水饱和离子液体中萘普生的酶法拆分

 考察了五种水饱和离子液体反应介质中固定化脂肪酶催化外消旋萘普生甲酯的水解. 结果表明,这些具有不同阴阳离子组合的咪唑基离子液体作为反应介质都能促进水解反应的有效进行,但在水饱和1-正丁基-3-甲基咪唑六氟磷酸盐(［bmim］PF6)中,反应进行得更快,转化率更高. 这些离子液体对脂肪酶均有一定的溶解作用并使溶解的脂肪酶失活. 脂肪酶在离子液体中的溶解度与其剩余活性之间有一定的相关性. 为了解决脂肪酶在离子液体中的溶解问题,使用非极性、高比表面积的无定形多孔硅胶YWG-C6H5对脂肪酶进行了固定化. 在水饱和［bmim］PF6中使用固定化脂肪酶催化反应,反应72 h的转化率为28.3%, 产物的对映体过量值为98.2%, 继续进行反应,转化率将增加,但产物的对映体过量值明显下降. 利用离子液体有别于传统有机溶剂的特性,对离子液体的循环使用、产物的回收和水的补充方法进行了研究. 在反复批式反应中,固定化脂肪酶连续使用五次,活性仅略微下降.

Enzymatic Resolution of (R,S)-Naproxen in Water-Saturated Ionic Liquids

Ionic liquids are a new type of reaction medium for the enzymatic hydrolysis of Naproxen methyl ester because they can not only enhance the water capacity but also promote the solubility of product Naproxen((S)-( )-2-(6-methoxy-2-naphthyl) propionic acid).In this paper,a water-saturated ionic liquid system has been selected to increase the conversion and product recovery for the hydrolysis of(R,S)-Naproxen methyl ester.Five imidazolium-based ionic liquids with different anions and organic cations were tested as the reaction medium.These ionic liquids can all facilitate the hydrolysis,but only the reaction in water-saturated PF_6((1-butyl)-3-methylimidazolium hexafluorophosphate) proceeds rapidly and gives high conversion.The ionic liquids can slightly dissolve the lipase and make the dissolved lipase inactive.A rough correlation between the solubility of lipase in ionic liquids and its remaining activity is observed.To prevent the dissolving of lipase in ionic liquids,a nonpolar amorphous multiporous silica YWG-C_6H_5 with a high specific surface area has been used as the support to immobilize the lipase.Enzymatic resolution of(R,S)-Naproxen was conducted in a reactor containing immobilized lipase and water-saturated PF_6.After 72 h reaction,98.2% enantiomeric excess of(S)-Naproxen is obtained with 28.3% conversion.Further increasing the conversion leads to a great loss of the enantiomeric excess for the product.Based on the particular properties of ionic liquids,the reaction medium recycling,product recovery,and water recruiting have been studied.In the batch reaction,the immobilized lipase can be repeatedly used 5 times,and only a slight decrease in the conversion is found.