* Inductive Effect: The methyl group (-CH3) is electron-donating due to its inductive effect. It pushes electron density towards the benzene ring, making it more electron-rich.
* Resonance Effect: The methyl group also participates in resonance with the benzene ring. This further increases the electron density in the ring, particularly at the ortho and para positions.
* Stabilization of the Intermediate: During nitration, an electrophilic attack by the nitronium ion (NO2+) occurs. The electron-rich nature of toluene allows for a more stable carbocation intermediate to form. This stabilization makes the nitration reaction more favorable.
* Increased Reactivity: The increased electron density in toluene makes it more susceptible to electrophilic attack, leading to a faster reaction rate compared to benzene.
In contrast: Benzene is a relatively electron-poor molecule, and the nitronium ion faces a higher energy barrier to attack.
In Summary: The presence of the electron-donating methyl group in toluene enhances the electron density of the benzene ring, making it more reactive towards electrophilic substitution reactions like nitration. This results in an easier and faster nitration process compared to benzene.
