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ChineseJournalofChemicalEngineering,16(2)223227(2008)

    ;DirectSynthesisofDiphenylCarbonatewithHeterogeneousCatalyst

    ;andOptimalSynthesisConditionsoftheSupportPreparedbySol-gel

    ;Method

    ;GUOHongx(郭红霞),(陈红萍),(梁英华),f芮玉兰),LU..ia

    ;(吕敬

    ;C

    ;

    ;H

    ;)

    ;ENHongping

    ;(付占达

    ;L

    ;)

    ;IANGYinghuaRUIYulan

    ;JingdeandFUZhanda

    ;SchoolofChemicalEngineeringandBiologicalTechnology,HebeiPolytechnicUniversit

    y,Tangshan063009,China

    ;1INTRoDUCTIoN

    ;PolycarbonaterPC)hasbeenrecognizedasat. ;tractiveengineeringthermoplastics,whichiswidely ;usedinindustriesassubstitutesformetalsandglass ;becauseofitsimpactstrength,heatresistanceand ;transparency.Thereisincreasingdemandforasafer ;andenvironmentallyfavorableprocessforPCproduc. ;tion.Thetransesterificationprocessusingdiphenols ;anddiphenylcarbonate(DPC)hasbeengivenmore ;andmorerecognitioninsteadoftheinterfacialpoly. ;condensationofdiphenolswithphosgeneduetothe ;advantagessuchasnotoxicphosgene,nosolventand ;nosaltformation【卜41.Phenolphosgenationmethod

    ;isgivenupbecausehighlytoxicsubstancesareused, ;whiletheansesterificationmethodusingdimethyl ;carbonatefDMC)isnotadirectmethodfortheprepa. ;rationofDPC.Inrecentyears,adirectmethodof ;oxidativecarbonylationforDPCsynthesishasat. ;tractedkeenattentionasitinvolvesonlyasinglestep ;

    ;

;reaction.

    ;Intheliterature,oxidativecarbonylationforDPC ;synthesisisbyhomogeneouscatalyticreactlonr571.

    ;Inthiscase,itisdifficulttoscale.uptheprocessdue ;toproblemsofproductseparationandcatalystrecov

    ;ery.Asitsolvesmeproblemsposedbyhomogeneous ;catalyticsystem.theheterogeneouscatalyticroutefor ;DPCsynthesishasagoodpotentialtoproduceDPCin ;industryf8-20].1waneeta1.21usedPorouscarriers,

    ;suchascarbon,alumina,silicaandthelike,supported ;palladiumcatalyststopromotethesynthesisofDPC ;andtheyieldofDPCcouldreach12.6%.Takagieta1. ;221reportedthat9.55%DPCyieldwasobtained ;whenusing5%rbymass)Pd/CascatalystandPbOas ;cocatalyst.

    ;Althloughtherewassomeachievementalready. ;theyieldofDPCwasstillrelativelylow.Inorderto ;improvetheyieldofDPCfurther,thesupportofthe ;catalystforthedirectsynthesisofdiphenylcarbonate ;(DPC,byheterogeneouscatalyticreacfionwaspre. ;paredbytheso1.gelmethod,andtheoptimumcondi. ;tionsforsynthesisofthesupportwerealsostudiedin ;thisworkbyo~hogonalexperiments.

    ;2EXPERIMEN1AL

    ;2.1Preparationofsupportbysol-gelmethod ;CufOAc)2?HEO,Mn(OAc)2?4H20,Co(OAc)2?4H20, ;citricacid.andethanediolwereusedasrawmaterials. ;CufOAc)2.HEO,Mn(OAc)2.4H20,Co(OAc)2.4HEO, ;citricacidweredissolvedwithdistilledwater,and ;theirconcentrationswere1.5,1.5,1.5,3.0mo1.L, ;respectively.Thestartingsolutionswerepreparedby ;mixingdifferentproportionofmetalacetatesolutions ;withl0mlcitricacidsolution,with2mlethanediolas ;additive.ThemolarproportionofCu,Mn,andCowas ;adjustedbychangingthevolumeofrespectivemetal ;acetatesolutionsandthetotalvolumeis30mlor40 ;m1.Theabovemixtureswerestirredforhoursinthe ;waterbathatpresettemperature,andthepHvaluewas ;adjustedto10bydropwiseadditionofaquaalT1.

