Acidic
The ethanol molecule contains polarized oxygen-hydrogen bonds, which when ionized produce alkoxy anions and protons.
CH3CH2OH→ (reversible) CH3CH2O- + H+
The pKa of ethanol is 15.9, which is similar to water.
EthanolAcidicWeak, but the presence of ionization equilibrium is sufficient for the isotope exchange between it and deuterium water to proceed rapidly.
CH3CH2OH+D2O→ (reversible) CH3CH2OD+HOD
Because ethanol can ionize a very small number of protons, it can only react with a small amount of metals (mainly alkali metals) to form corresponding alcohol metals and hydrogens:
2CH2CH2OH + 2Na→2CH3CH2ONa + H2
When the alcohol metal encounters water, it is rapidly hydrolyzed to form alcoholAlkali
Conclusion:
(1) Ethanol can react with sodium metal to produce hydrogen, but it is not as violent as water reacting with sodium metal.
(2) Reactive metals (potassium, calcium, sodium, magnesium, aluminum) can replace the hydrogen in the hydroxyl group of ethanol.
Reactions with acetic acid
Ethanol can be esterified with acetic acid catalyzed by concentrated sulfuric acid to form ethyl acetate.
CH3CH2OH + CH3COOH →CH3COOCH2CH3 + H2O
reacts with hydrohalogenic acid
C2H5OH + HBr→C2H5Br + H2O
C2H5OH + HX→C2H5X + H2O
Note: Normally usedSodium bromideWithSulfuric acidThe mixture is heated with ethanol to carry out this reaction. Therefore, reddish-brown gas is often produced.
Oxidation reaction
(1) Burning: emits a light blue flame that emits a lot of heat
C2H5OH+3O2→2CO2+3H2O
(2) Catalytic oxidation: It is carried out with heating and the presence of a catalyst (Cu or Ag).
2CH3CH2OH+O2→2CH3CHO+2H2O(Industrial system.)Acetaldehyde）
C2H5OH+CuO→CH3CHO+Cu+H2O
That is, the essence of catalytic oxidation (made of CuCatalyst）
Eliminate reactions
(1) Intramolecular elimination systemethylene(170°C Concentrated Sulfuric Acid)
C2H5OH→C2H4+H2O
(2) Intermolecular elimination systemEther(140°C Concentrated Sulfuric Acid)
C2H5OH + HOC2H5 →C2H5OC2H5 + H2O(This is a substitution reaction)
Esterification reaction
C2H5OH+CH3COOH - Thick H2SO4△ (reversible) →CH3COOCH2CH3+H2O
"Acid" dehydroxyl group, "alcohol" dehydrogenation
burn
Ethanol can undergo a violent oxidation reaction with oxygen in the air to produce combustion phenomena and produce water and carbon dioxide.
CH3CH2OH+3O2 → 2CO2+3H2O
2
Ethanol can also be burned by a mixture of concentrated sulfuric acid and potassium permanganate in a very violent oxidation reaction.
reacts with hydrogen halide
Ethanol can be substituted with hydrogen halide to produce halogenated hydrocarbons and water. For example:
CH3CH2OH + HBr → CH3CH2Br + H-OH
Dehydration reaction
Ethanol can be catalyzed by concentrated sulfuric acid and high temperatures, and the products vary with different temperatures.
If the temperature is around 140°C, the product is ether
CH3CH2-OH + HO-CH2CH3 → CH3CH2OCH2CH3 + H2O
If the temperature is around 170°C, the product is ethylene
CH2HCH2OH →CH2=CH2 + H2O