DOC

Catalytic

By Janet Richardson,2014-07-18 02:19
8 views 0
Catalytic

    Catalytic

    Dec.2007,Volume1,No.1(Monthly)JournalofChemistryandChemicalEngineering,ISSN19347375,USA

    ;CatalyticsynthesisofacetalsandketalswithH3PW6Mo6O40/TiO2 ;YANGShui-jinl.

    ;TONGWenlongI

    ;.

    ;PhilippeG.Merle2

    ;

    .HubeiKeyLaboratoryofBioanalyticalTechniqueDepartmentofChemistry

    ;andEnvironmentalEngineering,HubeiNormalUniversity,Huangshi435002,China,

    ;2.DepartmentofChemistryandBiochemistry,ConcordiaUniversity,MontrealH4B1R6,Canada)

    ;Abstract:Anewenvironmentalfriendlycatalyst,

    ;H3PW6Mo6040/TiO2wasprepared.Theoptimumconditions

    ;havebeenfound,thatis,massratioofm(TiO,):m

    ;(H3PW6Mo6O40)is1:2.0,volumeofwateris30mL,thereflux ;reactiontimeis2h,andactivatedtemperatureis150?.

    ;H3PW6Mo6040/TiO2wasusedascatalystincatalyticsynthesis ;ofacetalsandketals.Effectsofn(aldehyde(ketone)):n(glyco1) ;catalystdosageandreactiontimeonyieldwereinvestigated. ;Optimalconditionswere:n(aldehyde(ketone)):n ;(glyco1)=1.0:1.4;massfractionofcatalysttoreactants,0.8%: ;reactiontime,1.0handcyclohexaneaswater-strippedreagent, ;10mL.Undertheseconditions,yieldsofacetalsandketalscan ;reach53.0%86.9%.

    ;Keywords:H3PW6Mo6040;TiO2;acetalation;ketalation; ;catalysis

    ;1.Introduction

    ;Therehasbeenconsiderableinterestin

    ;synthesizingacetalsandketalsasimportantperfume ;substanceandindustrialrawmaterialsoforganic ;synthesis.Theconcentratedsulfuricacidandother

    ;analogousBr6nstedacid,whichhasbeenusedas

    ;catalystsintheseindustrialprocessesformanyyears, ;exposedtheirdefects,suchastheerosionofplantunit, ;difficultyforpost?treatment,lowyieldoftheproducts, ;etc.LateliteraturesreportedthattheFeZSM5

    ;molecularsieve,Fe2(so4)3?xH2O3_PVC.FeC13[,

    ;SO4z-/TiO2-WOhadexcellentcatalyticactivityto

    ;acetalsandketals.Heteropolyacids(HPA)andtheirsalts ;Acknowledgements:Thisworkwasfinanciallysupportedby ;theNaturalScienceFoundationofHubeiProvince,China(No. ;2005ABA0531andtheNationalNaturalScienceFoundationof ;China(No.2047l044).

    ;CorrespondingauthorYANGShui~in(19641.male.

    ;professor.PhD.:researchfields:tungstenchemistryand ;inorganicfunctionmaterials.Email:yangshuijin@163.corn.

    ;havebeenextensivelystudiedfortheirinteresting ;catalyticproperties[一们.

    ;Itshowedthatthemain

    ;catalysisofHPAoccursthroughBr6nstedacid.The ;reportspointedthattherateofdehydrationand ;etherificationisdirectlyinproportiontototalacidityof ;heteropolyacids,HPAanditssaltsshowedexcellent ;catalyticactivitytotheesterificationandhaverecently ;attractedmuchattentionascatalystsforvarious ;industrialprocesses,becausethattheiracidicandredox ;propertiescanbecontrolledatatomic/molecularlevels. ;MizunoandMisono,Pope,KozhevnikovandWang

    ;Enbohavereviewedthehomogeneouscatalysisandfme ;organicsynthesiscatalyzedbyheteropolycompounds.

