Esters of soap fats interesting facts. Esters

01.11.2019 healthy eating

Esterification reactionreactions between alcohols and acids,
resulting in complex
ethers and water is released (from lat. ether -
ether). The catalysts are mineral
acids.

Hydrolysis

This reaction is reversible. Back
process - cleavage of an ester
under the action of water to form
carboxylic acid and alcohol are called
ester hydrolysis.

Specific aroma of berries, fruits and fruits

Esters are widely
common in
nature.
Specific flavor
berries, fruits and fruits
to a large extent
conditioned
representatives of this
Esters of lower carboxylic acids
organic class
and lower monohydric alcohols
have a pleasant smell of flowers,
connections.
berries and fruits.

Waxes

Esters
fatty acids and
alcohols with long
hydrocarbon
called radicals
waxes.
For example, bee
wax contains complex
palmitic ester
acids
and myricil
alcohol
CH3(CH2)14–CO–OCH2(CH2)29CH3.

Complex ethers. Physical Properties

Esters -
liquids that have
pleasant fruity
smells.
Their density is less
water density, they
almost no
dissolve in water.
Good
soluble in alcohols.

Esters are of great practical importance

1. They are used in industry in
as solvents and intermediates
products in the synthesis of various
organic compounds.
2. Esters with a pleasant smell
used in perfumery and food
industry.
3. Esters often serve as starting materials
substances in the production of many
pharmaceutical preparations.

Fats

CH2-O-CO-R1 - esters
triatomic
I
glycerin alcohol and
CH-O-CO-R2
higher monatomic
I
CH2-O-CO-R3, carboxylic acids.
where R1, R2 and R3 are radicals (sometimes different)
fatty acids.

The common name for these compounds is triglycerides.

From the history:

For the first time
chemical
fat composition
identified in
the beginning of the past
century french
chemist Michel
Eugene Chevrel

From the history:

What is in the composition of fats
and oils included
glycerin, for the first time
found out in 1779
famous swedish
chemist
Carl Wilhelm
Scheele.

Composition of fats

Fats may contain residues
saturated and unsaturated acids,
containing an even number of atoms
carbon and unbranched carbon
skeleton.
Natural fats are usually
mixed esters, i.e. them
molecules are made up of different
carboxylic acids.

Physical properties of fats:

Fats are insoluble in water, but readily soluble in
organic solvents - benzene, hexane. (this
ability is used to clean clothes from
fat spots)
Their density is less than 1g/cm3
If at room temperature they have a solid
state of aggregation, then they are called fats, and if
liquid, then oils.
Fats have low boiling points.
With an increase in the length of the hydrocarbon radical, the temperature
fat melting increases.

Fat classification

Fats \u003d higher limiting carboxylic acids + glycerin

The fats formed
marginal
acids (butyric,
palmitic,
stearic, etc.),
have, as a rule,
hard
consistency.
These are animal fats.
origin.
beef, pork,
lamb, etc.

Fat classification:
Animal fats are mostly solid
or semi-liquid substances:
creamy
butter,
animal
fat, fish
fat, etc.

Fats = higher unsaturated carboxylic acids + glycerin

If in the composition of fat
contains remnants
unsaturated acids
(oleic and linoleic),
they represent
viscous liquids are oils.
These are: linen, hemp,
sunflower, olive,
soy, corn, etc.

Fat classification:

Vegetable fats are called oils.
These are usually liquid substances:
sunflower, olive, linseed, castor
oils, etc.

hydrogenation reaction
Liquid fats are converted into
solid by reaction
hydrogenation
(hydrogenation).
At the same time, hydrogen
joins double
connection contained in
hydrocarbon radical
oil molecules.

Chemical properties of fats

Hydrogenation of fats:
CH3
CH3
CH3

Chemical properties of fats

Hydrolysis (saponification with water and alkalis -
caustic soda or caustic potash).

Hydrogenation product of oils - hard fat
(artificial lard, lard). Margarine -
edible fat, consists of a mixture
hydrogenated oils (sunflower,
corn, cotton, etc.), animal fats,
milk and flavoring
additives (salt,
sugar, vitamins
and etc.).

Fats as esters
a reversible reaction
hydrolysis catalyzed
mineral acids. At
participation of alkalis hydrolysis
fat occurs irreversibly.
Products in this case
are soaps - salts of higher
carboxylic acids and alkaline
metals.

