Chemical reactions in subcritical or near-critical solvents have been the subject of great interest in many industrial and environmental applications . Kinetic rates and selectivity of various industrially relevant reactions, such as dehydration of alcohols, Diels-Alder, alkylation, and cyclization, can be enhanced in subcritical water or organic solvents . Waste plastics can be effectively decomposed and recycled by depolymerization reactions in subcritical water or alcohols . Subcritical fluids also serve as excellent reaction media for the conversion of biomass to fuels and other valuable chemicals . In nuclear power plants, subcritical or supercritical water is used as a coolant for a reactor, and a knowledge of the kinetic mechanisms of water radiolysis is essential for designing a safe water-coolant reactor that can suppress the formation of oxidizing species and mitigate corrosion .