    ;monia.Thentheyweredriedundervacuumtogetthe ;precursors.Finallytheprecursorswerecalcinedatset ;temperaturefor6htogetblacknanometerpowderas ;thesupport,whosespecltlCsurIacearea,3’BET,wasin

    ;therangeof7.5—9.0mz’g.

;2.2Preparationofcatalysts

    ;Thecatalystswerepreparedbyimpregnation ;Received20070629.accepted20071126.

    ;Towhomcorrespondenceshouldbeaddressed.Email:Liangyh64@yahoo.corn.ca ;

    ;Chin.J.Chem.Eng.,Voi.16,No.2,April2008 ;method,whichusedactivatedcharcoal(purchased, ;madebvTaJ1gshanSuolideActivatedCarbonCo.), ;HZSM5Omolecularsieve(purchased.byNankai ;University),porousceramics(purchased,byTangshan ;CeramicCo.),hopcalite(purchased,byShanxiXinhua ;ActivatedCarbonCo.),andthesupportpreparedby ;thesolgelmethodascarrier,respectively.PdCl2was ;thekeYcatalyst,andCo(OAc),?4HEOwasthecocata

    ;lyst.Atfirst,PdCl2andCo(OAc)2.4HEOweredis

    ;solvedinabout25mlaquaammonia,andtheircon

    ;

    ;centrationsinsolutionwere0.034and0.24mol’L.

    ;respectively.Thesolutionwasdividedintofiveali

    ;quots.Eachsupportwiththemassof1gwasdipped ;intoanaliquot,thenstirredfor1h,andagedfor13h, ;finallydriedundervacuumfor2hat55.C,andcal

    ;cinedat6O0oCfor6h.

    ;2.3Characterizationofthecatalystandsupport ;2.3.1XRD

    ;X-raypowerdiffractionpatternswereobtainedat ;roomtemperatureusingBDX??3200withNi??filtered ;CuK?radiation.TheXraytubewasoperatedat40

    ;kVand20mA.20anglewasscannedfrom10.to90.. ;2.3.2

    ;Theparticlediameterdistributionandaverage ;diameterofthecatalystweremeasuredbytransmis

    ;sionelectronmicroscope(TEM)(JEMIOOCXII).

    ;2.3.3Specificsurfacearea

    ;Thespecificsurfaceareasofallsampleswere ;determinedonaconstantvolumeadsorptionapparatus ;(GeminiV3365/2380)bytheN2BETmethodatliq

    ;uidnitrogentemperature.

    ;2.4Oxidativecarbonylationofphenol

    ;SynthesisofDPCwascarriedoutina500ml ;highpressureautoclave(madeinW_emai,China) ;equippedwithamagneticallydrivenimpeller,which ;wasprefilledwith50mldichloromethane.1gcata

    ;lyst(Pdinthecatalyst=0.17mmo1),80mmolphenol,

    ;3mmolfC4H9)4NBr(tetrabutylammoniumbromide, ;TBAB),4mnaolhydrochinone,and2gof4A

    ;fl80-250~yn.608Omesh)molecularsieveusedas

    ;dryingagent.COandO2wererechargedintothere- ;actortothedesirepressure,andthereactionstarted. ;,enthereactionendedtheliquidproductwastaken ;out,weightedandanalyzedbygaschromatography(GC). ;2.5Orthogonalexperiments

    ;InordertoinvestigatetheeflfectOfdiflusionon ;selectivityandyieldofDPCbeforelookingforthe ;optimumconditionsofDPCsynthesis,thesynthesis ;OfDPCwascarriedoutunderdifferentratesofagita. ;tion,t}leresultsshowed.

    ;whentherotationratewas

    ;greaterthan600r.min1,theyieldandselectivityof ;DPCapproachedalmosttheasymptoticValues.Inad. ;dition,theaverageparticlediameterofthecatalyst ;wasonthenanometerscale,sotheeffectofdiflusion ;couldbeneglected.TheL9f3)orthogonaltablewas ;choseninthiswork,factorsandtheirlevelswerede

    ;signedinTable1.

    ;Table1Factorsandlevelsoftheorthogonaiexperiment ;3RESUIrSANDDISCUSSION

    ;3.1Activityofdifferentcatalysts

    ;Table2showstheactivitiesofdifferentcatalysts. ;Theresultsindicatethatthecatalystusedthesupport ;preparedbythesolgelmethodhashigheractivity.

