简介:Micro-mesoporouscompositemolecularsievesH-ZSM-5/MCM-41werepreparedbythehydrothermaltechniquewithalkali-treatedH-ZSM-5zeoliteasthesourceandcharacterizedbyscanningelectronmicroscopy,transmissionelectronmicroscopy,energydispersivespectroscopy,X-raydiffraction,N2adsorption-desorptionmeasurementandNH3temperature-programmeddesorption.ThecatalyticperformancesforthemethanoldehydrationtodimethyletheroverH-ZSM-5/MCM-41wereevaluated.Amongthesecatalysts,H-ZSM-5/MCM-41preparedwithNaOHdosage(nNa/nSi)varyingfrom0.4to0.47presentedexcellentcatalyticactivitywithmorethan80%methanolconversionand100%dimethyletherselectivityinawidetemperaturerangeof170—300℃,andH-ZSM-5/MCM-41preparedwithnNa/nSi=0.47showedconstantmethanolconversionofabout88.7%,100%dimethyletherselectivityandexcellentlifetimeat220℃.Theexcellentcatalyticperformanceswereduetothehighlyactiveanduniformacidicsitesandthehierarchicalporosityinthemicro-mesoporouscompositemolecularsieves.ThecatalyticmechanismofH-ZSM-5/MCM-41forthemethanoldehydrationtodimethyletherprocesswasalsodiscussed.
简介:Removalofcarbonylsulfide(COS)fromCO2streamissignificantfortheproductionandutilizationoffoodgradeCO2.ThisstudyinvestigatestheadsorptionperformanceofAg/NaZSM-5asadsorbentpreparedbyincipientwetnessimpregnationfortheremovalofCOSfromaCO2streaminafixed-bedadsorptionapparatus.Effectsofvariousconditionsonthepreparationofadsorbent,adsorptionanddesorptionwereintensivelyexamined.TheresultsrevealedthatCOScanberemovedtobelow1×10-9fromaCO2stream(1000ppmCOS/CO2)usingAg/NaZSM-5(10wt%AgNO3)withanadsorptioncapacityof12.86mg·g-1.Theadsorbentcanbefullyregeneratedusinghotairat450C.Theadsorptionabilityremainedstableevenaftereightcyclesofregeneration.
简介:Directconversionoffructose-basedcarbohydratesto5-ethoxymethylfurfural(EMF)catalyzedbyLewisacidinethanolwasinvestigated.ItwasfoundthatBF3(Et)2Owasfavorablefor5-hydroxymethylfurfural(HMF)etherificationtoEMF.BF3(Et)2OcombinationwithAlCl36H2Owiththemolarratioof1wasaneffectivecatalystsystemforsynthesisofEMFfromfructose-basedcarbohydrates.55.0%,45.4%and23.9%ofEMFyieldswereobtainedfromfructose,inulinandsucroseunderoptimizedconditions,respectively.