Efficient and reusable ruthenium salophen catalysts immobilized on carboxylated multi-walled carbon nanotubes for the epoxidation of hydrocarbons with sodium periodate

In this research, multi-walled carbon nanotubes containing carboxylic acid groups were utilized as support and modified with 1,4-diamminobenzene, 4-aminophenol and 4-aminopyridine, and the Ru(salophen)Cl complex was attached to these supports via axial coordination. These catalysts were characterized by different techniques such as elemental analysis, UV–vis, FT-IR and SEM. Then, these heterogeneous catalysts were used for epoxidation of alkenes under magnetic stirring and under ultrasonic irradiation conditions. The effect of various oxygen donors such as sodium periodate, hydrogen peroxide, tert -butyl hydroperoxide, tetrabutylammonium periodate and sodium hypochlorite and also the effect of different solvents such as acetonitrile, acetone, methanol, ethanol, chloroform and dichloromethane on the product yield were investigated. The results showed that these heterogeneous catalysts are efficient and reusable in the epoxidation reactions.