) 2 mg + 2СO 2 + 2N 2 O

(NSO + NSO 3 - → NSOO - + CO2 + H2O)

5. Reactions with ammonia

CH 3 coam + NH 3 → CH 3 Coonh 4

II. Sentation of the group -one

1. Interaction with alcohols (esterification reaction)

2. Interaction with NH 3 when heated (acid amides are formed)

Amida acids hydrolyzed with acid formation:

or their salts:

3. Education halogengidrides

Chloranhydrides have the greatest importance. Chlorining reagents - PCL 3, PCl 5, thionyl chloride SOCL 2.

4. Education of acid anhydrides (intermolecular dehydration)

Acid anhydrides are also formed by the interaction of acid chloride hydrhydrides with anhydrous carboxylic acid salts; In this case, mixed anhydrides of various acids can be obtained; eg:

III. Reactions of substitution of hydrogen atoms in the α-carbon atom

Features of the structure and properties of formic acid

The structure of the molecule

Molecule of formic acid, in contrast to other carboxylic acids, contains an aldehyde group in its structure.

Chemical properties

Formic acid enters the reaction characteristic of both acids and aldehydes. Showing the properties of aldehyde, it is easily oxidized to coalic acid:

In particular, the NSON is oxidized ammonia solution AG 2 O and copper hydroxide (II) Cu (OH) 2, i.e. gives qualitative reactions on aldehyde group:

When heated with concentrated H 2 SO 4, formic acid is decomposed on carbon monoxide (II) and water:

Formic acid is noticeably stronger than other aliphatic acids, since the carboxyl group is associated with a hydrogen atom, and not with an electron-donor alkyl radical.

Methods for obtaining limit monocarboxylic acids

1. Oxidation of alcohols and aldehydes

General scheme of oxidation of alcohols and aldehydes:

KMNO 4, K 2 CR 2 O 7, HNO 3 and other reagents are used as oxidizing agents.

For example:

5C 2N 5 ON + 4KMNO 4 + 6H 2 S0 4 → 5CH 3 Soam + 2K 2 SO 4 + 4MNSO 4 + 11N 2 O

2. Hydrolysis of esters

3. Oxidative splitting of double and triple bonds in alkenes and alkina

Methods for producing NSON (specific)

1. Carbon oxide interaction (II) with sodium hydroxide

Co + Naoh → HCoona Sodium Formate

2hCoona + H 2 SO 4 → 2NCOs + Na 2 SO 4

2. Decarboxylation of oxalic acid

Methods for producing CH 3 Soam (Specific)

1. Catalytic oxidation of Bhutan

2. Synthesis from acetylene

3. Catalytic carbonylation of methanol

4. Acetic acid fermentation of ethanol

So get food acetic acid.

Getting higher carboxylic acids

Hydrolysis of natural fats

Unforeseen monocarboxylic acids

The most important representatives

General formula of alkene acids: C n h 2N-1 COOH (n ≥ 2)

CH 2 \u003d CH-COOH Propented (Acrylic) Acid

Higher unshakable acids

The radicals of these acids are included in the composition of vegetable oils.

C 17 H 33 COOH - oleic acid, or cis-Okdien-9-oovy acid

Trance- Oleic acid is called elaidinic acid.

C 17 H 31 COOH - Linoleic acid, or cis, cis-Okadien-9,12 ohic acid

C 17 H 29 COOH - Linolenic acid, or cis, cis, cis-Octadecitrine-9,12,15-ohic acid

Besides common properties Carboxylic acids, for unsaturated acids are characterized by the reaction of attachment to multiple bonds in the hydrocarbon radical. So, unsaturated acids, as well as alkenes, are hydrogenated and discolored by bromine water, for example:

Separate representatives of dicarboxylic acids

Limit dicarboxylic acids HOOC-R-COOH

HOOC-CH 2 -COOH Propandy (Malonic) Acid, (Salts and Esters - Malonates)

Hooc- (CH 2) 2 -COOH Butadic (Amber) Acid, (Salts and Esters - Succinate)

Hooc- (CH 2) 3 -COOH pentadic (glutar) acid, (salts and ethers - gluttones)

HOOC- (CH 2) 4 -COOH Hexadic (adipic) acid, (salts and esters - adipients)

Features chemical properties

Dicarboxylic acids are largely similar to monocarbonic, however, are stronger. For example, the oxalous acids of acetic is almost 200 times.

Dicarboxylic acids behave like a two-axis and form two rows of salts - sour and medium:

HOOC-COOH + NAOH → HOOC-COONA + H 2 O

HOOC-COOH + 2NAOH → Naooc-Coona + 2H 2 O

When heated, oxal and malonic acids are easily decarboxylated:

Definition

Carboxylic acids – organic compounds, whose molecules contain one or more functional carboxyl groups -oSon connected with a hydrocarbon radical.

The carboxyl group consists of a carbonyl group > C.= O. and the associated hydroxyl group -one.

General formula of carboxylic acids: R-COOH.

The acid properties of carboxylic acids are due to the displacement of electron density to carbonyl oxygen, which causes the occurrence of a partial positive charge on the atom.

As a result, the polarity of the O-N communication increases, and the dissociation process becomes possible:

The formed anion stabilizes due to charge delocalization:

Lower carboxylic acids containing up to 3 carbon atoms are colorless liquids with a characteristic sharp odor, mixed with water in any ratios. Most acids containing 4-9 atoms are oily liquids with an unpleasant smell. Acids containing more than 10 hydrogen atoms - solid substancesWater insoluble.

The solubility of carboxylic acids in water and high boiling temperatures are associated with the formation of intermolecular hydrogen bonds. In solid state, carboxylic acids exist mainly in the form of cyclic dimers, and a linear association is also in the liquid:

Types of carboxylic acids

Depending on the structure of a hydrocarbon radical, carboxylic acids are divided into:

• aromatic (benzoic acid)
• aliphatic (limit (caproic acid) and unsaturated (acrylic acid))
• alicyclic (chinic acid)
• heterocyclic (nicotinic acid).

According to the number of carboxyl groups, carboxylic acids are divided into:

• monomore ()
• two-mine (sorval acid)
• multi-stronger (citric acid).

With the introduction of other acid in the acid molecule functional groups (-On, \u003d CO, -NH 2, etc.) are formed by other classes of compounds: oxy-, ketokislotes, etc.

General formula for limiting monosular carboxylic acids:

FROM N. H 2N O 2 (n. \u003d 1,2,3 ...) or CN H 2N + 1 COOH (n. = 0,1,2…)

General formula of unsaturated monosocondary carboxylic acids:

FROM N. H. 2 N. –2 O. 2 (n. \u003d 1,2,3 ...) or C N H. 2 N. –1 Coool (n. = 0,1,2…)

General formula of limit two-axis carboxylic acids:

C N H 2N-2 O 4 (n. = 2,3…)

Names and formulas of some carboxylic acids

methana

muraury

ethan

acetic

propane

propionova

butanova

oil

pentanova Acid

valeric acid

hexaneic acid

capronic acid

okadekanova

stearinovaya

2-propane

acrylic

CH 3 -CH \u003d CH-COOH

2-buten

croton

CH 2 \u003d CH-CH 2 -COOH

3-buten

viniluxus

CH 2 \u003d C (CH 3) COOH

2-methyl-2-props

methacryl

ethadian

savleless

COOH-CH 2 -COOH

propandy

malonic

COOH- (CH 2) 2 -COOH

butani

amber

COOH- (CH 2) 3 -COOH

pentanty

glutarovaya

COOH- (CH 2) 4 -COOH

hexadic

adipinova

Examples of solving problems

Example 1.

Example 2.