Ln-substituted polytungstates as efficient hetergeneous catalysts for Knoevenagel condensation reaction  

作　　者：Baijie Xu Ruikun Zhao Zhen Jing Xinyi Ma Hui Zhao Pengtao Ma Jingping Wang Jingyang Niu 

机构地区：[1]Henan Key Laboratory of Polyoxometalate Chemistry,College of Chemistry and Chemical Engineering,Henan University,Kaifeng 475004,China

出　　处：《Chinese Chemical Letters》2023年第12期361-365,共5页中国化学快报（英文版）

基　　金：support from the National Science Foundation of China(Nos.21620102002,91422302,21371048,91222102 and 21573056).

摘　　要：Three isomorphic polytungstates,CsgK_(18)H_(10){[Sm_(2)(H_(2)O)_(4)W_(4)O_(10)(AsW_(9)0_(33))3]_(2)(N(CH_(2)PO_(3))_(2))}:46.5H_(2)O(1),CS_(10)K_(9)H_(18){[Eu_(2)(H_(2)O)_(4)W_(4)O_(10)(AsW_(9)0_(33))_(3)]_(2)(N(CH_(2)PO_(3))_(2))}.41.5H_(2)O(2),Cs_(10)K_(9)H_(18){[Gd_(2)(H_(2)O)_(4)W_(4)O_(10)(AsW_(9)O_(33))_(3)]_(2)(N(CH_(2)PO_(3))_(2))}:46H_(2)O(_(3)),have been successfully synthesized and characterized by routine methods,and demonstrated excellent catalytic activities in Knoevenagel condensation reaction as heterogeneous catalysts.Notably,catalyst 1 achieved higher reaction activity than catalysts 2 and 3,where a satisfactory reaction yield(95%)and high TON value(6380)could be obtained at moderate reaction condition.In addition,in the scale-up experiment,with the help of catalyst 1,7.8g benzaldehyde and 5.7g ethyl cyanoacetate could transform into corresponding condensation product with a satisfactory yield(83%)and impressive TON value(13.883).

关 键 词：POLYOXOMETALATES Polytungstates LANTHANIDE Lewis acid and base sites Knoevenagel condensation reaction 

分 类 号：O643.36[理学—物理化学] O621.251[理学—化学]