Sodium salts -
hard soaps,
potassium - liquid.
alkaline reaction
hydrolysis of fats, and
in general, all complex
ethers is called
also saponification.

Fats get:

Separation. It is the most
effective method of cleaning fats.
By rendering.
Hydrogenation. Hydrogenation is carried out in
special autoclaves. Used this
process for producing margarine.
Extraction or pressing.
The essence of the pressing process is
in squeezing oil from crushed seeds.

The use of fats

In medicine
Application
for food
Production
soap
Fats
Production
candles
Feed for
animals
AT
Production Production
paints
perfumery
glycerine

The value of fats:

Fats are of great importance in
human life: they perform very
important functions in the body such as
as energy, protective,
construction.

Conclusion:

1. Fats are trihydric alcohol esters
glycerin and fatty acids.
2. Fats are divided into animals and
vegetable.
3. Fats are obtained by rendering,
separation, hydrogenation,
pressing or extraction.
4. Fats in the human body perform
energy, protective, construction
functions.
5. The use of fats is varied.

Task number 1

Make formulas and give names
ethers formed
1 option:
butanoic acid and
methyl alcohol;
Option 2:
methane acid and propyl
alcohol;

Answer task number 1

1 option:
O
CH3 - CH2 - CH2 - COOH + CH3-OH → CH3 - CH2 - CH2 - C
+ H 2O
butanoic acid
methanol
methyl ester \
butanoic acid O - CH3
Option 2:
O
O
//
H - C + CH3 - CH2 - CH2 - OH → H - C
+ H 2O
\
propanol
\
IS HE
O - CH 2 - CH2 - CH3
methane
methane propyl ether
acid
acids

Task number 2
Finish the reaction, name the resulting substances
1 option:
C5H11COOH + C4H9OH →
Option 2:
C7H13COOH + C2H5OH →

Answer task number 2

Option 1: Saratov region
Position: chemistry teacher
Additional information: site
http://kalitina.okis.ru/
mini site
http://www.nsportal.ru/kalitina-tamara-mikhailovna

1 of 36

Presentation - Esters - Fats - Soaps

The text of this presentation

Complex ethers. Fats. Soap.
R–COOR"

General formula of esters
where R are radicals

Esters
- are called derivatives of carboxylic acids in which the hydrogen atom of the carboxyl group is replaced by a hydrocarbon radical. Their composition corresponds to the general formula R-COOR"

esterification reaction
reactions between alcohols and acids, as a result of which esters are formed and water is released (from lat. ether - ether). The catalysts are mineral acids.

Hydrolysis
This reaction is reversible. The reverse process - the splitting of an ester by the action of water to form a carboxylic acid and an alcohol - is called ester hydrolysis.

Specific aroma of berries, fruits and fruits
Esters are widely distributed in nature. The specific aroma of berries, fruits and fruits is largely due to representatives of this class of organic compounds.
Esters of lower carboxylic acids and lower monohydric alcohols have a pleasant smell of flowers, berries and fruits.

Waxes
Esters of fatty acids and alcohols with long hydrocarbon radicals are called waxes. For example, beeswax contains an ester of palmitic acid and myricyl alcohol.
CH3(CH2)14–CO–OCH2(CH2)29CH3.

Complex ethers. Physical Properties
Esters are liquids with pleasant fruity odors. Their density is less than the density of water, they practically do not dissolve in water. Well soluble in alcohols.

Esters are of great practical importance
They are used in industry as solvents and intermediates in the synthesis of various organic compounds. Esters with a pleasant smell are used in perfumery and the food industry. Esters are often used as starting materials in the manufacture of many pharmaceuticals.

Fats
CH2-O-CO-R1 I CH-O-CO-R2 I CH2-O-CO-R3, where R1, R2 and R3 are radicals of (sometimes different) fatty acids.
- esters of trihydric alcohol glycerol and higher monohydric carboxylic acids.

The common name for these compounds is triglycerides.

From the history:
For the first time, the chemical composition of fats was determined at the beginning of the last century by the French chemist Michel Eugene Chevrel.

From the history:
The fact that glycerin is included in the composition of fats and oils was first discovered in 1779 by the famous Swedish chemist Carl Wilhelm Scheele.

