Equilibria between Sulfur Rings in Carbon Disulfide Solution at Elevated Temperatures

Abstract

Abstract Cyclooctasulfur, S8, dissolved in CS2 reacts at 130-155 °C in sealed ampoules to give S6 and S7 whose concentrations have been determined by HPLC. The half-time of the reaction is independent of the initial S8 concentration and decreases from 232 min at 130 °C to 64 min at 150 °C. After long reaction times equilibrium concentrations are observed which are in agreement with the law of mass action. From the temperature dependence of the equilibrium constants the following reaction enthalpies (at 130-155 °C) have been calculated: 3/4S8⇌S6 ⊿H°=24kJ/mol 7/8S8⇌S7 ⊿H°=21kJ/mol