    ;Table2Theactivityofdifferentcatalystsmadefrom ;varioussupports

    ;Note:r11Thereactionwascarriedoutunderthecondition: ;phenol80mmol,(C4Hg)4NBr3mmol,hydrochinone4mmol, ;catalyst1g,4Amolecularsieve2g,Pco/Po10,p5 ;MPa.T=l0ooC.f=6h.’

    ;f21Theselectivitywascalculatedbypeakareaforeachcom

    ;ponentingaschromatograph.

    ;f31Theyieldwascalculatedbasedonpheno1. ;3.2Thecrystalphaseandaverageparticlediameter ;TheXRDpatternsofthesupportpreparedby

    ;solgelmethodareshowninFig.1.Thepatternsshow ;thepeakscorrespondingtocomplexoxidesCo2MnO4, ;Pd05Pd304,andSiO2,respectively.Inthepatternof ;thesupportbeforeloading,thereareonlystrongpeaks ;at3O.62..36-32.,44.O2.,58.6O.,4.33.intheirXRD ;patternsandthemalncrystalphaseisC02MnO4.So

    ;thecrystalphasemayhavemanycrystaldefects, ;whichspeedsupthecarbonylreaction.Afterloading, ;Figure1XRDpatternsofsupportpreparedbythesol?gel ;method(Cu:Mn:C01:1:1,calcination700.C,drying ;100.C,waterbath85.C)

    ;SiO2;OCo2MnO4;Pd0.

    ;5Pd304

    ;

    ;Chin.J.Chem.Eng.,Vo1.16,No.2,April2008 ;therearenotonlypeakscorrespondingtoCo2MnO4, ;butalsopeakscorrespondingtoPd05Pd3O4,forthe ;loadOfPdC1,.Afterreactiontheintensityofpeaks ;correspondingtoCo2MnO4andPd05Pd3O4decrease ;whilepeakscorrespondingtoSiO,appear,forthead

    ;ditionof4Amolecularsieveasdesiccant,whosemain ;componentisSiO.A1thoughCudoesnotenterthe

    ;crystalphase,italsocontributestotheactivityofcata- ;lystefficientlyaccordingtotheRefr2,6,14,23]. ;Inordertoinvestigatethedispersibilityandthe ;physicalstructure.theTEMpicturewiththesame ;supportinFig.1isshowninFig.2(a1.Theresults ;showthatthesupportdoesnothavegooddispersibil

    ;ity,fornodispersantusedastherawmaterialswhen ;thesupportwaspreparedbythesolge1method,orthe

    ;relativelylowtemperatureofcalcination(500.C, ;600.Cor700.C,.Itsaverageparticlediameterisas ;lowas40nm.Correspondingelectrondiffractionpat

    ;ternisalsoshowninFig.2(b1.Theresultscanbe ;seenthatthesupportformsthecrystalphase,which ;consistswiththeresultsofXRD.

    ;3.3Theresultsoforthogonalexperiments ;11ab1e3showstheresultsoftheninthorthogonal ;experimentalruns.WhenDPCsynthesisisunderthe ;conditionsoftheproportionof(Cu,Mn,andCo) ;1:1:1,temperatureofwaterbath80.C.temperature ;ofdrying800C,temperatureofcalcination700~C.bOth ;yieldandselectivityarehighestamong9experimental ;nJnS.

    ;11ofindouttheimportantfactorsinfluencingthe ;yieldandselectivityofDPC,theaNalysisofmaximum ;variancewasperformedandtheresultsareshownin ;11able4.

    ;IntermsoftheyieldofDPCfromTable4,the ;proportionofCu,Mn,andCoisthemostimportant

;factor.Thesecondimportantvariableisthetempera

    ;tureofcalcination,thethirdistemperatureofdrying. ;(a)

    ;(b)

    ;Figu

    ;.

