Liquid phase oxidation of glucose to gluconic acid using Bi promoted Pd catalysts was studied in a stirred cell. Gas-liquid mass transfer limitations are observed at lower but not at higher rotational speeds. The conversion and the deactivation of the Pd catalyst depend on the O-2 concentration in the liquid phase. With decreasing glucose concentration, the reaction rate decreases leading to higher oxygen concentration in the liquid, which deactivates the catalyst due to over-oxidation. Severe mass transfer limitations even at low Pd loadings could be attributed to intraparticle or liquid-to-solid mass transfer.