苯环上氯取代位对四苯基金属卟啉催化烯烃环氧化性能的影响

以苯乙烯、环己烯和反式二苯乙烯为烯烃底物,以双氧水、叔丁基过氧化氢和异丙苯过氧化氢为氧化剂,以苯环上对位和邻位氯取代的四苯基金属卟啉为仿生催化剂,对烯烃的催化环氧化反应进行了对比研究.讨论了不同氯取代位的四苯基金属卟啉对烯烃环氧化性能的影响.实验结果表明,在没有助催化剂存在下,邻位氯代的四(2,6-二氯苯基)铁(锰)卟啉对烯烃的环氧化具有优异的催化性能,烯烃底物的转化率和环氧选择性都比对位氯代的四苯基铁(锰)卟啉高,且反应条件温和.其中FeⅢ(TDCPP)Cl的催化性能最好,环氧化选择性最高,催化氧化苯乙烯时,环氧苯乙烷的选择性达到了90.4%.相同金属离子不同配体的金属卟啉传递氧原子的能力为TDCPP>T(p-Cl)PP>TPP.氧化剂的结构对环氧化物的选择性有较大影响.过氧键连有吸电子基团的异丙苯过氧化氢对环氧化物的选择性最高.根据实验结果,对金属卟啉催化环氧化机理进行了分析.

Effect of phenyl Cl substituent position on the catalytic performance for olefin epoxidation of tetraphenylmetalloporphyrins

The reaction of hydrogen peroxide,tert-butyl hydrogen peroxide or cumene hydrogen peroxide with styrene,cyclohexene and trans-stilbene,catalyzed by phenyl ortho or para Cl substituent position of tetraphenylmetalloporphyrins,have been studied in this paper.Effect of different Cl substituent position on the catalytic performance for olefins epoxidation of tetraphenylmetalloporphyrins has been investigated.The results show that 5,10,15,20-tetrakis-(2,6-dichlorophenyl)porphyrin iron(or manganese) chloride(FeⅢ(TDCPP)Cl or MnⅢ(TDCPP)Cl) on the epoxidation of olefin exhibits excellent catalytic properties,which the olefins conversion and epoxide selectivity is better than the tetra-(p-chorophenyl)-porphyrin iron(or manganese) chloride(FeⅢT(p-Cl)PPCl or MnⅢT(p-Cl)PPCl),and the reaction conditions is mild.FeⅢ(TDCPP)Cl exhibits the best catalytic performance and epoxide selectivity.When it applied to catalyze oxidation of styrene,the styrene oxide selectivity reached 90.4%.The catalytic performance of different metalloporphyrin ligands with same metal ions are in the following order: TDCPP>T(p-Cl)PP>TPP.Oxidant structure affects the selectivity of epoxides.Cumene hydrogen peroxide,which peroxy bond links with electron drawing groups,gets the highest epoxide selectivity.According to the experimental results,the metalloporphyrins’ epoxidation mechanism is also analyzed.