Composition of fats
The composition of fats may include residues of saturated and unsaturated acids containing an even number of carbon atoms and an unbranched carbon skeleton. Natural fats are usually mixed esters, i.e. their molecules are formed by various carboxylic acids.

Physical properties of fats:
Fats are insoluble in water, but readily soluble in organic solvents - benzene, hexane. (This ability is used to clean clothes from grease stains) Their density is less than 1 g / cm3 If at room temperature they have a solid state of aggregation, then they are called fats, and if liquid, then oils. Fats have low boiling points. With an increase in the length of the hydrocarbon radical, the melting point of fat increases.

Fat classification

Fats \u003d higher limiting carboxylic acids + glycerin
Fats formed by saturated acids (butyric, palmitic, stearic, etc.) usually have a solid consistency. These are animal fats. Beef, pork, lamb, etc.

Animal fats are most often solid or semi-liquid substances:
Fat classification:
butter, lard, fish oil, etc.

Fats = higher unsaturated carboxylic acids + glycerin
If the fat contains residues of unsaturated acids (oleic and linoleic), they are viscous liquids - oils. These are: linseed, hemp, sunflower, olive, soybean, corn, etc.

Vegetable fats are called oils.
These are usually liquid substances: sunflower, olive, linseed, castor oils, etc.
Fat classification:

Liquid fats are converted into solid ones by a hydrogenation reaction (hydrogenation). In this case, hydrogen is added to the double bond contained in the hydrocarbon radical of the oil molecules.
hydrogenation reaction

Chemical properties of fats
Hydrogenation of fats:

Chemical properties of fats
Hydrolysis (saponification with water and alkalis - caustic soda or caustic potash).

The product of hydrogenation of oils is solid fat (artificial lard, lard). Margarine is an edible fat that consists of a mixture of hydrogenated oils (sunflower, corn, cottonseed, etc.), animal fats, milk and flavorings (salt, sugar, vitamins, etc.).

Fats as esters are characterized by a reversible hydrolysis reaction catalyzed by mineral acids. With the participation of alkalis, the hydrolysis of fats occurs irreversibly. The products in this case are soaps - salts of higher carboxylic acids and alkali metals.

Sodium salts are solid soaps, potassium salts are liquid. The reaction of alkaline hydrolysis of fats, and in general of all esters, is also called saponification.

Fats get:
Separation. It is the most effective method of cleaning fats. By rendering. Hydrogenation. Hydrogenation is carried out in special autoclaves. This process is used to produce margarine. Extraction or pressing. The essence of the pressing process is the extraction of oil from crushed seeds.

The use of fats

The value of fats:
Fats are of great importance in human life: they perform very important functions in the body, such as energy, protective, building.

Conclusion:
Fats are esters of the trihydric alcohol glycerol and fatty acids. Fats are divided into animal and vegetable. Fats are obtained by rendering, separation, hydrogenation, pressing or extraction. Fats in the human body perform energy, protective, building functions. The use of fats is varied.

Esters are derivatives of oxo acids (both carboxylic and mineral) RkE (= O) l (OH) m, (l ≠ 0), which are formally products of substitution of hydrogen atoms of hydroxyls -OH of the acid function for a hydrocarbon residue (aliphatic, alkenyl, aromatic or heteroaromatic); are also considered as acyl derivatives of alcohols. In the IUPAC nomenclature, esters also include acyl derivatives of chalcogenide analogues of alcohols (thiols, selenols, and tellurols).

They differ from ethers, in which two hydrocarbon radicals are connected by an oxygen atom (R1-O-R2).

Fats are esters of glycerol and higher monohydric carboxylic acids.

The common name for such compounds is triglycerides or triacylglycerols, where acyl is a carboxylic acid residue -C(O)R.

The composition of natural triglycerides includes residues of saturated acids (palmitic C15H31COOH, stearic C17H35COOH) and unsaturated acids (oleic C17H33COOH, linoleic C17H29COOH).

Animal fats (mutton, pork, beef, etc.), as a rule, are solids with a low melting point (fish oil is an exception). Fats consist mainly of triglycerides and saturated acids.

Fats as esters are characterized by a reverse hydrolysis reaction catalyzed by mineral acids. With the participation of alkalis, the hydrolysis of fats occurs irreversibly. The products in this case are soaps - salts of higher carboxylic acids and alkali metals.

