Heterogeneous Copper Catalysts Catalyzed Ullmann Coupling Reaction

Phenyl ether has been widely applied in national defense and civilian industry. At present, the well-documented methods of its sysnthesis are palladium and CuI catalyzed Ullmann coupling reaction. And, the latter is the most effective way to obtain phenyl ethers. However, the significant drawbacks, including high CuI loading, high reaction temperature, hazardous ligand and environment pollution, bother the application and development of the Cu-catalyzed Ullmann coupling reaction.In this desertation, a new ligand,3-bromo-4-methylsulfanyl-pyridine, was developed and used for Ullmann coupling with CuI. The results showed that the loading of CuI was greatly reduced and the reaction temperature dropped when the new ligand was adopted.To further develop the green ways to synthesis of phenyl ethers, suppoted CuO/TiO2 catalyst was investigated in Ullmann coupling. It was found that reaction could be carried out successfully with CuO/TiO2 catalyst in the ligand-free condition. The catalyst could be recycled and the active center on supported catalyst should be CuO species that interacted with support.