Hóa 11 bài 40: Tính chất hóa học và công thức cấu tạo của Ancol

ĐH KD & CN Hà Nội 18/02/2023

0 5 8 minutes read

Bạn đang xem: Hóa 11 bài 40: Tính chất hóa học và công thức cấu tạo của Ancol tại TRƯỜNG ĐH KD & CN Hà Nội

Chemistry 11 lesson 40: Chemical properties and structural formula of alcohol. Alcohols are organic compounds in the molecule containing the -OH group bonded to the C atom of the hydrocarbon radical and alcohol have many applications in the field of food industry, medicine …

So how alcohol has chemical properties, physical properties and structural formula, is prepared and applied, we will learn through the article below.

I. Alcohol – definition, classification and nomenclature

1. What is the definition of alcohol?

Alcohols are organic compounds in molecules that contain an -OH group bonded to a C atom of a hydrocarbon radical.

2. Alcohol degree, alcohol classification

– Based on the number of -OH groups in the molecule, alcohols are classified as monofunctional alcohols and multifunctional alcohols.

The degree of an alcohol is calculated as the order of the carbon atom bonded to the -OH group.

– Open-chain monofunctional alcohol: Molecule with 1 -OH group attached to an alkyl radical: C_nH_2n+1-OH

For example: ONLY₃-OH, C₃H₇– OH…

– Unsaturated alcohol, monofunctional, open chain: Molecule with 1 -OH group bonded to the saturated carbon atom of the unsaturated hydrocarbon radical.

For example: ONLY₂=CH-ONLY₂-OH, ONLY₃-CH=CH-ONLY₂– OH, …

– Aromatic alcohol, monofunctional: molecule with -OH group attached to a saturated carbon atom of the branch chain of the benzene ring

For example: OLD₆H₅– ONLY₂-OH (benzyic alcohol)

– Saturated cyclic alcohol, monofunctional: A molecule with an -OH group attached to a saturated carbon atom of the saturated hydrocarbon group:

For example: OLD₆H₁₁OH cyclohexanol

– Polyfunctional alcohol: Molecule with 2 or more -OH alcohol groups

For example: HO-ONLY₂– ONLY₂-OH ethylene glycol ; HO-ONLY₂– ONLY₂OH- ONLY₂-OH glycerol ;

3. Nomenclature

a) Alternate name

Alternative name = Corresponding hydrocarbon name + position number OH + ol

b) Common name

Common name = alcohol (alcohol) + Hydrocarbon base name + ic

Attention: Some alcohols have their own names to remember:

ONLY₂OH-ONLY₂OH: Etilenglicol

ONLY₂OH-CHOH-JUST₂OH: Glycerine (Glixerol)

ONLY₃-CH(ONLY₃)-ONLY₂– ONLY₂OH: isoamyl alcohol

II. Physical properties of alcohol

1. Status of alcohols

– From_first to C_twelfth is liquid, from C₁₃ above is a solid.

2. Boiling point of alcohol

– Compared with substances with equivalent M, the boiling point of: Salts > Acids > Alcohols > Aldehits > Hydrocarbons, ethers and esters…

– Explanation: the boiling point of a substance usually depends on the following factors:

+ M: The larger the M, the higher the boiling point.

+ Polarity of the bond: ionic bond > polar covalent bond > nonpolar covalent bond.

The number of hydrogen bonds: the more H bonds, the higher the boiling point.

+ Strength of hydrogen bonds: The stronger the H bond, the higher the boiling point.

3. Solubility of alcohols

– Alcohols with 1, 2, 3 C atoms in the molecule are infinitely soluble in water.

– The more C alcohol alcohol has, the lower the water solubility because the hydrophobicity of the hydrocarbon radical increases.

III. Chemical properties of alcohol

1. Alcohol reacts with alkali metal (Alcol + Na).

– reaction of alcohol + Na

R(OH)_z + zNa → R(ONa)_z +z/2H₂↑

– Alcohol almost does not react with NaOH, but on the contrary, sodium alcohol is completely decomposed

R(ONa)_z + zH₂O → R(OH)_z + zNaOH

Attention: In the reaction of alcohols with Na:

m_Na _increase = m_alcohol – m_H2 = n_alcohol.(CODE)_CHEAP + 16z).

m_{alcohol bottle} _increase = m_Na – m_H2 = n_alcohol.22z.

– If an alcohol solution is reacted with Na, in addition to the reaction of alcohol, there is also a reaction of H .₂O with Na.

– Number of alcohol functional groups = 2.n_H2/n_alcohol.

2. Alcohols react with acids

a) Alcohol reacts with inorganic acid HX (Alcol + H₂SO₄Alcohol + HCl)

OLD_nH_2n+2-2k-z(OH)_z + (z + k)HX → C_nH_{2n + 2 – z}X_{z + k}

→ the number of atoms X is equal to the sum of the number of OH groups and the number of pi bonds.

b) Alcohols react with organic acids (esterification reaction)

ROH + R’COOH R’COOR + H₂O

yR(OH)_x + xR'(COOH)_y R’_x(COO)_xyCHEAP_y + xyH₂O

* Attention:

The reaction is carried out in an acidic medium and heated.

