Structural Modification of Ru‐Bi Catalysts and its Impact on One‐Pot Synthesis of 2,3,5‐trimethyl‐1,4‐benzoquinone with Hydrogen Peroxide

Abstract Oxidative transformation of phenols is an efficient route towards the production of moieties for naturally occurring quinones with a wide range of biological activities. Silica supported Ru−Bi catalysts were prepared by microwave‐assisted loading (MW) and deposition (DP) methods. The as‐prepared catalysts were characterized by XRD (X‐ray diffraction), N 2 physisoption, SEM (Scanning electron microscopy), TEM (Transmission electron microscopy) and XPS (X‐ray photoelectron spectrometry) techniques. Catalysts with low Bi loading, 5 %Ru‐1 %Bi, have narrow particle size distributions that correspond to an average particle size of 2.21–2.59 nm. 5 %Ru‐5 %Bi catalysts consist of Ru−Bi nanochains. The outcome of the catalytic oxidation of 2,3,5‐trimethylhydroquinone ( TMHQ, 1 ) to 2,3,5‐trimethyl‐1,4‐benzoquinone ( TMBQ, 2 ) depends on the catalyst preparation method, promoter loading, solvent and temperature used. MW‐5Ru1Bi is the most active catalyst with conversions that range between 99–100 % at both room temperature (r.t) and under refluxing MeNO 2 and MeOH. The highest yields of TMBQ (100 %) were obtained over MW‐5 %Ru‐1 %Bi and DP‐5 %Ru‐5 %Bi catalysts.