Test Point 1 Molecular composition and structure of ethylene
(1) Molecular composition: C2H4 (belonging to olefins)
(2) Molecular structure:
(1) Electronic
(2) Structural formula
(3) Structural simplicity: CH2 === CH2
Stick model
Space fill model
Test Point 2 Physical Properties of Ethylene
Ethylene is a colorless, slightly sweet odor gas, slightly less dense than air, and difficult to dissolve in water.
Test Point 3 Chemical properties of ethylene
(1) Oxidation reaction
ignite
(1) Flammability CH2=CH2+ 3O2
2CO2 ＋2H2O
Phenomenon: The flame is bright and accompanied by black smoke and emits a lot of heat at the same time.
(2) Oxidation by KMnO4 (H+): fade the KMnO4 solution. Generate CO2
(2) Addition reaction The reaction of unsaturated carbon atoms in organic molecules directly combining with other atoms or atomic groups to form new compounds is called an addition reaction. Ethylene can be added with halogen elements, water, hydrogen, hydrogen halide, etc.
CH2=CH2＋Br2―→CH2BrCH2Br
CH2=CH2＋H2
CH3CH3
CH2=CH2+HCl
CH3CH2Cl
CH2=CH2+H2O
CH3CH2OH。
(3) Polymerization reaction The reaction of a compound with relatively small molecular mass is combined into a polymer with relatively large molecular mass, called a polymerization reaction.
catalyst
Polyethylene from ethylene: n CH2=CH2
—[- CH2 —CH2-] n—
Test Centre 4 Uses of Ethylene
The production of ethylene can be used to measure the level of petrochemical development in a country.
(1) The most important basic raw materials for the petrochemical industry (polyethylene, polyvinyl chloride, polystyrene, etc.)
(2) Plant growth regulator: fruit ripening agent.
Test Centre 5 Molecular Composition and Structure of Benzene (Elective Content)
(1) Molecular composition of benzene: molecular formula C6H6
(2) Structure simplified:
(3) Molecular model:
(4) Structural characteristics: There is no single and double alternating structure in the benzene molecule, and the bonds between the 6 carbon atoms are completely equivalent, which is a unique bond between single and double bonds. 6 carbon atoms form a planar regular hexagonal structure, and 12 atoms are coplanar.
Test Centre 6 Physical Properties of Benzene (Optional Content)
Benzene is usually a colorless, toxic liquid with a special odor odor, less dense than water, insoluble in water, and miscible with organic solvents (ethanol, chloroform, ether, carbon disulfide, carbon tetrachloride, acetone, etc.), benzene is also a commonly used organic solvent, the melting point is low (melting point is 5.5 °C, boiling point is 80.1 °C), volatile, vapor toxic.
Test Centre 7 Chemical Properties of Benzene (Optional Content)
Benzene is difficult to oxidize, easy to replace, can be added. (Both saturated hydrocarbons and unsaturated hydrocarbon properties) is more active than saturated hydrocarbons, prone to substitution reactions, more stable than unsaturated hydrocarbons, and difficult to add reactions.
(1) Oxidation reaction Benzene can not be oxidized by KMnO4 (H+), can be burned in air.
Reaction equation: 2C6H6 + 15 O2
12CO2 + 6H2O
Phenomenon: The flame is bright with thick smoke.
Interpretation: Benzene contains high carbon mass fraction, can not be fully burned, free carbon particles.
(2) Substitution reaction
(1) Bromination reaction of benzene:
Bromobenzene produced: is a colorless oily liquid, insoluble in water, denser than water.
(2) Nitrification of benzene: Benzene reacts with concentrated nitric acid and concentrated sulfuric acid mixed acid to 50 °C-60 °C.
Concentrated sulfuric acid
Bromobenzene produced: is a colorless oily liquid, insoluble in water, denser than water. It has a bitter almond flavor and the vapor is toxic.
(3) Addition reaction of benzene In the presence of a nickel catalyst and 180 °C----250 °C, it is added to H2.
Compounds containing a benzene ring structure, such as toluene, xylene, etc., can occur similar substitution reactions and
Addition reaction.
Test Point 1 Composition and structure of ethanol
Molecular Formula: C2H6O
Functional group: hydroxy-OH
Simplified structure: CH3CH2OH or C2H5OH
Structural Formula: BallStick Model: Space Fill Model:
Test Point 2 Physical properties of ethanol
Ethanol is commonly known as alcohol. Colorless transparent volatile liquid with special fragrance, the density is smaller than water, the boiling point is 78.5 °C, and it can be miscible with water in any ratio.
