Isomerization of C8-Cyclohexanes in the Presence of Aluminum Chloride

Liquid-phase isomerization of ethylcyclohexane, 1, 2-dimethylcyclohexane, 1, 3-dimethylcyclohexane, and 1, 4-dimethylcyclohexane has been investigated at temperatures ranging from 50 to 120°C using aluminum chloride as catalyst. The isomerization reaction takes place producing eight C8-cyclohexane isomers which are in their equilibrium compositions. C8-cyclopentanes are also formed, but they do not exceed 4% of the total isomerization products. Because of the carbonium ion chain mechanism involved, the isomerization is pronouncedly accelerated by the addition of cyclohexene, hexene-1, cyclohexylchloride, and t-butylchloride. Some comments are also given on the values of kinetic parameters of the reaction as well as the apparent reaction order with respect to catalyst concentration.