Synthesis of isosorbide-based polycarbonates via melt polycondensation catalyzed by quaternary ammonium ionic liquids

Article abstract of DOI:10.1016/S1872-2067(17)62822-5

A series of quaternary ammonium ionic liquids (ILs) were synthesized and employed as catalysts for the production of poly(isosorbide carbonate) (PIC) from diphenyl carbonate and isosorbide via a melt polycondensation process. The relationship between the anions of the ILs and the catalytic activities was investigated, and the readily-prepared IL tetraethylammonium imidazolate (TEAI) was found to exhibit the highest catalytic activity. After optimizing the reaction conditions, a PIC with a weight-average molecular weight (M_w) of 25600 g/mol was obtained, in conjunction with an isosorbide conversion of 92%. As a means of modifying the molecular flexibility and thermal properties of the PIC, poly(aliphatic diol-co-isosorbide carbonate)s (PAIC)s were successfully synthesized, again using TEAI, and polymers with M_w values ranging from 29000 to 112000 g/mol were obtained. ¹³C NMR analyses determined that the PAIC specimens had random microstructures, while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from 50 to 115 °C. Thermogravimetric analyses found T_d-5% values ranging from 316 to 332 °C for these polymers. Based on these data, it is evident that the incorporation of linear or cyclohexane-based diol repeating units changed the thermal properties of the PIC.

Full text of DOI:10.1016/S1872-2067(17)62822-5

ChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917
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ꢀ ꢀ ꢀ
ꢀ ꢀ ꢀ ꢀ
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
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j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
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Article
Synthesisꢀofꢀisosorbide‐basedꢀpolycarbonatesꢀviaꢀmeltꢀ ꢀ
polycondensationꢀcatalyzedꢀbyꢀquaternaryꢀammoniumꢀionicꢀliquidsꢀ
a,b
b
b
b
a,#
b,
WeiꢀSunꢀ ,ꢀFeiꢀXuꢀ ,ꢀWeiguoꢀChengꢀ ,ꢀJianꢀSunꢀ ,ꢀGuoqingꢀNingꢀ ,ꢀSuojiangꢀZhangꢀ *
ꢀ
aꢀCollegeꢀofꢀChemistryꢀandꢀChemicalꢀEngineering,ꢀChinaꢀUniversityꢀofꢀPetroleum‐Beijing,ꢀBeijingꢀ102249,ꢀChinaꢀ
bꢀKeyꢀLaboratoryꢀofꢀGreenꢀProcessꢀandꢀEngineering,ꢀBeijingꢀKeyꢀLaboratoryꢀofꢀIonicꢀLiquidsꢀCleanꢀProcess,ꢀStateꢀKeyꢀLaboratoryꢀofꢀMultiphaseꢀComplexꢀ
Systems,ꢀInstituteꢀofꢀProcessꢀEngineering,ꢀChineseꢀAcademyꢀofꢀSciences,ꢀBeijingꢀ100190,ꢀChinaꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
Aꢀseriesꢀofꢀquaternaryꢀammoniumꢀionicꢀliquidsꢀ(ILs)ꢀwereꢀsynthesizedꢀandꢀemployedꢀasꢀcatalystsꢀ
forꢀtheꢀproductionꢀofꢀpoly(isosorbideꢀcarbonate)ꢀ(PIC)ꢀfromꢀdiphenylꢀcarbonateꢀandꢀisosorbideꢀviaꢀaꢀ
meltꢀ polycondensationꢀprocess.ꢀTheꢀ relationshipꢀbetweenꢀtheꢀ anionsꢀofꢀtheꢀILsꢀandꢀtheꢀcatalyticꢀ
activitiesꢀ wasꢀ investigated,ꢀ andꢀ theꢀ readily‐preparedꢀ ILꢀ tetraethylammoniumꢀ imidazolateꢀ (TEAI)ꢀ
wasꢀfoundꢀtoꢀexhibitꢀtheꢀhighestꢀcatalyticꢀactivity.ꢀAfterꢀoptimizingꢀtheꢀreactionꢀconditions,ꢀaꢀPICꢀ
Receivedꢀ27ꢀFebruaryꢀ2017ꢀ
Acceptedꢀ22ꢀMarchꢀ2017ꢀ
Publishedꢀ5ꢀMayꢀ2017ꢀ
withꢀaꢀweight‐averageꢀmolecularꢀweightꢀ(M )ꢀofꢀ25600ꢀg/molꢀwasꢀobtained,ꢀinꢀconjunctionꢀwithꢀanꢀ
isosorbideꢀconversionꢀofꢀ92%.ꢀAsꢀaꢀmeansꢀofꢀmodifyingꢀtheꢀmolecularꢀflexibilityꢀandꢀthermalꢀprop‐
ertiesꢀ ofꢀ theꢀ PIC,ꢀ poly(aliphaticꢀ diol‐co‐isosorbideꢀ carbonate)sꢀ (PAIC)sꢀ wereꢀ successfullyꢀ synthe‐
w
Keywords:ꢀ
Quaternaryꢀammoniumꢀionicꢀliquidꢀ
ꢀ
catalystꢀ
sized,ꢀagainꢀusingꢀTEAI,ꢀandꢀpolymersꢀwithꢀM ꢀvaluesꢀrangingꢀfromꢀ29000ꢀtoꢀ112000ꢀg/molꢀwereꢀ
w
Isosorbideꢀ
obtained.ꢀ 13Cꢀ NMRꢀ analysesꢀ determinedꢀ thatꢀ theꢀ PAICꢀ specimensꢀ hadꢀ randomꢀ microstructures,ꢀ
whileꢀdifferentialꢀscanningꢀcalorimetryꢀdemonstratedꢀthatꢀeachꢀofꢀtheꢀPAICsꢀwereꢀamorphousꢀandꢀ
hadꢀglassꢀtransitionꢀtemperaturesꢀrangingꢀfromꢀ50ꢀtoꢀ115ꢀ°C.ꢀThermogravimetricꢀanalysesꢀfoundꢀ
Polycarbonateꢀ
Meltꢀpolycondensationꢀ
Aliphaticꢀdiol
Td‐5%ꢀvaluesꢀrangingꢀfromꢀ316ꢀtoꢀ332ꢀ°Cꢀforꢀtheseꢀpolymers.ꢀBasedꢀonꢀtheseꢀdata,ꢀitꢀisꢀevidentꢀthatꢀ
theꢀincorporationꢀofꢀlinearꢀorꢀcyclohexane‐basedꢀdiolꢀrepeatingꢀunitsꢀchangedꢀtheꢀthermalꢀproper‐
tiesꢀofꢀtheꢀPIC.ꢀ
©ꢀ2017,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
1
.ꢀ ꢀ Introductionꢀ
edꢀtoꢀreplacingꢀthisꢀcompoundꢀwithꢀbio‐basedꢀmonomersꢀ[7–9].ꢀ
Isosorbideꢀ (1,4:3,6‐dianhydro‐D‐sorbidol)ꢀ isꢀ aꢀ well‐knownꢀ
potentialꢀreplacementꢀandꢀhasꢀtheꢀadvantagesꢀofꢀrigidity,ꢀchi‐
ralityꢀandꢀlowꢀtoxicityꢀ[10,11].ꢀMoreover,ꢀitꢀisꢀtheꢀonlyꢀcarbo‐
hydrate‐basedꢀ bicyclicꢀ monomerꢀ currentlyꢀ commerciallyꢀ
availableꢀ [12]ꢀ andꢀ soꢀ couldꢀ representꢀ anꢀ idealꢀ renewableꢀ
monomerꢀ forꢀ polymerꢀ synthesisꢀ[13].ꢀToꢀdate,ꢀisosorbideꢀhasꢀ
beenꢀwidelyꢀusedꢀforꢀtheꢀsynthesisꢀofꢀpolyestersꢀ[14–16],ꢀpoly‐
urethanesꢀ[17–19],ꢀpoly(ester‐co‐carbonate)sꢀ[20,21]ꢀandꢀPCsꢀ
Polycarbonateꢀ (PC)ꢀ isꢀ anꢀ excellentꢀ engineeringꢀ plasticꢀ
widelyꢀ usedꢀ forꢀ variousꢀ industrialꢀ applicationsꢀ owingꢀ toꢀ itsꢀ
uniqueꢀ properties,ꢀ includingꢀ highꢀ tensileꢀ strength,ꢀ impactꢀ re‐
sistance,ꢀ andꢀ goodꢀ transparencyꢀ [1,2].ꢀ Currently,ꢀ oneꢀ ofꢀ theꢀ
mostꢀimportantꢀandꢀwidelyꢀcommercializedꢀPCsꢀisꢀbisphenolꢀAꢀ
PCꢀ (BPAPC)ꢀ [3,4].ꢀ However,ꢀ bisphenolꢀ Aꢀ isꢀ aꢀ toxic,ꢀ petrole‐
um‐derivedꢀchemicalꢀ[5,6],ꢀandꢀsoꢀmuchꢀeffortꢀhasꢀbeenꢀdevot‐
*
ꢀ
ꢀCorrespondingꢀauthor.ꢀTel/Fax:ꢀ+86‐10‐82627080;ꢀE‐mail:ꢀsjzhang@home.ipe.ac.cnꢀ
Correspondingꢀauthor.ꢀFax:ꢀ+86‐10‐69724721;ꢀE‐mail:ꢀngq@cup.edu.cn
#
ThisꢀworkꢀwasꢀsupportedꢀbyꢀtheꢀNationalꢀKeyꢀProjectsꢀforꢀFundamentalꢀResearchꢀandꢀDevelopmentꢀofꢀChinaꢀ(2016YFB0600903),ꢀtheꢀNationalꢀNatu‐
ralꢀScienceꢀFoundationꢀofꢀChinaꢀ(91434107,ꢀ21506226,ꢀ21476245),ꢀandꢀtheꢀKeyꢀResearchꢀProgramꢀofꢀFrontierꢀSciencesꢀofꢀChineseꢀAcademyꢀofꢀSci‐
encesꢀ(QYZDY‐SSW‐JSC011).ꢀ
DOI:ꢀ10.1016/S1872‐2067(17)62822‐5ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ38,ꢀNo.ꢀ5,ꢀMayꢀ2017ꢀ ꢀ ꢀ

ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
909ꢀ
[
22–26].ꢀ Theꢀ large‐scaleꢀ productionꢀ ofꢀ poly(isosorbideꢀ car‐
purchasedꢀ fromꢀ Shanghaiꢀ Aladdinꢀ Bio‐chemꢀ Technology.ꢀ Theꢀ
remainingꢀreagents,ꢀ1,4‐butanediol,ꢀsilverꢀnitrate,ꢀbenzoicꢀacid,ꢀ
tetrabutylammoniumꢀhydroxideꢀsolutionꢀ(TBAH,ꢀ10%ꢀaqueousꢀ
solution),ꢀ aceticꢀ acid,ꢀ lacticꢀ acid,ꢀ isopropylꢀ alcohol,ꢀ dichloro‐
methane,ꢀ phosphorusꢀ oxide,ꢀ sodiumꢀ hydroxideꢀ andꢀ tetrae‐
thylammoniumꢀ bromide,ꢀ wereꢀ purchasedꢀ fromꢀ Sinopharmꢀ
ChemicalꢀReagent.ꢀ
bonate)ꢀ(PIC)ꢀviaꢀtheꢀmeltꢀpolycondensationꢀofꢀisosorbideꢀwithꢀ
dimethylꢀ carbonateꢀ (DMC)ꢀ orꢀ diphenylꢀ carbonateꢀ (DPC)ꢀ hasꢀ
alsoꢀbeenꢀinvestigatedꢀrecentlyꢀ[5,27–29].ꢀ
Isosorbideꢀhasꢀsomeꢀassociatedꢀchallengesꢀsuchꢀasꢀitsꢀhigherꢀ
hydrophilicꢀandꢀlowerꢀacidityꢀthanꢀthatꢀofꢀbisphenolꢀA,ꢀsoꢀtheꢀ
synthesisꢀofꢀPICꢀisꢀcomplexꢀ[10].ꢀTheꢀproductionꢀofꢀhighꢀmolec‐
ularꢀ weightꢀ PICꢀ requiresꢀ suitableꢀ catalystsꢀ forꢀ theꢀ meltꢀ poly‐
condensationꢀ processꢀ becauseꢀ ofꢀ theꢀ severeꢀ reactionꢀ condi‐
tions.ꢀToꢀdate,ꢀbasicꢀcatalystsꢀhaveꢀbeenꢀfoundꢀtoꢀbeꢀtheꢀmostꢀ
efficientꢀforꢀPICꢀsynthesisꢀ[5,30,31].ꢀLiꢀetꢀal.ꢀ[29]ꢀsynthesizedꢀaꢀ
PICꢀ byꢀ meltꢀ polycondensationꢀ ofꢀ isosorbideꢀ withꢀ DMC,ꢀ usingꢀ
lithiumꢀacetylacetonateꢀasꢀtheꢀcatalyst.ꢀShinꢀetꢀal.ꢀ[5]ꢀreportedꢀ
thatꢀ cesiumꢀ carbonateꢀ exhibitedꢀ superiorꢀ catalyticꢀ activityꢀ
duringꢀ theꢀ synthesisꢀ ofꢀ aꢀ PICꢀ byꢀ meltꢀ polycondensationꢀ withꢀ
DPC.ꢀAlthoughꢀinorganicꢀbasesꢀhaveꢀbeenꢀusedꢀforꢀthisꢀreactionꢀ
1HꢀNMRꢀspectraꢀwereꢀrecordedꢀinꢀdeuteratedꢀwaterꢀ(D
orꢀ deuteratedꢀ chloroformꢀ (CDCl )ꢀ withꢀ tetramethylsilaneꢀ
(TMS)ꢀasꢀtheꢀinternalꢀreference,ꢀusingꢀaꢀBrukerꢀAvanceꢀIII‐600ꢀ
spectrometer.ꢀGPCꢀwasꢀemployedꢀtoꢀestimateꢀtheꢀM ꢀandꢀpoly‐
dispersityꢀ(PDIꢀ=ꢀM /number‐averageꢀmolecularꢀweightꢀ(M )),ꢀ
2
O)ꢀ
3
w
w
n
usingꢀanꢀAgilentꢀPL‐GPCꢀ50ꢀsystemꢀatꢀ30ꢀ°C,ꢀwithꢀchloroformꢀasꢀ
theꢀ eluentꢀ (1.0ꢀ mL/min)ꢀ andꢀ generatingꢀ aꢀ calibrationꢀ curveꢀ
withꢀ polystyreneꢀ standards.ꢀ Theꢀ glassꢀ transitionꢀ temperatureꢀ
(T
g
)ꢀ ofꢀ eachꢀ polymerꢀ wasꢀ determinedꢀ byꢀ DSCꢀ usingꢀ aꢀ DSCꢀ 1ꢀ
ꢀ
[32,33],ꢀtheyꢀtendꢀtoꢀhaveꢀseveralꢀdrawbacks,ꢀincludingꢀunsat‐
instrumentꢀ(MettlerꢀToledo)ꢀatꢀaꢀheatingꢀrateꢀofꢀ10°C/minꢀwithꢀ
aꢀ nitrogenꢀ gasꢀ purgeꢀ (50ꢀ mL/min).ꢀ TGAꢀ dataꢀ wereꢀ acquiredꢀ
withꢀaꢀNETZSCHꢀSTA449F3ꢀthermogravimetricꢀanalyzerꢀunderꢀ
aꢀnitrogenꢀflowꢀrateꢀofꢀ20ꢀmL/min,ꢀheatingꢀ samplesꢀ(2.0‒3.0ꢀ
mg)ꢀfromꢀ50ꢀtoꢀ600ꢀ°Cꢀatꢀaꢀrateꢀofꢀ10ꢀ°C/min.ꢀFourierꢀtransformꢀ
infraredꢀ(FT‐IR)ꢀspectraꢀwereꢀrecordedꢀusingꢀaꢀThermoꢀNicoletꢀ
380ꢀspectrophotometer.ꢀ
isfactoryꢀ activities,ꢀ difficultꢀ separationsꢀ andꢀ branching.ꢀ Moreꢀ
recently,ꢀbasicꢀionicꢀliquidsꢀ(ILs)ꢀhaveꢀbeenꢀshownꢀtoꢀbeꢀprom‐
isingꢀ substitutesꢀ forꢀ inorganicꢀ basesꢀ [34–39].ꢀ Asꢀ anꢀ example,ꢀ
Parkꢀetꢀal.ꢀ[40]ꢀdemonstratedꢀtheꢀtransesterificationꢀofꢀethyleneꢀ
carbonateꢀ withꢀ methanolꢀ catalyzedꢀ byꢀ 1‐alkyl‐3‐ꢀ methylimid‐
azoliumꢀILs.ꢀ ꢀ
Inꢀrecentꢀyears,ꢀmanyꢀresearchersꢀhaveꢀpaidꢀmuchꢀattentionꢀ
toꢀtheꢀfunctionalizedꢀILsꢀbyꢀdesigningꢀtheꢀstructuresꢀofꢀcationsꢀ
orꢀanionsꢀaccordingꢀtoꢀpracticalꢀrequirementsꢀandꢀspecialꢀpur‐
posesꢀ[41–46].ꢀInꢀtheꢀpresentꢀwork,ꢀweꢀdesignedꢀandꢀsynthe‐
sizedꢀseveralꢀbasicꢀILsꢀandꢀinvestigatedꢀtheꢀeffectsꢀofꢀtheꢀanionsꢀ
onꢀtheꢀcatalyticꢀactivitiesꢀofꢀtheseꢀcompoundsꢀduringꢀtheꢀsyn‐
thesisꢀofꢀaꢀPICꢀviaꢀtheꢀmeltꢀpolycondensationꢀofꢀDPCꢀwithꢀiso‐
sorbide.ꢀTheꢀresultsꢀdemonstrateꢀthatꢀtheꢀreadilyꢀsynthesizedꢀ
ILꢀtetrabutylammoniumꢀimidazolateꢀ(TEAI)ꢀshowsꢀtheꢀhighestꢀ
activity,ꢀ producingꢀ aꢀ PICꢀ withꢀ aꢀ weight‐averageꢀ molecularꢀ
2.2.ꢀ ꢀ SynthesisꢀofꢀtheꢀquaternaryꢀammoniumꢀILꢀcatalystsꢀ
Theꢀ structuresꢀ ofꢀ theꢀ quaternaryꢀ ammoniumꢀ ILꢀ catalystsꢀ
synthesizedꢀ inꢀ thisꢀ studyꢀ areꢀ shownꢀ inꢀ Schemeꢀ 1,ꢀ andꢀ theꢀ
methodsꢀusedꢀtoꢀobtainꢀtheseꢀcompoundsꢀareꢀdescribedꢀbelow.ꢀ
Tetraethylammoniumꢀimidazolateꢀ(TEAI)ꢀwasꢀpreparedꢀus‐
ingꢀ aꢀ modificationꢀ ofꢀ aꢀ reportedꢀ procedureꢀ [47].ꢀ Imidazoleꢀ
(0.68ꢀg,ꢀ0.01ꢀmol)ꢀwasꢀaddedꢀtoꢀaꢀsolutionꢀofꢀNaOHꢀ(0.40ꢀg,ꢀ0.01ꢀ
mol)ꢀinꢀisopropylꢀalcoholꢀ(20ꢀmL)ꢀfollowedꢀbyꢀrefluxingꢀforꢀ30ꢀ
min.ꢀTetraethylammoniumꢀbromideꢀ(3.09ꢀg,ꢀ0.01ꢀmol)ꢀwasꢀthenꢀ
addedꢀatꢀroomꢀtemperatureꢀandꢀtheꢀresultingꢀmixtureꢀwasꢀre‐
fluxedꢀforꢀaꢀfurtherꢀ6ꢀh.ꢀTheꢀsolidꢀportionꢀofꢀtheꢀreactionꢀmix‐
tureꢀ wasꢀ removedꢀ byꢀ filtration,ꢀ theꢀ solventꢀ wasꢀ evaporatedꢀ
weightꢀ(M
)ꢀofꢀ25600ꢀg/molꢀinꢀconjunctionꢀwithꢀanꢀisosorbideꢀ
w
conversionꢀ ofꢀ 92%.ꢀ Inꢀ addition,ꢀ theꢀ molecularꢀ flexibilityꢀ andꢀ
thermalꢀ propertiesꢀ ofꢀ theꢀ PICꢀ wereꢀ modifiedꢀ byꢀ synthesizingꢀ
poly(aliphaticꢀ diolꢀ carbonate)sꢀ (PAIC)sꢀ throughꢀ combiningꢀ
isosorbideꢀ andꢀ variousꢀ aliphaticꢀ diolsꢀ (diethyleneꢀ glycol,ꢀ
underꢀvacuum,ꢀandꢀtheꢀresidueꢀ(TEAI)ꢀwasꢀdriedꢀatꢀ60ꢀ°Cꢀunderꢀ
1
1
,3‐propanediol,ꢀ 1,4‐butanediol,ꢀ 1,5‐pentanediol,ꢀ 1,6‐
ꢀ
hex‐
vacuumꢀoverꢀ2ꢀd.ꢀYield:ꢀ1.87ꢀgꢀ(95%);ꢀ HꢀNMRꢀ(600ꢀMHz,ꢀD
2
O,ꢀ
anediolꢀ andꢀ 1,4‐cyclohexanedimethanol).ꢀ Theꢀ PICꢀ andꢀ PAICsꢀ
298ꢀK):ꢀ7.62ꢀ(s,ꢀ1H),ꢀ7.00ꢀ(d,ꢀ2H),ꢀ3.08‒3.11ꢀ(q,ꢀ8H),ꢀ1.10‒1.13ꢀ
(m,ꢀ12H).ꢀ
1
13
samplesꢀwereꢀcharacterizedꢀbyꢀ HꢀNMRꢀandꢀ CꢀNMRꢀspectros‐
copy,ꢀgelꢀpermeationꢀchromatographyꢀ(GPC),ꢀdifferentialꢀscan‐
ningꢀcalorimetryꢀ(DSC)ꢀandꢀthermogravimetricꢀanalysisꢀ(TGA).ꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ tetraethylammoniumꢀ 1,2,4‐tria‐
ꢀ
zolateꢀ(TEAT)ꢀwasꢀtheꢀsameꢀasꢀthatꢀusedꢀtoꢀobtainꢀTEAI,ꢀexceptꢀ
thatꢀ 1,2,4‐triazoleꢀ (0.69ꢀ g,ꢀ 0.01ꢀ mol)ꢀ wasꢀ addedꢀ toꢀ theꢀ NaOHꢀ
ꢀ
1
2.ꢀ ꢀ Experimentalꢀ
solution.ꢀYield:ꢀ1.90ꢀgꢀ(96%); HꢀNMRꢀ(600ꢀMHz,ꢀD
2
O,ꢀ298ꢀK):ꢀ
8.02ꢀ(s,ꢀ2H),ꢀ3.10‒3.14ꢀ(q,ꢀ8H),ꢀ1.12‒1.15ꢀ(m,ꢀ12H).ꢀ
2.1.ꢀ ꢀ Materialsꢀandꢀmeasurementsꢀ
Isosorbideꢀ (98%)ꢀ wasꢀ purchasedꢀ fromꢀ Alfaꢀ Aesar,ꢀ whileꢀ
1
,4‐cyclohexanedimethanolꢀ (cis+trans,ꢀ 99%),ꢀ 1,5‐pentanediolꢀ
97%),ꢀ 1,6‐hexanediolꢀ (98%),ꢀ 1,3‐propanediolꢀ (≥99.5%),ꢀ im‐
idazoleꢀ (99%),ꢀ 1,2,4‐triazoleꢀ (99%),ꢀ sodiumꢀ dicyanamideꢀ
96%),ꢀ diethyleneꢀ glycolꢀ (>99%),ꢀ tetramethylammoniumꢀ hy‐
(
(
droxideꢀ solutionꢀ (TMAH,ꢀ 25%ꢀ aqueousꢀ solution),ꢀ tetrae‐
thylammoniumꢀhydroxideꢀsolutionꢀ(TEAH,ꢀ25%ꢀaqueousꢀsolu‐
tion),ꢀ tetrapropylammoniumꢀ hydroxideꢀ solutionꢀ (TPAH,ꢀ 1.0ꢀ
mol/Lꢀaqueousꢀsolution)ꢀandꢀdiphenylꢀcarbonateꢀ(99%)ꢀwereꢀ
Schemeꢀ1.ꢀStructuresꢀofꢀtheꢀquaternaryꢀammoniumꢀionicꢀliquidsꢀsyn‐
thesizedꢀinꢀthisꢀwork.ꢀ

910ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
Tetraethylammoniumꢀdicyanamideꢀ(TEAD)ꢀwasꢀsynthesizedꢀ
Tableꢀ1ꢀ
accordingꢀtoꢀreferenceꢀ[48].ꢀAꢀslightꢀexcessꢀofꢀfreshlyꢀpreparedꢀ
silverꢀ dicyanamideꢀ (1.90ꢀ g,ꢀ 0.011ꢀ mol,ꢀ obtainedꢀ byꢀ mixingꢀ
aqueousꢀ solutionsꢀ ofꢀ sodiumꢀ dicyanamideꢀ andꢀ silverꢀ nitrate,ꢀ
removingꢀtheꢀresultingꢀwhiteꢀsolidꢀbyꢀfiltrationꢀandꢀthenꢀwash‐
ingꢀ withꢀ water)ꢀ wasꢀ addedꢀ toꢀ anꢀ aqueousꢀ solutionꢀ ofꢀ tetrae‐
thylammoniumꢀbenzoateꢀ(TEAB,ꢀ3.09ꢀg,ꢀ0.01ꢀmol),ꢀafterꢀwhichꢀ
theꢀ mixtureꢀ wasꢀ heatedꢀ toꢀ 30‒40ꢀ °Cꢀ andꢀ stirredꢀ forꢀ approxi‐
ResultsꢀobtainedꢀfromꢀtheꢀmeltꢀpolycondensationꢀofꢀisosorbideꢀandꢀDPCꢀ
usingꢀvariousꢀcatalysts.ꢀ
wꢀaꢀ
Conversionꢀofꢀ
isosorbideꢀ(%)ꢀ
M
Sampleꢀ
Catalystꢀ
M
w
/M ꢀ
n
(g/mol)ꢀ
17200ꢀ
21300ꢀ
22300ꢀ
19700ꢀ
23600ꢀ
17500ꢀ
19400ꢀ
21800ꢀ
15500ꢀ
19600ꢀ
PIC‐1ꢀ
PIC‐2ꢀ
PIC‐3ꢀ
PIC‐4ꢀ
PIC‐5ꢀ
PIC‐6ꢀ
PIC‐7ꢀ
PIC‐8ꢀ
PIC‐9ꢀ
PIC‐10ꢀ
TMAHꢀ
TEAHꢀ
TPAHꢀ
TBAHꢀ
TEAIꢀ
TEADꢀ
TEATꢀ
TEABꢀ
TEALꢀ
TEAAꢀ
94ꢀ
95ꢀ
92ꢀ
96ꢀ
93ꢀ
74ꢀ
92ꢀ
81ꢀ
77ꢀ
77ꢀ
1.92ꢀ
1.98ꢀ
2.36ꢀ
1.94ꢀ
1.96ꢀ
2.08ꢀ
2.14ꢀ
2.33ꢀ
2.17ꢀ
2.09ꢀ
matelyꢀ 1ꢀ h.ꢀ Theꢀ solidꢀ precipitateꢀ (AgIꢀ andꢀ excessꢀ AgN(CN) )ꢀ
2
wasꢀfilteredꢀoffꢀandꢀtheꢀwaterꢀwasꢀremovedꢀbyꢀrotaryꢀevapora‐
tion.ꢀTheꢀresultingꢀmaterialꢀwasꢀdissolvedꢀinꢀdichloromethaneꢀ
toꢀprecipitateꢀaꢀsmallꢀquantityꢀofꢀsilverꢀdicyanamide,ꢀwhichꢀwasꢀ
filteredꢀoff,ꢀfollowingꢀwhichꢀtheꢀfiltrateꢀwasꢀevaporatedꢀtoꢀdry‐
ness.ꢀTheꢀTEADꢀwasꢀthenꢀdriedꢀunderꢀvacuumꢀoverꢀ2ꢀd.ꢀYield:ꢀ
Reactionꢀ conditions:ꢀ isosorbideꢀ (0.03ꢀ mol),ꢀ DPCꢀ (0.03ꢀ mol),ꢀ catalystꢀ
1
(1.50ꢀ×ꢀ10–5ꢀmol),ꢀ98ꢀ°C,ꢀ5ꢀhꢀ(firstꢀstep),ꢀ230ꢀ°C,ꢀ5ꢀhꢀ(secondꢀstep).ꢀ
1
.90ꢀ gꢀ (97%);ꢀ Hꢀ NMRꢀ (600ꢀ MHz,ꢀ D
2
O,ꢀ 298ꢀ K):ꢀ 3.25‒3.28ꢀ (q,ꢀ
a
ꢀ
ꢀ
DeterminedꢀbyꢀGPCꢀinꢀchloroformꢀ(1.0ꢀmL/min)ꢀatꢀ30 °Cꢀwithꢀpoly‐
8H),ꢀ1.26‒1.29ꢀ(m,ꢀ12H).ꢀ
styreneꢀstandards.ꢀ
ꢀ
Tetraethylammoniumꢀ lactateꢀ (TEAL)ꢀ wasꢀ synthesizedꢀ byꢀ
theꢀ acid‐baseꢀ neutralizationꢀ method.ꢀ Lacticꢀ acidꢀ (0.90ꢀ g,ꢀ 0.01ꢀ
mol)ꢀwasꢀaddedꢀdropwiseꢀtoꢀaꢀ100ꢀmLꢀsingle‐neckedꢀflaskꢀcon‐
tainingꢀTEAHꢀ(1.47ꢀg,ꢀ0.01ꢀmol),ꢀafterꢀwhichꢀtheꢀmixtureꢀwasꢀ
stirredꢀforꢀapproximatelyꢀ5ꢀhꢀatꢀroomꢀtemperature.ꢀFollowingꢀ
this,ꢀwaterꢀwasꢀremovedꢀbyꢀrotaryꢀevaporationꢀandꢀtheꢀsampleꢀ
stirrer,ꢀ nitrogenꢀ inlet,ꢀ refluxꢀ condenser,ꢀ thermometerꢀ andꢀ
feedingꢀ funnel.ꢀ Duringꢀ theꢀ transesterificationꢀ stage,ꢀ theꢀ reac‐
ꢀ
tionꢀ mixtureꢀ wasꢀ heatedꢀ toꢀ 98 °C,ꢀ afterꢀ whichꢀ theꢀ catalystꢀ
–5
TMAHꢀ(0.014ꢀg,ꢀ1.50ꢀ×ꢀ10 ꢀmol)ꢀwasꢀinjectedꢀintoꢀtheꢀflaskꢀandꢀ
theꢀmixtureꢀstirredꢀcontinuouslyꢀforꢀ5ꢀh.ꢀTheꢀtemperatureꢀwasꢀ
1
wasꢀdriedꢀunderꢀvacuumꢀforꢀ2ꢀd.ꢀYield:ꢀ2.10ꢀgꢀ(96%);ꢀ HꢀNMRꢀ
ꢀ
(600ꢀ MHz,ꢀ 298ꢀ K):ꢀ 3.96‒3.99ꢀ (q,ꢀ 1H),ꢀ 3.13‒3.17ꢀ (q,ꢀ 8H),ꢀ
thenꢀ graduallyꢀ increasedꢀ toꢀ 180 °C,ꢀ whileꢀ theꢀ pressureꢀ wasꢀ
1
.21‒1.22ꢀ(d,ꢀ3H),ꢀ1.14‒1.17ꢀ(m,ꢀ12H).ꢀ
Tetraethylammoniumꢀ acetateꢀ (TEAA)ꢀ wasꢀ obtainedꢀ usingꢀ
graduallyꢀreducedꢀtoꢀ10ꢀkPaꢀandꢀmaintainedꢀatꢀthisꢀlevelꢀforꢀ10ꢀ
minꢀtoꢀcompletelyꢀremoveꢀtheꢀphenolꢀbyproductꢀasꢀwellꢀasꢀanyꢀ
unreactedꢀDPC.ꢀInꢀtheꢀpolycondensationꢀstage,ꢀaꢀhighꢀvacuumꢀ
(10ꢀ Pa)ꢀ wasꢀ appliedꢀ andꢀ theꢀ temperatureꢀ wasꢀ graduallyꢀ in‐
theꢀ sameꢀ methodꢀ employedꢀ toꢀ synthesizeꢀ TEAL,ꢀ exceptꢀ thatꢀ
aceticꢀacidꢀ(0.60ꢀg,ꢀ0.01ꢀmol)ꢀwasꢀadded.ꢀYield:ꢀ1.80ꢀgꢀ(95%);ꢀ Hꢀ
1
ꢀ
NMRꢀ(600ꢀMHz,ꢀD
.14‒1.17ꢀ(m,ꢀ12H).ꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ tetraethylammoniumꢀ benzoateꢀ
2
O,ꢀ 298ꢀK):ꢀ 3.13‒3.17ꢀ(q,ꢀ8H),ꢀ 1.80ꢀ(s,ꢀ 3H),ꢀ
creasedꢀtoꢀ240°Cꢀandꢀmaintainedꢀatꢀthatꢀlevelꢀforꢀ5ꢀh.ꢀTheꢀre‐
1
sultingꢀpolymerꢀwasꢀdissolvedꢀinꢀaꢀminimalꢀamountꢀofꢀchloro‐
formꢀ andꢀ thenꢀ precipitatedꢀ byꢀ additionꢀ toꢀ methanol.ꢀ Theꢀ PCꢀ
wasꢀrecoveredꢀbyꢀfiltrationꢀandꢀdriedꢀatꢀ80ꢀ°Cꢀunderꢀvacuumꢀ
overnight.ꢀTheꢀPICꢀsamplesꢀobtainedꢀbyꢀtheꢀmeltꢀpolyconden‐
sationꢀ ofꢀ isosorbideꢀ andꢀ DPCꢀ usingꢀ theꢀ variousꢀ catalystsꢀ areꢀ
referredꢀtoꢀhereinꢀasꢀPIC‐1ꢀtoꢀPIC‐10ꢀasꢀshownꢀinꢀTableꢀ1.ꢀPIC‐1,ꢀ
(TEAB)ꢀwasꢀtheꢀsameꢀasꢀthatꢀforꢀTEAL,ꢀexceptꢀthatꢀbenzoicꢀacidꢀ
1
(1.22ꢀg,ꢀ0.01ꢀmol)ꢀwasꢀadded.ꢀYield:ꢀ2.41ꢀgꢀ(96%);ꢀ HꢀNMRꢀ(600ꢀ
MHz,ꢀ D
2
O,ꢀ 298ꢀ K):ꢀ 7.79ꢀ (d,ꢀ 2H),ꢀ 7.47ꢀ (m,ꢀ 1H),ꢀ 7.40ꢀ (d,ꢀ 2H),ꢀ
3.09‒3.13ꢀ(q,ꢀ8H),ꢀ1.12‒1.15ꢀ(m,ꢀ12H).ꢀ
1HꢀNMRꢀ(600ꢀMHz,ꢀCDCl
(m,ꢀ 1H),ꢀ 4.87ꢀ (t,ꢀ 1H),ꢀ 5.06‒5.09ꢀ (m,ꢀ 2H);ꢀ 13C{ H}ꢀ NMRꢀ (150ꢀ
,ꢀ298ꢀK):ꢀ3.89‒4.06ꢀ(m,ꢀ4H),ꢀ4.50‒4.54ꢀ
3
1
2.3.ꢀ ꢀ Synthesisꢀofꢀhomopolycarbonatesꢀ ꢀ
MHz,ꢀ CDCl ,ꢀ 298ꢀ K):ꢀ 70.6,ꢀ 73.1,ꢀ 76.9,ꢀ 81.0,ꢀ 81.6,ꢀ 85.8,ꢀ 153.3,ꢀ
3
Isosorbide‐basedꢀhomopolycarbonatesꢀwereꢀsynthesizedꢀbyꢀ
153.6,ꢀ154.0.ꢀ
aꢀone‐potꢀmeltꢀpolycondensationꢀmethod,ꢀincludingꢀtransester‐
ificationꢀandꢀpolycondensationꢀ(Schemeꢀ2).ꢀAꢀtypicalꢀpolymer‐
izationꢀ procedureꢀ (sampleꢀ PIC‐1)ꢀ wasꢀ performedꢀ asꢀ follows.ꢀ
Underꢀaꢀnitrogenꢀatmosphere,ꢀisosorbideꢀ(4.38ꢀg,ꢀ0.03ꢀmol)ꢀandꢀ
DPCꢀ (6.43ꢀ g,ꢀ 0.03ꢀ mol)ꢀ wereꢀ transferredꢀ intoꢀ aꢀ 250ꢀ mLꢀ
three‐neckedꢀround‐bottomꢀflaskꢀequippedꢀwithꢀaꢀmechanicalꢀ
2.4.ꢀ ꢀ Synthesisꢀofꢀcopolycarbonatesꢀ
Theꢀ copolycarbonatesꢀ ofꢀ isosorbideꢀ andꢀ variousꢀ aliphaticꢀ
diolsꢀwereꢀalsoꢀsynthesizedꢀusingꢀaꢀone‐potꢀmeltꢀpolyconden‐
sationꢀ methodꢀ (Schemeꢀ 3).ꢀ Aꢀ typicalꢀ copolymerizationꢀ proce‐
HO
O
O
O C O
O
O
OH
(
1) Transesterification
Basic ILs
(2) Polycondensation
Basic ILs
O
OH
O
O
Isosorbide
Bulk, heat, 1 atm
O
Bulk, heat, high vacuum
O
O C
O
O C O
O
n
O
O
O
PIC
O
O
O C O
DPC
Schemeꢀ2.ꢀOne‐potꢀmeltꢀpolycondensationꢀofꢀisosorbideꢀandꢀDPC.ꢀ

ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
911ꢀ
Schemeꢀ3.ꢀOne‐potꢀmeltꢀpolycondensationꢀofꢀDPCꢀwithꢀisosorbideꢀandꢀaliphaticꢀdiols.ꢀ
dureꢀ (sampleꢀ PCIC)ꢀ wasꢀ carriedꢀ outꢀ asꢀ follows.ꢀ Inꢀ theꢀ trans‐
esterificationꢀ stage,ꢀ isosorbideꢀ (2.19ꢀ g,ꢀ 0.015ꢀ mol),ꢀ 1,4‐cyclo‐
hexanedimethanolꢀ (2.16ꢀ g,ꢀ 0.015ꢀ mol)ꢀ andꢀ DPCꢀ (6.43ꢀ g,ꢀ 0.03ꢀ
mol)ꢀ wereꢀ transferredꢀ intoꢀ aꢀ 250ꢀ mLꢀ three‐neckedꢀ
round‐bottomꢀflask.ꢀTheꢀtemperatureꢀwasꢀgraduallyꢀincreasedꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ PHICꢀ wasꢀ theꢀ sameꢀ asꢀ thatꢀ forꢀ
PCIC,ꢀexceptꢀthatꢀ1,6‐hexanediolꢀ(1.77ꢀg,ꢀ0.015ꢀmol)ꢀwasꢀadded.ꢀ
ꢀ
1Hꢀ NMRꢀ (600ꢀ MHz,ꢀ CDCl
,ꢀ 298ꢀ K):ꢀ 1.31‒1.47ꢀ (br,ꢀ 1.6H),ꢀ
3
1.60‒1.72ꢀ(br,ꢀ1.6H),ꢀ3.82‒4.08ꢀ(br,ꢀ4H),ꢀ4.08‒4.17ꢀ(br,ꢀ1.6H),ꢀ
4.47‒4.56ꢀ (br,ꢀ 1H),ꢀ 4.86ꢀ (t,ꢀ 1H),ꢀ 5.01–5.11ꢀ (br,ꢀ 2H).ꢀ 13C{ H}ꢀ
1
ꢀ
–5
toꢀ98 °CꢀandꢀtheꢀcatalystꢀTEAIꢀ(0.003ꢀg,ꢀ1.5×10 ꢀmol)ꢀwasꢀin‐
jectedꢀintoꢀtheꢀflaskꢀfollowedꢀbyꢀcontinuousꢀstirringꢀforꢀ5ꢀh.ꢀTheꢀ
remainingꢀ synthesisꢀ stepsꢀ wereꢀ theꢀ sameꢀ asꢀ thoseꢀ appliedꢀ inꢀ
theꢀ synthesisꢀ ofꢀ theꢀ homopolycarbonates.ꢀ Asꢀ aꢀ result,ꢀ aꢀ PAICꢀ
NMRꢀ(150ꢀMHz,ꢀCDCl ,ꢀ298ꢀK):ꢀ25.3,ꢀ28.5,ꢀ67.8,ꢀ68.4,ꢀ70.6,ꢀ73.1,ꢀ
3
73.3,ꢀ76.6,ꢀ77.3,ꢀ81.2,ꢀ81.6,ꢀ81.7,ꢀ85.8,ꢀ86.0,ꢀ153.9,ꢀ153.6,ꢀ153.0,ꢀ
154.3,ꢀ154.6,ꢀ155.3.ꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ PGICꢀ wasꢀ theꢀ sameꢀ asꢀ thatꢀ forꢀ
incorporatingꢀ 1,4‐cyclohexanedimethanolꢀ wasꢀ obtained,ꢀ re‐
PCIC,ꢀ exceptꢀ thatꢀ diethyleneꢀ glycolꢀ (1.59ꢀ g,ꢀ 0.015ꢀ mol)ꢀ wasꢀ
1
1
ferredꢀtoꢀhereinꢀasꢀPCIC.ꢀPCIC,ꢀ HꢀNMRꢀ(600ꢀMHz,ꢀCDCl
3
,ꢀ298ꢀ
3
added.ꢀ HꢀNMRꢀ(600ꢀMHz,ꢀCDCl ,ꢀ298ꢀK):ꢀ3.64‒3.76ꢀ(br,ꢀ4.4H),ꢀ
K):ꢀ 0.99‒1.08ꢀ (br,ꢀ 2.6H),ꢀ 1.37‒1.50ꢀ (br,ꢀ 2.6H),ꢀ 1.50‒1.72ꢀ (br,ꢀ
.9H),ꢀ 1.77‒1.91,ꢀ (br,ꢀ 3.9H),ꢀ 3.88‒4.13ꢀ (br,ꢀ 9.2H),ꢀ 4.52‒4.60ꢀ
3.92‒4.08ꢀ (br,ꢀ 4H),ꢀ 4.21‒4.34ꢀ (br,ꢀ 4.4H),ꢀ 4.46‒4.55ꢀ (br,ꢀ 1H),ꢀ
13
1
3
4.85ꢀ(t,ꢀ1H),ꢀ5.00‐5.11ꢀ(br,ꢀ2H).ꢀ C{ H}ꢀNMRꢀ(150ꢀMHz,ꢀCDCl ,ꢀ
3
13
1
(
br,ꢀ1H),ꢀ4.88ꢀ(br,ꢀ1H),ꢀ5.06‒5.12ꢀ(br,ꢀ2H);ꢀ C{ H}ꢀNMRꢀ(150ꢀ
MHz,ꢀCDCl ,ꢀ298ꢀK):ꢀ25.1,ꢀ28.6,ꢀ34.5,ꢀ37.1,ꢀ70.6,ꢀ71.1,ꢀ72.8,ꢀ73.3,ꢀ
6.7,ꢀ77.2,ꢀ81.0,ꢀ81.2,ꢀ81.5,ꢀ85.9,ꢀ85.7,ꢀ154.0,ꢀ153.6,ꢀ153.3,ꢀ154.4,ꢀ
298ꢀK):ꢀ66.8,ꢀ67.1,ꢀ67.2,ꢀ67.4,ꢀ70.5,ꢀ73.0,ꢀ73.2,ꢀ76.1,ꢀ77.3,ꢀ80.9,ꢀ
81.1,ꢀ81.4,ꢀ85.8,ꢀ85.9,ꢀ154.2,ꢀ153.6,ꢀ153.0,ꢀ154.2,ꢀ154.5,ꢀ155.1.ꢀ
3
7
1
54.7,ꢀ155.5.ꢀ
3.ꢀ ꢀ Resultsꢀandꢀdiscussionꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ PRICꢀ wasꢀ theꢀ sameꢀ asꢀ thatꢀ forꢀ
PCIC,ꢀexceptꢀthatꢀ1,3‐propanediolꢀ(1.14ꢀg,ꢀ0.015ꢀmol)ꢀwasꢀadd‐
3.1.ꢀ ꢀ Synthesisꢀandꢀcharacterizationꢀofꢀcatalystsꢀ ꢀ
1
3
ed.ꢀ Hꢀ NMRꢀ (600ꢀ MHz,ꢀ CDCl ,ꢀ 298ꢀ K):ꢀ 2.01‒2.13ꢀ (br,ꢀ 0.4H),ꢀ
3
4
2
8
.86‒4.08ꢀ (br,ꢀ 4H),ꢀ 4.11‒4.29ꢀ (br,ꢀ 0.8H),ꢀ 4.52‒4.58ꢀ (br,ꢀ 1H),ꢀ
Sixꢀ quaternaryꢀ ammoniumꢀ ILꢀ catalystsꢀ wereꢀ synthesizedꢀ
andꢀtheꢀstructuresꢀofꢀtheseꢀcompoundsꢀwereꢀdeterminedꢀbyꢀ Hꢀ
13
1
1
.89ꢀ(t,ꢀ1H),ꢀ5.06‒5.13ꢀ(br,ꢀ2H).ꢀ C{ H}ꢀNMRꢀ(150ꢀMHz,ꢀCDCl
3
,ꢀ
98ꢀK):ꢀ28.0,ꢀ64.3,ꢀ64.8,ꢀ70.6,ꢀ73.0,ꢀ73.1,ꢀ77.0,ꢀ77.2,ꢀ80.0,ꢀ81.2,ꢀ
1.5,ꢀ85.7,ꢀ85.8,ꢀ153.9,ꢀ153.5,ꢀ153.0,ꢀ154.1,ꢀ154.4,ꢀ155.1.ꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ PBICꢀ wasꢀ theꢀ sameꢀ asꢀ thatꢀ forꢀ
NMR.ꢀTheꢀresultingꢀspectraꢀagreedꢀwithꢀtheꢀanticipatedꢀchemi‐
calꢀstructuresꢀandꢀwithꢀdataꢀfromꢀaꢀpriorꢀstudy.ꢀTheꢀthermalꢀ
stabilityꢀ ofꢀ eachꢀ ofꢀ theꢀ synthesizedꢀ ILsꢀ wasꢀ alsoꢀ testedꢀ usingꢀ
TGAꢀ(Fig.ꢀ1),ꢀandꢀeachꢀofꢀtheseꢀcompoundsꢀexhibitedꢀexcellentꢀ
thermalꢀstability.ꢀ
PCIC,ꢀexceptꢀthatꢀ1,4‐butanediolꢀ(1.35ꢀg,ꢀ0.015ꢀmol)ꢀwasꢀadded.ꢀ
1Hꢀ NMRꢀ (600ꢀ MHz,ꢀ CDCl
,ꢀ 298ꢀ K):ꢀ 1.70‒1.91ꢀ (br,ꢀ 3.2H),ꢀ
.91‒4.10ꢀ (br,ꢀ 4H),ꢀ 4.12‒4.28ꢀ (br,ꢀ 3.2H),ꢀ 4.50‒4.61ꢀ (br,ꢀ 1H),ꢀ
3
3
4
2
8
13
1
.85ꢀ(t,ꢀ1H),ꢀ5.03‒5.13ꢀ(br,ꢀ2H).ꢀ C{ H}ꢀNMRꢀ(150ꢀMHz,ꢀCDCl
3
,ꢀ
3.2.ꢀ ꢀ Effectꢀofꢀcatalystsꢀ ꢀ
98ꢀK):ꢀ25.0,ꢀ67.3,ꢀ67.8,ꢀ70.6,ꢀ73.1,ꢀ73.3,ꢀ77.0,ꢀ77.2,ꢀ81.0,ꢀ81.2,ꢀ
1.6,ꢀ85.8,ꢀ86.0,ꢀ153.9,ꢀ153.6,ꢀ153.0,ꢀ154.2,ꢀ154.6,ꢀ155.2.ꢀ
Theꢀ syntheticꢀ methodꢀ forꢀ PPICꢀ wasꢀ theꢀ sameꢀ asꢀ thatꢀ forꢀ
Asꢀ noted,ꢀ theꢀ polymerizationꢀ ofꢀ isosorbideꢀ andꢀ DPCꢀ wasꢀ
performedꢀinꢀtheꢀpresenceꢀofꢀaꢀseriesꢀofꢀILsꢀbasedꢀonꢀquater‐


