Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un

Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un

ID:81816771

大小:2.46 MB

页数:10页

时间:2023-07-21

上传者:U-14522
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第1页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第2页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第3页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第4页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第5页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第6页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第7页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第8页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第9页
Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un_第10页
资源描述:

《Mechanistic Study on E ff ect of Electron Donors in Propylene Polymerization Using the Ziegler − Natta Catalyst - Guo et al. - 2021 - Un》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库

pubs.acs.org/JPCCArticleMechanisticStudyonEffectofElectronDonorsinPropylenePolymerizationUsingtheZiegler−NattaCatalystXingGuo,LiangCui,YisenWang,JianjunYi,JingwenSun,ZhenLiu,*andBopingLiu*CiteThis:J.Phys.Chem.C2021,125,8533−8542ReadOnlineACCESSMetrics&MoreArticleRecommendations*sıSupportingInformationABSTRACT:TiCl4/MgCl2catalystsarestillthemainindustrialcatalystforisotacticpolypropyleneatpresent.However,themechanismofisotacticpolymerizationofpropylenehasnotbeenfullyunderstood.DFTcalculationsrevealedthatthebareTiactivesitewasregioselectiveandnonstereoselectiveintheabsenceofanelectrondonor.Theroleofelectrondonorethylbenzoate(EB),diethyl-2,3-diisobutylsuccinate(DiBS),cyclohexylmethyldimethox-ysilane(CMDMS),anddicyclopentyldimethoxysilane(DCPDMS)ontheactivesitewasinvestigated.ThepresenceofEB,DiBS,CMDMS,orDCPDMSaroundtheTiactivesitecanpromotetheactivityandretaintheregioselectivity.ItisworthnotingthatinthepresenceofEBandDCPDMS,thestereoselectivebehaviorcanbepromotedwiththeadvantageof1kcal/mol.ThecopresenceofAlEt2Clspeciesandexternaldonorscanincreaseboththestereoselectivityandregioselectivity.1.INTRODUCTIONdonorsontheactivesiteremainselusive,presumablyduetotheheterogeneityandmulticomponentnatureofthecatalyst.In1953,KarlZieglerfirstdiscoveredthatsomecertainFortunately,greateffortshavebeencarriedouttounderstandtransitionmetal(mainlyTi,V,andZr)compoundswithAl-alkylswereabletocatalyzethepolymerizationofalkenesundertheroleofelectrondonorsontheactivesitebyexperimental28−32relativelymildconditions,lowertemperatures,andlowerandtheoreticalmethods.Andonietal.observedapressuresthanthoseoftheradicalpolymerization.1Thenextstructuredirectingroleofelectrondonorsintheformation33,34year,GiulioNattausedasimilarcatalysissystemtoproduceofMgCl2crystalmorphology.Thepresenceof1,3-dietherstereoregularpolymers.2ThesefindingsmadeitpossibleforledtothepreferentialgrowthofMgClcrystalsalongthe2themassiveproductionofstereoregularpolymers.Therefore,(110)surface,whereasdiisobutylphthalateorethylbenzoateKarlZieglerandGiulioNattawerejointlyawardedtheNobelwaslessselectiveandallowedthegrowthofMgCl2crystalsPrizeinchemistryfortheiroutstandingcontributionsin1963.alongboth(110)and(104)surfaces.Furthermore,electronInaddition,thiscatalysissystemwasnamedtheZiegler−NattadonorsinfluencethedistributionandamountofTiCl4inthecatalyst.ultimatecatalyst.ItisgenerallybelievedthattheadsorptionofTheZiegler−NattacatalystisoneofthemostimportantmononuclearTiCl4ontheMgCl2(110)surfacewouldformDownloadedviaUNIVOFCALIFORNIASANTABARBARAonMay16,2021at06:44:21(UTC).Seehttps://pubs.acs.org/sharingguidelinesforoptionsonhowtolegitimatelysharepublishedarticles.catalystsforindustrialpolyolefinproduction,whichmainlyatacticactivesites,andtheadsorptionofdinuclearTiClon283producespolyethyleneandisotacticpolypropylene.Nowa-theMgCl2(104)surfacewouldgenerateisotacticactivedays,atypicalsupportedZiegler−Nattacatalysissystemsites.6,35Busicoetal.andCorradinietal.proposedthattheconsistsoffourkeyelements:TiCl4(thecatalystprecursor),electrondonortendedtocoordinateonthemore-acidic(110)MgCl2(thesupport),electrondonors(Lewisbases),andsurface,therebypreventingTiClfromanchoringonthealkylaluminum(thecatalystactivator).4,5Theintroductionof4nonstereoselective(110)surfaceandinhibitingthenon-electrondonorsisagreatbreakthroughintheZiegler−Natta6,36,37stereospecificactivesites.Actually,experimentalstudiescatalysissystemforpropylenepolymerization.Electrondonorsremarkedamore“direct”effectoftheelectrondonorsonthecanbedividedintotwotypes:(i)theinternaldonor(addedactivesite,improvingthestereoselectivityofalreadyselectiveduringthecatalystpreparation),e.g.,ethylbenzoate,phthalate,6−16succinate,1,3-diether,malonates,etc.,and(ii)theexternaldonor(addedduringtheolefinpolymerization),e.g.,silane,Received:December18,2020alkoxysilane.17−23ThesuitableinternalandexternalelectronRevised:April6,2021donorpaircancontroltheregularityofpolypropyleneandPublished:April20,202124−27increasetheyieldofisotacticpolypropylenegreatly.Althoughthisfamouscatalystattractsmuchattentionfrombothacademiaandindustry,themechanismoftheelectron©2021AmericanChemicalSocietyhttps://doi.org/10.1021/acs.jpcc.0c112738533J.Phys.Chem.C2021,125,8533−8542

1TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticlesitesandprobablytransformingthenonstereoselectiveactiveclustermethods.Thecoadsorptionmodesofthesefoursitesintostereoselectiveones.donorsonthetitaniumactivesitewerefirststudied.Then,theThedensityfunctionaltheory(DFT)isutilizedasaeffectsofthedonorsontheπ-complexformationandinsertionpowerfultooltoidentifythemechanismofthechemicalbehaviorofpropylenemonomerstotheTiactivesitewerereaction.Recently,Piovanoetal.observedtheexistenceofinvestigatedsystematically.Finally,theeffectsoftheTiCl4(EB)andTiCl4(EB)2complexeschemisorbedonthecopresenceofexternaldonorsandAlEt2ClspeciesontheMgCl2surfaces,andtheinternaldonorethylbenzoate(EB)propyleneinsertionwerediscussed.couldinduceacertainmobilityfortheTiCl4moleculethroughcombinationofFT-IRspectraofCOadsorptionandDFT2.COMPUTATIONALDETAILS38methods.Credendinoetal.studiedthecoordinationAllDFTcalculationsincludinggeometryoptimizationsandpropertiesofdimethylphthalate,9,9-bis(methoxymethyl)-frequencycalculationswereperformedusingtheGaussian09fluorene,andalkoxysilanetotheMgCl(110)and(104)472programpackage.39,40surfaces.ThesedonorsshoweddifferentmobilitiesontheGeometryoptimizationswerecarriedoutwithoutany(110)surface,andthedonorinterlayermigrationrequiredsymmetryconstraintbyusingtheB3LYPfunctionalindonordissociation.Kuklinetal.estimatedthestabilizationof48,49combinationwiththedef2-SVPbasissetforallatoms.theMgCl2surfacebymono-andbidentateelectrondonors,ThedispersioncorrectionsweretakenintoconsiderationwithsuchasEB,2,2-dimethyl1,3-dimethoxypropane,dimethyltheDFT-D3(zero-damping)method.Throughout,wehave41phthalate,anddimethylsuccinate.Boththeidealandemployedharmonicvibrationalfrequencycalculationstodefective(104)and(110)MgCl2surfacescouldbestabilizedconfirmthatthestructureshavebeenproperlyoptimized.byalldonors.Also,theelectrondonorsplayanimportantroleTheenergiesofallstructureshavebeenrefinedbycarryingoutintheactivationmechanismoftheZiegler−Nattacatalyst.single-pointenergycalculationsusingtheM06LfunctionalinKumawatetal.foundthatonthepureTiClsiteorwith504combinationwiththeTZVPbasissetforallatoms.dietherandEBcoordinatingneartheTisite,thealkylationofTheβ-MgCl2(110)surfacewasusedinthiswork.Infact,thetheTiIVClprecursortotheTiIIIClEtactivesiteproceeds42activesiteTi-alkylmaybeformedbytheadsorbedTispecies42easily.Notonlytheelectroniceffectbutalsothestericontheperfectsurfaceordefectivesurfacefollowedbythe9,51hindranceofthesubstitutedgroupofdonorshasaninfluencealkylationassistedbythecocatalystAlR3.TheTi-isobutylontheactivesite.Wondimagegnetal.observedthatbulkygroup,formedby1,2-insertionofapropylene,wasconfirmedsubstituentgroupsofalkoxysilaneR1R2Si(OMe)2couldtobethesmallestunitfordescribingthegrowing52significantlypromotethestereoselectivebehaviorofthepolypropylenechain.Thestructureofthebareactivesite(110)edgeactivesiteinthepresenceofphthalateandTiCl2iBu/MgCl2(110)isdepictedinFigure1.Alltheatomsin43increasethemolecularweightofthepolymer.However,onebulkysubstituentonR1orR2couldnotproducehighlyisotacticpolymers.Also,researchershaveconsideredtheinfluencethatthecocatalystalkylaluminummayhavehadontheexternaldonorsduringthepolymerization.Khatrietal.carriedoutatheoreticalstudyofthecomplexesformedbyexternaldonorsand44triethylaluminium(TEA).TheexistenceofweakinteractionsbetweenexternaldonorsandTEAthroughchargetransferhasbeenprovedbytheDFTandNBOstudies.TheAlR2ClmoleculeistheactivationreagentortheproductgeneratedfromtheactivationeventalongwiththeformationoftheTiactivesite.Credendinoetal.reportedthatthestronglyFigure1.StructureofthebareactivesiteTiCl2iBu/MgCl2(110).adsorbedAlEt3andAlEt2ClspeciescouldenhancethestereoselectivityoftheTiactivesiteonthestep-defected45(104)surface.ThesameresultswereobtainedbyFallahetal.,whentheAlMe3andAlMe2Clspeciescoordinatednearthethemodeloftheβ-MgCl2(110)surfacewerekeptfixed,exceptTiactivesiteonthe(110)surface.46SincetheexternaldonorforthetwoClatomsfromthesurface,whichhavedirectbondsalkoxysilaneisalwaysusedincombinationwiththecocatalystwiththeTicenter.AlltheotheratomswererelaxedforalltheAlR3duringthepolymerization,itisobviousthattheAlR2Clcalculations.speciescanaffectolefininsertioninthepresenceoftheFortheDiBS,CMDMS,andDCPDMSstudiedhere,theexternaldonors.conformationalanalysiswasperformedusingtheTinker53Consideringthattheelectrondonorsplayanimportantroleprogram.TheatomswereassignedtheappropriateatomintheZiegler−Nattacatalyst,itiscrucialtostudytheeffectoftypesbasedontheMMFFforcefielddefinition.Alltheinitialdonorsontheregio-andstereoselectivebehavioroftheactivestructuresobtainedatthemolecularmechaniclevelwerethensite.Inolefincoordinationpolymerization,theinsertionstepisfullyoptimizedusingtheGaussian09program(TablesS1,S2therate-determiningstep,andtherelativeenergyoftheintheSupportingInformation).Theglobalminimumvaluesoftransitionstateisthemeasureoftheregio-andstereo-EB,DiBS,CMDMS,andDCPDMSaregraphicallyshowninselectivity.Inthiswork,theinsertionstepfortheMgCl2-Figure2.supportedZiegler−NattacatalystwithEB,diethyl-2,3-ThedonoradsorptionenergyΔGadwascalculatedaccordingdiisobutylsuccinate(DiBS),cyclohexylmethyldimethoxysilaneto(CMDMS),anddicyclopentyldimethoxysilane(DCPDMS)00wasinvestigatedbydensityfunctionalcalculationsusingΔGGGGad=−−A/DAD8534https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

2TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticlecatalyst,withaCObondlengthof1.210ÅandC−Obondlengthof1.347Å.ThemoststableadsorptionstateofEBontheMgCl2(110)surfaceisamonodentateonewiththeOatomofthecarbonylgroupcoordinatedtotheMgatom,whichisadjacenttotheTiactivesiteornot.IthasbeenpreviouslyreportedthatbidentatestructuresofEBwithO−COboundtotheMgatomwerelessfavorablethanthemonodentate54one.Therefore,onlythemonodentatecoordinationwasconsideredinthiscase.Thenearest5-coordinatedMgatomontheleftsideoftheTiactivesitewasdefinedastheMg1site,andthe4-coordinatedMgatomlocatednexttotheMg1sitewasdefinedastheMg2site.TheoptimizedgeometryofEBbindingtotheMg1atom,Mg2atom,andTiatomontheTiCl2iBu/MgCl2(110)surfaceisshowninFigure3.AdsorptionoftheEBmoleculewasFigure2.Optimizedgeometryof(a)EB,(b)DiBS,(c)CMDMS,consideredinthe“planar”conformation,wherethearomaticand(d)DCPDMSelectrondonors.ringwasparalleltotheplainofthecarboxylgroup.TheadsorptionenergiesandinteratomicdistancesforEB,DiBS,CMDMS,andDCPDMSontheTiCl2iBu/MgCl2(110)whereGA/DistheGibbsfreeenergyoftheactivesiteabsorbedsurfacearelistedinTable1.bytheelectrondonor,andG0andG0aretheGibbsfreeADenergiesoftheisolatedactivesiteandtheisolatedelectronTable1.AdsorptionEnergies(kcal/mol)andInteratomicdonormolecule,respectively.TheadsorptionenergyΔGad<0DistancesforEB,DiBS,CMDMS,andDCPDMSAdsorbediftheadsorbatewasboundwiththesurface.ontheTiCl2iBu/MgCl2(110)SurfaceTheπ-complexformationenergyΔGπwascalculatedaccordingtodistance(Å)00coordinationmodeΔGadO1−MgO2−MgO−TiΔGGππ=−−complexGGM−AEBwhereGπ−complexistheGibbsfreeenergyoftheπ-complexEB−Mg1−25.72.025formedbytheisolatedpropylenemonomerandtheisolatedEB−Mg2−23.52.037activesite,andG0andG0aretheGibbsfreeenergiesoftheEB−Ti−14.92.025AMisolatedactivesiteandtheisolatedpropylenemonomer,DiBSrespectively.DiBS−Mg2−M−28.22.005TheapparentactivationenergyistheenergydifferenceDiBS−Mg2−C−42.82.0522.080betweenthetransitionstateandtheseparatedreactants.TheDiBS−Mg1(2)−40.92.0152.120apparentactivationenergyΔGAwascalculatedaccordingtoCMDMSCMDMS−Mg1−23.42.13900ΔGGGGAM=−−TSACMDMS−Mg2−33.02.1402.150whereGTSistheGibbsfreeenergyofthetransitionstate.CMDMS−Ti−15.22.130DCPDMS3.RESULTSANDDISCUSSIONDCPDMS−Mg1−18.82.142DCPDMS−Mg2−31.52.1542.1703.1.AdsorptionofElectronDonorsontheTiCl2iBu/DCPDMS−Ti−11.52.110MgCl2(110)Surface.Themonoester-typeelectrondonorEBisusedastheinternaldonorduringthepreparationoftheFigure3.StructuresofEBandDiBScoadsorptionaroundtheTiactivesite.8535https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

3TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticleTheadsorptionenergyfortheEB−Mg1modelis−25.7bridgemodegives−40.9kcal/moloftheadsorptionenergy.kcal/mol,whichhasanO−Mgbondlengthof2.025ÅandanEnergetically,themonodentateisthemostunfavorableO−Mg−Clangleof95.4°,closetoaCl−Mg−Clangleof86.8°adsorptionmode.Nevertheless,incontrasttothemonofunc-inMgCl2crystals.IntheEB−Mg1model,theMg1atomtotionalEB,theadsorptionofthebifunctionalDiBSismuchwhichtheLewisbaseiscoordinatedalsointeractswiththeClmorestable.atomsoftheTispecies.TheEB−Mg2modelislessfavorableThealkoxysilane-typeelectrondonorCMDMSandwithanadsorptionenergyof−23.5kcal/mol,showingtheDCPDMSareusedasexternaldonorsduringthepropylenedifferentaffinityofEBforthefive-andfour-coordinatedMgpolymerization.Thedistancebetweentheirtwooxygenatomsatoms.WhenEBbindstotheTiatom,theadsorptionenergyisabout2.7Å.Therefore,thealkoxysilane-typeelectrondonoroftheEB−Timodelis−14.9kcal/mol,higherthanEBcanonlyadsorbattheMgCl(110)surfacethroughthe2bindingtoMgatoms.TheactivesiteispoisonedintheEB−TimonodentateandchelatemodesowingtotheshortspacercaseduetothesaturatedTiatomwithoutanyvacantsiteforbetweenthecoordinatingoxygenatoms.Thepossiblepropylenemonomercoordination.adsorptionmodelsofCMDMSandDCPDMSontheThediester-typeinternaldonorsuccinateisusuallyusedinTiCl2iBu/MgCl2(110)surfaceareshowninFigure5.thepreparationofthesixth-generationZiegler−Nattacatalyst.ThemostpreferredadsorptionmodelforCMDMSandThedistancebetweenthetwocarbonyloxygenatomsintheDCPDMSelectrondonorsisthechelatemodeduetotheDiBSmoleculeisaround3.1Å.ThelargespacerbetweentheshortdistancebetweenthecoordinatingOatoms,thetwooxygenatomsconfersenoughflexibilitytotheDiBSCMDMS−Mg2model,andtheDCPDMS−Mg2model,withdonor,sothatitcanadsorbontheMgCl2(110)surfaceanadsorptionenergyofaround−32kcal/mol.Forboththroughvariouscoordinationmodes,i.e.,monodentate,externaldonors,theadsorptionenergiesdecreaseintheorderchelate,andbridge(Figure4).Thechelatemode,alsocalledmonodentatemodeontheTiatom

4TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticleinsertionbehaviorofthepropylenemonomertotheTiactivesitewereinvestigatedsystematically.3.2.1.TheBareActiveSite.TheinsertionofpropylenefollowsthemodifiedCossee−Arlmanmechanism,whichisthecommonlyacceptedmechanismofolefincoordination56−58polymerization.Thismechanisminvolvestwosteps:(1)theolefinmoleculecoordinatestotheTi-alkylchain(theactivesite)toformaπ-complex;(2)then,theπ-complexundergoesinsertionviaafour-memberedtransitionstateassistedbyaremarkableα-agosticinteractiontoformanincreasedTi-alkylchain.TheinsertionofaprochiralpropylenemonomerintotheTi-alkylbondcanoccurviatwoways,1,2-insertion(alsocalledprimary)and2,1-insertion(alsocalledsecondary),withthere-andsi-enantiofaces.Therefore,therearefourpathwaysforthepropyleneinsertion:1,2-re,1,2-si,2,1-re,and2,1-si.Table2liststheπ-complexationenergy(ΔGπ),Figure6.FourpossiblepathwaysofpropyleneinsertionintothebareTi-iBugrowingchain(onlythereactionregionisshown).Table2.π-ComplexFormationEnergy(ΔGπ),theApparentActivationEnergy(ΔGA),andtheRelativeEnergyofaTransitionStatesonDifferentActiveSiteModelstheconformationassumedbythegrowingchainbefore/during37theformationofthenewC−Cbond.The(+)iBugrowinginsertiontypeΔGπΔGAΔΔGAchainwasonlyusedinthecaseof1,2-siinsertion,whiletheBare(−)iBugrowingchainwasusedinotherthreecases,to1,2-re−1.910.00.0minimizerepulsiveinteractionswiththemethylgroupofthe1,2-si−3.19.8−0.2monomer.ThemethylgroupatCβinthe(−)or(+)growing2,1-re−2.612.12.1chainswasonthefrontsideagainstcoordinatedpropylene.2,1-si−3.211.71.7Theinsertionwasassistedbytheα-agosticinteractionbetweenEBtheα-Hofthemethylenegroupandthetitaniumcenter.1,2-re−3.08.60.0Inthetransitionstate,oneCα−Hαbondwasstretchedwith1,2-si−4.010.01.4thecorrespondingCα−HαandTi−Hαbondlengthsof1.142,1-re−0.913.14.5and1.94Å,respectively.ThenewlyformedC−Cbondofthe2,1-si−3.110.31.7propylenemonomerinsertionintotheTi−CbondwasaroundDiBS2.30Å.1,2-re−4.67.80.0Therelativeenergy,representedasΔΔGA(Table2),isthe1,2-si−5.67.5−0.3energydifferencebetweenthetransitionstates(corresponding2,1-re−3.410.72.9‡to1,2-reinsertion).ΔGRegio,ameasureofregioselectivity,is2,1-si−5.59.31.5theenergydifferencebetweentheminimumof1,2-insertionCMDMS‡and2,1-insertion.ΔGStereo,ameasureofstereoselectivity,is1,2-re−4.08.40.0theenergydifferencebetween1,2-reinsertionand1,2-si1,2-si−4.78.70.3‡‡insertion.ThehighertheΔGRegioandtheΔGStereovalues,the2,1-re−3.310.11.7highertheregioselectivityandthestereoselectivity,respec-2,1-si−4.110.21.8‡tively.TheΔGStereovalueis0.2kcal/molindicatingthattheDCPDMSbareTiactivesiteontheMgCl2(110)surfaceisaspecificdue1,2-re−2.58.90.0totheinabilitytodistinguishthesi-andre-enantiofacesinthe1,2-si−4.010.21.3absenceofelectrondonors.2,1-re−2.611.52.6‡TheΔGRegiovalueis1.7kcal/mol,indicatingthatthebare2,1-si−3.210.81.9aTiactivesiteontheMgCl2(110)surfaceismoderatelyEnergiesareinkcal/mol.regioselectiveevenintheabsenceofelectrondonors,in9,52,59−61accordancewithothertheoreticalresults.Thus,1,2-theapparentactivationenergy(ΔGA),andtherelativeenergyinsertionoftenoccursduringthepropylenepolymerization.Inoftransitionstates.Theπ-complexformationenergyisintheaddition,after2,1-insertion,thesterichindranceofthemethylrangefrom−1.9to−3.2kcal/mol,whichindicatesthatthegroupontheα-Cofthegrowingpolymerchainwouldpreventcomplexationofthepropylenetothetitaniumcenterisstablethenextpropylenemonomerfromcoordinatingtotheactivethroughthefourconfigurations.TheΔGπvaluefor1,2-site.Both1,2-reinsertionand1,2-siinsertioncanoccurintheinsertionisslightlyhigherthanthatfor2,1-insertion,indicatingnonstereoselectiveTiactivesiteduringpolymerization,withthatthestericinterferencebetweenthemethylmoietyofthethepossibilityofthestereoerroroccurring.Therefore,itispropylenemonomerandthegrowingpolymerchainishigherimportanttointroducethethirdcomponenttocontrolthethantherepulsionbetweenthemethylgroupandtheMgCl2structureoftheactivesiteandincreasethestereoselectivityofsurface.theactivesite.Figure6showsthetransitionstatesofthefourinsertion3.2.2.TheActiveSitewithElectronDonors.Accordingtomodesofpropyleneinsertiononthebareactivesite.Corradinithecalculations,themonodentatemodeforEB(EB-Mg1)andproposedthetwochiralorientationsofthegrowingpolymerthechelatemodeforDiBS(DiBS-Mg2-C),CMDMSchainas(−)or(+)growingchains,whichdependedonlyon(CMDMS-Mg2),andDCPDMS(DCPDMS-Mg2)werethe8537https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

5TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticlestableadsorptionstructures.Thesemodelswereselectedinthissectiontoinvestigatetheeffectofelectrondonorsontheπ-complexationandinsertionofpropylenemonomerstotheTiactivesite.ThecalculatedGibbsfreeenergies(Table2)indicatethattheproperelectrondonorcanpromotetheactivityandstereoselectivityoftheTiactivesite.InthepresenceofanEBmoleculecoadsorbedatthenearestMg1atom,theΔGπvaluefor1,2-insertionslightlydecreasescomparedtothatforthebareactivesite,indicatingthattheelectrondonorstabilizedtheπ-complexthroughreinforcementintheelectrondensityoftheTiactivesiteviaO→Mg→Tielectron-donatingeffect.Nevertheless,inthecaseof2,1-reinsertion,theπ-complexationisnotfavoredowingtothesterichindrancebetweentheEBmoleculeandthemethylgroupofthemonomer.The1,2-reinsertionofpropyleneintotheTi−iBubondrequires8.6kcal/molofΔGA,being1.4kcal/mollowerthanthatintheabsenceofanelectrondonor.TheΔG‡valueincreasesfrom0.2to1.4kcal/mol,indicatingStereotheimprovementinstereoselectivityinthepresenceofEB,in62agreementwiththeexperimentalfindings.Thetransitionstatesforprimarypropyleneinsertion(1,2-reand1,2-si)aresketchedinFigure7.TheenhancedelectrondensityattheTiatompromotestheπ-complexationandtheactivationoftheCCdoublebondofthepropylenemonomerleadingtoaloweractivationenergy.Inthiscase,theactivesiteisstillregioselective.TheΔGπvalueswiththeDiBSmoleculearelowerthanthosewithoutandwithotherdonors,whichsuggeststheexceptionalstabilityofthediester-typeinternaldonorDiBStotheπ-complex.Furthermore,inthiscase,the1,2-insertiongivesthelowestΔGAvaluesamongallcases,whichindicatestheexcellentabilityofsuccinatetoincreasethecatalyticactivity.However,theactivationenergydifferencebetween1,2-reand1,2-siisonly0.3kcal/mol(Table2),slightlyhigherthanthesituationinthebareactivesite,indicatingthepoorabilitytodistinguishthesi-andre-enantiofacesinthepresenceFigure7.TopviewoftransitionstatesleadingtoprimarypropyleneoftheDiBSdonor.insertionintotheTi−iBubondinthecaseofEBandDiBS:(a)EB-Figure7illustratesthetransitionstatesforthe1,2-insertion1,2-re,(b)EB-1,2-si,(c)DiBS-1,2-re,and(d)DiBS-1,2-si.Colorcode:withtheDiBS.Apparently,thesterichindrancecausedbytheMgyellow,Clgreen,Tiviolet,Ored,Hwhite,Cofthedonorgray,Cofpropyleneorange,andCofthegrowingchainblue.isobutylgroupoftheDiBSdonoradsorbedbythechelatemodeissoweakthatthestereoselectivitycanbarelybepromoted.InanalogytotheEBdonor,theactivesiteretainsregioselectivityinthissituation.propyleneinsertionincreases,withaΔG‡valueof1.3StereoItiswell-knownthattheexternaldonorhasasignificantkcal/mol.TheDCPDMSexhibitsahigherΔG‡valuethanStereo63,64effectontheisotacticityofthefinalpolymerproduct.ThetheCMDMS;thissupportsthefactthatitcanpromotethePPmostlyusedalkoxysilane-typedonorCMDMSandDCPDMSproductionwithhigherisotacticity,whichisconsistentwithadsorbontheMgCl(110)surfacethroughthestablechelate652theexperimentalfindings.Furthermore,withprimarymode.FromtheenergydatashowninTable2,itisobservedpropyleneinsertionremainingfavoredforbothCMDMSandthatCMDMSstabilizestheπ-complexformationwiththeDCPDMS,theΔG‡valueisalwaysabove1.7kcal/mol.Regioadvantageofaround1kcal/mol.ThelowerΔGπvalueforThelargesterichindranceofthecyclopentylgroupinCMDMSascomparedtoDCPDMSrevealsthattheπ-complexDCPDMShasanimportantinfluenceontheresistancetocanbebetterstabilizedbythecyclohexylgroupascomparedtotheconfigurationwiththemethylgroupclosetothethecyclopentylgroup.ThelowΔG‡valueof0.3kcal/molStereocyclopentylgroupinthe1,2-insertion.ThepresenceofaalsoindicatesthattheenantiofacesareindistinguishableinthehighlyhinderedcyclopentylgroupinhibitstheinsertionofthecaseofCMDMS.si-enantiofaceinthe1,2-insertionandimprovesthestereo-Nevertheless,thelowestactivationenergyofCMDMS(8.4selectivityoftheactivesite.Figure8reportsthetransitionkcal/mol)islowerthanthatofDCPDMS(8.9kcal/mol).ThestatesforprimarypropyleneinsertionofCMDMSandresultsagreewellwiththecalculationsofalkoxysilane-typeDCPDMS.electrondonorsontheedgesitebyWondimagegnetal.,who3.3.TheRoleofAlEt2ClSpecies.TheAlR2Clmoleculeisobtainedthelowestactivationenergyof13.0kcal/molfortheactivationreagentortheproductreleasedbytheactivation43CMDMSand16.1kcal/molforDCPDMS.reaction,whichcanadsorbontheMgatomnearbytheTiConcerningthecaseofDCPDMSbindingtothesurfaceinactivesite.TheAlEt2Clmoleculewasselectedinthissectiontothevicinityneartheactivesite,thestereoselectivityofprimaryinvestigatetheimpactofthecopresenceofexternaldonorsand8538https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

6TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticlebenoticedthattheΔG‡values,theactivationenergyStereodifferencebetween1,2-reand1,2-siinsertion,increasesignificantlyinbothcasesofCMDMSandDCPDMStogetherwithAlEtCl.Inaddition,theΔG‡valuesincreaseslightly.2RegioInshort,thestereoselectivityandregioselectivitycanbeenhancedbytherestrictedstericenvironmentresultedfromthecopresenceofAlEt2Clandtheexternaldonor.AcomparisonoftheapparentactivationenergiesandΔG‡valuesfordifferentdonorcatalystsystemsisprovidedStereoinFigure9.ItisclearthattheactivityofthecatalystcanbeFigure9.BargraphforthecomparativestudyofapparentactivationenergiesandΔG‡valuesfordifferentdonorcatalystsystem.StereopromotedinthepresenceofdonorsandtheΔG‡valuesStereocanbeincreasedinthecaseofEBandDCPDMS.TheFigure8.Topviewoftransitionstatesleadingtoprimarypropylenecoadsorptionoftheelectrondonor,likeEBandDCPDMS,insertionintotheTi−iBubondinthecaseofCMDMSandconvertstheaspecificTiactivesiteintoanisospecificonebyDCPDMS:(a)CMDMS-1,2-re,(b)CMDMS-1,2-si,(c)DCPDMS-stericallycontrollingtheorientationofthegrowingchainatthe1,2-re,and(d)DCPDMS-1,2-si.Colorcode:Sipurple,andothersastransitionstate.mentionedabove.Inshort,theproperelectrondonorcoadsorbedonthetheAlEt2Clmoleculeontheπ-complexationandinsertionTiCl2iBu/MgCl2(110)surfacecanyieldamoderatelystereo-selectivesite.ThisfindingisinagreementwithDFTbehaviorofpropylenetotheTiactivesite.66,67calculationsofKumawatetal.andVankaetal.WithTheAlEt2ClmoleculecanbestronglyadsorbedontheproximityoftheTiactivesitetogetherwiththeexternaldonorregardtothecopresenceofAlEt2Clspeciesandtheexternaldonor,thestereoselectivitycanbepromotedbytheincreasedviatheCl−MgbondandAl−Clbond(FigureS1inthesterichindrancearoundtheTiactivesite.SupportingInformation).Therelatedenergydatafortheπ-Busicoetal.proposedathree-sitemodelforZiegler−NattacomplexationandinsertioneventsaresummarizedinTable3.Clearly,theexistenceoftheAlEtClspeciesdisfavorsthecatalystswherethebulkyligandL1,2(Clordonor)22+coordinatingtotheadjacentunsaturatedMgcorrespondsformationoftheπ-complexcomparedtoothercases.Itshould68totheisotacticpropagation.Correaetal.hadattemptedtorationalizetheinfluenceofelectrondonorsontheTiactivesiteTable3.π-ComplexFormationEnergy(ΔGπ),theApparentusingquadrantrepresentation,wheregrayorwhitequadrantsActivationEnergy(ΔGA),andtheRelativeEnergyof9representregionsstericallyoccupiedbythedonorsornot.InTransitionStatesontheTiActiveSitewiththeCopresenceathiswork,thebareTiactivesite(Scheme1a),theTiactivesiteofExternalDonorsandAlEt2ClSpecieswithoneadsorbeddonor(Scheme1b),andtheTiactivesiteinsertiontypeΔGπΔGAΔΔGAwithoneadsorbedexternaldonorandoneAlEt2ClmoleculeCMDMS+AlEtCl(Scheme1c)weresketchedinthequadrantrepresentationof21,2-re−1.19.90.0Scheme1.1,2-si−0.913.83.9FromScheme1a,itisobviousthatthe1,2-insertionchain2,1-re−2.212.12.2orientationtendstobeoppositetothemethylgroupof2,1-si−1.212.82.9propylenetoreducestericinterferencebetweenthegrowingDCPDMS+AlEt2Clpolymerchainandmonomer.Moreover,inthecaseof2,1-1,2-re−0.99.40.0insertion,thechainorientationisofnosensesincethemethyl1,2-si−1.912.02.6groupofpropylenedoesnotinterferewiththegrowingchain.2,1-re−0.312.63.2Themainstericrepulsionisbetweenthemethylmoietyand2,1-si−1.112.93.5theMgCl2surface.Afteradonorcoordinating,thestericregionaroundthemonomercanleadtoanincreaseintheenergyaEnergiesareinkcal/mol.differencebetweenre-andsi-enantiofaces,thusincreasingthe8539https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

7TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticleScheme1.QuadrantRepresentationof(a)BareTiActiveSite,(b)TiActiveSitewithOneAdsorbedDonor,and(c)TiActiveSitewithOneAdsorbedDonorandOneAlEt2ClMoleculestereoselectivityoftheTiactivesite,especiallyforthelargespeciesandexternaldonorscanincreaseboththestereo-DCPDMSmoleculeandmono-estertypeEBmolecule.selectivityandregioselectivity.ConsideringthecopresenceofAlEt2Clspeciesandexternaldonors,thesterichindranceofonepieceofregionaroundthe■ASSOCIATEDCONTENTmonomeroccupiedbytheAlEt2Clmoleculefurtherincreases*sıSupportingInformationtheenergydifferencebetweenre-andsi-enantiofaces.TheTheSupportingInformationisavailablefreeofchargeatactivationenergydataofthetransitionstate(Tables2and3)https://pubs.acs.org/doi/10.1021/acs.jpcc.0c11273.areinagreementwiththesefindings.Structureoftheco-presenceofCMDMSandAlEt2ClaroundtheTiactivesite;energiesofvariousconforma-4.CONCLUSIONStionalCMDMSandDCPDMS;andCartesiancoor-DFTcalculationshavebeenperformedtosystematicallydinatesofthestructures(PDF)investigatetheeffectofelectrondonorsontheactivesite.ThecoadsorptionperformanceofEB,DiBS,CMDMS,and■DCPDMSontheactivesiteisstudied.ThemostprobableAUTHORINFORMATIONdonorcoadsorptionstructuresareobtained,andtheeffectofCorrespondingAuthorsthedonorontheregio-andstereoselectivebehavioroftheZhenLiu−SchoolofChemicalEngineering,EastChinaactivesiteisdiscussed.UniversityofScienceandTechnology,Shanghai200237,Thepreferredcoadsorptionmodeofdiester-typeelectronChina;orcid.org/0000-0003-3103-4011;donorDiBSandalkoxysilane-typeelectrondonorCMDMSEmail:liuzhen@ecust.edu.cnandDCPDMSisthechelatemodeonthe4-coordinatedMg2BopingLiu−CollegeofMaterialsandEnergy,SouthChinasiteadjacenttotheTiactivesite,whereastheEBmoleculeisAgriculturalUniversity,Guangzhou510642,China;preferentialtocoordinateonthe5-coordinatedMg1siteEmail:boping@scau.edu.cnthroughthemonodentatemode.ThebareactivesiteAuthorsTiCl2iBu/MgCl2(110)isregioselectiveandnonstereoselectiveXingGuo−SchoolofChemicalEngineering,EastChinaintheabsenceofanelectrondonorduringpropyleneUniversityofScienceandTechnology,Shanghai200237,polymerization.Therearetworeasons:(i)thesterichindranceChinabetweenthemethylgroupofthepropylenemonomerandtheLiangCui−PolyolefinResearchDepartment,PetrochinaMgCl2surfacecontributestothehighapparentactivationPetrochemicalResearchInstitute,Beijing102206,Chinaenergyof2,1-insertion;thus,the1,2-insertionismoreYisenWang−PolyolefinResearchDepartment,Petrochinafavorable;(ii)theα-CH3ofthegrowingchainformedafterPetrochemicalResearchInstitute,Beijing102206,Chinathe2,1-insertionpreventsthefurtherπ-complexationandJianjunYi−PolyolefinResearchDepartment,Petrochinainsertionofpropylene.PetrochemicalResearchInstitute,Beijing102206,ChinaThepresenceofEB,DiBS,CMDMS,orDCPDMSaroundJingwenSun−SchoolofChemicalEngineering,EastChinatheTiactivesitepromotestheactivityandretainstheUniversityofScienceandTechnology,Shanghai200237,regioselectivity.ItisworthnotingthatthestereoselectivitycanChinabesignificantlyenhancedbythecoadsorptionofEBorDCPDMSneartheactivesite,whichcanbeexplainedfromCompletecontactinformationisavailableat:boththeelectronicandthestericaspects.Theelectron-https://pubs.acs.org/10.1021/acs.jpcc.0c11273donatingdonorsenrichingtheelectrondensityoftheTiatommakeitmorefacilefortheTiatomattackingtheCCdoubleNotesbond.ThesterichindrancecausedbythephenylgroupofEBTheauthorsdeclarenocompetingfinancialinterest.orthecyclopentylgroupofDCPDMSresultsinthecontinuingpropylenemonomerinsertionintothegrowingpolymerchain■ACKNOWLEDGMENTSinthesameconfiguration.TheintroductionofsuitableWethankthefinancialsupportoftheNationalNaturalScienceelectrondonorscouldenhancetheactivityandthestereo-FoundationofChina(21674036),ShanghaiPujiangProgramselectivityoftheactivesite.Finally,thecopresenceofAlEt2Cl(18PJ1402500),andtheOpenProjectofStateKeyLaboratory8540https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

8TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticleofChemicalEngineering(SKL-ChE-18C01)attheEastChinaDonorsforMgCl2-SupportedTiCl4TypePolypropyleneCatalystsUniversityofScienceandTechnology.andTheirMechanisticAspects,Part1.J.Mol.Catal.A:Chem.2007,273,211−217.■(17)Spitz,R.;Bobichon,C.;Guyot,A.SynthesisofPolypropyleneREFERENCESwithImprovedMagnesium-Dichloride-SupportedZiegler-NattaCata-(1)Ziegler,K.;Holzkamp,E.;Breil,H.;Martin,H.DasMülheimerlysts,IncludingSilaneCompoundsasExternalBases.Makromol.Normaldruck-Polyathylen-Verfahren.̈Angew.Chem.1955,67,541−Chem.1989,190,707−716.547.(18)Härkönen,M.;Seppälä,J.V.;Väänänen,T.Effectsofthe(2)Natta,G.;Pino,P.;Corradini,P.;Danusso,F.;Mantica,E.;StructureofExternalAlkoxySilaneDonorinHigh-ActivityZiegler-Mazzanti,G.;Moraglio,G.CrystallineHighPolymersofα-Olefins.J.NattaCatalystontheMicrostructureofPolypropylene.Stud.Surf.Sci.Am.Chem.Soc.1955,77,1708−1710.Catal.1990,56,87−105.(3)Pasquini,N.PolypropyleneHandbook.Product,technology,Market.(19)Hakim,S.;Nekoomanesh,M.;Shahrokhinia,A.TheEffectof2ed.Munich:Hanser,2005.(4)Bahri-Laleh,N.;Hanifpour,A.;Mirmohammadi,S.A.;Poater,MixedandIndividualSilaneExternalDonorsontheStereo-DefectA.;Nekoomanesh-Haghighi,M.;Talarico,G.;Cavallo,L.Computa-Distribution,ActiveSitesandPropertiesofPolypropyleneSynthe-tionalModelingofHeterogeneousZiegler-NattaCatalystsforOlefinssizedwithFourthGenerationZiegler-NattaCatalyst.Polym.Sci.,Ser.Polymerization.Prog.Polym.Sci.2018,84,89−114.A2015,57,573−580.(5)Kumawat,J.;Gupta,V.K.FundamentalAspectsof(20)Tu,S.T.;Lou,J.Q.;Fu,Z.S.;Fan,Z.Q.InfluencesofSilane/HeterogeneousZiegler-NattaOlefinPolymerizationCatalysis:AnEtherCompositeExternalDonorsonPropylenePolymerizationwithExperimentalandComputationalOverview.Polym.Chem.2020,11,MgCl2-SupportedZiegler-NattaCatalystinthePresenceofHydrogen.E-6107−6128.Polymers2011,11,DOI:10.1515/epoly.2011.11.1.550.(6)Busico,V.;Corradini,P.;DeMartino,L.;Proto,A.;Savino,V.;(21)Shimizu,F.;Pater,J.T.M.;VanSwaaij,W.P.M.;Weickert,G.Albizzati,E.PolymerizationofPropeneinthePresenceofMagnesiumKineticStudyofaHighlyActiveMgCl2-SupportedZiegler-NattaChloride-SupportedZiegler-NattaCatalysts,1.TheRoleofEthylCatalystinLiquidPoolPropylenePolymerization.II.TheInfluenceBenzoateas″Internal″and″External″Base.Makromol.Chem.1985,ofAlkylAluminumandAlkoxysilaneonCatalystActivationand186,1279−1288.Deactivation.J.Appl.Polym.Sci.2002,83,2669−2679.(7)Chadwick,J.C.;Morini,G.;Balbontin,G.;Camurati,I.;Heere,(22)Zhou,Q.;Zheng,T.;Li,H.;Li,Q.;Zhang,Y.;Zhang,L.;Hu,J.J.R.;Mingozzi,I.;Testoni,F.EffectsofInternalandExternalY.EffectsofSomeNewAlkoxysilaneExternalDonorsonPropyleneDonorsontheRegio-andStereoselectivityofActiveSpeciesinPolymerizationinMgCl2-SupportedZiegler-NattaCatalysis.Ind.Eng.MgCl2-SupportedCatalystsforPropenePolymerization.Macromol.Chem.Res.2014,53,17929−17936.Chem.Phys.2001,202,1995−2002.(23)Lou,J.Q.;Tu,S.T.;Fan,Z.Q.PolypropyleneChainStructure(8)Morini,G.;Albizzati,E.;Balbontin,G.;Mingozzi,I.;Sacchi,M.RegulationbyAlkoxysilaneandEtherTypeExternalDonorsinTiCl4/C.;Forlini,F.;Tritto,I.MicrostructureDistributionofPolypropy-DIBP/MgCl2-AlEt3Ziegler-NattaCatalyst.Iran.Polym.J.2010,19,lenesObtainedinthePresenceofTraditionalPhthalate/Silaneand927−936.NovelDietherDonors:AToolforUnderstandingtheRoleof(24)Barbe,C.;Cecchin,G.;Noristi,L.TheCatalyticSystemTi-̀ElectronDonorsinMgCl2-SupportedZiegler-NattaCatalysts.Macro-Complex/MgCl2.Adv.Polym.Sci.1987,81,1−81.molecules1996,29,5770−5776.(25)Chadwick,J.C.;Morini,G.;Balbontin,G.;Busico,V.;Talarico,(9)Correa,A.;Piemontesi,F.;Morini,G.;Cavallo,L.KeyElementsG.;Sudmeijer,O.AdvancesinPropenePolymerizationUsingintheStructureandFunctionRelationshipoftheMgCl2/TiCl4/LewisMagnesiumChloride-SupportedCatalysts.Macromol.Symp.2001,BaseZiegler-NattaCatalyticSystem.Macromolecules2007,40,9181−173,21−36.9189.(26)Cecchin,G.;Marchetti,E.;Baruzzi,G.OntheMechanismof(10)Song,B.G.;Ihm,S.K.TheRoleofTwoDifferentInternalPolypropeneGrowthoverMgCl2/TiCl4CatalystSystems.Macromol.Donors(Phthalateand1,3-Diether)ontheFormationofSurfaceChem.Phys.2001,202,1987−1994.StructureMgCl2-SupportedZiegler-NattaCatalystsandTheir(27)Jiang,B.;He,F.;Yang,P.;Zhang,Z.;Weng,Y.;Cheng,Z.;Fu,CatalyticPerformanceofPropylenePolymerization.J.Appl.Polym.Z.;Fan,Z.EnhancingStereoselectivityofPropylenePolymerizationSci.2014,131,131.withMgCl2-SupportedZiegler-NattaCatalystsbyElectronDonor:(11)Wen,X.;Ji,M.;Yi,Q.;Niu,H.;Dong,J.Y.MagnesiumStrongEffectsofTitaniumDispersionState.Catal.Commun.2019,ChlorideSupportedZiegler-NattaCatalystsContainingSuccinate121,38−42.InternalElectronDonorsforthePolymerizationofPropylene.J.Appl.(28)Weng,Y.;Jiang,B.;Fu,Z.;Fan,Z.MechanismofInternalandPolym.Sci.2010,118,1853−1858.ExternalElectronDonorEffectsonPropylenePolymerizationwith(12)Jiang,T.;Chen,W.;Zhao,F.;Liu,Y.X.NovelMgCl2-MgCl2-SupportedZiegler-NattaCatalyst:NewEvidencesBasedonSupportedCatalystsContainingSuccinateDonorsforPropyleneActiveCenterCounting.J.Appl.Polym.Sci.2018,135,46605.Polymerization.Chin.J.Chem.Eng.2005,13,604−607.(29)Zhang,B.;Zhang,L.;Fu,Z.;Fan,Z.EffectofInternalElectron(13)Toto,M.;Morini,G.;Guerra,G.;Corradini,P.;Cavallo,L.Influenceof1,3-DiethersontheStereospecificityofPropeneDonorontheActiveCenterDistributioninMgCl2-SupportedZiegler-NattaCatalyst.Catal.Commun.2015,69,147−149.PolymerizationbySupportedZiegler-NattaCatalysts.ATheoretical(30)Busico,V.;Cipullo,R.;Talarico,G.;Segre,A.L.;Chadwick,J.InvestigationonTheirAdsorptionon(110)and(100)LateralCutsofMgCl2Platelets.Macromolecules2000,33,1134−1140.C.NewEvidenceontheNatureoftheActiveSitesinHeterogenous(14)Credendino,R.;Pater,J.T.M.;Correa,A.;Morini,G.;Cavallo,Ziegler-NattaCatalystsforPropenePolymerization.MacromoleculesL.ThermodynamicsofFormationofUncoveredandDimethylEther-1997,30,4786−4790.CoveredMgClCrystallites.ConsequencesintheStructureof(31)Thushara,K.S.;Gnanakumar,E.S.;Mathew,R.;Jha,R.K.;2Ziegler-NattaHeterogeneousCatalysts.J.Phys.Chem.C2011,115,Ajithkumar,T.G.;Rajamohanan,P.R.;Sarma,K.;Padmanabhan,S.;13322−13328.Bhaduri,S.;Gopinath,C.S.TowardanUnderstandingofthe(15)Chadwick,J.C.;Morini,G.;Albizzati,E.;Balbontin,G.;MolecularLevelPropertiesofZiegler-NattaCatalystSupportwithMingozzi,I.;Christofori,A.;Sudmeijer,O.;VanKessel,G.M.M.andwithouttheInternalElectronDonor.J.Phys.Chem.C2011,115,AspectsofHydrogenActivationinPropenePolymerizationUsing1952−1960.MgCl2/TiCl4/DietherCatalysts.Macromol.Chem.Phys.1996,197,(32)Singh,G.;Kaur,S.;Makwana,U.;Patankar,R.B.;Gupta,V.K.2501−2510.InfluenceofInternalDonorsonthePerformanceandStructureof(16)Tanase,S.;Katayama,K.;Yabunouchi,N.;Sadashima,T.;MgCl2SupportedTitaniumCatalystsforPropylenePolymerization.Tomotsu,N.;Ishihara,N.DesignofNovelMalonatesasInternalMacromol.Chem.Phys.2009,210,69−76.8541https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

