Comparison of selective oxidation of aromatic alcohols using copper(II) chromite-titanium dioxide nanocomposite at reflux, light irradiation, and microwave conditions

ABSTRACT

CuCr₂O₄/TiO₂ nanocomposites with different TiO₂ contents were synthesized by using sol-gel method. Products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Results demonstrated a cubic normal spinel structure for copper (2+) chromite, with the particle sizes of about 25–40 nm. Activities of CuCr₂O₄ nanopowders and CuCr₂O₄/TiO₂ nanocomposite were tested for oxidation of benzylic alcohols to aldehydes at reflux, light irradiation, and microwave conditions. The influence of some parameters on the oxidation of alcohol, such as optimum molar ratio of chromite to titanium dioxide, catalyst dosage, and type and amount of oxidant and solvents (dichloromethane, acetonitrile, and ethanol) was studied to determine the optimal operating conditions for alcohol oxidation in reflux, light irradiation, and microwave conditions.

KEYWORDS:

• Copper chromite
• nanocomposite
• alcohols oxidation
• TiO₂
• microwave

Funding

The authors are grateful to the Research Council of University of Guilan for the financial assistance of this study.