– The reaction is reversible, so pay attention to the equilibrium shift.

3. Water splitting reaction (dehydration)

a) Extract water from an alcohol molecule to form an alkene of a saturated, monofunctional, open-chain alcohol.

OLD_nH_2n+1OH → C_nH_2n+ FRIENDS₂O (HOT)₂SO₄ solid, >1700C)

– Conditions of alcohol participating in the reaction: alcohol has Hα.

* Attention:

– If an alcohol is saturated, an open-chain monomer does not split water to form an alkene, then that alcohol does not have Hα (it is only Hα).₃OH or alcohol where the C atom is bonded to the OH only bonded to another tertiary C).

– If an alcohol splits water to give a mixture of many alkenes, it is a higher order alcohol (second order, tertiary) and the C chain is asymmetric through C bonded to OH.

– Many alcohols split water to form an alkene, the following possibilities occur:

There are alcohols that do not separate from water.

Alcohols are isomers of each other.

– The main product in the process of water separation according to Zaixep rule.

– When solving exercises related to the water splitting reaction, remember:

m_alcohol = m_alkenes + m_H2O + m_{Residual alcohol}

n_{alcohol reacts} = n_alkenes = n_water

Special dehydration reactions:

ONLY₂OH-ONLY₂OH → ONLY₃FOR + THEM₂O

ONLY₂OH-CHOH-JUST₂OH → ONLY₂=CH-FOR + 2FUL₂O

b) Splitting water from 2 alcohol molecules to form ethers

ROH + ROH → ROR + H₂O (HOT)₂SO₄ solid; 1400C)

ROH + R’OH → ROR’ + H₂O (HOT)₂SO₄ solid; 1400C)

Attention:

– From n different alcohols when separating water, we get n.(n + 1)/2 ethers in which n ethers are symmetrical.

– If water is separated to yield ethers with the same number of moles, the alcohols participating in the reaction also have the same number of moles and n_alcohol = 2.n_ether = 2.n_H2O and n_alcohol = m_ether + n_H2O + m_{Residual alcohol}.

4. Oxidation reaction (Alcol + O₂)

a) Complete oxidation

OLD_xH_yO_z + (x + y/4 – z/2)O₂ → xCO₂ + y/2H₂O

Attention:

– The combustion reaction of alcohols has similar characteristics to the corresponding hydrocarbon combustion reaction.

+ If alcohol is burned, it gives n_H2O > n_CO2 → alcohol that is burned is saturated alcohol and n_alcohol = n_H2O – n_CO2.

+ If alcohol is burned, it gives n_H2O > 1.5.n_CO2 → alcohol is ONLY₃OH. ONLY₄ and ONLY₃OH has this property (excluding amines).

– When an organic compound X is burned, n . is found_H2O > n_CO2 → the substance is an alkane, an open-chain saturated alcohol or an open-chain saturated ether (with the same formula C_nH_2n+2O_x).

b) Incomplete oxidation (Alcol + CuO or O₂ catalyst is Cu)

– Primary alcohol + CuO to form aldehydes:

RCH₂OH + CuO → RCHO + Cu + H₂O

– Secondary alcohol + CuO to form ketones:

RCHOHR’ + CuO → RCOR’ + Cu + H₂O

– Tertiary alcohols are not oxidized by CuO.

* Attention: m_solids _reduce = m_CuO _react – m_Cu _create = 16.n_alcohol _unit.

5. Specific reactions of some alcohols

a) Ethyl alcohol ONLY₃ONLY₂OH:

OLD₂H₅OH + O₂ → ONLY₃COOH + HOW₂O (vinegar yeast)

2 C₂H₅OH → ONLY₂=CH-CH=ONLY₂ + 2 HOUSES₂O + H₂ (Al₂O₃ZnO, 4500C)

b) Unsaturated alcohols react like corresponding hydrocarbons

– Reaction with Hydrogen, allylicium ONLY₂ = CH – ONLY₂OH: Alcohol + H₂

ONLY₂=CH-ONLY₂OH + H₂ → ONLY₃– ONLY₂– ONLY₂OH (Ni, t0)

– Reaction with Bromine: Alcohol + Br₂

ONLY₂=CH-ONLY₂OH + Br₂ → ONLY₂Br-CHBr-ONLY₂OH

– Reaction with potassium permanganate: Alcohol + KMnO₄

3 ONLY₂=CH-ONLY₂OH + 2KMnO₄ + 4 HOURS₂O → 3C₃H₅(OH)₃ + 2KOH + 2MnO₂

c) Polyfunctional alcohol with adjacent OH groups: give a blue solution with Cu(OH)₂ At normal temperature:

2R(OH)₂ + Cu(OH)₂ → [R(OH)O]₂Cu + 2H₂O

d) Some cases of unstable alcohols:

