Epoxidation of pinene catalyzed by lipase immobilized on rape pollen biochar
Chemical-enzymatic epoxidation is an economical and environmentally friendly process to produce olefin epoxides,but the enzyme inactivation phenomenon caused by high concentrations of hydrogen peroxide is still a challenge that hinders its development.In this paper,rape pollen,a natural biological resource,was selected as the raw material for biochar preparation,porous biochar materials of uniform size and pore size were obtained after organic solvent washing and etching in 12mol/L sulfuric acid,and immobilized Candida antarctica lipase B(CRP@GA@CALB)was prepared by cross-linking with glutaraldehyde.The immobilized enzyme was characterized using scanning electron microscopy(SEM)and contact angle.The organic-water biphasic epoxidation reaction system was constructed by using rape pollen biochar with hydrophobic and low-density characteristics.The optimal reaction efficiency was obtained by optimizing the conditions of acyl donor,hydrogen peroxide,immobilized enzyme dosage and reaction temperature.Under the optimal reaction conditions:1.5mol/L n-octanoic acid,30%hydrogen peroxide,30mg/mL(organic phase volume)enzyme addition,and reaction temperature of 30℃,1mol/L α-pinene reached 100%conversion in 60min and obtained 99.1%epoxidation yield,which was maintained at 51.8%epoxidation yield after nine reapplications.