Question

Predict the major product(s) you would obtain from sulfonation of 1-bromo-2-methylbenzene.

A) 2-methylbenzenesulfonic acid
B) 1-bromo-2-methylsulfonic acid
C) 2-methylbenzene
D) 1-bromo-2-methylbenzenesulfonic acid

Answer 1

The major product of sulfonation of 1-bromo-2-methylbenzene is predicted to be 1-bromo-2-methylbenzenesulfonic acid due to the directing effects of the methyl and bromine groups on the benzene ring.

Step-by-step explanation:

The sulfonation of 1-bromo-2-methylbenzene would likely yield 1-bromo-2-methylbenzenesulfonic acid as the major product. The process of sulfonation involves the introduction of a sulfonic acid group (-SO3H) to the benzene ring. Sulfonation is typically carried out using sulfur trioxide (SO3) in the presence of sulfuric acid (H2SO4).

In this case, the methyl group is an activating and ortho/para-directing group, while the bromine atom is a deactivating and ortho/para-directing group. Despite being deactivating, bromine is also ortho/para-directing due to its size and ability to disperse charge through resonance. Since the methyl group is already occupying one of the ortho positions and bromine the other ortho position, sulfonation would occur at the para position with respect to the methyl group, leading to the formation of 1-bromo-2-methylbenzenesulfonic acid.