    ;However,thereisnoreportonthesynthesisofacetals ;andketalscatalyzedbyH3PW6Mo6040/TiO2.Inthis ;paper,thesynthesisofacetalsandketalscatalyzedby ;H3PW6Mo6040/TIO2arestudiedwithaldehyde/ketone ;andglycolasreactantsforthefirsttimeandthe ;correspondingcatalyticactivitywasinvestigated. ;2.Experimental

    ;2.1Materialsandmeasurements

    ;CyclohexanOne,butanone,butyraldehyde, ;benzaldehyde,ethyleneglycol,1,2-propanediol, ;cyclohexane,TIC14andNH3H20wereofanalytical ;reagentgrade.H3PW6Mo6040wassynthesized ;accordingtoreferenceandexaminedbyIRspectra. ;TheIR(infrared)spectrawereobtainedusingan ;Nicolet5DXIRspectrometer(Nicolet,U.S.A.).H ;NMRspectraweredeterminedonaMercury-VX300 ;MHzspectrometerwithtetramethylsilane(TMS)as ;interna1standardinCDCl1.

    ;CatalyticsynthesisofacetalsandketalswithH3PW6Mo604o/TiO2

    ;2.2PreparationofH3PW6Mo6O40riO2

    ;Wedesignedtheo~hogonalexperiments.and ;m(TiO2):m(H3PW6Mo6040),volumeofwater,reflux

    ;reactiontime,activatedtemperaturewerechosenas ;thefactorsoftheorthogonalexperiments.Thefactors, ;levelsandresultsanalysisoftheo~hogonal ;experimentsareshowninTable1andTable2.

    ;Table1Thefactorsandlevelsof

    ;theorthogonaiexperiments

    ;Note:A:re(Tit2):m(H3PW6Mo6040);B:volumeofwater ;(mL);C:refluxreactiontime(h);D:activatedtemperature(.C) ;Table2Theresultsandanalysisofthe

    ;orthogonalexperiments

    ;Note:A:m(TiO2):m(H3PW6Mo604o);B:volumeofwater ;(mL);C:refluxreactiontime(h);D:activatedtemperature(oC) ;ThesolutionofH3PW6Mo6040waspreparedby

    ;dissolvingH3PW6Mo6040inwatersolution.Thensolid ;TiO2wasstoichiometricallydroppedintotheabove ;solutionundervigorousstirring,andtheresulting ;solutionwasrefluxed.Cyclohexanone1,2-propanediol ;ketalwassynthesizedfromcyclohexanoneand ;1,2propanediolasprobingreactioninthepresenceof ;H3PW6Mo604oriO2.Theoptimumconditionsof

    ;probingreactionare:molarratioofcyclohexanoneto ;1,2-propanediolis1:1.4,thequantityofcatalystisequal

    ;tO1.4%Offeedstocks.andthereactiontimeis50min. ;Undertheseconditions,theyieldofcyclohexanone ;1.2-propanediolketalcanreachover89.1%. ;Table2showsthemostimportantfactorinthe ;preprationofH3PW6Mo60iO2isfoundtobethe ;massratioofTiO2toH3PW6Mo604o,theotherfactors ;areinordervolumeofwater,therefluxreactiontime ;andactivatedtemperature.Analyticresultsshowthe ;optimumcomposingisA2B2CIDI.Anew

    ;environmentalfriendlycatalyst,H3PW6Mo604oriO2

    ;wasprepared.Theoptimumconditionshavebeenfound. ;thatis,massratioofm(Ti02):m(H3PW6Mo6040)isl:2, ;volumeofmethantlis30mL.therefluxreactiontime ;is2handactivatedtemperatureis150?.After

    ;activatedat150oCfor3h,thewhitecatalystwas ;obtained.Finallythecatalystswerestoredina ;desiccatoruntiIuse.H3PW6Mo6040,TiO2,and ;H3PW6Mo604o/PAnwereidentifiedbymeansofFT.

    ;2.3Synthesisofacetalsandketals

    ;Thereactionwascarriedoutinathreeneckflask

    ;equippedwithastirrer,arefluxcondenseranda ;thermometer.Certainamountsofcyclohexanone,

    ;butanone,butyraldehyde,benzaldehydewereadded ;separatelywithalcohol(ethyleneglycolor ;1,2-propyleneglyco1)andthecatalyst.Thesolutionwas ;heatedtoboilingandrefluxeduntilnowaterflowedoff. ;Theresultsolutionwasdistilledandpurified. ;3.Resultsanddiscussion

    ;3.1CharacterizationofcatalystH3PW6MO6o40 ;/TiO2

    ;ThecharacteristicabsorptionpeaksofTiO2are ;exploredat1401cm~.,H3PW6Mo6040?xH20at1072, ;978,879,792,599,518cm-.Intheinfraredspectrum ;ofH3PW6Mo6040厂】riO2theabsorptionbandsat1420, ;9

