Abstract
The liquid phase ammoxidation of ethylcyclohexane, selected as a representative monoalkylcyclohexane subsrtrate, was performed in this study. The effects of reaction conditions on conversion of the substrate and the plausible reaction mechanisms of formation of nitrile were investigated.
1) The optimum reaction conditions for the liquid phase ammoxidation of 0.133mole of ethylcyclohexane in benzonitrile as solvent were as follows: Reaction temperature, 150°C; reaction time, 10hr; flow rate of oxygen, 4.5l/hr; flow rate of ammonia, 2.0l/hr; mole of benzonitrile used as solvent, 0.436; catalyst, consisting of cobalt-acetate and NH4Br in the mole ratio of 0.024 and 0.03 to the ethylcyclohexane used, respectively. Under these conditions noted above, 84.6% of ethylcyclohexane was converted and 82.5% of benzonitrile was obtained.
2) Effects of various metal catalyst on the reaction were examined. The increase in the activity of the catalysts was in the following order: Cu<Mn<Co. In the case of cobalt, a pronounced catalytic activity was observed. However, under the conditions of high catalyst concentration levels, marked lowering of reactivity was observed.
3) From the experimental results of liquid phase ammoxidation, we confirmed that the reaction proceeded not only via ethylbenzene, which was a dehydrogenation product of the cyclohexane ring but also via some other intermediates, that were not confirmed.
