Microwave-assisted resolution of (R,S)-2-octanol by enzymatic transesterification

Novozym 435 (Candida antarctica lipase B immobilized on polyacrylic resin) was used for the resolution of (R,S)-2-octanol with vinyl acetate as the acyl donor through transesterification. Comparison was studied to illustrate the advantage of microwave irradiation superior to the conventional heating on the enzymatic resolution reaction. It was found that the activity and enantioselectivity of Novozym 435 were enhanced dramatically under microwave irradiation. Increased thermal stability and reusability of Novozym 435 under microwave irradiation were also observed. Effects of reaction conditions, such as temperature, organic solvents, water activity, substrate ratio and enzyme load on the activity as well as enantioselectivity of Novozym 435 were also investigated. Under the optimum conditions, (S)-2-octanol was obtained at 50.5% conversion with 99% enantiomeric excess in 2 h under microwave irradiation.