Membrane-based air separation for catalytic oxidation of isolongifolene

Oxygen-enriched air (OEA) from membrane-based air separation has been widely used in the industrial field in the past two decades. Isolongifolenone, an oxygenated derivative of isolongifolene, is an important perfume ingredient in the perfumery industry. In this paper, the OEA produced by the membranes was employed as oxidant to convert isolongifolene into isolongifolenone with cobaltous acetate as catalyst. The effects of the reaction conditions on the conversion and the yield were investigated thoroughly. It was found that the conversion of isolongifolene increased with the oxygen concentration of the OEA and the reaction temperature. The maximum yield was obtained under the conditions of the oxygen concentration of 33.1% and the temperature of 60°C. Both the conversion and the yield increased with the flux of OEA. In addition, the solvent-free reaction process not only facilitated the catalyst recovery, but also minimized the effluent discharge.