1-丁基-3-甲基咪唑磷钨酸盐在环己酮氨肟化反应中的重复使用性能

Reusability of 1-Butyl-3-Methylimidazolium Phosphotungstate in Cyclohexanone Ammoximation

制备了1-丁基-3-甲基咪唑磷钨酸盐((C8H16N2)3PW12O40),并将其用于催化环己酮氨肟化反应。采用FTIR、TG-DSC、XRD以及核磁共振等方法对反应前后的催化剂进行了表征。结果表明,反应后催化剂的咪唑阳离子碳链发生了断裂,同时其磷钨阴离子[PW12O40]3-也转变成一种缺位型杂多阴离子[PW11O39]7-。催化剂重复使用2次后,仍然获得与新鲜催化剂相同的环己酮肟产率,表明在氨肟化体系中结构改变了的丁基咪唑磷钨酸盐催化剂仍然具有良好的催化性能。

1-Butyl-3-methylimidazolium phosphotungstate （（C8H16N2）3PW12O40） was prepared and used as the catalyst for cyclohexanone ammoximation.The （C8H16N2）3PW12O40 catalyst before and after reaction was characterized by means of FT-IR,TG-DSC,XRD,NMR and so on.The results showed that the carbon chain of positive ion imidazoline of （C8H16N2）3PW12O40 was broke down and the heteropoly anion [PW12O40]3 was changed into the lacunary structure [PW11O39]7-after eyclohexanone ammoximation.The yield of cyclohexanone-oxime obtained from the cyclohexanone ammoximation catalyzed by the recovered catalyst after two times reuse was as the same as that catalyzed by the fresh catalyst,which indicated that the recovered catalyst with changed structure still exhibited good reusability without significant loss of its catalytic activity.