摘要
利用离子液体C_6MIm·BF_4(20%,v/v)/叔丁醇混合介质中脂肪酶Novozym 435催化对羟基苯甘氨酸甲酯不对称氨解反应,高效地制备了对映体纯D-对羟基苯甘氨酸酰胺。该反应的最适氨源为氨基甲酸铵,其较佳浓度为120~160mmol·L^(-1);最适水活度、反应温度、pH值、对羟基苯甘氨酸甲酯浓度分别为0.55~0.75、35~40℃、7.5~8.0和40mmol·L^(-1)。在上述条件下,反应初速度和对映体选择比分别为5.88mmol·L^(-1)·h^(-1)和83(E值),反应6h,产率为47.6%,产物e.e.值为92.9%。与有机溶剂叔丁醇相比,脂肪酶Novozym 435在C_6MIm·BF_4(20%,v/v)/叔丁醇混合溶剂中的操作稳定性显著提高,反应7批次后,仍能维持90%以上的催化活性,而在叔丁醇反应介质中,仅能维持41%的催化活性。
Using lipase Novozym 435 as mediator and the ionic liquid （IL）, CsMIm＇BF4 （20%, v/v）/ terrt-butanol co-solvent mixture, as reaction medium, the enantiomerically pure D-p-hydroxyphenylglycine amide was prepared via asymmetric ammonolysis of D,L-p-hydroxyphenylglycine methyl ester （D,L-HPGME）. Ammonium carbamate was found to be the best ammonia donor for the reaction and its favorable concentration is 120-160 mmol·L^-1, The optimal water activity, reaction temperature, pH value and concentration of D,L-HPGME are 0.55-0.75, 35-40 ℃, 7.5-8.0 and 40 mmol·L^-1, respectively. Under above mentioned conditions, the initial reaction rate and enantiomeric ratio （E） of the reaction are 5.88 mmol·L^-1·h^-1 and 83. After reaction time of 6 h, the yield and the product e.e. are 47.6% and 92.9%, respectively. Comparing with using terrt-butanol as reaction medium, using C6MIm.BF4 （20%, v/v）/tert-butanol co-solvent mixture as reaction medium, the operating stability of Novozym 435 increases remarkably and its enzymatic activity retains above 90% of its original value after being repeatedly used for 7 batches, while with tert-butanol as medium, only 41% original activity of Novozym 435 can be retained.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2007年第3期481-487,共7页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金项目(20406006)
关键词
脂肪酶
不对称氨解
对羟基苯甘氨酸甲酯
离子液体
lipase
asymmetric ammonolysis
D,L.p.hydroxyphenylglycine methyl ester
ionic liquid
