Question

The major product of acid catalysed dehydration of 2-methylcyclohexanol and butan -1-ol are respectively ?

• A. 1-methylcyclohexence and but - 1-ene
• B. 2-methylcyclohexence and but - 2-ene
• C. 2-methylcyclohexence and butane
• D. 1-methylcyclohexence and but -2-ene.

Answer 1

The correct option is A 1-methylcyclohexence and but - 1-ene

Dehydration reaction of an alcohol can be represented as:

$CH-C-OH\stackrel{H^{+}}{\to }-C=C-$

Primary alcohol undergo dehydration via E2 mechanism and secondary and tertiary alcohol undergo dehydration by E1 mechanism via most stable carbocation formation through rearrangement.

For 2-methylcyclohexanol the dehydration product is 1-methylcyclohex-1-ene or 1-methylcyclohexene

and For Butan-1-ol the dehydration product is But-1-ene.