    ;re2TEMimagesandelectrondiffracffonpatternof ;earrlerDe10reloamng

    ;FromTable4itwasconcludedthatthebestconditions ;areproportion1:1:1,temperatureofwaterbath80.C. ;temperatureofdrying90.C.andtemperatureofcalci

    ;nation700.C,

    ;IntermsoftheselectivityofDPC,theproportion ;ofCu,Mn,andCoisalsothemostimportant.The ;secondisthetemperatureofcalcination,andfollowed ;bytemperatureofwaterbathandtemperatureofdry

    ;ing.Theoptimumconditionsare:proportion1:1:1. ;Table3Conditionsandresultsoftheorthogonalexperiment ;Table4Marginsofyieidandselectivity,Rl,andRx,forDPC(%) ;

    ;Chin.J.Chem.Eng.,Vo1.16,No.2,April2008 ;temperatureofwaterbath85oC.temperatureofdrying ;90~C,andtemperatureofcalcination7OooC. ;Althoughtheoptimumconditionsweretestedby ;theorthogonalexperimentabove,manyfactorssuch ;astemperaturesofwaterbath,drying,andcalcination ;wereattheborderoforthogonalexperiments,sothe ;secondorthogonalexperimentwasconducted. ;Basedontheresultsabove,theproportionofCu, ;Mn,andCocouldbefixedto1:1:1,butthetem. ;peraturesofwaterbath,drying,andcalcinationneed ;tObetestedfurther.Inordertogettheiroptimumfac. ;tors,theL9(3)orthogonaltablewaschosenandthe9 ;experimentalrunswereconducted(Table51.There ;wereonlythreefactors,soanemptycolumnwas ;added.Theresultsareshownin]r2le6.

    ;Table5Factorsandlevelofthe2ndorthogonalexperiment ;Fromle6.itisclearthatwhenthereaction

    ;takesplacewithtemperatureofwaterbam85.C.tem. ;peratureofdrying1OooC.temperatureofcalcination ;700~C,theyieldandselectivityarethebest. ;Table7showstheresultsofmarginanalysisin ;thesecondexperimentalset.Itrevealsthatregarding ;theyieldOfDPC.temperatureofcalcinationisthe

    ;firstimportantfactor.Thesecondistemperatureof ;waterbath,followedbytemperatureofdrying.Ac. ;cordingtoTable7,thebestreactionconditionsshould ;betemperatureofcalcination700~C,temperatureof ;drying100.C.temperatureofwaterbath85oC. ;AsfortheselectivityOfDPC.temperatureofca1. ;cinationisalsothefirsteffectivefactor,followedby ;temperatureofwaterbath,andtemperatureofdrying. ;Thebestreactionconditionsshouldbetemperatureof ;calcination7OooC,temperatureofdrying110~C.tem, ;peratureofwaterbath85.C.

    ;Inordertoacknowledgethesignificanceofthe ;factorsofthe2ndorthogonalexperimentfurther,the ;varianceofyieldwasanalysed(Table8,.Theresults ;showthattemperatureofcalcinationishighlvobvious ;(),andtemperatureofwaterbat}lissignificant(), ;whichcorrespondswiththemarginanalysisfle71. ;Thevarianceanalysisofselectivityissimilartovari. ;anceanalysisofyield,soitisnotnecessarytointro

    ;duceagain.

    ;Table8Thevarianceofyield,SrforDPC

    ;Ontheonehand,itcanbeseenfromtheexperi

    ;mentsthattheproportionOfCu.Mn.andCoplaysan ;importantroletotheyieldandselectivity,Itshows ;thatmoreandmorecocatalystsarenotfavorableto ;thereaction.Ithasanoptimalvalue,underwhichthe ;effectOfsynergismisthebest.Thereasonthatthe ;temperatureofcalcinationisthesecondimportant ;factorshouldbethatitiscloselyrelatedtothesurface ;areaofthesupport,whichisvitaltotheactivityofthe ;catalyst.Ontheotherhand,itcanbeconcludedthat ;coppercobaltmanganesemixedoxidesusedasthe ;supportanditspreparationbytheso1.gelmethodare ;allresponsiblefortheenhancementofthecatalytic ;Table6Conditionsandresultsoftheorthogonalexperiment ;Table7Marginsofyieldandselectivity,RrandRxforDPC ;,%y,%,%R,%Srx104x:,%x,%/%

    ;274

    ;247

    ;225

    ;222

    ;,%

    ;59

    ;9

;68

    ;38

    ;Sxxl0

    ;435.125

    ;10.125

    ;578

    ;180.5

    ;temperatureofwaterbath

    ;temperatureofdrying

    ;temperatureofcalcination

    ;emptycolumn ;2l

    ;28

    ;84

    ;4l

    ;39

    ;49

    ;24

    ;44

    ;66

    ;49

    ;l8

    ;4l

    ;45

    ;2l

    ;66

    ;3

    ;253.125

    ;55.125

    ;544.5

    ;1.125

    ;2l5

    ;238

    ;286

    ;260

    ;24o

    ;244

    ;2l8

    ;247

    ;

    ;Chin.J.Chem.Eng.,Vo1.16,No.2,April2008227

    ;activityaccordingtomeRef.[23],butmechoiceof

    ;coppercobaltmanganesemixedoxideswithproper6

    ;compositionismoreimportant.

