To understand the influence of experimental conditions on the chemistry of biomass degradation in supercritical water, the effect of heating rate and of different catalysts (1 wt % of Raney nickel and 0.5 wt % K2CO3) on the product distribution during hydropyrolysis of glucose is investigated. Glucose in aqueous solution (5 wt %) is selected as a model compound for cellulosic biomass. The heating rates are 1 or 3 K/min up to 500 degreesC, and then, the reactor is kept at this temperature for I h. Despite the long reaction time of 1 h at 500 degreesC, the presence of catalysts has an significant influence on intermediates of glucose gasification such as phenols or furfurals. The influence of catalyst and the heating rate on these intermediates and the product yields points to the assumption that the chemical processes during heating have a drastic effect on the results of the gasification process at 500 degreesC.