金属卟啉-聚乙二醇催化烯烃环氧化反应

研究了聚乙二醇在模拟细胞色素P-450酶、CH_2Cl_2-H_2O两相体系中的相转移催化作用;并和季铵盐类相转移催化作用进行了比较。把PEG-400键联到金属卟啉上,进一步考察了连接大分子后对金属卟啉的催化活性及稳定性的影响;同时比较了键联后的聚乙二醇和自由聚乙二醇所起的相转移催化作用;最后,对反应机理进行了讨论。

Epoxidation of Olefin Catalyzed by Metal Porphyrins and PEG

The phase transfer catalysis of PEG-X(X = 200, 400, 1000, 2000) in epoxidation of olefins catalyzed by metal porphyrin with NaOCl in CH2C12-H2O biphase system, a model for mimicking cyto-chrome P450, was studied, and compared with that of CH3(CH2)15N+(CH3)3Br- as the PTC. The experimental results showed that PEG-X as a PTC were superior to CH3(CH2)15N+(CH3)3Br-, on the basis of their higher catalytic activity and anti-oxidation ability. By anchoring PEG-400 to the metal porphyrin, manganese tetra-(p-hydrophenyl)porphyrin acotate, the catalytic activity and stability of the metal porphyrin catalyst thus synthesized were greatly enhanced. The transfer of -OCl from the aqueous phase to the oil phase was also facilitated. Compared with the free PEG-400 as a PTC, the PEG-4 00 on the metal porphyrin showed the better tranfer ability .