Su_2021_Mol.Catal_508_111585

Taking advantage of the intersolubility of alcohol and water, we developed an efficient single-phase system for chemoenzymatic epoxidation of (-)-alpha-pinene. Different from traditional methods, it included all substrates, such as (-)-alpha-pinene, acyl donors and oxidants, into one phase. Isopropanol was eventually selected as the epoxidation medium to optimize three controllable parameters. Under the optimal conditions of 3.35 mol/L ethyl acetate and 1.1 mol/L H2O2, the conversion and selectivity reached 92.3% and 86.6% in 90 min, respectively, and the initial reaction rate was 13.58x10-4 mmol.min-1.mg-1 with Novozym435 as a catalyst. Trisodium citrate was screened as an acid-trapping reagent to eliminate the negative impact of acetic acid on (-)-alpha-pinene oxide. The enzyme reusability was at least 6 cycles with a relative activity of 57.5% at the sixth cycle.