The increasing demand for raw materials due to population growth makes the organization of a post-fossil and sustainable era of energy and material supply, and the development of new chemical processes for intermediates essential. One possibility is to use biomass as a renewable material source. This is the reason why several mono-and polyols, which are easily available from sugars via biochemical conversion or hydrogenolytic cleavage, were dehydrated in sub-and supercritical water. During the dehydration of polyols in sub-and supercritical water important industrial intermediates are formed.