Balakovo, Saratov region
Tribunskaya Elena Zhanovna
Slide 2
Target
Show the practical orientation of using the chemical and physical properties of glycerin
Slide 3
Glycerin in medicine
Properties
- The antiseptic and preservative properties of glycerin are associated with its hygroscopicity, due to which dehydration of bacteria occurs.
- good solvent
Application
- added to drugs used to treat skin diseases
- iodine, phenol, bromine, thymol, tannin, mercuric chloride, alkaloids are dissolved in glycerin
Slide 4
Glycerin in the food industry
Properties
- Reacts with fatty acids
- stabilizer and emulsifier
- increases the viscosity of substances
Application
- used as a food additive E422
- improves the consistency of creams and sweets
- prevents sagging of chocolate in confectionery products
- reduces stickiness in pasta
Slide 5
Properties
- Does not spoil or go bitter, has preservative properties
Application
- Prevents starch from sticking during baking of baked goods
- used to prepare extracts of tea, coffee, ginger and other plant substances
Slide 6
Glycerin in agriculture
Properties
- accelerates seed germination
Application
- used for treating seeds and seedlings
Slide 7
Glycerin in military affairs
Properties
- Aqueous solutions of glycerol freeze at low temperatures
Application
- used as antifreeze - liquids with a low freezing point used to cool internal combustion engines
- cooling gun barrels during prolonged firing
Slide 8
Properties
- Glycerol reacts with nitric acid
Application
- From nitroglycerin are produced: dynamite, smokeless gunpowder
Slide 9
Glycerin in the tobacco industry
Properties
- It is hygroscopic
Application
- Regulates tobacco moisture
- eliminates unpleasant taste
Slide 10
Glycerin in electronic cigarettes
Properties
- glycerin does not evaporate at room temperature
Application
- regulates the water content in the electronic cigarette cartridge.
Slide 11
Glycerin in plastic production
Properties
- Odorless, viscous, transparent and colorless liquid
Application
- Used in the manufacture of foamed plastics
- cellophane retains its flexibility, transparency and strength in any conditions (hot and cold)
Slide 12
Glycerin in radio and electrical engineering
Properties
- Binder
Application
- Indispensable in the manufacture of electrolytic capacitors
- present in alkyd resins used as insulating materials
Slide 13
Glycerin in the paper industry
Properties
- Binder
Application
- Tracing paper
- cigarette paper
- parchment
- paper napkins
- greaseproof paper
Slide 14
Glycerin in the leather industry
Properties
- Glycerin is used to add it to aqueous solutions of barium chloride
Application
- For preserving various types of leather
- used for tanning leather
- softens rough leathers
Slide 15
Glycerin in the textile industry
Properties
- Antiseptic and hygroscopic component
Application
- Used in paints for printing on fabrics
- in the production of artificial silk and wool
- softens fabrics and gives them elasticity
Slide 16
Glycerin in the paint and varnish industry
Properties
- Reacts with esterification with rosin
Application
- Used for the production of electrical insulating varnishes
Slide 17
Glycerin in cosmetology
Properties
- Has a good ability to draw moisture from the air (the use of glycerin in cosmetology is recommended only when there is sufficient air humidity)
- creates a moisture-saving film on the surface of the skin
Application
- Is an integral part of cosmetics
- Soap's cleaning power increases
Slide 18
Glycerin in other applications
- Production of stationery putties, hectographic masses, inks for copying and printing, stamp inks
- production of resins for various applications
- creation of lubricants for automotive, engineering and other industries;
- making shoe polishes
- glue production
Slide 19
Conclusion
Main properties of glycerin:
- Viscous liquid, colorless and odorless, sweet in taste. Mixes with water in any ratio. Not poisonous. Melting point – 8°C, boiling point – 245°C. Density – 1.26 g/cm3.
- It dissolves well in alcohol, but is not soluble in fats.
