Abstract:

Lipase-catalyzed optical resolution of R(-)-mandelic acid via RS-ethyl mandelate in non-aqueous media was studied.Lipase N435 was screened as the catalyst, and tert-butanol was used as the solvent.When lipase N435 was 2.5 g·L^-1, RS-ethyl mandelate was 0.25 mol·L^-1, water to RS-ethyl mandelate was 5∶1(molar ratio),the reaction temperature was 40℃, the speed of agitation was 200 r·min^-1, the R (-)-ethyl mandelate conversion could reach 41.6%, and enantiomeric excess (e.e.) was 84.0% after 24 h.Inhibition by the substrate and product was also investigated.A kinetic model was established by following the ordered bi-bi mechanism and quasi-steady state.Good agreement between experimental data and the simulation results was obtained.

摘要：

对在非水体系中，利用脂肪酶催化水解扁桃酸乙酯外消旋混合物拆分R(-)-扁桃酸进行了初步的研究.筛选出脂肪酶N435作为催化剂，叔丁醇作为溶剂.确定了最适的反应条件：脂肪酶N435浓度为2.5 g·L^-1，RS-扁桃酸乙酯浓度为0.25 mol·L^-1，水∶RS-扁桃酸乙酯的摩尔比为5∶1，反应温度为40℃，摇床转速为200 r·min^-1，反应时间为24 h.在此条件下，R(-)-扁桃酸乙酯的转化率为41.6%，对映体过量百分率达84.0%.考察了底物R(-)-扁桃酸乙酯和产物R(-)-扁桃酸对反应的抑制作用，在此基础上运用顺序机制和拟稳态法，建立了反应的动力学模型，模拟计算结果和实验结果吻合较好.