A green and efficient photo-driven route for the selective oxidation of aqueous isopropanol solution to pinacol (C6) with hydrogen peroxide

Abstract

Selective oxidation of alcohols to highly valued chemicals in a clean manner (e.g., with water as a solvent and O₂ or H₂O₂ as the primary oxidant) is the subject of considerable research attention. This paper presents a simple and environmentally friendly approach for the selective oxidation of isopropanol to pinacol C₆ (2,3-dimethyl-2,3-butanediol) in water with hydrogen peroxide (H₂O₂) through UV irradiation under mild conditions. A selectivity of 82–95% is achieved at H₂O₂ feeding rates below 4 mL h⁻¹. The introduction of TiO₂ nanotubes can further accelerate isopropanol conversion and enhance pinacol C₆ formation. The highest formation rate of pinacol C₆ and the highest conversion rate of isopropanol are 29.4 and 71.4 mmol h⁻¹, respectively. The proposed strategy provides a green solution for the synthesis of aliphatic pinacol and offers a new design for the construction of C–C bonds with alphatic alcohol.