- The chemical properties of glycerin are typical of polyhydric alcohols
Slide 20
Electronic resources
- http://ru.wikipedia.org/wiki/%C3%EB%E8%F6%E5%F0%E8%ED
- http://www.naturalmask.ru/glycerin.html
- http://netvreda.ru/news/95-glycerol_all_of_this_stuff.html
- http://www.biodieselmach.com/glicerin.htm
- http://www.tallann.ru/chemical/node/15?PHPSESSID=27c5f39abe944452c004b96906fef263
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Class: 10
Class: Grade 10
Lesson type: lesson on learning new material
The purpose of the lesson: give the concept of polyhydric alcohols
Lesson objectives:
- Educational: reveal the relationship: composition -> structure -> properties -> use of glycerin
- Developmental: continue to develop skills: observe physical and chemical phenomena, explain observed phenomena.
- Educational: developing interest in the subject
Used literature: Rudziti With G.E., Feldman F.G. Organic chemistry, grade 10
Equipment used:
- Reagents: solutions of copper (II) sulfate, crystalline sodium, glycerin, water, sodium chloride, snow
- Equipment: media projector, presentation, test tubes, filter paper, alcohol lamp, matches, splinter
During the classes
I. Organizational moment: greeting
II. Updating the reference data points
Oral frontal conversation
What are alcohols? (Alcohols are hydrocarbon derivatives in whose molecules one or more hydrogen atoms are replaced by hydroxyl groups)
What is the general formula of monohydric alcohols? (CnH2n+1OH)
What types of isomerism are characteristic of alcohols? ( Isomerism of the carbon skeleton, isomerism of the position of the hydroxyl group)
How are alcohols named? ( The names are derived from the names of the corresponding hydrocarbons with the addition of the suffix –ol)
III. Logical transition to new material. Determining the topic and purpose of the lesson.
Classification of alcohols
Monatomic Polyatomic
Polyhydric alcohols are organic compounds whose molecules contain several hydroxyl groups connected to hydrocarbon radicals.
CH 2 OH-CH 2 OH - ethanediol-1,2, ethylene glycol
CH 2 OH-CHON-CH 2 OH - propanetriol – 1,2,3, glycerol
The purpose of the lesson: consider glycerin, its physical and chemical properties, methods of its preparation and use
Determining the topic of the lesson ( Glycerol)
IV. Formation of new training centers
1. Obtaining glycerin
Glycerin was first obtained by K.V. Scheele (1779) and again by M.E. Chevreul (1813).
In the laboratory, glycerin is obtained from halogen derivatives of the corresponding hydrocarbons.
CH 2 Cl – CHCl-CH 2 Cl +3H2O -> 2CH 2 OH – CHOH-CH 2 OH +3HCl
To shift the reaction equilibrium to the right. The released hydrochloric acid is neutralized with alkali.
Glycerin is produced in production from propylene, which is formed during cracking and pyrolysis of oil, as well as from fats.
C 3 H 5 (OS 17 H 35) 3 + 3H 2 O -> CH 2 OH - CHON - CH 2 OH + 3C 17 H 35 COOH
2. Physical properties
Glycerin is a colorless, syrupy liquid with a sweetish taste, soluble in water and ethanol, boils at a temperature of 290 0 C, and is hygroscopic.
Experience No. 1. Lowering the freezing point of aqueous solutions of glycerol.
Pour 5 ml of glycerin into a test tube and gradually layer the same volume of magenta-tinted water on top, shake. Place the test tube in a cooling mixture (a mixture of snow and solid sodium chloride), and at the same time place a test tube with water in the mixture.
Questions during the demonstration:
What are you observing? (the liquid becomes homogeneous and colored)
What conclusion can be drawn as a result of the experiment? (Glycerin is an antifreeze liquid and can be used as an antifreeze liquid for cooling motors)
Experience No. 2. Hygroscopicity of glycerol
Apply a few drops of water to a sheet of filter paper, and a few drops of glycerin to a second sheet. Leave it for a while.