Sodium salts are soap solids, potassium salts are liquid. The reaction of alkaline hydrolysis of fats, and in general of all esters, is also called amilennyam.

Fats are widely distributed in nature. In plants, they accumulate mainly in the nasinny, in the fetal pulp, in animal organisms - in the connective, subcutaneous and adipose tissue.

Fats are high calorie foods. Some fats contain vitamins A, D (for example, fish oil, especially cod oil), E (cotton, corn oil).

Soap history. In ancient times, hairs were smeared with oils and plowed for beauty. In the days of the complaint, the chairman was sprinkled with ashes. And then - a strange thing - the fat was easily washed off, the hair became clean, shiny. After all, ashes in combination with oils are the prototype of soap.

Soap- water-soluble washing mass (piece or thick liquid), obtained by the interaction of fats and alkalis, used either as a cosmetic product - for cleansing and skin care (toilet soap); or as a means of household chemicals - detergent (laundry soap).

Not to be confused with soap products which are made from synthetic surfactants, mainly from petroleum products (sodium lauryl sulfate), etc.

In recent years, soap as a cosmetic product of mass use has been increasingly used in liquid form. Solid soap is often used in the form of author's products. As household chemicals, the use of soap is declining every year around the world: consumers are choosing washing powders, dishwashing detergents, etc.

Chemically, the main component of solid soap is a mixture of soluble salts of higher fatty acids. Usually these are sodium, less often potassium and ammonium salts of acids such as stearic, palmitic, myristic, lauric and oleic.

One of the options for the chemical composition of solid soap is C 17 H 35 COONa (liquid - C 17 H 35 COOK).

Additionally, the composition of the soap may contain other substances that have a detergent effect, as well as flavors and dyes and powders.

End of work -

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Goals:

Tutorials:

to form an idea of fats and soaps as chemical compounds, having studied their chemical composition and chemical properties, to consolidate the ability to write reaction equations, to introduce methods for their processing;

Developing:

improve logical thinking, update knowledge about fats from the biology course; to develop the horizons of students, introducing them to the use of fats and fat-like substances and their derivatives, to teach them to draw conclusions.

Educational:

to create a positive motivation for studying chemistry by introducing students to the role of fats and soaps in human life, to show a creative approach to completing tasks.

Methodological support of the lesson: interactive board. Slides containing information on new material, tasks to test the initial assimilation of knowledge, test tasks. For the experiment: test tubes, vegetable oil, butter, margarine, acetone, solutions of sodium hydroxide, sulfuric acid, potassium permanganate.

On the teacher's display table: herbarium and images of oil plants, animals from which fat is obtained; samples of butter, sunflower, olive oils, margarine, drying oil, glycerin, liquid and solid soap, a candle, synthetic detergents. Black box with bar of soap.

Lesson type- a lesson in learning new material - a lecture, supplemented by viewing slides, a conversation, a demonstration of an experiment, student messages, a game moment, testing.

Lesson plan.

1. Organizing time.

Greetings

Checking student attendance

Filling out the log

2. Actualization of students' knowledge.

Checking existing knowledge and skills

Preparing to study a new topic.

3. Learning new material.

From the history of the study of fats

Composition structure, nomenclature

Fat classification

Physical Properties

Chemical properties

Practical advice.

Getting fat

The use of fats and soaps

4. Black box game.

5. Primary consolidation of the material covered.

Solution of test tasks

6. Reflection.

7. Homework.

During the classes

I. Organizational moment.

2. Actualization of students' knowledge.

You know that there is such a serious childhood disease - rickets. It turns out that its prevention and treatment cannot do without fat, namely, fish oil that is well known to you. What are these substances - fats that play such a big role in our life? That's what we're going to talk about in today's lesson. So, the topic of the lesson: “Fats. Soap".

front poll.

1. What substances are called polyhydric alcohols? Give examples of alcohols.

2. What substances are called carboxylic acids? Give examples of higher carboxylic acids (saturated and unsaturated).

3. What substances are called esters?

4. What properties are characteristic of esters?

5. What is an esterification reaction?

3. Learning new material.

Now we can talk about fats. You deal with fat every day. In the school course, one lesson is allotted to study the topic. You learned about the biological role of fats in the course “General Biology”. In this lesson, you will gain an understanding of fats and soaps as chemical compounds, their properties, how they are processed, and applications. Get some practical advice.

