Hot compressed water as reaction medium and reactant - 2. Degradation reactions

Hot compressed water (HCW, here water above 200 degrees C) owns interesting properties. The impact of the unique properties is discussed exemplary for the thermal degradation of tert-butylbenzene and the oxidation of methanol. Both reactions have been conducted not only in HCW but also in other high-pressure media and from the comparison the impact of the special properties of HCW can be settled. In addition the degradation of glycerol, a model substance for carbohydrates and biomass in HCW was studied. This reaction shows a strong dependence on the properties of HCW. The examples picture an increased specific impact of HCW with rising polarity of the reactants and intermediates. The studies also points to higher importance of microscopic properties for understanding reactions in HCW than assumed in the past. (C) 2006 Elsevier B.V. All rights reserved.