ꢀ
ꢀ
PCIC,ꢀexceptꢀthatꢀ1,5‐pentanediolꢀ(1.56ꢀg,ꢀ0.015ꢀmol)ꢀwasꢀadd‐
ed.ꢀ Hꢀ NMRꢀ (600ꢀ MHz,ꢀ CDCl
naryꢀammoniumꢀcationsꢀcombinedꢀwithꢀIm (imidazolate),ꢀTr




1
3
,ꢀ 298ꢀ K):ꢀ 1.40‒1.50ꢀ (br,ꢀ 1H),ꢀ
(1,2,4‐triazolate),ꢀ OH ,ꢀ OAc ,ꢀ PhCOO ,ꢀ N(CN)
2
ꢀ
orꢀ

1
.61‒1.74ꢀ (br,ꢀ 2H),ꢀ 3.82‒4.10ꢀ (br,ꢀ 4H),ꢀ 4.10‒4.20ꢀ (br,ꢀ 2H),ꢀ
CH
3
CHOHCOO ꢀ anionsꢀ (Tableꢀ 1).ꢀ Theꢀ effectsꢀ ofꢀ theseꢀ cationsꢀ
.46‒4.56ꢀ (br,ꢀ 1H),ꢀ 4.86ꢀ (t,ꢀ 1H),ꢀ 5.01–5.12ꢀ (br,ꢀ 2H).ꢀ 13C{ H}ꢀ
,ꢀ298ꢀK):ꢀ22.0,ꢀ28.4,ꢀ67.7,ꢀ68.2,ꢀ70.6,ꢀ73.1,ꢀ
3.3,ꢀ76.7,ꢀ77.3,ꢀ81.0,ꢀ81.2,ꢀ81.7,ꢀ85.8,ꢀ86.0,ꢀ153.9,ꢀ153.6,ꢀ153.0,ꢀ
54.3,ꢀ154.6,ꢀ155.3.ꢀ
1
andꢀanionsꢀonꢀtheꢀcatalyticꢀactivityꢀwereꢀinvestigatedꢀbyꢀcom‐
paringꢀ theꢀ M ꢀ valuesꢀ ofꢀ theꢀ resultingꢀ PIC.ꢀ Inꢀ theꢀ caseꢀ ofꢀ theꢀ
ammonium‐basedꢀ ILs,ꢀ theꢀ catalyticꢀ activityꢀ ofꢀ theꢀ anionsꢀ de‐
4
NMRꢀ(150ꢀMHz,ꢀCDCl
3
w
7
1






ꢀ
creasedꢀinꢀtheꢀorder:ꢀIm ꢀ>ꢀOH ꢀ>ꢀTr ꢀ>ꢀPhCOO >ꢀN(CN) ,ꢀOAc ,ꢀ
2

912ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
Tableꢀ2ꢀ
1
00
TEAT
pHꢀvaluesꢀofꢀtheꢀcatalysts.ꢀ
TEAL
Catalystꢀ
TMAHꢀ
TEAHꢀ
TPAHꢀ
TBAHꢀ
TEAIꢀ
pHꢀaꢀ
Catalystꢀ
TEADꢀ
TEATꢀ
TEABꢀ
TEALꢀ
TEAAꢀ
pHꢀaꢀ
ꢀ 7.39ꢀ
10.48ꢀ
ꢀ 7.98ꢀ
ꢀ 7.54ꢀ
ꢀ 6.62ꢀ
TEAA
TEAB
TEAD
TEAI
8
6
4
2
0
0
0
0
0
13.01ꢀ
13.00ꢀ
12.99ꢀ
12.90ꢀ
12.31ꢀ
aꢀ Determinedꢀ byꢀ pHꢀ meterꢀ atꢀ 25 °Cꢀ atꢀ aꢀcatalystꢀconcentrationꢀofꢀ0.1ꢀ
mol/L.ꢀ
ꢀ
ꢀ
fromꢀ 14800ꢀtoꢀ 23600ꢀ g/mol,ꢀasꢀ n(catalyst):n(isosorbide)ꢀ wasꢀ
increasedꢀfromꢀ1ꢀ×ꢀ10 ꢀtoꢀ5ꢀ×ꢀ10 ,ꢀandꢀthenꢀdeclinedꢀoverꢀtheꢀ
rangeꢀofꢀ5ꢀ×ꢀ10 ꢀtoꢀ1ꢀ×ꢀ10 .ꢀTheꢀconversionꢀvaluesꢀalsoꢀroseꢀ
1
00
200
300
400
500
600
–4
–4
o
Temperature ( C)
–4
–3
Fig.ꢀ1.ꢀTGAꢀtracesꢀofꢀtheꢀquaternaryꢀammoniumꢀILs.ꢀ
significantly,ꢀfromꢀ84%ꢀtoꢀ93%,ꢀasꢀtheꢀn(catalyst):n(isosorbide)ꢀ
ratioꢀwasꢀincreasedꢀfromꢀ1ꢀ×ꢀ10 ꢀtoꢀ5ꢀ×ꢀ10 ,ꢀalthoughꢀthereꢀ
–4
–4

–4
–3
CH
3
CHOHCOO .ꢀ Theseꢀ resultsꢀ implyꢀ thatꢀ theꢀ basicityꢀ ofꢀ theꢀ
wereꢀnoꢀfurtherꢀobviousꢀvariationsꢀinꢀtheꢀ5ꢀ×ꢀ10 ꢀtoꢀ1ꢀ×ꢀ10 ꢀ

