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

Selective oxidation of alcohols to highly valued chemicals in a clean manner (e.g., with water as a solvent and O-2 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 C-6 (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 C-6 formation. The highest formation rate of pinacol C-6 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.