1. Reactants:
* Benzene: Your starting material.
* Methyl chloride (CH3Cl): The source of the methyl group.
* Aluminum chloride (AlCl3): A Lewis acid catalyst.
2. Mechanism:
* Step 1: The aluminum chloride (AlCl3) acts as a Lewis acid, accepting a lone pair from the chlorine atom of methyl chloride. This creates a carbocation (CH3+) and a tetrachloroaluminate anion (AlCl4-).
* Step 2: The electrophilic carbocation (CH3+) attacks the electron-rich benzene ring, forming a sigma complex (intermediate).
* Step 3: The sigma complex loses a proton, regenerating the aromatic system and forming toluene.
3. Reaction Equation:
```
C6H6 + CH3Cl → C6H5CH3 + HCl
```
Key Points:
* Catalyst: Aluminum chloride (AlCl3) is essential for this reaction. It helps generate the carbocation, making the reaction possible.
* Electrophilic Attack: The methyl carbocation acts as an electrophile, attacking the benzene ring.
* Aromatic Stability: The reaction regenerates the aromatic system, making it favorable.
Overall, the Friedel-Crafts alkylation of benzene with methyl chloride is a common and efficient way to synthesize toluene.
