Organic conversion

Toluene to benzoic acid

1 step: oxidation

Class 12, Chapter 8 Aldehydes, Ketones and Carboxylic Acids

TolueneC₆H₅CH₃Arene
Step 1
KMnO₄, KOH, heat; then H₃O⁺
i
Any alkyl side chain with a benzylic hydrogen is oxidised to COOH.
Benzoic acidC₆H₅COOHCarboxylic acid

Alternative routes (4)

Toluene → Benzaldehyde → Benzoic acid
1. Toluene to benzaldehyde: (i) CrO₂Cl₂, CS₂ (ii) H₃O⁺.
2. Benzaldehyde to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺.
Toluene → Benzaldehyde → Benzyl alcohol → Benzoic acid
1. Toluene to benzaldehyde: (i) CrO₂Cl₂, CS₂ (ii) H₃O⁺.
2. Benzaldehyde to benzyl alcohol: NaBH₄.
3. Benzyl alcohol to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺.
Toluene → Benzyl chloride → Benzyl alcohol → Benzoic acid
1. Toluene to benzyl chloride: Cl₂, UV light (or heat).
2. Benzyl chloride to benzyl alcohol: aq. NaOH.
3. Benzyl alcohol to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺.
Toluene → Benzyl chloride → Benzyl alcohol → Benzaldehyde → Benzoic acid
1. Toluene to benzyl chloride: Cl₂, UV light (or heat).
2. Benzyl chloride to benzyl alcohol: aq. NaOH.
3. Benzyl alcohol to benzaldehyde: PCC.
4. Benzaldehyde to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺.

Why these reagents

Reagent and reason, step by step

Step 1: Toluene to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺ Any alkyl side chain with a benzylic hydrogen is oxidised to COOH.

Questions

How many steps does it take to convert toluene to benzoic acid?

1 step: Toluene, then benzoic acid.

Which named reaction is used to convert toluene to benzoic acid?

None of the steps has a name. They are oxidation, so write the reagent and the condition for each step.

What is the reagent for step 1 of toluene to benzoic acid?

Toluene to benzoic acid: KMnO₄, KOH, heat; then H₃O⁺. Any alkyl side chain with a benzylic hydrogen is oxidised to COOH.