Question

Two types of alcohols namely as methylcyclohexanol and 2-methyl-2-hexanol were subjected to dehydration reaction and yield a mixture of two isomeric alkenes. Proposed a chemical reaction of both alcohols and determine which one is the major product. Justify your answer.

Answer 1

Answer:

a) Methylcyclohexanol = 1-methylcyclohex-1-ene and methylenecyclohexane

b) 2-methyl-2-hexanol = 2-methylhex-1-ene and 2-methylhex-2-ene

Explanation:

We have to remember that the dehydration of alcohols follows the Zaitsev rule. So, the most substituted alkene would be the major product for both molecules

In the case of methylcyclohexanol we have several options to put the double bond. Inside of the cyclic structure (1-methylcyclohex-1-ene) or between the cyclic structure and the methyl group (methylenecyclohexane). The most substituted one is 1-methylcyclohex-1-ene, so this is our major product.

In the case of 2-methyl-2-hexanol we have again several options for the double bond. Between the tertiary carbon (the carbon that holds the "OH" group) and the carbon in the left (2-methylhex-2-ene). The other option is to put the double between the tertiary carbon the carbon in the right (2-methylhex-1-ene). The most substituted one is 2-methylhex-2-ene, so this is our major product.

See figure 1

I hope it helps!