3. Chemical properties.
The chemical properties of glycerin are similar to the chemical properties of monohydric alcohols.
1. Interaction with crystalline sodium
Experience 3. Reaction with sodium
Pour 2-3 ml of glycerol into a test tube and drop a pea-sized amount of metallic sodium into the solution. Heat the test tube slightly and ignite the released gas.
Questions during the demonstration
What are you observing? ( gas is released, charring)
What gas is released? ( hydrogen, because the splinter burns with a blue flame)
2CH 2 OH – CHON-CH 2 OH + 6Na -> 2CH 2 ONa –CHONa- CH 2 ONa + 3H 2
sodium glycerate
Interaction with copper (II) hydroxide in the presence of alkali. The precipitate dissolves and a bright blue solution is formed - copper glycerate.
Experience 4. Pour sodium hydroxide into a test tube and add copper sulfate drop by drop until a precipitate forms; add glycerin to the resulting precipitate.
The reaction equation is given in a simplified form, since compounds of a more complex composition are also formed at the same time. This reaction proves that polyhydric alcohols have weak acidic properties. This reaction is qualitative for polyhydric alcohols.
An increase in the number of hydroxyl groups in the molecules of polyhydric alcohols gives greater mobility to hydrogen atoms compared to monohydric alcohols. This is the result of the mutual influence of hydroxyl groups on each other.
4. Interaction with nitric acid.
As a result, nitroglycerin is formed - an ester of nitric acid and glycerol.
For the practical use of nitroglycerin, it is converted into dynamite by impregnating infusor soil or wood flour with nitroglycerin. The author of dynamite is A. Nobel
CH 2 OH – CHON – CH 2 OH + 3HNO 3 -> CH 2 ONO 2 – CHNONO 2 – CH 2 ONO 2 + 3H 2 O
1,2,3 – trinitroglycerin
Interaction with hydrogen halides
CH 2 OH – CHOH – CH 2 OH + 3HCl -> CH 2 CL – CHCl – CH 2 CL + 3H2O
1,2,3 - trichloropropane
5. Application
Glycerin is used to produce nitroglycerin and dynamite. Glycerin is used in perfumery and medicine (for the production of ointments that soften the skin), in the tanning industry (to protect leather from drying out), in the textile industry (to give fabrics softness and elasticity). In medicine, a 1% solution of nitroglycerin in alcohol serves as one of the means to dilate blood vessels.
6. Genetic relationship of polyhydric alcohols with other classes of organic compounds
Let's return to the experiment with filter paper
What are you observing? ( paper with water dried out, but with glycerin it became even more important)
What can you say about glycerin? (glycerin can absorb moisture, thereby moisturizing objects).
V. Consolidation.
Reveal genetic blueprint
VI. Message d/z: paragraph 24
So, today in the lesson we got acquainted with polyhydric alcohols using the example of glycerin, looked at its physical and chemical properties, methods of production and use. This concludes the lesson.
- Polyhydric alcohols - these are organic compounds whose molecules contain two or more hydroxyl groups connected to a hydrocarbon radical .
Alcohols containing two OH groups are called diatomic.
Their general formula WITH P N 2p (HE) 2
Alcohols containing three OH groups are called triatomic.
Their general formula WITH P N 2p-1 (HE) 3
Name glycols - is explained by the sweet taste of the first representative of the series - glycol (from the Greek "glycos" - sweet). According to IUPAC nomenclature, these alcohols are called alkanediols.
The simplest representative of alkanediols is alcohol of the composition HO-CH 2 CH 2 -OH , so-called ethylene glycol or ethanediol .
The simplest trihydric alcohol is glycerin or propanetriol.
Structure
In terms of molecular structure, polyhydric alcohols are similar to monohydric alcohols. The difference is that their molecules contain several hydroxyl groups. The oxygen they contain displaces the electron density from the hydrogen atoms. This leads to increasing the mobility of hydrogen atoms and enhancing acidic properties.