Test Point 3 Chemical Properties of Ethanol
1. Reaction of ethanol with sodium
2CH3CH2OH+2Na→2CH3CH2ONa+H2↑
Experimental phenomenon: (1) Sodium particles sink at the bottom of the test tube, do not melt, and colorless gas is generated on the surface; (2) Ignite the gas, the flame is light blue, and there are droplets on the dry beaker; (3) Clarify that the lime water does not change turbidity.
Oxidation of ethanol
(1) Combustion:
(2) Catalytic oxidation - the formation of acetaldehyde.
Reaction mechanism of ethanol catalytic oxidation process:
The catalytic oxidation law of alcohol: a. Alcohol with two or three hydrogen atoms on the carbon atom connected to the hydroxyl group (-OH) is oxidized to form an aldehyde.
2RCH2OH+O2
2RCHO+2H2O
b. The carbon atom connected to the hydroxyl group (-OH) has an alcohol of a hydrogen atom, which is oxidized to form ketones.
+O2
+2H2O
c. Alcohols without hydrogen atoms on carbon atoms connected to hydroxyl groups (-OH) cannot be oxidized under normal circumstances.
3. React with strong oxidants
Ethanol can also react with acidic potassium permanganate solutions (fading) or acidic potassium dichromate solutions (orange-yellow to green) and are oxidized to acetic acid.
4. Dehydration reaction of ethanol (dehydration within molecules to form ethylene; intermolecular dehydration to form ether) (optional content)
CH3－CH2OH
CH2=CH2↑+H2O
2CH3CH2OH
CH3-CH2-O-CH2CH3+H2O
Test Centre 4 Composition and Structure of Acetic Acid
Molecular formula: C2H4O2
Simplified structure: CH3COOH
Functional Group: —COOH (Carboxyl)
Test Centre 5 Physical Properties of Acetic Acid
Acetic acid is a colorless liquid with a strong pungent odor, the boiling point is 117.9 °C, the melting point is 16.6 °C, when the temperature is lower than 16.6 °C, acetic acid condenses like ice-like solid, so anhydrous acetic acid is also known as glacial acetic acid. Acetic acid is easily soluble in water and ethanol.
Test Point 6 Chemical Properties of Acetic Acid
1. Acetic acid is acidic, monobasic weak acid, has acid passability, and the acidity of acetic acid is stronger than that of carbonic acid.
CH3COOHCH3COO-+H+
a. Can make the purple litmus solution turn red.
b. Reaction with reactive metals to release hydrogen:
2CH3COOH+Zn= (CH3COO)2Zn+H2↑。
c. Neutralization reaction with alkali:
CH3COOH+NaOH=CH3COONa+H2O。
d. Reaction with alkaline oxides:
CaO+2CH3COOH=(CH3COO)2Ca+H2O。
e. Reaction with certain weak acids:
CaCO3+2CH3COOH = (CH3COO)2Ca+H2O+CO2↑, this reaction is evidenced
Amyanolic acid is more acidic than carbonic acid.
2. Esterification reaction (substitution reaction)
The reaction of alcohols with acids to form esters and water is called esterification. Acid dehydroxyol dehydrogenation
3. Esterification reaction experiment
Take a large test tube and use it as a container for the reaction mixture. Add 3 mL of absolute ethanol, 2 mL of concentrated sulfuric acid (slowly added dropwise); 2 mL glacial acetic acid (slowly drip) and plug the rubber stopper with the catheter. Fix the tube to an iron frame table. Take another tube as the tube for the absorption product, add saturated sodium carbonate solution, and extend the catheter into the tube. After the instrument is installed, the reaction mixture begins to be heated.
Notes:
(1) When adding chemicals to large test tubes, do not first add concentrated sulfuric acid.
(2) Heating should be carried out carefully and evenly to prevent the liquid from boiling violently and volatilizing a large amount of acetic acid and ethanol.
(3) Do not enter the liquid at the end of the trachea to prevent the liquid from being sucked back.
(4) The role of saturated Na2CO3 solution: absorb ethanol, react acetic acid, reduce the solubility of ethyl acetate, and make it precipitate in layers.
(5) At the end of the experiment, remove the catheter first and withdraw the alcohol lamp.
The role of concentrated sulfuric acid: catalyst, water absorbent.
Anti-vandal boiling: Several pieces of broken porcelain or zeolite are often added to the reaction test tube.
Experimental phenomenon The characteristics of the device of the esterification reaction and the experimental phenomenon, there is a transparent oily liquid on the liquid surface, and the fragrance can be smelled.
Experimental Conclusion Under the condition of concentrated sulfuric acid presence and heating, acetic acid and ethanol react to form a colorless, transparent, insoluble water, fragrant oily liquid. This oily liquid is ethyl acetate.