    ;CatalyticsynthesisofacetalsandketalswithH3PW6Mo604o/TiO2

    ;1072,978,885,798cmcanbeassignedtothe

    ;stretchingvibrationsofTiO,POP,MOd,MObM,

    ;M-OcMbond,respectively.Timstretchingvibrations ;OfTiOat1401cm-intitaniumhydroxidedecreasein ;compositeofH3PW6Mo60iO2.Similarbondsinthe ;region1100—700cm’.confirmedthepresenceofred

    ;shiftofabsorptionpeaksatthebasedof

    ;H3PWrMo6040?xH20.Theresultsindicatedthatthe

;KegginstructureofH3PW6Mo604o?xH20was

    ;maintainedaftercompoundingatthesurfaceofsuppo~. ;3.2Optimizingofreactioncondition

    ;Forexample,cyclohexanone1,2-propanediol ;ketalwassynthesized,theeffectsofoperation ;parameterssuchasmolarratioofcyclohexanoneto ;1,2propyleneglycol,thedosageofcatalystand ;reactiontimeontheyieldweremeasuredandanalyzed ;inordertooptimizetheseoperationconditions. ;3.2.1Effectofmolarratioofcyclohexanoneto ;1,2propyleneglycolontheyield

    ;Table3showedtheeffectofmolarratioof

    ;cyctohexanoneto1,2?propyleneglycolonyield.The ;molarratioofcyclohexanoneto1,2-propyleneglycol ;(r)directlyinfluencedtheyield.

    ;Table3Effectofmolarratioofcyclohexanoneto ;1,2-propyleneglycolontheyield

    ;Reactionconditions:cyclohexanone,0.20mol; ;massfractionofcatalysttoreactants.0.8%:reaction ;time,1.0h;cyclohexaneaswater-strippedreagent,10mL ;Theyieldincreaseswithmolarratioof

    ;cyclohexanoneto1,2-propyleneglycolincreasing.

    ;Whentheratiois1:1.4,theyieldisthehighest.To ;increasemolarratioofcyclohexanoneto1,2propylene

    ;glycolcausedaloweryield,becauseoftheloweringof ;thetemperature.Thustheoptimummolarratioof ;cyclohexanoneto1,2propyleneglycolis1:1.4.

    ;3.2.2Effectofcatalystdosageonyield

    ;Theeffectofcatalystdosageontheyieldisshown ;intable4

    ;10

    ;Table4Effectofcatalystdosageonyield

    ;Reactionconditions:cvc1Ohexan0ne.0.20mol; ;n(cyclohexanone):n(1,2-propyleneglyco1)=l:1.4; ;reactiontime,1.0h;cyclohexaneaswaterstripped

    ;reagent,10mL.

    ;FromTable4,wecanseethattheyieldincreased ;whenthecatalystconcentrationincreases.Whenthe ;massratioofthecatalysttothereactantswas0.8%.the ;yieldwas86.9%.Theyielddidnotvmygreatlywhen ;morecatalystwasadded.Therefore,themassratioofthe ;catalysttothereactantswas0.8%fortheseexperiments. ;3.2.3Effectofreactiontimeonyield

    ;Reactiontimeisalsoanimportantfactorforthe

    ;reaction.Table5showstheeffectofthereactiontime ;ontheyield.

    ;Table5Effectofreactiontimeonyield

    ;Reactionconditions:cvclOhexanOne.0.20mol; ;n(cyclohexanone):n(1,2propyleneglyco1)=l:1.4;

    ;massfractionofcatalysttoreactants,0.8%; ;cyclohexaneaswaterstrippedreagent,10mL

    ;WecanseefromTable5thattheyieldincreases ;withincreaseoftime.After60min,theyieldisthe ;highest.Sowechose60minasoptimumreactiontime. ;3.2.4Comparisonofcatalyticactivitiesof ;differentcatalysts

    ;Table6givesthecatalyticactivitiesofniobicacidl

    ;Fe2(so4)3.xH2Of3J.vitamincfI2and

    ;H3PW6Mo6040/TiO2.

    ;Table6Comparisonofcatalyticactivity

    ;ofdifferentcatalysts

    ;CatalyticsynthesisofacetaisandketalswithH3PW6Mo604o/TiO2

    ;Thefollowingconclusionscanbeobtained:allof ;thecatalystsshowcertaincatalyticactivitiesforthe ;synthesisofcyclohexanone1,2-propanediolketal,but ;thecatalyticactivityofH3PW6Mo6040/TiO2isthe

Report this document

For any questions or suggestions please email
cust-service@docsford.com