简介：Adirectsynthesisofmethyllevulinatefromcellulosealcoholysisinmethanolmediumundermildcondition(180210C)catalyzedbyextremelylowconcentrationsulfuricacid(0.01mol/L)andtheproductisolationweredevelopedinthisstudy.Effectsofdifferentprocessvariablestowardsthecatalyticperformancewereperformedasafunctionofreactiontime.Theresultsindicatedthatsulfuricacidconcentration,temperatureandinitialcelluloseconcentrationhadsignificanteffectsonthesynthesisofmethyllevulinate.Anoptimizedyieldofaround50%wasachievedat210Cfor120minwithsulfuricacidconcentrationof0.01mol/Landinitialcelluloseconcentrationbelow100g/L.Theresultingproductmixturewasisolatedbyadistillationtechniquethatcombinesanatmosphericdistillationwithavacuumdistillationwheren-dodecanewasaddedtohelpdistilltheheavyfraction.Thelightfractionincludingmainlymethanolcouldbereusedasthereactionmediumwithoutanysubstantialchangeintheyieldofmethyllevulinate.ThechemicalcompositionandstructuraloflowerheavyfractionwerecharacterizedbyGC/MS,FTIR,1H-NMRand13C-NMRtechniques.Methyllevulinatewasfoundtobeamajoringredientoflowerheavyfractionwiththecontentover96%.Thispathwayisefficient,environmentallybenignandeconomicalfortheproductionofpurelevulinateestersfromcellulose.

简介：Aseriesofmetalsalt-modifiedcarboncatalystshadbeenpreparedtostudytheselectivetransformationofvariouscarbohydratesintoethyllevulinateinanethanolmedium.ThespecifictexturalandchemicalcharacteristicsofpreparedcarbonsampleswereidentifiedbyRaman,XRD,XPS,NH3-TPD,FT-IRandnitrogenphysisorption.Variousparameterssuchasethanol/watervolumeratio,NaCladdition,reactiontemperature,andcatalystdosageplayedagreatroleinethyllevulinateproduction.Adesirableethyllevulinateyieldof58.0mol%withahighestROF（rateofethyllevulinateformationpergramofcatalystperhour）valueof2148.3μmol/(gcat·h)wasachievedat468KoverFeCl3modifiedcarboncatalystwithrespecttofructoseconversion.Therecyclingexperimentsrevealedthatthesulfonatedcarboncatalystsexhibitedrelativelysatisfiedactivityandstability.

简介：One-potachievementofethyllevulinatefromcassavawasconductedinethanol-watersystemoverseveralsimplesulfatesaltcatalysts.Al2（SO4）3catalysthadthebestperformanceinsynthesizingethyllevulinatecomparingwiththoseofaseriesofsulfatesalts.Thehighestyieldsofethyllevulinatewasupto39.27%aswellas7.78%levulinateacidwhencassavawascatalyzedinethanolmediumbyadding10wt%water.13Cand1HNMRspectroscopicinvestigationsconfirmedthatisomerizationofglucosetofructoseoverAl2（SO4）3catalystisanimportantstepinproducingethyllevulinateandlevulinateacid.DuetoaggregationsofAl3+underhydrothermalconditions,tinyamountofAl3+weredetectedinfiltrateatthepercentageof0.32%evenifinabsolutewater.BronstedandLewisacidscouldimprovetheyieldofethyllevulinateandlevulinateacidbysynergisticeffect.AllresultssuggestedthatA12（SO4）3wasasimpleandefficientcatalystforethyllevulinateandlevulinateacidproduction.