Hydrocarbon Radicals Involved Reactions In Sub-and Supercritical Water

Hydrocarbon radicals involved reactions occurred in sub- and supercritical water were theoretically and experimentally investigated in this work. The ab initio MD based calculations show that water clusters around the hydrocarbon radical could be formed with following prerequisites:the bulk density of water is close to liquid phase, and the state point of water on its phase diagram is far away from the critical point and from the vapor-liquid equilibrium boundary. The occurrence of water clusters superimposes a negative influence on the originally depressed diffusivity of the radical under the dense hydrothermal environments, and the interference from the immediately adjacent water molecules with the frontier orbitals of the radical results in randomly reduced activity of the radical. Thermal cracking using n-hexadecane as a model compound suggests that pyrolysis of paraffins in sub- and supercritical water still follows FSS mechanism, whose main products consist of C8-C14 n-alkanes andα-alkenes with the same carbon number. The hydrothermal environment plays a subtle influence on the thermal cracking mechanism of n-hexadecane as well as the product distribution.