From the history of the study of fats.

Fats along with carbohydrates and proteins are a valuable food product. For a healthy human body, the daily need for fat is 70-100 g. Excess fat in the human body is one of the main causes of many diseases, in particular, especially cardiovascular, obesity.

People have long since learned to isolate fat from natural objects and use it in everyday life. Fat burned in primitive lamps, illuminating the caves of primitive people, grease was smeared on skids, along which ships were lowered into the water; Athletes of ancient Hellas rubbed their naked bodies with vegetable oils to make their skin more elastic.

Chemists have long wanted to understand what fat is. However, only in 1779 the great Swedish chemist K. Scheele approached the solution of this problem. By heating olive oil with lead oxide, he got a precipitate and some sweet, water-soluble substance. He called it "fat sugar". Only 45 years later, the French chemist M. Chevrel determined the structure of this fatty sugar and called it glycerin (from the Greek “glycos” - sweet). He also proved that the precipitate is lead salts of the so-called fatty acids.

Composition, structure of fats.

Fats - it is a mixture of esters formed by a trihydric alcohol (glycerol) and fatty acids having from 4 to 24 carbon atoms in the hydrocarbon radical.

Of all the unsaturated acids found in natural fats, the most common are:

oleic acid C 17 H 33 COOH,
linoleic acid C 17 H 31 COOH,
linolenic acid C 17 H 29 COOH.
Of the saturated acids are common:
palmitic acid C 15 H 31 COOH,
stearic acid C 17 H 35 COOH,
myristic acid C 13 H 27 COOH.

Nomenclature.

According to the systematic nomenclature, fats are called triacylglycerols. Atyls have a suffix - oil (lenoleoyl, palmitoyl, stearoyl, etc.)

Classification of fats.

Fats can be classified by composition into simple - if all the acyl residues are the same, and mixed - if the acyl residues are different.

Fats can be classified according to their origin into animal and vegetable. Vegetable fats are called oils.

Fats can be divided into liquid (most vegetable oils, fish and marine mammal fats) and solid (terrestrial animal fats, coconut oil). Liquid fats contain 70-85% unsaturated acids, and solid fats contain about 50% or more saturated acids.

Vegetable fats (oils) are divided into:

Drying out, i.e. oxidizing and hardening in air (having two or more double bonds: linseed, poppy, hemp oil).

Semi-drying, (having one or two double bonds: sunflower, soybean, cottonseed oil).

Non-drying, (having one double bond: peanut, castor, olive, palm, coconut oil).

What physical properties of fats do you know and can name?

Yes. Fats are liquid, ointment-like or solid substances, fusible, insoluble in water, soluble in non-polar solvents (acetone, gasoline, carbon tetrachloride), poorly soluble in lower alcohols. They do not have a melting point, they melt in the temperature range, as they are mixtures of different molecules. Do not boil under normal conditions, decompose at high temperatures. Emulsified with alkalis. The density of fats is less than 1 g/ml.

Experiment: pour 5 ml of water, acetone, sodium hydroxide solution into three test tubes and add a few drops of vegetable oil to them. Students observe what happens when the tubes are shaken. After discussing the experiment, students write down the conclusion in a notebook about the physical properties of fats: insoluble in water, lighter than water, readily soluble in organic solvents, emulsifiable with alkalis.

Chemical properties of fats.

one). Everyone has heard this phrase: when exercising, a person burns fat. The expression is figurative, but not devoid of chemical meaning. We have already recalled that during the breakdown and oxidation of fats in the body, a significant amount of energy is released, which is necessary for the occurrence of vital endothermic processes to maintain a constant body temperature. That is, fats, like most organic compounds, burn.

Experiment: a few ml of vegetable oil is poured into a porcelain cup and a wick is placed. Set fire to the wick. Fat burns with a bright, very smoky flame.

Until the 19th century whale oil and lard were used to illuminate streets and houses. In addition to the fact that food raw materials were used for technical purposes, this led to the mass extermination of rare animals.

2). Double bonds of unsaturated acids, which are part of the fat, can be hydrogenated in the presence of nickel catalysts. Hydrogenation products are known as salolin, salomas. Some common vegetable oils (peanut, soybean, cottonseed) are hydrogenated to produce edible fats such as margarines.

