2018 Volume 61 Issue 5 Pages 316-321
Catalytic direct decomposition of t-butyl mercaptan (TBM), which is a sulfur compound added to city gas as an odorant, was investigated over H-beta zeolite catalyst without hydrogen addition. High TBM conversion was achieved at the initial stage of the reaction at 60 °C, and hydrogen sulfide was only detected in the outlet gas. Subsequently, TBM conversion decreased and concentration of isobutene increased. TBM was stably decomposed to hydrogen sulfide and isobutene after 490 min, indicating that the activity of H-beta zeolite was sufficiently durable. Temperature programmed oxidation (TPO) analysis of the spent catalyst suggested that hydrocarbon species were desorbed below 300 °C and carbon species were oxidized to carbon dioxide above 300 °C. Spent catalyst heated under a flow of air at 300 °C completely recovered the catalytic activity. Therefore, hydrocarbon species formed at the initial stage of the reaction were oligomerized within the zeolite pores and caused the decrease in catalytic activity for TBM decomposition.
