Question

Outline a mechanism for the dehydration of 4-methylcyclohexanol catalyzed by phosphoric acid

Answer 1

Dehydration of 4-methylcyclohexanol
Here are the steps for the dehydration of 4-methylcyclohexanol:

The OH group is protonated.
OH2 evaporates as a water molecule
Only carbocation left over.
At last,
A proton leaves and the double bond comes into existence.
See the diagram in the attachment.

Answer 2

Detailed mechanism has been shown below.

Step-by-step explanation:

4-methylcyclohexanol is a secondary alcohol. We know that secondary and tertiary alcohol undergoes dehydration through E1 elimination pathway in presence of an acid catalyst.

Here 4-methylcyclohexanol gets protonated first. Then one
`H_(2)O` molecule leaves to form a carbocation. After that deprotonation takes place by
`H_(2)O` to form an alkene.

Here the product forms due to dehydration is - 4-methylcyclohexene.

detailed mechanism has been shown below.