Physical properties
Ethylene glycol- representative of dihydric alcohols -glycols.
Syrup-like liquid, sweetish taste, odorless, poisonous.
Mixes well with water and alcohol, hygroscopic.
Glycerol- representative of trihydric alcohols - glycerols .
Colorless, viscous, hygroscopic liquid, sweet in taste.
Miscible with water in any ratio.
Receipt
- Glycols are produced by oxidation alkenes in an aquatic environment. For example, under the action of potassium permanganate or atmospheric oxygen in the presence of a silver catalyst, alkenes are converted into dihydric alcohols:
Receipt
- Another way to obtain polyhydric alcohols is the hydrolysis of halogenated hydrocarbons:
Receipt
In production, glycerin is obtained according to the following scheme:
- Ethylene glycol and glycerin are similar to monohydric alcohols. Yes, they react with active metals :
- Polyhydric alcohols in reaction with hydrogen halides exchange one or more OH hydroxyl groups for halogen atoms:
- Glycerol interacts with nitric acid with the formation of esters. Depending on the reaction conditions (molar ratio of reagents, catalyst concentration - sulfuric acid and temperature) mono-, di- and trinitroglycerides are obtained:
- The qualitative reaction of polyhydric alcohols, which makes it possible to distinguish compounds of this class, is interaction with freshly prepared copper(II) hydroxide. In an alkaline medium with a sufficient concentration of glycerol, a blue precipitate of Cu(OH) 2 dissolves to form a bright blue solution – copper(II) glycolate:
- An important property of ethylene glycol is the ability to lower the freezing point of water, which is why the substance is widely used as a component of automobile antifreezes and antifreeze liquids.
- It is used to produce lavsan (a valuable synthetic fiber).
Application of glycerin
Glycerol is widely used in cosmetics, food industry, pharmacology, and production of explosives. Pure nitroglycerin explodes even with a slight impact; it serves as a raw material for the production of smokeless gunpowder and dynamite - an explosive
“Structure of esters” - Determination of the class of esters. Fats do not dissolve in water. Chemically active substances. Solvents. Hydrogenation. Source of energy. Derivatives of carboxylic acids. Fats. Liquids. Esters.
“Properties and uses of fats” - Determination of unsaturation of fats. The resulting product. German scientist. Fats are the main source of energy for living organisms. Glycerol. Use of fats. Getting soap. Chemical composition of fats. Chemical properties of fats. A mixture of esters. Cocoa beans. Desert ships. Fat hydrolysis reaction equation.
“Esters” - New antifog. Nitroglycerine. Structure. Preparation of esters. Esters of fatty acids. Tishchenko Vyacheslav Evgenievich. Connections. Drawing. Discovery of esters. Classification and composition of esters. Esters are isomeric. Structural isomerism. Oils. Hydrogen atom. Machine oil. Derivatives of carboxylic acids.
“Use of fats” - Paint. Perfumery. Glycerol. Use of fats. How much and what kind of fats does a person need? Candles. Fats. Animal food. Soap. Why sweet is better than fatty? Chocolate. Propolis.
“Chemistry Fats grade 10” - Conclusion: Strong acids displace weak acids from salt solutions. Plan. Esters. Name the substances. Fats. Laboratory experiment No. 1 “The effect of strong acids on soap” L. 1. Survey on the topic “Carboxylic acids” Option No. 1. Stearic acid. Properties of carb. to-t, similar to mineral ones, using acetic acid as an example.
“Esters and fats” - Ester of acids and glycerol. Esters are of great practical importance. Lesson plan. 3. Fats. Fats are essential foods. Fats. The role of fats in life. This is how carboxylic acids interact with alcohols. To shift the equilibrium to the right, it is necessary to remove water or ether. Vegetable fats are called oils.