Perparation Of The Sciff Base Complex And Application In Class Wacker Catalytic System

Schiff base can reaction with most of metal to Schiff base metal complex, which have stable structure and different function. And this makes them have unique character for application. In recently years, researches have shown that Schiff base and Schiff base metal complex have a widely application in the domain of catalytic, analysis, medicine and so on. In this article, a series of Schiff bases and Schiff base metal complexes have been synthesized. And the structures of Schiff base metal complexes have been characterized and determined. For the first time, we employ the Schiff base metal complexes and Pd(NO3)2 make up class Wacker catalysis system, and apply to the oxidation reaction of cyclohexene to cyclohexanone. The effects of factors on the catalytic system were studied.Four kind of Schiff base ligand, such as L- glutamate shrinkage salicylic aldehyde ligand(L1), bisvanillie-ethylenediamine(L2), N,N’-bis( salicylidene) ethylenediamino(L3) and bis-salicylaldehyde-o-phenylenediamine(L4), and their metal(Fe, Co, Ni, Cu) complexes have been synthesized. The structures of Schiff base metal complexes have been determined by FT-IR, UV-Vis, elemental analysis, thermo gravimetric, and ICP analysis, the structures of Schiff base metal complexes CuL1 and CuL2, which have a good catalytic effect on the reaction of cyclohexene to cyclohexanone, have been speculated by quantum chemical calculations.We employ the Schiff base metal complexes, Pd(NO3)2 and HQ make up class Wacker catalysis system, and apply to the oxidation reaction of cyclohexene to cyclohexanone. There are four catalysis systems, respectively are Pd(NO3)2/HQ/CuL1, Pd(NO3)2/HQ/CuL2, Pd(NO3)2/CuL2 and Pd(NO3)2/FeL2, showed a good catalytic activity on the oxidation reaction of cyclohexene to cyclohexanone. And the optimal reaction condition has been studied.Under the optimized reaction condition, the yields of cyclohexene to cyclohexanone on the class Wacker catalytic systems of Pd(NO3)2/HQ/Cu L1, Pd(NO3)2/HQ/CuL2, Pd(NO3)2/CuL2 and Pd(NO3)2/FeL2 are 41.6%,58.6%,54.0% and 86.0%, respectively. The result showed that, for the Schiff base ligands with bigger space structure, and their metal complexes composed of the class Wacker catalytic system have a better catalytic activity and the yield of cyclohexanone is higher. For Schiff base metal complexes that have same Schiff base ligand, composed of the class Wacker catalytic system on the cyclohexene oxidation reaction, Fe(Ⅱ) has a better catalytic activity than Cu(Ⅱ). In the class Wacker catalytic system, the existence of HQ can improve the yield of cyclohexanone.The reaction mechanism of class Wacker catalytic systems, Pd(NO3)2/HQ/ML and Pd(NO3)2/ML, for the oxidation reaction of cyclohexene to cyclohexanone have been supposed. On the reaction of cyclohexene to cyclohexanone, the mechanism of class Wacker is similar with the mechanism of Wacker.