Abstract:

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.

Key words: rape pollen, biochar, immobilized lipase, α-pinene, epoxidation

摘要：

化学-酶法环氧化是生产烯烃环氧化物的一种经济环保型工艺，但高浓度的过氧化氢引起的酶失活现象仍是阻碍其发展的难题。本文选用天然生物资源油菜花粉作为生物炭制备的原料，经有机溶剂洗涤，在12mol/L硫酸刻蚀后，获得了大小均一、孔径均匀的多孔生物炭材料，并用戊二醛交联制备了固定化南极假丝酵母脂肪酶B（CRP@GA@CALB）。采用扫描电子显微镜（SEM）和接触角对固定化酶进行了表征。利用油菜花粉生物炭具有疏水性强且密度低的特点，构建了有机-水的双相环氧化反应体系。通过优化酰基供体，过氧化氢、固定化酶用量和反应温度等条件，获得了最佳反应效率。在最优反应条件：1.5mol/L正辛酸、30%过氧化氢、30mg/mL（有机相体积）酶添加量、反应温度为30℃下，1mol/L α-蒎烯在60min达到100%转化率，并获得99.1%环氧化收率，经9次重用后仍能保持51.8%环氧化收率。

关键词: 油菜花粉, 生物炭, 固定化脂肪酶, α-蒎烯, 环氧化