–4
anionꢀ(withꢀtheꢀexceptionꢀofꢀIm ,ꢀTableꢀ2)ꢀisꢀanꢀimportantꢀfac‐
torꢀinꢀdeterminingꢀtheꢀcatalyticꢀactivityꢀofꢀtheꢀIL.ꢀHowever,ꢀalt‐
range.ꢀAꢀlowꢀn(catalyst):n(isosorbide),ꢀsuchꢀasꢀ1ꢀ×ꢀ10 ,ꢀresult‐
edꢀinꢀdifficultyꢀinꢀobtainingꢀtheꢀdesiredꢀpolymerizationꢀactivity,ꢀ


houghꢀIm ꢀisꢀaꢀweakerꢀbaseꢀthanꢀOH ,ꢀtheꢀcatalyticꢀactivityꢀofꢀitsꢀ
ILꢀwasꢀgreaterꢀ(Tableꢀ1ꢀandꢀTableꢀ2).ꢀTheꢀweaklyꢀnucleophilicꢀ
suchꢀthatꢀtheꢀM ꢀandꢀisosorbideꢀconversionꢀwereꢀlower.ꢀHow‐
w
–3
ever,ꢀratiosꢀaboveꢀ1ꢀ×ꢀ10 ꢀgaveꢀaꢀbrownishꢀPIC.ꢀTheseꢀresultsꢀ
demonstratedꢀ thatꢀ theꢀ optimumꢀ catalystꢀ amountꢀ forꢀ theꢀ PICꢀ



anions,ꢀ includingꢀ N(CN)
2
,ꢀ OAc ꢀ andꢀ CH CHOHCOO ,ꢀ alsoꢀ re‐
3
–4
sultedꢀinꢀlowerꢀactivitiesꢀforꢀthisꢀmeltꢀpolycondensationꢀreac‐
synthesisꢀwasꢀ5ꢀ×ꢀ10 .ꢀ

tionꢀ(PIC‐6,ꢀ9ꢀandꢀ10,ꢀTableꢀ1).ꢀInꢀtheꢀcaseꢀofꢀtheꢀOH ꢀanion,ꢀtheꢀ
Theꢀ effectsꢀ ofꢀ polycondensationꢀ timeꢀ onꢀ theꢀ M ꢀ andꢀ iso‐
w
+
sorbideꢀ conversionꢀ wereꢀ investigatedꢀ atꢀ 230ꢀ °Cꢀ andꢀ aꢀ cata‐
(
Et) N ꢀ cationꢀ producedꢀ aꢀ higherꢀ catalyticꢀ activityꢀ thanꢀ theꢀ
4
–4
otherꢀcationsꢀ(Tableꢀ1,ꢀPIC‐14).ꢀAmongꢀtheseꢀcatalysts,ꢀTEAI,ꢀ
TEAHꢀandꢀTPAHꢀshowedꢀtheꢀhighestꢀcatalyticꢀactivities.ꢀSimilarꢀ
isosorbideꢀconversionsꢀwereꢀachievedꢀusingꢀallꢀthreeꢀofꢀtheseꢀ
catalysts,ꢀbutꢀtheꢀPIC‐3ꢀhadꢀaꢀhigherꢀPDI.ꢀAsꢀwell,ꢀevenꢀthoughꢀ
theꢀPDIꢀvaluesꢀofꢀtheꢀPIC‐2ꢀandꢀPIC‐5ꢀwereꢀalmostꢀtheꢀsame,ꢀtheꢀ
lyst‐to‐isosorbideꢀ ratioꢀ ofꢀ 5ꢀ ×ꢀ 10 ꢀ (Fig.ꢀ2(b)).ꢀTheꢀM ꢀvaluesꢀ
w
increasedꢀsignificantlyꢀasꢀtheꢀpolycondensationꢀtimeꢀwasꢀpro‐
longedꢀfromꢀ3ꢀtoꢀ5ꢀh,ꢀandꢀthenꢀdecreasedꢀoverꢀtheꢀrangeꢀofꢀ5ꢀtoꢀ
7ꢀh.ꢀTheꢀchangeꢀinꢀtheꢀisosorbideꢀconversionꢀwasꢀnotꢀsignificantꢀ
betweenꢀ3ꢀandꢀ7ꢀhꢀowingꢀtoꢀtheꢀexcellentꢀthermalꢀstabilityꢀofꢀ
theꢀPIC.ꢀHowever,ꢀoverlyꢀlongꢀtimeꢀspansꢀcanꢀleadꢀtoꢀdegrada‐
tionꢀ ofꢀ theꢀ PICꢀ atꢀ highꢀ temperatures,ꢀ suchꢀ thatꢀ aꢀ brownishꢀ
productꢀ wasꢀobtainedꢀ followingꢀ 7ꢀh.ꢀTheseꢀ dataꢀindicateꢀthatꢀ
theꢀidealꢀpolycondensationꢀtimeꢀforꢀtheꢀPICꢀwasꢀ5ꢀh.ꢀ
M ꢀofꢀtheꢀPIC‐5ꢀwasꢀhigher,ꢀandꢀsoꢀweꢀselectedꢀTEAIꢀasꢀtheꢀbestꢀ
w
catalyst.ꢀ Theꢀ dataꢀ inꢀ Tableꢀ 1ꢀ alsoꢀ demonstrateꢀ thatꢀ theꢀ iso‐
sorbideꢀ conversionꢀ rangedꢀ fromꢀ 74%ꢀ toꢀ 96%,ꢀ whichꢀ canꢀ beꢀ
attributedꢀtoꢀtheꢀevaporationꢀofꢀsomeꢀofꢀtheꢀisosorbideꢀduringꢀ
theꢀ reactionꢀ process,ꢀ inꢀ keepingꢀ withꢀ previousꢀ reportsꢀ inꢀ theꢀ
literatureꢀ[49].ꢀTherefore,ꢀweꢀproposeꢀthatꢀtheꢀcatalyticꢀactivityꢀ
dependsꢀonꢀbothꢀtheꢀbasicityꢀofꢀtheꢀcatalystꢀandꢀtheꢀcoordinat‐
ingꢀstrengthꢀofꢀtheꢀanionꢀinꢀtheꢀILꢀ[50].ꢀ
Theꢀ dependenceꢀ ofꢀ M
w
ꢀ andꢀ isosorbideꢀ conversionꢀ onꢀ theꢀ
polycondensationꢀ temperatureꢀ wereꢀ alsoꢀ investigated,ꢀ atꢀ aꢀ
–4
catalyst‐to‐isosorbideꢀratioꢀofꢀ5ꢀ×ꢀ10 ꢀoverꢀ5ꢀhꢀ(Fig.ꢀ2(c)).ꢀTheꢀ
ꢀvaluesꢀwereꢀfoundꢀtoꢀincreaseꢀgraduallyꢀasꢀtheꢀtemperatureꢀ
M
w
wasꢀraisedꢀfromꢀ210ꢀtoꢀ240ꢀ°C,ꢀfollowedꢀbyꢀaꢀdeclineꢀbetweenꢀ
240ꢀandꢀ250ꢀ°C.ꢀTheꢀchangeꢀinꢀtheꢀisosorbideꢀconversionꢀwasꢀ
insignificantꢀfromꢀ210ꢀtoꢀ250ꢀ°C,ꢀagainꢀowingꢀtoꢀtheꢀsuperiorꢀ
thermalꢀ stabilityꢀofꢀtheꢀ PIC.ꢀBecauseꢀ theꢀ productꢀisꢀmoreꢀvis‐
cousꢀatꢀlowꢀtemperatures,ꢀelevatedꢀtemperaturesꢀareꢀnecessaryꢀ
forꢀ theꢀ polycondensation,ꢀ althoughꢀ theyꢀ canꢀ promoteꢀ unde‐
3
.3.ꢀ ꢀ Effectsꢀofꢀotherꢀreactionꢀparametersꢀ
AsꢀcanꢀbeꢀseenꢀfromꢀFig.ꢀ2(a),ꢀtheꢀcatalyst‐to‐isosorbideꢀra‐
tioꢀ hadꢀ aꢀ pronouncedꢀ effectꢀ onꢀ theꢀ reactionꢀ asꢀ itꢀ wasꢀ variedꢀ
fromꢀ1ꢀ×ꢀ10 ꢀtoꢀ1ꢀ×ꢀ10 .ꢀTheꢀM ꢀvaluesꢀincreasedꢀsignificantly,ꢀ
–4
–3
w
1
9
00
5
100
100
95
90
85
80
75
2
2
2
1
1
1
1
4
2
0
8
6
4
2
(a)
24
(b)
26
24
22
20
18
16
14
(c)
9
9
8
5
0
5
2
2
1
2
0
8
90
8
8
5
0
80
75
70
16
75
10 11
1
4
0
1
2
3
4
5
6
7
8
9
210
220
230
240
250
o
3
4
5
6
7

4
n(Catalyst):n(Isosorbide) (10 )
Polycondensation time (h)
Polycondensation temperature ( C)
Fig.ꢀ2.ꢀEffectꢀofꢀtheꢀcatalyst‐to‐isosorbideꢀratioꢀ(a),ꢀpolycondensationꢀtimeꢀ(b)ꢀandꢀpolycondensationꢀtemperatureꢀ(c)ꢀonꢀM ꢀandꢀisosorbideꢀconver‐
w
sion.ꢀ

ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
913ꢀ
a
(a)
O
OH
(b)
6
O
C
H2
C
d
H2
C
O
C
5
4
6
1
O
C
b
O
O
3
O
O
O
O 
c
5
O
3
O
O
b
a
4
O

