Give equations to show how sulfuric acid can convert 4-methylcyclohexene into a mixture of four isomeric c7H12 compounds(including starting material). Predict the relative amounts of each isomer.

Answer 1

This is related to an interesting reaction that has been popular as a lab practical experiment in various forms for the last 20+ years.

Addition reaction of the acid with the alkene will produce 4 methylcyclohexanol and 3 methyl cyclohexanol, both as cis/trans mixtures. These can then be dehydrated to form a mixture of 4 alkenes:

4-methylcyclohexene
3-methylcyclohexene
1-methylcyclohexene
and methylenecyclohexane

(ignoring the optical isomers of 4-methylcyclohexene and
3-methylcyclohexene)

Further information and the structures are here:

http://ochemonline.pbwiki.com/f/Dehydration_Blog.doc

Answer 2

futo