Acetic acid : properties

Acetic acid

source: wikipedia

source: Physics learn

Acetic acid-Chemical properties :

1) Acidic nature :

a) It neutralizes bases:

CH₃COOH + NaOH ——-> CH₃COONa  + H₂O

b) It reacts with carbonates and bicarbonates evolving CO₂.

2CH₃COOH +Na₂CO₃ ——-> 2CH₃COONa + H₂O + CO₂

CH₃COOH + NaHCO₃ —–> CH₃COONa +H₂O +CO₂

c) Highly electropositive metals evolve H₂ when react with CH₃COOH.

2CH₃COOH + 2Na ——–> 2CH₃COONa + H₂

d) It combines with alcohols in presence of dehydrating agent forming ester.

CH₃COOH +C₂H₅OH ——> CH₃COOC₂H₅ (ester) + H₂O

e) It reacts with PCl₅ or SOCl₂ to give acetyl chloride

CH₃COOH + PCl₅ ——–> CH₃COCl + POCl₃ + HCl

CH₃COOH + SOCl₂ —–> CH₃COCl + SO₂ + HCl

2) Reaction with Cl₂:

Acetic acid react with Cl₂ in presence of Red Phosphorous  forming mono, di and tri-chloro acetic acid.

3) Dehydration :

Acetic anhydride is obtained when  heated in presence of  phosphorous pentaoxide (P₂O₅).

4) Borodine Hunsdiecker reaction :

Silver salt of carboxylic  acid is treated with Br₂ or Cl₂ in presence of carbon tetrachloride (CCl₄). This method is used for the preparation of alkyl halides.

CH₃COOAg + Br₂    ———-> CH₃Br + CO₂ + AgBr

C₂H₅COOAg + Br₂    ———-> C₂H₅Br + CO₂ + AgBr

5) Schmidt Reaction :

 Primary amines are prepared by this method when acetic acid reacts  with hydrazoic acid in presence of concentrated H₂SO₄ at 0⁰C then methyl amine is obtained.

CH₃COOH + N₃H ——-> CH₃NH₂ + CO₂ + N₂

6) Reduction :

a) When heated with HI/Red Phosphorous  or H₂/Ni, ethane is obtained.

CH₃COOH + 3H₂ ——> CH₃CH₃ (ethane) +2H₂O

b) When acetic acid (CH₃COOH) is reduced by Lithium Aluminium Hydride ( LiAlH₄) then ethyl alcohol is obtained.

CH₃COOH + 4[H] ——> CH₃CH₂OH + H₂O

7) Action of heat on salts :

a) When  Sodium acetate is heated with Soda-lime (a mixture of NaOH & CaO), methane is obtained.

CH₃COONa +NaOH ——-> CH₄ + Na₂CO₃

b) Acetamide is obtained when ammonium  acetate is heated.

CH₃COONH₄ ——-> CH₃CONH₂ +H₂O

c) Methyl cyanide is obtained when ammonium acetate is heated with Phosphorous pentaoxide           (P₂O₅).

CH₃COONH₄ —–> CH₃CN + 2H₂O

d) Calcium  acetate on dry distillation gives acetone.

e) When Calcium acetate and Calcium formate are dry distilled then acetaldehyde ( CH3CHO) is            formed.