Tungstic Acid: A Simple and Effective Solid Catalyst in Terpene Alcohol Oxidation Reactions with Hydrogen Peroxide

Abstract

In this work, we report for the rst time, the tungstic acid-catalyzed oxidation of terpene alcohols with hydrogen peroxide. This simple, solid, and commercially available catalyst e ciently promoted the conversion of borneol, geraniol and nerol to camphor and epoxide products, respectively. Effects of main reaction parameters, such as catalyst load, the molar ratio of oxidant to the substrate, time, and reaction temperature were investigate. Conversions and selectivity greater than 90% were achieved using 1.0 mol % of H 2 WO 4 after 2 h of reaction at 90°C. The activation energy was equal to 66 kJmol -1 . We propose a reaction mechanism based on the experimental results. This solid catalyst was easily recovered and reused without loss of activity. As far as we know, it is the rst time that tungstic acid was used as the catalyst in the oxidation reactions of terpene alcohols.