Compare the prices of 1 liter of vegetable oil and 1 kg of animal fat. Solid fats are more expensive and valuable. In terms of chemical composition, they differ only in the presence of double C = C bonds in the hydrocarbon radicals of liquid fats.

Experiment: Shake 3 drops of vegetable oil + 2 drops of Na 2 CO 3 + 2 drops of KMnO 4 solution. The crimson color disappears. This means that there was a discoloration of the KMnO 4 solution, which showed and proved the presence of multiple bonds in vegetable fats.

Margarine first appeared over 100 years ago to designate a product obtained by the French chemist Mezh-Mourier in 1869. Emperor Napoleon III of France promised a big prize to anyone who can find a cheap substitute for butter in the soldiers' diet. Mezh-Mourier proposed a scheme of production that has survived in its essence up to the present day. He submitted a product to the competition, which was called margarine because it was supposed to contain margaric acid C 16 H 33 COOH. In choosing the name, the appearance of the translucent bluish mass of the product (from the Greek “margon” - pearls) was of no small importance.

In 1930, margarine began to be received in the USSR.

Margarine is a hard fat containing only residues of saturated carboxylic acids. Therefore, margarine will not exhibit the properties of unsaturated hydrocarbons.

Butter - contains residues of unsaturated acids, therefore it will discolor bromine water or potassium permanganate solution.

Imagine that you are a private entrepreneur in the field of trade and are going to buy a bulk batch of butter. Now there are many unscrupulous manufacturers who falsify food products, and butter often becomes the object of falsification. Cheaper products are mixed with it: margarine or vegetable oils. It is possible to detect a fake and prove it with the help of complex and expensive analyzes. But there are also signs that can be detected without any analysis and which should alert you when buying. What are these signs?

Experiment: dip a piece of the studied fat into the KMnO 4 solution, if the solution is discolored, then it is butter, if not discolored, then it is margarine.

3). One of the most important properties of fats, like other esters, is the hydrolysis reaction - (hydro - water, lysis - destruction). To a small extent, hydrolysis also occurs during storage of fat under the influence of moisture, light and heat. Fat becomes rancid - i.e. acquires an unpleasant taste and odor due to the resulting acids:

This reaction is reversible. To obtain glycerol and fatty acids, the reaction is carried out in an acidic medium at boiling or under pressure.

4). Among the reactions of fats, hydrolysis in the presence of bases is of particular importance. Alkaline hydrolysis is called saponification. It, unlike acidic, is irreversible, and as a result of it, alkaline salts of higher carboxylic acids, soaps, are obtained.

Soap is an alkaline salt of higher carboxylic acids.

Liquid soap is formed by potassium salts, and solid soap is formed by sodium salts.

Laundry soap is intended for washing. Its quality in accordance with the purpose is determined by the content of fatty acids, the mass fraction of which (in%) is imprinted on one of the faces of the piece: the higher it is, the more abundant the foam, the better it washes and erases the soap. The second quality criterion is the presence of free alkali. Here, on the contrary: the less it is, the better - after all, alkali is harmful both to human skin and to fabrics, especially wool and silk. In recent years, laundry soap has been made from synthetic fatty acids.

To obtain top grade soap, the sound soap formed at the initial stage of the technological process is dried, ground 2-3 times on rollers, mixed with additives (perfume, dyes, skin softeners) and formed into pieces of toilet, bath, baby soap. In such a product, the mass fraction of fatty acids reaches 80%.

And what happened before that, what did you wash before? In ancient times, women in Russia, trying to preserve the fluffiness, softness and shine of their hair, used the following recipe: in an oak bucket, a ladle of ash is thoroughly mixed with fresh spring or rain water, and not simple, but better spruce or from sunflower, such a mixture will stand for a day. Strain carefully through a clean rag or the girl will drain the water from the sediment, dilute it with clean water, heat it in a chopped bath and wash her beautiful hair. The ash contains a lot of carbonate - ions and potassium ions, which creates an alkaline environment in its aqueous solution and helps soften water by removing calcium and magnesium ions in the form of insoluble substances. Such a solution, when washing or washing the hair, continues to hydrolyze, destroying fats. The result is a highly water-soluble glycerin. The anions of the higher fatty acid, together with other types of contaminants, form an emulsion, which is carried out by the solution during rinsing.