;4CONCLUSIoNS

    ;f1,Theactivityofmecatalystbasedonthesup

    ;portpreparedbythesolgelmethodishighermanme ;othertestedcatalysts.

    ;f2,Theorthogonalexperimentshowsthatthe ;proportionofCu.MnandCoismefirstimportant ;factorinfluencingmeyieldandselectivitytoDPCand ;thetemperatureofcalcinationisthesecondone. ;f3,Theoptimumreactionconditionsshouldbe ;proportionofCu,Mn,andCo1:1:1,temperatureof ;calcination700~C.temperatureofdrying100.C,tem

    ;peratureofwaterbath85.C.

    ;f4,TheyieldandselectivityofDPCinmeproc

    ;esscanreach38%and99%.respectively. ;(5)Choosingcoppercobaltmanganesemixed ;oxidesasthesupportisanimportantfactoronthe ;highercatalyticactivitymanthatbasedonthesupport ;preparedbymesolgelmemod.

    ;NoMENCLATURE

    ;statisticalparameter

    ;degreeoffreedom

    ;reactionpressure,MPa

    ;maximumvarianceofXamongfactors.% ;maximumvarianceofYamongfactors.% ;varianceofXforeachfactor

    ;varianceofYforeachfactor

    ;reactiontemperature,.C

    ;reactiontime,h

    ;selectivityofDPC.%

    ;yieldofDPCbasedonpheno1.%

    ;scanningangleofXRD,(.)

    ;REFERENCES

    ;2

    ;3

    ;4

    ;5

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    ;basedredoxcatalyst’’,J.Mo1.Cat.AChem..

    ;137,147154(1999).

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    ;cocatalystonPd.catalyzedfordirectsynthesisofdiphenylcarbon

    ;ate’’,

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;Hirotoshi,I.,Mistsuru,U.,Kazuhiko.T,”0xidativecarbonylation

    ;ofphenolcarbonatecatalyzedbyPdSncomplexeswithredoxcata- ;lyst”,Mo1.Cam1.AChem.,138.311—313(1999).

    ;Hirotoshi,I.,Mistsuru,U.,Kazuhiko,,”Oxidativecarbonylation

    ;ofPhenolcarbonatecatalyzedbvPd.Snheterotrinuclearcomplexes

    ;alongwimMnredoxcatalystwithoutanyadditionofammonium

    ;ha1ide”,Mo1.Cata1.AChem.,144,369372(1999).

    ;Goyal,M.,Nagahata,R.,Sugiyama,J.,”Directsynthesisofdiphenyl

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    ;redoxcatalystsystem”J.Mo1.Cata1.AChem.,137,147—154(1999). ;Liu,H.W.,Zhao,X.Q.,Wang,Y.J.,”Oxidativecarbonylationof

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    ;Sichuanfv.,34(1),4749(2002).(inChinese) ;Okuyama,K.,Sugiyama,J.,Nagahata,R.,’’Oxidativecarbonylation

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    ;metalpreparationofdiarylcarbonates”,EurPat.,736325(1996).

    ;Buysch,H.J.,Jentsch,J.D,Rechner,J.,”Supportedplatinumcata

    ;lystsandprocessforpreparationofdiarycarbonates”,Eur,Pat.,

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    ;Hesse,C.,Nothesis,U.,Rechner.J.”Supportedplatinum—group

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    ;Pat..9908786(1999).

    ;Takagi..”Preparationofaromaticcarbonatesasmaterialsfor ;polycarbonates”,JapanPat.,09278716(1997).

    ;Song,H.Y,Yark,D.,Lee,J.S.,”Oxidativecarbonylationofphenol

    ;todiphenylcarbonateoversupported?

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