Synthesis of polysulfides using diisobutylene, sulfur, and hydrogen sulfide over solid base catalysts

A series of solid base catalysts were prepared with several alkali and alkaline earth metal species. The catalysts were used in one-stage synthesis processes of polysulfides using diisobutylene (DIB), sulfur, and hydrogen sulfide (H2S). The possibility of using solid base catalyst as an alternative for a liquid amine catalyst and the effects of preparation conditions on the catalytic activity were discussed. Alumina-supported potassium catalysts showed a catalytic activity comparable to that of dicyclohexylamine. The alkali metal catalysts proved to be more effective than alkaline earth metal catalysts. Further, a three-stage mechanism for polysulfide synthesis using the system of diisobutylene, sulfur, and hydrogen sulfide in the presence of solid base catalysts was suggested. Moreover, a novel [<F>14C</F>]CO2 radioisotope pulse tracer method was developed to determine the amount of CO2 adsorption on solid base catalysts at the temperatures between 100–400 °C and under 0.6–3.1 MPa. The relationship between the uptake amount of CO2 on the alkali metal catalysts and the catalytic activity in syntheses of polysulfides was discussed. [Copyright &y& Elsevier]