Epoxidation of styrene using carbon nanotubes-supported cobalt catalysts

• Co/CNTs was effective for epoxidation of styrene.
• The structure of the oxidant was crucial for the epoxidation of styrene.
• The nature of the solvent affected the catalytic activity and the selectivity.

Cobalt supported on carbon nanotubes (Co/CNTs) was developed as a novel cost-effective catalyst by impregnating CNTs in metallic precursor solution. The structures of the Co/CNTs catalysts were extensively characterized, and the presence of nanometer-sized Co particles was confirmed. The activity of Co/CNTs catalysts were examined for the epoxidation of styrene with tert-butyl hydroperoxide (TBHP) as the oxidant. The results showed that the catalytic behavior of Co/CNTs catalysts was closely correlated with the nature of oxidants, the structure of supports, and the polarity of the solvents. Compared with hydrogen peroxide, TBHP was a better oxidant for the epoxidation of styrene with the Co/CNTs catalyst, due to the lower dissociation energy. The favorable catalytic performance was obtained in acetonitrile solvent. The oxygen species with a radical nature activated by TBHP on the Co(II) site was proposed for the epoxidation reaction. This study also demonstrated that Co/CNTs catalysts were stable and could be reused without significant loss of activity.

The activity of cobalt catalysts supported on carbon nanotubes were examined for the oxidation of styrene using TBHP as oxidant. The catalytic behavior of cobalt catalysts was strongly dependent on the nature of oxidants, the structure of supports and polarity of the solvents. The cobalt catalysts were stable and could be reused without significant loss of activity.Figure optionsDownload as PowerPoint slide