9TheJournalofPhysicalChemistryCpubs.acs.org/JPCCArticle(33)Andoni,A.;Chadwick,J.C.;Niemantsverdriet,H.J.W.;DefectiveMgCl2SurfacesandPropylenePolymerizationoverZiegler-Thüne,P.C.APreparationMethodforWell-DefinedCrystallitesofNattaCatalyst:ADFTStudy.Chin.J.Polym.Sci.2013,33,591−600.MgCl2-SupportedZiegler-NattaCatalystsandTheirObservationby(52)Taniike,T.;Terano,M.CoadsorptionModelforFirst-PrincipleAFMandSEM.Macromol.RapidCommun.2007,28,1466−1471.DescriptionofRolesofDonorsinHeterogeneousZiegler-Natta(34)Andoni,A.;Chadwick,J.;Niemantsverdriet,H.;Thune,P.ThePropylenePolymerization.J.Catal.2012,293,39−50.RoleofElectronDonorsonLateralSurfacesofMgCl2-Supported(53)Ponder,J.W.;Richards,F.M.AnEfficientNewton-LikeZiegler-NattaCatalysts:ObservationbyAFMandSEM.J.Catal.MethodforMolecularMechanicsEnergyMinimizationofLarge2008,257,81−86.Molecules.J.Comput.Chem.1987,8,1016−1024.(35)Monaco,G.;Toto,M.;Guerra,G.;Corradini,P.;Cavallo,L.(54)Stukalov,D.V.;Zakharov,V.A.;Zilberberg,I.L.AdsorptionGeometryandStabilityofTitaniumChlorideSpeciesAdsorbedonSpeciesofEthylBenzoateinMgCl2-SupportedZiegler-Nattathe(100)and(110)CutsoftheAFMandSEMSupportoftheCatalysts.ADensityFunctionalTheoryStudy.J.Phys.Chem.CHeterogeneousZiegler-NattaCatalysts.Macromolecules2000,33,2010,114,429−435.8953−8962.(55)Flisak,Z.;Ziegler,T.DFTStudyofEthyleneandPropylene(36)Corradini,P.;Guerra,G.ModelsfortheStereospecificityinCopolymerizationoveraHeterogeneousCatalystwithaCoordinatingLewisBase.Macromolecules2005,38,9865−9872.HomogeneousandHeterogeneousZiegler-NattaPolymerizations.(56)Arlman,E.J.;Cossee,P.Ziegler-NattaCatalysis.III.Prog.Polym.Sci.1991,16,239−257.StereospecificPolymerizationofPropenewiththeCatalystSystem(37)Corradini,P.;Guerra,G.;Cavallo,L.DoNewCenturyCatalystsUnraveltheMechanismofStereocontrolofOldZiegler-TiCl3-AlEt3.J.Catal.1964,3,99−104.(57)Cossee,P.Ziegler-NattaCatalysis,I.MechanismofPolymer-NattaCatalysts?Acc.Chem.Res.2004,37,231−241.izationofα-OlefinswithZiegler-NattaCatalysts.J.Catal.1964,3,(38)Piovano,A.;D’Amore,M.;Thushara,K.S.;Groppo,E.80−88.SpectroscopicEvidencesforTiCl4/DonorComplexesontheSurface(58)Brookhart,M.;Green,M.L.H.Carbon-Hydrogen-TransitionofMgCl2-SupportedZiegler-NattaCatalysts.J.Phys.Chem.C2018,MetalBonds.J.Organomet.Chem.1983,250,395−408.122,5615−5626.(59)Correa,A.;Credendino,R.;Pater,J.T.M.;Morini,G.;Cavallo,(39)Credendino,R.;Liguori,D.;Morini,G.;Cavallo,L.L.TheoreticalInvestigationofActiveSitesattheCornersofMgCl2InvestigatingPhthalateand1,3-DietherCoverageandDynamicsonCrystallitesinSupportedZiegler-NattaCatalysts.Macromoleculesthe(104)and(110)SurfacesofMgCl2-SupportedZiegler-Natta2012,45,3695−3701.Catalysts.J.Phys.Chem.C2014,118,8050−8058.(60)Lee,J.W.;Jo,W.H.ChemicalStructure-Stereospecificity(40)Credendino,R.;Pater,J.T.M.;Liguori,D.;Morini,G.;RelationshipofInternalDonorinHeterogeneousZiegler-NattaCavallo,L.InvestigatingAlkoxysilaneCoverageandDynamicsontheCatalystforPropylenePolymerizationbyDFTandMMCalculations.(104)and(110)SurfacesofMgCl2-SupportedZiegler-NattaJ.Organomet.Chem.2009,694,3076−3083.Catalysts.J.Phys.Chem.C2012,116,22980−22986.(61)Ratanasak,M.;Parasuk,V.RolesofMalonateDonoron(41)Kuklin,M.S.;Bazhenov,A.S.;Denifl,P.;Leinonen,T.;ActivityandStereoselectivityofZiegler-NattaCatalyzedPropyleneLinnolahti,M.;Pakkanen,T.A.StabilizationofMagnesiumPolymerization.J.Organomet.Chem.2015,775,6−11.DichlorideSurfaceDefectsbyMono-andBidentateDonors.Surf.