Study On The Catalytic Reaction Of Iso-butyl Mercaptan Over HZSM-5 Zeolites In The Presence Of Mechanol

The catalytic desulfurization conversion and mechanism of iso-butyl mercaptan as probe molecules over HZSM-5 zeolites have been studied in a fixed-bed micro-reactor.Iso-butyl mercaptan was easily thermally transformed to yield hydrogen sulfide, the thermal conversion was perfect under the condition of more than 400℃. The course of thermal reaction for iso-butyl mercaptan is free radical mechanism.Mercaptan over HZSM-5 zeolite catalysts was comparatively easily transformed to yield hydrogen sulfide. Iso-butyl mercaptan may be full transformed while the reaction temperature got up to 300℃.They showed higher cracking conversion of iso-butyl mercaptan over the Ce-modified or La-modified HZSM-5 zeolites than one over parent HZSM-5 zeolites. The transformation mechanism of mercaptan was carbenium ion mechanism.Alcohol-type substances especially methanol had not only certain polarity, but also higher reaction activity, they were usually as reaction assist to accelerate the reaction. The catalytic transformation pathway could be changed to decrease the yield of hydrogen sulfide and yielded methyl–contained sulfides such as methyl mercaptan, dimethyl sulfide and dimethyl disulfide, but overage concentration of methanol would holdback the transformation of iso-butyl mercaptan. The transformation of iso-butyl mercaptan was favorable if the volume ratio of methanol and benzene was 0.2.