+ Alcohols with an OH group bonded to a C double bond convert to an aldehyde or a ketone:

ONLY₂=CH-OH → ONLY₃GIVE

ONLY₂=COH-ONLY₃ → ONLY₃-CO-ONLY₃

+ Alcohols with 2 OH groups attached to 1 C atom are separated to form aldehydes or ketones:

RCH(OH)₂ → RCHO + Surname₂O

HO-CO-OH → HO₂O + CO₂

RC(OH)₂R’ → RCOR’ + OR₂O

+ Alcohols with 3 OH groups attached to 1 C atom are separated from water to form acids:

RC(OH)₃ → RCOOH + HIM₂O

IV. Alcohol modulation

1. Hydrolysis of halogen derivatives

OLD_nH_2n+2-2k-xX_x + xMOH → C_nH_2n+2-2k-x(OH)_x + xMX

2. Add water to alkenes to form saturated, monofunctional, open-chain alcohols

OLD_nH_2n + FRIENDS₂O → C_nH_2n+1OH (H+)

The reaction follows Maccoph’s rule of addition, so if the alkene is symmetrical, the reaction will only form one alcohol.

3. Hydrolysis of esters in alkaline environment

RCOOR’ + NaOH → RCOONa + R’OH

4. Plus Families₂ into aldehydes or ketones

RCHO + Surname₂ → RCH₂OH (Ni, t0)

RCOR’ + SURVEY₂ → RCHOHR’ (Ni, t0)

5. Oxidation of compound with double bond with KMnO . solution₄

3 ONLY₂= ONLY₂ + 2KMnO₄ + 4 HOURS₂O → 3JUST₂OH-ONLY₂OH + 2KOH + 2MnO₂

6. Modulation specific method ONLY₃OH

ONLY₄ + FRIENDS₂O → CO + 3H₂

CO + 2H₂ → ONLY₃OH (ZnO, CrO .)₃4000C, 200atm)

2 ONLY₄ + O₂ → 2 JUST₃OH (Cu, 2000C, 100 atm)

7. C modulation method₂H₅OH

– Starch fermentation:

(C)₆H_tenO₅)_n → OLD₆H_twelfthO₆ → OLD₂H₅OH

Specific reactions:

(C)₆H_tenO₅)_n + n₂O → nC₆H_twelfthO₆

OLD₆H_twelfthO₆ → 2C₂H₅OH + 2CO₂ (wine yeast)

– Hydration of ethylene, acid catalysis:

OLD₂H₄ + FRIENDS₂O → C₂H₅OH

– These are the methods of preparing ethyl alcohol in industry.

V. How to recognize alcohol

Alcohol produces colorless gas with alkali metals (note that all solutions have this reaction).

– Alcohol makes CuO heated from black to red Cu.

– Multifunctional alcohol with adjacent OH groups that dissolve Cu(OH)₂ form a blue solution.

– Unsaturated alcohol reacts to discolor Bromine solution.

BECAUSE. Applications of alcohols

– Methanol is mainly used to produce Formic Andehit, a raw material for the plastics industry.

– Ethanol is used to prepare a number of organic compounds such as acetic acid, diethyl ether, ethyl acetate, etc. Due to its good solubility in some organic compounds, it is used to make varnishes, pharmaceuticals, and perfumes. …

– In daily life, Ethanol is used to prepare drinks with different alcohol levels.

VII. Exercises Ancol

Lesson 2, page 186 Chemistry textbook 11: Write the chemical equation for the reaction of propane-1-ol with each of the following substances:

a. Metallic sodium.

b. CuO, heated

c. HBr acid, with catalyst

In each reaction, what role does alcohol play: reducing agent, oxidizing agent, acid, base? Explain.

* Solution for lesson 2, page 186, Chemistry 11 textbook:

a) 2 ONLY₃– ONLY₂– ONLY₂OH + 2Na → 2CH₃– ONLY₂– ONLY₂ONa + FAMILY₂↑

Alcohol acts as an oxidizing agent

b) ONLY₃– ONLY₂– ONLY₂OH + CuO → ONLY₃– ONLY₂-GIVE + Cu + HO₂O

Alcohol acts as a reducing agent

c) ONLY₃– ONLY₂– ONLY₂OH + HBr → ONLY₃– ONLY₂– ONLY₂Br + HOLY₂O

Alcohol acts as base

Lesson 3, page 186 Chemistry textbook 11: Presenting a chemical method to distinguish liquids in unlabelled vials: ethanol, glycerol, water and benzene.

* Solution of lesson 3, page 186, Chemistry 11 textbook:

Hopefully, the article on chemical properties, physical properties of alcohol and the exercises above will be useful to you. If you have any questions and suggestions, please leave a comment below the article so that Soc Trang High School can recognize and support you, and wish you all the best in your studies.

Posted by: Soc Trang High School

Category: Education

Copyright of the article belongs to Soc Trang City High School. Any copying is fraud! Shared source: Soc Trang High School (hubm.edu.vn) TagsChemistry 11