Numford
Organic conversion

Chlorobenzene to toluene

1 step: Wurtz-Fittig reaction

Class 12, Chapter 6 Haloalkanes and Haloarenes

  1. Cl
    ChlorobenzeneC₆H₅ClHaloarene
  2. Step 1

    CH₃Cl, Na, dry ether

    Wurtz-Fittig reaction
    i

    Wurtz-Fittig reaction: an aryl halide and an alkyl halide couple with sodium.

    TolueneC₆H₅CH₃Arene

Exam answer

  1. Step 1: Chlorobenzene to toluene: CH₃Cl, Na, dry ether.
Alternative routes (3)
  • Chlorobenzene → Phenol → Benzene → Toluene
    1. Chlorobenzene to phenol: (i) NaOH, 623 K, 300 atm (ii) H⁺.
    2. Phenol to benzene: Zn dust, heat.
    3. Benzene to toluene: CH₃Cl, anhydrous AlCl₃.
  • Chlorobenzene → Phenol → Benzene → Bromobenzene → Toluene
    1. Chlorobenzene to phenol: (i) NaOH, 623 K, 300 atm (ii) H⁺.
    2. Phenol to benzene: Zn dust, heat.
    3. Benzene to bromobenzene: Br₂, anhydrous FeBr₃.
    4. Bromobenzene to toluene: CH₃Br, Na, dry ether.
  • Chlorobenzene → Phenol → Benzene → Benzaldehyde → Toluene
    1. Chlorobenzene to phenol: (i) NaOH, 623 K, 300 atm (ii) H⁺.
    2. Phenol to benzene: Zn dust, heat.
    3. Benzene to benzaldehyde: CO + HCl, anhydrous AlCl₃ / CuCl.
    4. Benzaldehyde to toluene: Zn-Hg, conc. HCl.
Why these reagents

Reagent and reason, step by step

  • Step 1: Chlorobenzene to toluene: CH₃Cl, Na, dry ether Wurtz-Fittig reaction: an aryl halide and an alkyl halide couple with sodium.
Questions

Chlorobenzene to toluene: quick answers

How many steps does it take to convert chlorobenzene to toluene?

1 step: Chlorobenzene, then toluene.

Which named reaction is used to convert chlorobenzene to toluene?

Wurtz-Fittig reaction. A mixture of an aryl halide and an alkyl halide reacts with sodium in dry ether to give an alkylbenzene.

What is the reagent for step 1 of chlorobenzene to toluene?

Chlorobenzene to toluene: CH₃Cl, Na, dry ether. Wurtz-Fittig reaction: an aryl halide and an alkyl halide couple with sodium.

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