O
C
O
O
O
2
O
C
O
O
1
1+6
2
n
d
c
b
a
5+2
d
1
+6
4
.40 4.35 4.30 4.25
3
a+b
c
4
CDCl
3
d
c
7.4
7.2
7.0
5+2
3
4
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
7.2
6.4
5.6
4.8
4.0
3.2
2.4
1.6
Chemical shift (ppm)
Chemical shift (ppm)
1
Fig.ꢀ3.ꢀ HꢀNMRꢀspectraꢀofꢀPIC‐1ꢀ(a)ꢀandꢀPCICꢀ(b).ꢀ
siredꢀsideꢀreactions,ꢀresultingꢀinꢀaꢀbrownꢀcolorꢀandꢀcrosslink‐
ing.ꢀ Theꢀ resultsꢀ showꢀ thatꢀ theꢀ optimumꢀ polycondensationꢀ
temperatureꢀforꢀtheꢀPICꢀwasꢀ240ꢀ°C.ꢀ
lyꢀtheꢀcarbonylꢀcarbonsꢀthatꢀareꢀsensitiveꢀtoꢀsequenceꢀeffectsꢀatꢀ
theꢀ dyadꢀ level.ꢀ Theꢀ sixꢀ differentꢀ carbonylꢀ carbonꢀ signalsꢀ areꢀ
denotedꢀ hereinꢀ asꢀ AA,ꢀ AIsꢀ (orꢀ IsA)ꢀ andꢀ IsIsꢀ respectively,ꢀ asꢀ
shownꢀinꢀFig.ꢀ5(b).ꢀTheꢀdyadꢀcontentsꢀwereꢀcalculatedꢀbyꢀinte‐
grationꢀofꢀtheꢀpeaksꢀincludedꢀinꢀtheseꢀsignals.ꢀBasedꢀonꢀtheseꢀ
3.4.ꢀ ꢀ SynthesisꢀandꢀstructureꢀcharacterizationꢀofꢀPICꢀandꢀPAICsꢀ
values,ꢀ theꢀ number‐averageꢀ sequenceꢀ lengthꢀ (L )ꢀandꢀtheꢀde‐
n
TheꢀchemicalꢀstructuresꢀofꢀtheꢀPIC‐1ꢀandꢀPAICsꢀspecimensꢀ
wereꢀ determinedꢀ byꢀ Hꢀ NMRꢀ spectroscopy,ꢀ andꢀ theꢀ Hꢀ NMRꢀ
spectraꢀ ofꢀ theꢀ PIC‐1ꢀ andꢀ PCICꢀ areꢀ presentedꢀ inꢀ Fig.ꢀ 3.ꢀ Inꢀ Fig.ꢀ
greeꢀofꢀrandomnessꢀ (B)ꢀ wereꢀ calculatedꢀ accordingꢀ toꢀ theꢀ fol‐
lowingꢀequationsꢀ[51].ꢀ
1
1
LnACꢀ=ꢀ(fAC/IsCꢀ+ꢀ2ꢀfAC/AC)ꢀ/ꢀfAC/IsCꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (1)ꢀ
3
(a),ꢀtheꢀtwoꢀmultipletꢀsignalsꢀbetweenꢀ4.28ꢀandꢀ4.40ꢀppmꢀareꢀ
attributedꢀtoꢀterminalꢀisosorbideꢀgroupsꢀandꢀtheꢀtwoꢀsingletsꢀatꢀ
.09ꢀandꢀ7.43ꢀppmꢀareꢀassignedꢀtoꢀterminalꢀphenylꢀcarbonateꢀ
L
nIsCꢀ=ꢀ(fAC/IsCꢀ+ꢀ2ꢀfIsC/IsC)ꢀ/ꢀfAC/IsCꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (2)ꢀ
Bꢀ=ꢀ1ꢀ/ꢀLnACꢀ+ꢀ1ꢀ/ꢀLnIsCꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (3)ꢀ
7
Here,ꢀfAC/AC,ꢀfAC/IsCꢀandꢀfIsC/IsCꢀrepresentꢀtheꢀmolarꢀfractionsꢀofꢀ
theꢀ dyads,ꢀ calculatedꢀ fromꢀ theꢀ integralꢀ intensitiesꢀ ofꢀ theꢀ car‐
bonylꢀcarbonꢀsignalsꢀfromꢀtheꢀAA,ꢀAIsꢀ(orꢀIsA),ꢀandꢀIsIsꢀdyads,ꢀ
respectively,ꢀ andꢀ LnACꢀ andꢀ LnIsCꢀ areꢀ theꢀ numberꢀ averageꢀ se‐
quenceꢀlengthsꢀofꢀtheꢀaliphaticꢀcarbonateꢀ(AC)ꢀandꢀisosorbideꢀ
carbonateꢀ(IsC)ꢀunits,ꢀrespectively.ꢀTheꢀresultsꢀareꢀsummarizedꢀ
inꢀTableꢀ4.ꢀAsꢀshown,ꢀallꢀtheꢀBꢀvaluesꢀofꢀtheꢀPAICsꢀwereꢀdiffer‐
entꢀ fromꢀoneꢀ another,ꢀdemonstratingꢀthatꢀisosorbideꢀhadꢀ dif‐
ferentꢀlevelsꢀofꢀreactivityꢀwithꢀtheꢀvariousꢀaliphaticꢀdiols.ꢀThus,ꢀ
theꢀACꢀandꢀIsCꢀunitsꢀexhibitedꢀstatisticallyꢀrandomꢀdistributionꢀ
inꢀeachꢀofꢀtheꢀPAICs.ꢀ ꢀ
groups.ꢀ Theꢀ PAICsꢀ compositionsꢀ (Tableꢀ 3)ꢀ wereꢀ determinedꢀ
basedꢀ onꢀ theꢀ integrationꢀ valuesꢀ forꢀ peaksꢀ resultingꢀ fromꢀ theꢀ
repeatingꢀunits,ꢀandꢀtheꢀcalculatedꢀcompositionsꢀwereꢀfoundꢀtoꢀ
deviateꢀ fromꢀ theꢀ feedꢀ ratios.ꢀ Itꢀ isꢀ thereforeꢀ evidentꢀ thatꢀ theꢀ
hydroxylꢀgroupsꢀofꢀtheꢀdifferentꢀmonomersꢀhadꢀvaryingꢀlevelsꢀ
ofꢀreactivity,ꢀwithꢀtheꢀdiethyleneꢀglycolꢀandꢀ1,4‐
imethanolꢀbeingꢀtheꢀmostꢀactive.ꢀ
Theꢀ CꢀNMRꢀspectrumꢀofꢀtheꢀPIC‐1ꢀisꢀprovidedꢀinꢀFig.ꢀ4.ꢀAsꢀ
isosorbideꢀhasꢀtwoꢀdifferentꢀhydroxylꢀgroupsꢀ(exoꢀandꢀendo),ꢀ
theꢀspectrumꢀdisplaysꢀthreeꢀCꢀ=Oꢀsignalsꢀwithꢀintensityꢀratiosꢀofꢀ
ꢀ
cyclohexaned‐
13
1:2:1,ꢀ attributedꢀ toꢀ theꢀ endo‐endo,ꢀ endo‐exo,ꢀ exo‐endoꢀ andꢀ
exo‐exoꢀ linkedꢀ carbonateꢀ groups.ꢀ Thisꢀ randomꢀ sequenceꢀ wasꢀ
consistentꢀwithꢀtheꢀPICꢀstructureꢀreportedꢀbyꢀChattiꢀetꢀal.ꢀ[26].ꢀ
TheꢀmicrostructuresꢀofꢀtheꢀPAICꢀsamplesꢀwereꢀdeterminedꢀ
byꢀ Cꢀ NMRꢀ spectroscopy,ꢀandꢀtheꢀassignmentsꢀofꢀsignalsꢀareꢀ
summarizedꢀinꢀFig.ꢀ5.ꢀAsꢀshownꢀinꢀFig.ꢀ5(a),ꢀallꢀtheꢀpeaksꢀas‐
cribedꢀtoꢀtheꢀPCICꢀrepeatingꢀunitsꢀwereꢀwellꢀresolved,ꢀespecial‐
3.5.ꢀ ꢀ Thermalꢀpropertiesꢀ
TheꢀthermalꢀpropertiesꢀofꢀtheꢀPICꢀandꢀPAICꢀspecimensꢀwereꢀ
evaluatedꢀbyꢀDSCꢀandꢀTGA,ꢀwithꢀtheꢀresultsꢀshownꢀinꢀTableꢀ5.ꢀ
13
CDCl3
Tableꢀ3ꢀ
Resultsꢀ obtainedꢀ fromꢀ theꢀ copolycondensationꢀ ofꢀ isosorbideꢀ andꢀ ali‐
phaticꢀdiols.ꢀ
b
Sampleꢀ
PHICꢀ
PPICꢀ
PBICꢀ
PCICꢀ
Is/Diolꢀaꢀ Conversionꢀ ꢀ(%)ꢀ Mwꢀcꢀ(g/mol)ꢀ
M
w
/M ꢀ
n
1/0.4ꢀ
1/0.5ꢀ
1/0.8ꢀ
1/1.3ꢀ
1/1.1ꢀ
1/0.2ꢀ
82ꢀ
88ꢀ
87ꢀ
83ꢀ
89ꢀ
ꢀ 43700ꢀ
ꢀ 40400ꢀ
ꢀ 70500ꢀ
ꢀ 95300ꢀ
112000ꢀ
ꢀ 29000ꢀ
2.60ꢀ
2.32ꢀ
3.07ꢀ
2.87ꢀ
3.17ꢀ
3.47ꢀ
154.0
153.5
153.0
5
PGICꢀ
3
4
2
1
6
a
PRICꢀ
75ꢀ
1
a
ꢀ
Molarꢀcompositionꢀdeterminedꢀbyꢀ HꢀNMRꢀspectroscopy.ꢀ
Conversionꢀofꢀisosorbideꢀandꢀaliphaticꢀdiolsꢀtoꢀcopolycarbonates.ꢀ
cꢀDeterminedꢀbyꢀGPCꢀinꢀchloroformꢀ(1.0ꢀmL/min)ꢀatꢀ30°C,ꢀwithꢀpoly‐
155 150 145 140 135 130 125 120 115 110 105 100 95 90 85 80 75 70
b
ꢀ
Chemical shift (ppm)
ꢀ
13
Fig.ꢀ4.ꢀ CꢀNMRꢀspectrumꢀofꢀPIC‐1.ꢀ
styreneꢀstandards.ꢀ

914ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
(
a)
(b)
AA
AIs or IsA
IsIs
CDCl3
PIs
PIC
b
PP
RR
RIs or IsR
a
PGIC
PBIC
PPIC
PHIC
PCIC
IsIs
PP
37
36
35
c
IsP
PIs or IsP
8
0.96
80.92
IsIs
1
HIs or IsH
6
HH
e
155.5 155.0 154.5 154.0 153.5
3
5
4
2
d
150
135
120
105
90
75
60
45
30
155.6 155.2 154.8 154.4 154.0 153.6 153.2 152.8 152.4
Chemical shift (ppm)
Chemical shift (ppm)
13
Fig.ꢀ5.ꢀ(a)ꢀ CꢀNMRꢀspectrumꢀofꢀPCICꢀandꢀ(b)ꢀexpandedꢀspectraꢀofꢀtheꢀPAICsꢀinꢀtheꢀcarbonylꢀcarbonꢀregion.ꢀ
Allꢀsamplesꢀwereꢀfoundꢀtoꢀbeꢀinꢀanꢀamorphousꢀstate.ꢀFig.ꢀ6(a)ꢀ
presentsꢀtheꢀDSCꢀtracesꢀofꢀtheseꢀsamples.ꢀTheꢀPICꢀdisplayedꢀaꢀ
Schemeꢀ4,ꢀusingꢀaꢀhomopolycarbonateꢀasꢀanꢀexample.ꢀInitially,ꢀ
isosorbideꢀisꢀtransitionedꢀtoꢀanꢀalkoxideꢀanionꢀbyꢀtheꢀactionꢀofꢀ
theꢀfeedꢀcatalystꢀ(TEAI).ꢀSimultaneously,ꢀtheꢀDPCꢀisꢀpolarizedꢀ
byꢀ theꢀ tetraethylammoniumꢀ cationꢀ andꢀ thusꢀ undergoesꢀ reac‐
tionꢀ moreꢀ readilyꢀ (stepsꢀ 1ꢀ andꢀ 2).ꢀ Subsequently,ꢀ theꢀ anionsꢀ
generatedꢀinꢀtheꢀpreviousꢀstepꢀattackꢀtheꢀpolarizedꢀDPC,ꢀwhileꢀ
theꢀ phenolꢀ isꢀ removedꢀ underꢀ vacuumꢀ atꢀ aꢀ highꢀ temperatureꢀ
(stepꢀ 3).ꢀ Anꢀ intermediateꢀ isꢀ producedꢀ andꢀ theꢀ polymerꢀ chainꢀ
continuesꢀtoꢀgrowꢀuntilꢀtheꢀPICꢀisꢀobtainedꢀ(stepꢀ4).ꢀTheꢀpoly‐
condensationꢀ mechanismꢀ affordingꢀ theꢀ copolycarbonatesꢀ isꢀ
similar.ꢀHowever,ꢀbecauseꢀtheꢀhydroxylꢀgroupsꢀofꢀtheꢀvariousꢀ
aliphaticꢀ diolsꢀ haveꢀ differentꢀ reactivities,ꢀ irregularlyꢀ orderedꢀ
PAICꢀchainsꢀareꢀeventuallyꢀformed.ꢀTheꢀvalidityꢀofꢀthisꢀmecha‐
nismꢀwasꢀalsoꢀassessedꢀbasedꢀonꢀFT‐IRꢀdata.ꢀ
ꢀ
remarkablyꢀhighꢀT
g
ꢀofꢀ162°C.ꢀThisꢀsampleꢀwasꢀamorphousꢀasꢀaꢀ
resultꢀofꢀtheꢀunsymmetricalꢀcarbonateꢀlinkagesꢀbetweenꢀrepeatꢀ
units,ꢀ whileꢀ itsꢀ highꢀ T ꢀ wasꢀ dueꢀ toꢀ theꢀ rigidꢀ structureꢀ ofꢀ iso‐
g
sorbide.ꢀAꢀsingleꢀuniqueꢀT
g
ꢀwasꢀobservedꢀforꢀeachꢀofꢀtheꢀPAICsꢀ
ꢀ
throughoutꢀtheꢀ–100toꢀ200ꢀ°Cꢀrange,ꢀandꢀtheꢀT
g
ꢀvaluesꢀrangedꢀ
ꢀ
fromꢀ47ꢀtoꢀ115 °Cꢀdependingꢀonꢀtheꢀstructureꢀofꢀtheꢀcomono‐
mer.ꢀTheꢀT
toꢀlowerꢀtemperaturesꢀwithꢀincreasingꢀmethyleneꢀnumbersꢀinꢀ
theꢀlinearꢀaliphaticꢀ diolꢀunits.ꢀTheꢀPCICꢀdisplayedꢀaꢀhigherꢀT
g
ꢀofꢀtheꢀlinearꢀdiolꢀPAICsꢀwereꢀalsoꢀobservedꢀtoꢀshiftꢀ
g
ꢀ
thanꢀtheꢀPAICsꢀmadeꢀwithꢀlinearꢀdiolsꢀbecauseꢀofꢀtheꢀrigidꢀcy‐
clohexaneꢀgroups.ꢀ
TheꢀTGAꢀtracesꢀofꢀPICꢀandꢀPAICsꢀareꢀpresentedꢀinꢀFig.ꢀ6(b).ꢀ
Eachꢀ ofꢀ theseꢀ polymersꢀ displayedꢀ aꢀ single‐stepꢀ thermalꢀ de‐
ItꢀisꢀevidentꢀfromꢀtheꢀresultingꢀIRꢀspectraꢀ(Fig.ꢀ7(a)ꢀandꢀ(b))ꢀ
compositionꢀprocess.ꢀTableꢀ4ꢀsummarizesꢀtheꢀT ꢀvaluesꢀofꢀtheꢀ
d
thatꢀtheꢀcharacteristicꢀsharpꢀabsorbanceꢀofꢀtheꢀhydroxylꢀgroupsꢀ
ofꢀtheꢀisosorbideꢀshiftꢀfromꢀ3370ꢀtoꢀ3415ꢀcm ꢀafterꢀtheꢀaddi‐
–1
samplesꢀatꢀ5%ꢀweightꢀlossꢀ(Td‐5%)ꢀandꢀmaximumꢀdegradationꢀ
rateꢀ(Td‐max).ꢀTheꢀPCIC,ꢀincorporatingꢀcyclohexaneꢀgroups,ꢀdis‐
playedꢀaꢀhigherꢀTd‐5%ꢀandꢀTd‐maxꢀcomparedꢀtoꢀtheꢀPIC‐1,ꢀwhileꢀ
bothꢀtheꢀPIC‐1ꢀandꢀPCICꢀshowedꢀgreaterꢀthermalꢀstabilityꢀthanꢀ
theꢀ PAICsꢀ incorporatingꢀ linearꢀ diols.ꢀ Theꢀ thermalꢀ stabilityꢀ ofꢀ
eachꢀofꢀtheꢀlatterꢀsamplesꢀwasꢀimprovedꢀwithꢀincreasesꢀinꢀtheꢀ
quantityꢀofꢀmethyleneꢀgroupsꢀinꢀtheꢀlinearꢀaliphaticꢀdiolꢀunits.ꢀ
tionꢀ ofꢀ theꢀ TEAI.ꢀ Thisꢀ resultꢀ suggestsꢀ theꢀ formationꢀ ofꢀ NHꢀ

