Selective Oxidation of Thiols and Alcohols by Physically Encapsulated Nickel Schiff-Base Complex Prepared Via Sol-Gel Method as Nano-Catalyst

Abstract

A heterogeneous catalyst was prepared by direct physical encapsulation of nickel Schiff-base complex into the silicon dioxide matrix via sol-gel method. The compounds were characterized by FT-IR, SEM, TEM, XRD, CHNS, and AAS. The catalytic performance in the alcohols and thiols oxidation was investigated in the presence of H₂O₂ (10 mmol, 30%) as oxidant. After five recycle runs, the catalyst showed 13% reduction in activity with slightly Ni(II)-complex leached to the solvent. Varieties of primary and secondary alcohols were efficiently oxidized to the corresponding ketones. Thiols were oxidized in coupling reaction to disulfides in excellent yields using nano-catalyst with H₂O₂.

Keywords:

• aldehyde
• disulfides
• heterogeneous catalyst
• Schiff-base
• selective oxidation

Acknowledgments

The authors acknowledge the financial support of Ferdowsi University of Mashhed for this project (Ph/548).