Salen配合物仿生催化氧化安息香

Oxidation of Benzoin Using Salen Complexes as Biomimetic Catalysts

合成了双水杨醛缩乙二胺席夫碱(H_2Salen)及其与5种金属离子(Co^(2+)、Cu^(2+)、Nd^(3+)、Gd^(3+)、Er^(3+))的配合物,通过元素分析、红外光谱、质谱、核磁共振氢谱和X射线单晶衍射等方法对其进行表征。推测H_2Salen化学式为C_(16)H_(16)N_2O_2,配合物的组成分别为[M(Salen)](M=Co、Cu),[Ln_2(H_2Salen)_3·(NO_3)_6]·3H_2O(Ln=Nd、Gd、Er)。以空气为氧源,通过正交试验法得到[Co(Salen)]催化氧化安息香的最佳反应条件为:以DMSO为溶剂,反应温度75℃,时间45 min,KOH加入量和催化剂投入量分别为底物安息香的25 mol%和10 mol%。在该条件下考察了不同金属配合物的催化效果。其中[Co(Salen)]催化性能最好;[Cu(Salen)]的催化效果次之;[Ln_2(H_2Salen)_3·(NO_3)_6]·3H_2O则有负催化的作用。重点研究了NaY负载[Co(Salen)]的方法及其循环催化效果,循环使用3次,催化效果稳定仍有58%的产率,催化剂套用回收方便。

Five complexes of different metal ions（Co^（2＋）,Cu^（2＋）,Nd^（3＋）,Gd^（3＋）,Er^（3＋））,with N,N＇-bis（salicylidene）ethylene diamine were successfully synthesized and characterized by elemental analysis,IR spectra,mass spectrum,H-NMR and single crystal-XRD. They are confirmed as [M（Salen）]（M = Co、Cu）,[Ln_2（H_2Salen）_3·（NO_3）_6]·3H_2O（Ln = Nd、Gd、Er）. The optimal condition of the [Co（Salen）] catalized benzoin oxidation reaction with air was found by orthogonal experiment： 75 ℃ reaction temperature,45 min reaction time,10 mol% catalyst dosage and 25mol% additive dosage. Under the optimal condition,the catalytic performances of different M-Salen complexes were evaluated： the sequence of catalytic activity from high to low is [Co（Salen）] [Cu（Salen）] [Ln_2（H_2Salen）_3·（NO_3）_6]·3H_2O,the complex of [Ln_2（H_2Salen）_3·（NO_3）_6]·3H_2O reduces the concentration of the chemical reaction rate. And finally,the cyclic catalytic performance of Na Y zeolite supported [Co（Salen）] in benzoin oxidation reaction was studied. The result shows that the [Co（Salen）]supported by NaY zeolite can be recovered effectively,the yield of benzil products still remained as high as about 58% after three cycles.