Carboxylic acid Preparation

• Carboxylic acid Preparation is done by various methods, each one involving specific reactants and conditions.
• Here is an overview of the Carboxylic acid primary preparation methods:

Oxidation of Primary Alcohols and Aldehydes

1. Oxidation of Primary Alcohols:

   • Primary alcohols are oxidized to carboxylic acids using strong oxidizing agents like potassium permanganate (KMnO₄) or potassium dichromate (K₂Cr₂O₇) under acidic conditions.
   • Reaction: RCH₂OH + 2[O] ⟶ RCOOH
   • Example: Ethanol to Acetic Acid
     • CH₃CH₂OH + 2[O] (from KMnO₄) ⟶ CH₃COOH

2. Oxidation of Aldehydes:

   • Aldehydes are converted to carboxylic acids using oxidizing agents like silver(I) oxide (Ag₂O) or Tollens’ reagent.
   • Reaction: RCHO + [O] ⟶ RCOOH
   • Example: Acetaldehyde to Acetic Acid
     • CH₃CHO + [O] (from Ag₂O) ⟶ CH₃COOH

Oxidation of Alkyl Side Chains of Aromatic Compounds

• Alkylbenzenes with a benzylic hydrogen can be oxidized to aromatic carboxylic acids using oxidizing agents such as KMnO₄ or chromium trioxide (CrO₃) in an acidic medium.
• Reaction: Ar-CH₃ + 2[O] ⟶ Ar-COOH
• Example: Toluene to Benzoic Acid
  • C₆H₅CH₃ + 2[O] (from KMnO₄) ⟶ C₆H₅COOH

Hydrolysis of Nitriles

• Nitriles can be hydrolyzed into carboxylic acids under acidic or basic conditions, producing ammonia as a byproduct.
• Reaction: RC≡N + 2H₂O ⟶ RCOOH + NH₃
• Example: Acetonitrile to Acetic Acid
  • CH₃C≡N + 2H₂O ⟶ CH₃COOH + NH₃

Carboxylation of Grignard Reagents

• Grignard reagents react with carbon dioxide to form carboxylate salts, which are then acidified to yield carboxylic acids.
• Reaction: RMgX + CO₂ ⟶ RCOOMgX followed by RCOOMgX + H₃O⁺ ⟶ RCOOH + MgX(OH)
• Example: Methylmagnesium bromide to Acetic Acid
  • CH₃MgBr + CO₂ ⟶ CH₃COOMgBr
  • Then, CH₃COOMgBr + H₃O⁺ ⟶ CH₃COOH + MgBr(OH)

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