【摘要】 采用雪白根霉脂肪酶催化二氢杨梅素和乙酸乙烯酯合成二氢杨梅素单酯化物,探索不同溶剂作为酶促酯化的反应体系,确定最佳的反应体系为:以乙腈为溶剂,雪白根霉脂肪酶的量为500U,乙酸乙烯酯与二氢杨梅素的物质的量之比为15~20,温度45℃,时间24~36h。二氢杨梅素转化率最高可达83.6%,利用薄层层析法分离出二氢杨梅素单酯化物的条件:V(氯仿)V(丙酮)V(乙酸)=60382,二氢杨梅素单酯化物的纯度可达96%。更多还原

【Abstract】 Dihydromyricetin esters is achieved with dihydromyricetin and vinyl acetate by lipase catalyzed synthesis.The best system for the enzymatic esterification reaction is explored by different solvents.The best system is determined:Acetonitrile as a solvent.The appropriate amount of Lipase is RN 500 U.The optimum substrate molar ratio(Dihydromyricetin:vinyl acetate)1:15 ~ 1:20.Optimum reaction temperature is 45℃.The reaction time is better controlled in 24 36 h.Under the optimal reaction conditions,Dihydromyricetin conversion rate could reach 83.6%.The separation condition was investigated.The results show that chloroform:acetone:acetic acid= 60:38:2(by volume).The purity of dihydromyricetin esters can reach up to 96%.更多还原