Soap entered Europe in the seventeenth century. It was not available to everyone, as it was expensive. The real soap industry developed in the first half of the nineteenth century thanks to the work of the French chemist M. Chevrel.

From the course of history, you remember that during the Great Patriotic War, Leningrad (and now St. Petersburg) was blocked by the Nazis for almost 2.5 years. Everything was in Leningrad during this time: hunger, cold, lack of medicines, but it is surprising that there were no epidemics of infectious diseases that usually accompany such vitally difficult situations. And it helped the Leningraders that they themselves made soap as a disinfectant from the fats of various animals - dogs, rats, cats.

soap making- one of the most ancient chemical processes in the service of man. Already in the 1st century used the saponification process to obtain solid and liquid soap-like products by boiling fats with the ashes of land plants (containing potassium salts) or seaweed (containing sodium salts). Sodium salts of higher carboxylic acids have a solid state of aggregation, and potassium salts have a liquid state.

“Scented soap” is indispensable in everyday life. But it is not without drawbacks: it does not lather well in hard water, and when washed in such water, a grayish coating remains on white clothes. Hard water contains Ca 2+ and Mg 2+ cations. In such water, soap loses its cleaning power. Calcium and magnesium salts of higher carboxylic acids are insoluble in water. Instead of foam, they form flakes (precipitate) and soap is used up uselessly:

2C 17 H 35 COONa + Ca 2+ -> (C 17 H 35 COO) 2 Ca + 2Na +

Synthetic detergents, which are sodium salts of higher sulfonic acids or alkylbenzenesulfonic acids, are deprived of this drawback. The principle of operation of synthetic detergents is exactly the same as that of soap, but they have some advantages:

Do not lose washing ability in hard water;

Do not corrode hands, tk. do not give an alkaline reaction in solution.

But synthetic detergent residues in wastewater are very slowly biodegradable and cause environmental pollution.

5). Oil polymerization reactions are very important. On this basis, vegetable oils are divided into drying, semi-drying and non-drying. Drying in a thin layer form brilliant thin films. This is the basis for the use of these oils for the preparation of varnishes and paints.

Practical advice.

You need to remove the sunflower oil stain. Vegetable oil dissolves well in gasoline or kerosene.

If you put a greasy stain on your clothes at the festive table and cannot get it out, it is recommended to immediately cover the stain with salt. Salt adsorbs fats. You can also use toothpaste for this purpose.

When vegetable oil stains age, especially in the light and at elevated temperatures, strong polymer compounds are formed, and fat molecules interact with tissue molecules due to double bonds. It is very difficult to remove such a stain, so remove the greasy stain immediately yourself or in Eurocleaning.

Getting fat.

Sources of fats are living organisms. Among the animals are cows, pigs, sheep, geese, whales, seals, fish: shark, codfish, herring. From the liver of cod and shark, fish oil is obtained - a medicine, from herring - fats used to feed farm animals.

Sources of oils are plants: cotton, flax, soybean, peanut, sesame, rapeseed, mustard, olive, sunflower, hemp, castor bean, poppy, oil palm, coconut and many others.

Fats are obtained from living organisms and plants:

by rendering
Extraction
pressing
Separation
Hydrogenation of fats in technology.

The use of fats and soaps.

Fats are used for food.

Some oils are used for the manufacture of cosmetics (creams, masks, ointments).

A number of fats have medicinal value: castor oil, sea buckthorn oil, fish and goose fat.

Herring fish fats are used to feed farm animals.

Drying vegetable oils are used for the production of drying oils.

The raw materials for the production of margarine are many vegetable oils and whale oil.

Animal fats are used for the production of soap, stearin candles.

Fats are used to produce glycerin and lubricants. However, the use of food products as chemical raw materials is an unaffordable luxury. Therefore, chemists have developed processes that make it possible to use paraffin to obtain, for example, higher carboxylic acids.

Soap in everyday life and industry is increasingly being replaced by synthetic detergents.

4. Black box game.

In the closed box is something related to the topic “Fats”. The teacher offers to find out what is in the box. Students ask questions that can only be answered with “yes” or “no”. You need to achieve the goal by asking the teacher the least number of questions.

The teacher can put fat products, glycerin, carboxylic acid, which is part of fats, some kind of oil in the box. For example, a box contains soap.

Questions might be: