STUDIES ON THE STABILITY OF ORGANIC DISULFIDE POLYSULFIDE SULFUR SOLVENTS USED IN SOUR GAS-PRODUCTION

This study examines the stability of organic polysulfides formed when organic disulfides react with elemental sulfur. This chemistry is utilized commercially to mitigate sulfur deposition which occurs during the production of sour natural gas. Dimethyl polysulfides were found to decompose to methanethiol, carbon disulfide, and hydrogen sulfide in an open-system reactor. The rate of the combined methanethiol/hydrogen sulfide production was found to follow pseudo-first-order kinetics with k = 2.02 X 10(2) and 3.08 X 10(4) s-1 at 50 and 150-degrees-C, respectively. Only traces of methanethiol were detected in closed-system experiments which gave carbon disulfide and hydrogen sulfide as major products. A mechanistic rationalization of the data based on radical pathways is presented. o- and p-tolyl polysulfides were found to be stable at temperatures below 200-degrees-C.