Innovative direct synthesis of adipic acid by air oxidation of cyclohexane

The direct synthesis of adipic acid by air oxidation of cyclohexane was made. A single-step air oxidation of cyclohexane, based on a new lipophilic catalytic system, leads to the production of adipic acid. Experiments were conducted with the aim of validating the feasibility of the concept with many carboxylic acids. The catalytic activity of six catalytic systems was monitored in a 100 mL semi-beach reactor by plotting the initial oxygen consumption rate with respect to the Hammett constant. A good correlation was found for four carboxylic acids, indicating the electronic configuration of the lipophilic acid played a crucial role on oxidation kinetics.