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1、英文参考文献及译文目：ANewLow-TemperatureSynthesisRouteofMethanol:CatalyticEffectoftheAlcoholicSolvent学 系 专 班院：别:业：级:指导教师：ANcwLow-TemperatureSynthesisRouteofMethanol:CatalyticEffectoftheAlcoholicSolvent1. IntroductionGas-phasemethanolisbeingproducedindustriallyby30-40milliontonperyeararoundtheworld,fromCO/CO2H
2、2atatemperaturerangeof523-573Kandapressurerangeof50-100bar,usingcopper-zinc-basedoxidecatalyst.Undertheseextremereactionconditions,theefficiencyofmethanolsynthesisisseverelylimitedbythermodynamicsasmethanolsynthesisisanextremelyexothermicreaction.1,2Forexample,at573Kand50bar,itiscalculatedbythermody
3、namicsthattheoreticmaximumone-passCOconversionisaround20%forflow-typereactorwhenH2CO=2.Alsoitisreportedthattheone-passCOconversionintheindustrialICIprocessisbetween15and25%,evenifH2-richgasisused(H2CO=5,523-573K).3Therefore,developingalow-temperatureprocessformethanolsynthesis,whichwillgreatlyreduce
4、theproductioncostandutilizethethermodynamicadvantageatlowtemperature,ischallengingandimportant.3Ifconversionishighenoughinmethanolsynthesis,recyclingoftheunreactedsyngascanbeomittedandaircanbeuseddirectlyinthereformer,insteadofpureoxygen.Generally,low-temperaturemethanolsynthesisisconductedintheliqu
5、idphase.methanolsynthesisfromCOH2containingCo2,asamorepracticalwayofmethanolsynthesis,isproposed.Itconsistsofthefollowingfundamentalsteps:Asformicacidwasnotdetectedintheproducts,wesuggestedthereactionpathasstep(2).TsubakietaLinvestigatedthesynthesisreactionofmethanolfromCOCO2H2,usingethanolasreactio
6、nmediuminabatchreactorandfoundhighselectivityformethanolformationattemperatureaslowas423-443K.26Inthiscommunication,thecatalyticpromotingeffectsofdifferentalcoholsonthesynthesisofmethanolfromCO/CO2H2onCu/ZnOcatalystwereinvestigated.HighyieldsOfmethanolwererealizedwhilesomealcoholswereutilized.2. Exp
7、erimentalSectionThecatalystwaspreparedbytheconventionalcoprecipitationmethod.Anaqueoussolutioncontainingcopper,zincnitrates(Cu/Zninmolarratio=1),andanaqueoussolutionofsodiumcarbonatewereaddedsimultaneouslywithconstantstirringto300mLofwaterTheprecipitationtemperatureandpHvalueweremaintainedat338Kand8
8、.3-8.5,respectively.Theresultingprecipitatewasfiltratedandwashedwithdistilledwater,followedbydryingat383Kfor24handcalcinationat623Kfor1h.Thisprecursorwasthenreducedbyaflowof5%hydrogeninnitrogenat473Kfor13handsuccessivelypassivatedby2%oxygendilutedbyargon-TheBETsurfaceareaforthecatalystwas59.4m2g.The
9、catalysthereisdenotedasCu/ZnO（八）Intheexperimentsusingreactantgasofdifferentcomposition,acommerciallyavailableICIcatalyst(ICI51-2)wasalsousedthroughthesamereduction3. ResultsandDiscussionTheanalysisresultsshowedthatonlyCOandCO2existedinthepostreactiongasandonlymethanolandthecorrespondingHCOORweretheo
10、btainedliquidproducts.Table1listedtheresultsof13kindsofalcoholsusedasreactionsolventseparatelyunderthesamereactionconditionswhereCu/ZnO（八）wasemployed.Forcomparison,theresultsinthecasesofnosolventandcyclohexanewerealsolistedinTable1.Thetotalconversionwasthesumoftheyieldsofbothmethanolandester.Fromthe
11、table,noactivityappearedwhencyclohexanewasusedornosolventwasused.However,inmostreactions,whenalcoholwasused,highactivitywasobserved,suggestingthecatalyticpromotingeffectofalcoholatlowtemperature.Thesealcoholsloweredthereactiontemperaturesignificantlyandacceleratedthereaction,butdidnotaffectstoichiom
12、etryoftheoverallreactionasinsteps(1)-(3)listedabove.Concerningthealcoholswiththesamecarbonnumberbutdifferentstructure,thesecondalcoholhadhighestactivity,asshowninthereactionsin2-propanol52-bu-tanoand2-pentanolseparately.2-Propanolexhibitedhighestactivityamongthesethree2-alcohols.Forexample,at443K,th
13、etotalconversioninthesolventof2-propanolwashighupto23.46%,amongwhichmethanoland2-propylformateyieldsaccountedfor13.19%and10.27%,respectively.Foralcoholswithlargerspatialobstacle,thereactionhadloweractivity,asshowninthecasesofiso-butanol5tert-butylalcohol,andcyclopentanol.Inaddition,forethyleneglycol
14、andbenzylalcohol,noactivitywasobserved.Butthereasonisnotveryclearnow.Onthereasonsfordifferentbehaviorsofthealcoholswiththesamecarbonnumberbutdifferentstructure,itisconsideredthatdifferentalcoholtypeaffectedstep(2)byboththeelectroniceffectandspatialeffect.For1-butanol,theelectrondensityofoxygenatomin
15、ROHislower.Asaresult,ROHattackedthecarbonatomofHCOOCu,theintermediateofstep(2),moreslowly.Butthespatialobstacleof1-butanolisthesmallestamongallbutanols,andthisisfavorabletothenucleophilicattackintheesterificationreaction.Ontheotherhand,iso-butanolhashighelectronicdensityinitsoxygenatomandthisshoulda
16、cceleratethereaction.Butitslargemolecularvolumebecameaseverespatialobstacleinthenucleophilicattack.Soitsesterificationratewaslow.Asabalancedeffectbetweenelectronicfactorandspatialfactor,2-butanolexhibitedhighestactivityamong4butanols,intherate-determiningstep(2).Astheoppositeexample,tert-butylalcoholgavetheyieldofmethanolaslowas5.83%here.Itshouldbepointedoutthattheaccumulatedester(HCOOR)canbeeasilytransferredtomethanolandROHunderhigherH2partialpr