bondsꢀbetweenꢀtheꢀhydroxylꢀgroupsꢀandꢀtheꢀIm .ꢀInꢀaddition,ꢀ
theꢀpeakꢀdueꢀtoꢀtheꢀC=OꢀbondꢀonꢀtheꢀDPCꢀ(Fig.ꢀ7(c)ꢀandꢀ(d))ꢀ
–1
shiftsꢀonlyꢀfromꢀ1775ꢀtoꢀ1771ꢀcm ꢀuponꢀaddingꢀtheꢀTEAI,ꢀsug‐
+
gestingꢀthatꢀtheꢀ(Et)
4
N ꢀcationꢀhasꢀlittleꢀeffectꢀonꢀtheꢀC=Oꢀbond.ꢀ
However,ꢀitꢀisꢀimportantꢀtoꢀnoteꢀthatꢀtheꢀadditionꢀofꢀtheꢀTEAIꢀtoꢀ
theꢀmixtureꢀofꢀtheꢀDPCꢀandꢀisosorbideꢀ(Fig.ꢀ7(e))ꢀdoesꢀinduceꢀ
relativelyꢀlargeꢀvariationsꢀinꢀtheꢀcharacteristicꢀabsorbancesꢀofꢀ
theꢀtwoꢀrawꢀmaterials.ꢀThisꢀresultꢀindicatesꢀthatꢀtheꢀisosorbide,ꢀ
3.6.ꢀ ꢀ Aꢀdiscussionꢀofꢀtheꢀreactionꢀmechanismꢀ
Basedꢀonꢀpublishedꢀreportsꢀandꢀtheꢀresultsꢀofꢀthisꢀwork,ꢀaꢀ
probableꢀ catalyticꢀ cycleꢀ wasꢀ proposedꢀ andꢀ isꢀ depictedꢀ inꢀ
Tableꢀ5ꢀ
ThermalꢀpropertiesꢀofꢀtheꢀPICꢀandꢀPAICs.ꢀ
Tableꢀ4ꢀ
Sampleꢀ
PICꢀ
PCICꢀ
PRICꢀ
PGICꢀ
PBICꢀ
PPICꢀ
Tgꢀ
a
ꢀ(°C)ꢀ
Td‐5%ꢀ
b
ꢀ(°C)ꢀ
Td‐maxꢀ ꢀ(°C)ꢀ
b
TheꢀmicrostructuralꢀanalysesꢀofꢀPAICs.ꢀ
162ꢀ
115ꢀ
ꢀ 90ꢀ
ꢀ 80ꢀ
ꢀ 84ꢀ
ꢀ 50ꢀ
ꢀ 47ꢀ
329ꢀ
332ꢀ
316ꢀ
328ꢀ
319ꢀ
322ꢀ
323ꢀ
375ꢀ
373ꢀ
379ꢀ
374ꢀ
367ꢀ
369ꢀ
370ꢀ
a
Dyadsꢀ ꢀ(molꢀ%)ꢀ
PAICsꢀ
L
nACꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ
L
nIsC
ꢀ
Bꢀ
AAꢀ
AIs/IsAꢀ
IsIsꢀ
PHICꢀ
PPICꢀ
PBICꢀ
PCICꢀ
PGICꢀ
PRICꢀ
ꢀ 0.55ꢀ
ꢀ 8.20ꢀ
21.01ꢀ
51.28ꢀ
33.44ꢀ
ꢀ 4.76ꢀ
45.37ꢀ
51.52ꢀ
52.10ꢀ
42.56ꢀ
61.20ꢀ
23.60ꢀ
54.08ꢀ
40.28ꢀ
26.89ꢀ
ꢀ 6.15ꢀ
ꢀ 5.35ꢀ
71.65ꢀ
1.02ꢀ
1.32ꢀ
1.81ꢀ
3.41ꢀ
2.09ꢀ
1.40ꢀ
3.38ꢀ
2.56ꢀ
2.03ꢀ
1.29ꢀ
1.17ꢀ
7.07ꢀ
1.27ꢀ
1.15ꢀ
1.05ꢀ
1.07ꢀ
1.33ꢀ
0.85ꢀ
PHICꢀ
aꢀ
Determinedꢀ byꢀ DSCꢀ measurementsꢀ atꢀ aꢀ heatingꢀ rateꢀ ofꢀ 10ꢀ °C/minꢀ
(secondꢀheating).ꢀ
bꢀ
T
d‐5%ꢀandꢀTd‐maxꢀdeterminedꢀbyꢀTGAꢀunderꢀN ꢀatꢀaꢀheatingꢀrateꢀofꢀ10ꢀ
2
aꢀExperimentalꢀvaluesꢀobtainedꢀfromꢀ CꢀNMRꢀsignals.ꢀ
13
°C/min.ꢀ

ꢀ
WeiꢀSunꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ908–917ꢀ
915ꢀ
1
00
PIC
(b)
PIC
(
a)
PCIC
PRIC
PBIC
PGIC
PPIC
PHIC
PRIC
PGIC
PBIC
PPIC
PHIC
PCIC
-
-
-
-
-
-
-
-
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
8
6
4
2
0
0
0
0
0
-
40
0
40
80
120
160
280
300
320
340
360
380
400
420
o
o
Temperature ( C)
Temperature ( C)
Fig.ꢀ6.ꢀDSCꢀ(a)ꢀandꢀTGAꢀ(b)ꢀtracesꢀofꢀtheꢀPICꢀandꢀPAICs.ꢀ
100
a
80
60
40
20
0
b
3
370
c
3
415
d
1
775
e
1771
1757
3
421
3500
3000
2500
2000
1500
1000
1
Wavenumber (cm )
Schemeꢀ4.ꢀMechanismꢀforꢀtheꢀpolymerizationꢀofꢀPICꢀwithꢀTEAIꢀasꢀthe
catalyst.ꢀ
Fig.ꢀ7.ꢀIRꢀspectraꢀofꢀisosorbideꢀwithoutꢀTEAIꢀ(a),ꢀisosorbideꢀwithꢀTEAI
(b),ꢀDPCꢀwithoutꢀTEAIꢀ(c),ꢀDPCꢀwithꢀTEAIꢀ(d),ꢀandꢀisosorbideꢀandꢀDPCꢀ
withꢀTEAIꢀ(e).ꢀ
whichꢀ transitionsꢀ toꢀ anꢀ alkoxideꢀ anion,ꢀ attacksꢀ theꢀ polarizedꢀ
DPC.ꢀ Basedꢀ onꢀ theꢀ experimentalꢀ resultsꢀ andꢀ thisꢀ proposedꢀ
mechanism,ꢀ weꢀ believeꢀ thatꢀ ILsꢀ thatꢀ haveꢀ significantꢀ nucleo‐
philicꢀ andꢀ electrophilicꢀ propertiesꢀ areꢀ moreꢀ favorableꢀ toꢀ theꢀ
polymerization.ꢀ However,ꢀ overlyꢀ nucleophilicꢀ orꢀ electrophilicꢀ
propertiesꢀ willꢀ leadꢀ toꢀ reciprocalꢀ annihilation.ꢀ Therefore,ꢀ anꢀ
optimalꢀrangeꢀofꢀsuchꢀpropertiesꢀisꢀrequiredꢀtoꢀachieveꢀsuperi‐
orꢀperformanceꢀforꢀtheꢀdesiredꢀreaction.ꢀ
tionsꢀfromꢀtheꢀtheoreticalꢀvaluesꢀpredictedꢀfromꢀtheꢀfeedꢀratios.ꢀ
Theꢀ PCICꢀ sampleꢀ showedꢀ theꢀ highestꢀ T ꢀ andꢀ exhibitedꢀ betterꢀ
g
thermalꢀ stabilityꢀ thanꢀ theꢀ polymersꢀ madeꢀ usingꢀ linearꢀ diols.ꢀ
Theꢀdataꢀpresentedꢀhereinꢀdemonstrateꢀthatꢀcopolycarbonatesꢀ
suchꢀ asꢀ PCICꢀ haveꢀ theꢀ potentialꢀ toꢀ functionꢀ asꢀ high‐perfor‐
ꢀ
manceꢀpolymericꢀmaterials.ꢀ
Referencesꢀ
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.ꢀ ꢀ Conclusionsꢀ
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