Free-radical substitution in aliphatic compounds. Part XXI. Gas-phase and solution-phase chlorination of chlorocyclohexane

Abstract

Chlorocyclohexane has been chlorinated in the gas phase and in solution, in carbon tetrachloride and carbon disulphide, over a range of temperatures in each case. In the gas phase competitive studies with 1-chlorobutane have enabled Arrhenius parameters to be calculated. Although the relative selectivities were governed principally by the pre-exponential term, an appreciable difference was found in the apparent activation energy for the gas-phase reactions leading to cis- and trans-1,3-dichlorocyclohexanes. In the solution phase the difference in the apparent activation energy was appreciable in the reactions leading to cis- and trans-isomers of both 1,2- and 1,3-dichlorocyclohexanes. In all cases the apparent activation energies for the reaction leading to the cis-isomer were greater than those for the corresponding trans-isomer.