Thiodiglycol hydrolysis and oxidation in sub- and supercritical water

Hydrolysis and oxidation of thiodiglycol [(HOC2H4)2S] were examined over temperatures ranging from 100 to 525°C at a pressure of approximately 250 bar. Two different organic feed systems were used. One method employed the preheating of a thiodiglycol solution in water, and a second method delivered pure thiodiglycol metered from a syringe pump through a cooled nozzle into the mixing tee of the reactor. Under supercritical conditions (T=400 to 525°C and P=250 bar), thiodiglycol degradation occurred rapidly with and without oxidant. Additional experiments were performed at subcritical temperatures from 100 to 360°C to further explore hydrolysis degradation. A series of subcritical batch reactions were employed to define hydrolysis kinetic parameters. Reaction products identified included carbon monoxide, carbon dioxide, hydrogen, methane, ethylene, acetaldehyde, acetic acid, formic acid, thioxane, sulfuric acid, hydrogen sulfide, and elemental sulfur.