(62)Liu,B.P.;Cheng,R.H.;Liu,Z.;Qiu,P.Y.;Zhang,S.L.;Sci.2015,635,5−10.Taniike,T.;Terano,M.;Tashino,K.;Fujita,T.Experimentaland(42)Kumawat,J.;Gupta,V.K.;Vanka,K.EffectofDonorsontheComputationalApproachesontheIsospecificRoleofMonoester-ActivationMechanisminZiegler-NattaCatalysis:AComputationalTypeInternalElectronDonorforTiCl4/MgCl2Ziegler-NattaStudy.ChemCatChem2016,8,1809−1818.Catalysts.Macromol.Symp.2007,260,42−48.(43)Wondimagegn,T.;Ziegler,T.TheRoleofExternal(63)Batt-Coutrot,D.;Wolf,V.;Malinge,J.;Saudemont,T.;Grison,AlkoxysilaneDonorsonStereoselectivityandMolecularWeightinC.;Coutrot,P.StudyofDimethoxysilacycloalkanesasExternalMgCl2-SupportedZiegler-NattaPropylenePolymerization:ADensityDonorsinZiegler-NattaStereospecificPropylenePolymerisation.FunctionalTheoryStudy.J.Phys.Chem.C2012,116,1027−1033.Polym.Bull.2005,54,377−385.(44)Khatri,V.;Sahoo,U.;Kaur,S.;Rani,R.;Singh,G.;Kapur,G.(64)Chirinos,J.;Fernández,J.;Pérez,D.;Rajmankina,T.;Parada,S.;Kashyap,H.K.ControlofZiegler-NattaCatalystActivitybytheA.EffectofAlkoxysilanesFormedinSituonthePropertiesofZiegler-StructuralDesignofAlkoxysilane-BasedExternalDonors.NewJ.NattaCatalystsforOlefinPolymerisation.J.Mol.Catal.A:Chem.Chem.2020,44,6845−6852.2005,231,123−127.(45)Credendino,R.;Liguori,D.;Fan,Z.;Morini,G.;Cavallo,L.(65)Shen,X.R.;Fu,Z.S.;Hu,J.;Wang,Q.;Fan,Z.Q.MechanismTowardaUnifiedModelExplainingHeterogeneousZiegler-NattaofPropylenePolymerizationwithMgCl2-SupportedZiegler-NattaCatalysis.ACSCatal.2015,5,5431−5435.CatalystsBasedonCountingofActiveCenters:TheRoleofExternal(46)Fallah,M.;Bahri-Laleh,N.;Didehban,K.;Poater,A.ElectronDonor.J.Phys.Chem.C2013,117,15174−15182.InteractionofCommonCocatalystsinZiegler-Natta-CatalyzedOlefin(66)Kumawat,J.;Trivedi,P.;Gupta,V.K.RoleofaMultidentatePolymerization.Appl.Organomet.Chem.2020,34,e5333.CarbonateDonorinMgCl2-SupportedZiegler-NattaOlefinPolymer-(47)Frisch,M.J.;Trucks,G.W.;Schlegel,H.B.;Scuseria,G.E.;izationCatalysis:AnExperimentalandComputationalApproach.J.Robb,M.A.;Cheeseman,J.R.;Scalmani,G.;Barone,V.;Mennucci,Phys.Chem.C2019,123,24501−24510.B.;Petersson,G.A.;etal.Gaussian09,RevisionD.01;GaussianInc.:(67)Vanka,K.;Singh,G.;Iyer,D.;Gupta,V.K.DFTStudyofLewisWallingford,CT,2009.BaseInteractionswiththeMgCl2SurfaceintheZiegler-NattaCatalyticSystem:ExpandingtheRoleoftheDonors.J.Phys.Chem.C(48)Lee,C.;Yang,W.;Parr,R.G.DevelopmentoftheCollesalvetti2010,114,15771−15781.Correlation-EnergyFormulaintoaFunctionaloftheElectron(68)Busico,V.;Cipullo,R.;Monaco,G.;Talarico,G.;Vacatello,M.;Density.Phys.Rev.B:Condens.MatterMater.Phys.1988,37,785−Chadwick,J.C.;Segre,A.L.;Sudmeijer,O.High-ResolutionC-13789.NMRConfigurationalAnalysisofPolypropyleneMadewithMgCl2-(49)Becke,A.D.Density-FunctionalThermochemistry.III.TheSupportedZiegler-NattaCatalysts.1.The″Model″SystemMgCl2/RoleofExactExchange.J.Chem.Phys.1993,98,5648−5652.(50)Zhao,Y.;Truhlar,D.G.ImprovedDescriptionofNuclearTiCl4-2,6-Dimethylpyridine/Al(C2H5)3.Macromolecules1999,32,4173−4182.MagneticResonanceChemicalShieldingConstantsUsingtheM06-LMeta-Generalized-Gradient-ApproximationDensityFunctional.J.Phys.Chem.A2008,112,6794−6799.(51)Cheng,R.H.;Luo,J.;Liu,Z.;Sun,J.W.;Huang,W.H.;Zhang,M.G.;Yi,J.J.;Liu,B.P.AdsorptionofTiCl4andElectronDonoron8542https://doi.org/10.1021/acs.jpcc.0c11273J.Phys.Chem.C2021,125,8533−8542

当前文档最多预览五页,下载文档查看全文

此文档下载收益归作者所有

当前文档最多预览五页,下载文档查看全文
温馨提示:
1. 部分包含数学公式或PPT动画的文件,查看预览时可能会显示错乱或异常,文件下载后无此问题,请放心下载。
2. 本文档由用户上传,版权归属用户,天天文库负责整理代发布。如果您对本文档版权有争议请及时联系客服。
3. 下载前请仔细阅读文档内容,确认文档内容符合您的需求后进行下载,若出现内容与标题不符可向本站投诉处理。
4. 下载文档时可能由于网络波动等原因无法下载或下载错误,付费完成后未能成功下载的用户请联系客服处理。
最近更新
更多
大家都在看
近期热门
关闭