简介:
简介:在铁—钾系乙苯脱氢催化剂中,铁钾组分(以氧化物计)通常要占到催化剂质量的70%以上。钾可成几何数量级地增加氧化铁的活性,同时使苯乙烯选择性有所增加,并对水煤气反应有催化作用。钾还能使生成苯乙烯、苯的活化能明显降低。但是,钾在催化剂中的存在往往是不稳定的,由于脱氢反应的强吸热性,钾会从催化剂颗粒表面向中心转移,由反应器入口高温区向低温区转移,从而使催化剂失活。
简介:ThepolycrystallinephaseWO3/g-C3N4wassynthesizedunderstirringusingtungstenicacid(H2WO4)andgraphiticcarbonnitride(g-C3N4)asrawmaterials.ThecatalystwascharacterizedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),energydispersivespectroscopy(EDS),theFouriertransforminfraredspectroscopy(FT-IR),andtheBrunauer-Emmett-Telleranalysis(BET).ThepolycrystallinephaseWO3/g-C3N4wasdeterminedbyXRDtechnique.TheoxidativedesulfurizationprocesswasinvestigatedusingWO3/g-C3N4asthecatalyst,30%hydrogenperoxide(H202)astheoxidant,and1-butyl-3-methylimidazoliumtetrafluoroborate([bmim]BF4)ionicliquids(ILs)astheextractant.Theoperatingconditions,includingH2WO4amount,ILdose,H2O2volume,temperature,catalystdosage,andtypesofsulfurcompounds,weresystematicallyresearched.Thedesulfurizationratecouldreach98.46%forremovingdibenzothiophene(DBT)fromthemodeloilunderoptimalreactionconditions.Inaddition,thecatalyticactivitywasslightlydecreasedafterfiverecyclesofcatalysts.Thereactionkineticsanalysisshowsthattheoxidativedesulfurizationsystemwasinaccordwiththefirst-orderreactionkineticsequation.Themechanismofoxidativedesulfurizationwasproposed.