摘要
进行了以Jacobsen催化剂、硅胶型(Salen)-Mn(Ⅲ)配合物为催化剂(1,2),以离子液体1-丁基-3-甲基咪唑四氟硼酸盐(BMIMBF4)和1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF6)为反应介质,次氯酸钠为氧化剂,乙酸铵为轴向配体催化非官能团烯烃(苯乙烯、α-甲基苯乙烯、茚)的不对称环氧化反应。通过实验对比发现,反应介质离子液体与二氯甲烷相比可以有效提高催化反应的速率和ee值,并且离子液体BMIMPF6辅助催化能力高于(BMIMBF4);硅胶载体型配合物在离子液中催化烯烃具有比均相Jacobsen催化剂更好的立体催化效果。如α-甲基苯乙烯,在离子液BMIMPF6反应中获到97%～100%的ee值,且反应循环5次后催化剂活性没有明显的下降。
Asymmetric epoxidation of unfunctional olefin（styrene,α-methyl styrene,indene）was performed with Jacobsen＇s catalyst and silica gel supported（Salen）-Mn（Ⅲ） complex as catalysts（1,2）,ionic liquids tetrafluoroborate（1-methyl-3-butyl imidazole）onium salt（BMIMBF4）and hexafluorophosphate（1-methyl-3-butyl imidazole）onium salt（BMIMPF6）as reaction medium,sodium,hypochlorite as oxidant,ammonium acetate as axial ligand.The results indicated that the ionic liquids were more effective for enhancing the conversion and enantiomeric excess than dichloromethane,and（BMIMPF6）was better than（BMIMBF4）.At the same time,the silica gel supported（Salen）-Mn（Ⅲ） complex demonstrated satisfactory enantioselectivity and activity even higher than homogeneous Jacobsen＇s catalyst.Especially,in the epoxidation of ？-methylstyrene,the enantiomeric excess in the BMIMPF6 reached 100%,and could be recycled five times without obvious loss of activity.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2011年第6期1241-1246,共6页
Chemical Industry and Engineering Progress
