Study On The Catalytic Reaction Of Iso-butyl Mercaptan Over La-Ce-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 and modified HZSM-5 zeolites have been studied in a fixed-bed micro-reactor, and similarities and differences of the catalytic desulfurization conversion over La-modified,Ce-modified and La-Ce-modified HZSM-5 zeolites also have been studied. It makes theoretical principle to develope catalytical cracking accessory ingredient, catalyst of desulfurization and new desulfurization technics.Mercaptan over HZSM-5 zeolite catalysts was comparatively easily transformed to yield hydrogen sulfide. The transformation of organic sulfur compounds were more easily with more strong acidity of catalysts. They showed higher cracking conversion of iso-butyl mercaptan over the Ce-modified,La-modified and La-Ce-modified HZSM-5 zeolites than one over parent HZSM-5 zeolites. There were facilitation for the catalytic transformation of isobutyl mercaptan over La,Ce modified HZSM-5 zeolites catalysts. Effect is related to La,Ce charge number, and effct is not good enough with too large charge number . Over parent and modified HZSM-5, iso-butyl mercaptan conversion and H2S yield increase obviously, along with temperature heating. 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.