Aerobic oxidation of isoprene glycol with platinum-bismuth nanoparticles catalysts supported on metal oxides

β-Hydroxy β-methylbutyric acid (HMB) is expected as a promising therapeutic agent or a supplement. For industrial production of HMB, Pt-catalyzed aerobic oxidation of isoprene glycol is a potent synthetic method. However, the previous report using Pt-Bi catalyst supported on active carbon suffered from low tolerance to high substrate concentration conditions, which leads to low volumetric productivity. Herein, we report aerobic oxidation of isoprene glycol using Pt-Bi catalysts supported on ZrO2 or TiO2, showing high tolerance to the high substrate concentration conditions. In addition, these catalysts exhibited high recyclability. Scanning transmission electron microscopy analyses suggested the Pt-Bi species supported on ZrO2 or TiO2 are less likely to aggregate than those supported on activated carbon. Additionally, these metal oxides supported catalysts showed lower metal leaching than the carbon supported catalysts. Besides, the results of the various control experiments indicated the prevention of dehydration of an aldehyde intermediate is important for further improvement. [Display omitted] •Base-free aerobic oxidation of isoprene glycol at high substrate concentration conditions was achieved with Pt-Bi catalysts.•Pt-Bi/ZrO2 and Pt-Bi/TiO2 catalysts showed high recyclability.•The reaction pathway of oxidation of isoprene glycol was proposed based on control experiments.•Pt-Bi supported catalysts were characterized and compared with recycled catalysts.•Substrate scope was explored with Pt-Bi/ZrO2 catalysts.