Hydrothermal Decomposition of Glucose in the Presence of Ammonium

The hydrothermal decomposition of glucose in the presence of ammonium is investigated under a subcritical water condition between 220 and 280 °C using a microtubular flow reactor at short residence times (0.5–2 s) to evaluate the evolution of primary and secondary products. The consumed ammonium is mainly transformed into pyrazines, while other typical products of glucose such as fructose, glyceraldehyde, dihydroxyacetone, formic acid, acetic acid, 5-hydroxymethylfurfural (5-HMF), and furfural are also generated. For the first time, the effect of the reactant concentration, residence time, and reaction temperature on the formation of pyrazines is investigated. The kinetics of glucose decomposition was evaluated through a self-decomposition path and through interaction with ammonium, resulting in activation energies of 85.6 ± 6.7 and 97.4 ± 20.5 kJ mol–1, respectively.