The influence of supercritical water (SW) on reactions of organic chlorides at concentrations of 1.5 to 7 mole % has been examined. The aliphatic compounds were represented by 1-chloro-3-phenylpropane which reacted rapidly and completely at 400 degrees C by both pyrolysis and with SW. The presence of SW produced only a minor shift in organic products. SW did promote the reaction between the metal walls (whether Inconel or stainless steel) and the chloride, or HCl formed from it, to quantitatively produce metal chlorides, as confirmed by Inductively-Coupled Plasma (ICP) analysis. After dry pyrolysis, some HCl still remained. SW did significantly increase the rate of consumption of the aromatic chloride, 2-chlorotoluene, over that of dry pyrolysis at 450 and 500 degrees C. Metal chlorides were evident in the water layer, and HCl was not detected in the SW reaction. Because the reaction of organic chlorides, and/or the HCl formed from them, with the reactor walls may influence the rates and product distributions, experiments were conducted using Vycor(TM) inserts to provide a more inert surface. The results of these experiments, plus those with added NiCl2 or FeCl2 solutions in the VyCor(TM) insert, showed conclusively that both the metal wall and the metal salts had a catalytic effect in the reaction. Similar catalysis by the reactor wall was observed in a brief examination of the SW-4-chlorophenol reaction.