简介：TiCl_4/MgCl_2/claycompoundcatalystwaspreparedbychemicalreaction.Exfoliatedpolypropylene(PP)/claynanocompositesweresynthesizedbyinsitupolymerizationwiththiscompoundcatalyst.Effectsofpolymerizationtemperature,polymerizationtime,propylenepressure,solventconsumptionandpre-treattimeofcatalystoncatalystactivityandcatalyticstereospecificitywerestudied.Underoptimalconditions,activityofthenano-compoundcatalystisabout88.3kg/(molTi·h).IsotacticityofPPobtainedinthenanocompositesisintherangeof89%-99%,anditsmeltingtemperatureisabout159℃.Theweight-averagemolecularweightofPPcanreach6.7×10~5-7.8×10~5,andthemolecularweightdistributionisbetween7.7and7.9.

简介：Polyolefinsthatbearachiralsidechain(typicallyanisobutylgroup)experienceaso-calledmacromolecularamplificationofchirality:thechiralside-chaininducesaslightpreferenceforeithertgortg-mainchainconformation.Thisslightconformationalbiasisamplifiedcooperativelyalongthechain,andresultsinpreferredchiralityofthemainchainhelicalconformations.Asaresult,thesepolymersdisplayaliquid-crystal(LC)phasebothinsolutionand,inthemeltasatransientphaseonthewaytocrystallization.Theexistenceoftwoprocesses(melt-LCandLC-crystaltransitions)resultsinunconventionalbehaviorsthatwerefirstanalyzedbyPinoandcollaboratorsbackin1975.Thesepolymersalsoofferameanstotestthestructuralconsequencesofrecentlyintroducedcrystallizationschemes.Theseschemespostulatetheformationofatransientliquid-crystalphaseasageneralschemeforpolymercrystallization.

简介：Two-dimensional(2D)materialshavebeendemonstratedtoexhibituniquepropertiesoriginatingfromits2Dnature.Inrecentyears,theconstructionof2Dmaterialshasbecomeatopicofgreatinterest.Thisarticlesummarizestherecentadvanceof2Dsupramolecularorganicframeworks(SOFs)whicharehomogeneouslyconstructedinsolutionphasethroughself-assemblyofrationallydesignedbuildingblocks.These2DSOFsaresolubleandstillmaintainstablenetworkstructuresinsolutions,whichexhibituniquenessnotonlyinstructuresbutalsoinproperties.Inthisconcisereview,theSOFs-relatedbackgroundisbrieflyintroducedfirstly,followedbyoutliningtheresearchprogressofsoluble2DSOFsfromtheperspectiveofmonomerdesign,assembly,andstructuralcharacterization.Thearticleendswithapersonaloutlookonthefuturedevelopmentofthisnewclassofsupramolecularpolymers.

简介：N-acetyl-D-methionine,NaAcandtheremainsofN-acetyl-L-methioninedramaticallyaffectthepurificationofL-methioninewhenpurifiedfromthemixtureofenzymaticallydeacylatedN-acetyl-DL-methionine,leadingtoalowyieldconventionally.Here,thispaperreportsasuccessfulseparationandpurificationofbothL-methionineandN-acetyl-D-methioninebyanHion-exchangecolumn.ThepH,L-Metconcentrationandtheratiobetweenthecontentofsodiumcationandtheion-exchangecapacitywereoptimizedtoobtainthemaximumyield.Experimentalresultsindicatethat,undertheoptimizedconditions,theyieldsofL-methionineandN-acetyl-D-methioninecanreachashighas85%and75%,respectively.

简介：TheexchangebehaviorsofWO4^2-,MoO4^2-,H2W12O46^6-andMo8O26^4-anionswithinmacroporousexchangeresin(D290)phaseshavebeenstudied.Thevaluesofdiffusionconstant(B),innerdiffusioncoefficient(D^-),retartedtime(τd)half-exchange-period(t1/2),andactivationenergy(ΔE）werefoundfromthekineticanalyses.AnewmethodtoseparateW(VI)andMo(VI)fromeachotherwasalsosuggested.

简介：Gasphasereductionofcarbonmonoxidetoformaldehydeandethylenewasfoundinelectrochemicalcellwithaninorganicionexchangerα-Zr(HPO4)2·H2Ousedassolidproton-conductingelectrolyteatroomtemperatureandatmosphericpressure.ThetypeandamountoftheelectroreductionofCOdependonthedifferentmetalelectrodesandcurrentdensities,whichgivesalankbetweenheterogeneouscatalysisandelectrochemistry.

简介：Kineticsofchloride/sulfate,chloride/nitrateandnitrate/sulfateforwardexchangesandreverseexchangesatsolutionconcentrationsof1N,0.2Nand0.02Non201×7strongbaseanionexchangeresin,respectively,havebeenexaminedat25℃.Itisfoundthattheforwardandthereverseexchangeratesofthetwogivenionsatlowsolutionconcentration,respectively,underidenticalconditionscanbecontrolledbydifferentmechanisms,whilethoseathighsolutionconcentrationareallcontrolledbyparticlediffusion.Theternaryexchangeratesofsulfate/(chloride+nitrate)andnitrate/(chloride+sulfate)havealsobeenexamined.

简介：Dithia-monoaza18-Crown-6anditsimmobilizationproduct,silica-bound1,7-dithia-4-aza-10,13,16-trioxa-cyclooctadecaneviaaspacerofthreecarbonatoms,anditsplatinumcomplexhavebeensynthesized.Itisfoundthattheplatinumcomplexisanefficienthydrosilylationcatalystforolefins.TheXPSdataoftheplatinumcomplexarereported.

简介：Newmodelcompound1H,1′H-Bis（benz-Δ^4-imidazoline)2,2′-spiro-titaniumdichloridewaspreparedandthestructureofthecompoundwasdeterminedby1R,MSandelementaryanalysis.

简介：Inthispaperstudyonthepropertyandmechanismofadsorptingrheniumfromaqueoushydrochloricacidbyusingmethylphosphorousaciddimythylheptylesterlevextrelresin(CL-P350)isreported.Theeffectsoftime,acidity,concentrationofrhenium,andtemperatureontheadsorptionofrheniumwereinvestigated.ThemechanismofadsorptingrheniumwasdiscussedbychemicalanalyticandIRmethod,anddynamicadscrptionandelutionwerestudied.Experimentalresultsshowthattheadsorptionequilibrationisreachedin4min,thedistributioncoefficient(D)ofRe(Ⅶ）increaseswithincreaseofconcentrationofHClandreachesmaximum3.0-4.0moL/LHCl.ReO4^-istakenupbyionassociationmechanismandcanbedescribedbyLangmuirequationoftheequilibriumstate.ThethermodynamicparametersintheadsorptionprocessofReO4^-havebeendeterminedtobe:ΔH=-29KJ/moL,ΔG=-25KJ/moLandΔS=-13.5J/moLrespectively.Thesaturationadsorptioncapacityofrheniumis19.2mg/gwhenthesolutioncontaining0.372g/LReand3.0mol/LHClwaspassedthroughtheresincolumn.Therecoverypercentageofrheniumis98.4%whiledistilledwaterwasusedasaneluent.

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简介：Opticallyactive(R)-(+)-2,2’-bis(2-trifluoro-4-aminophenoxy)-1,1’-binaphthylwaspreparedfrom1,1’-bi-2-naphthol.Theopticallyactivearomaticpolyimidewasalsosuccessfullysynthesized.Thisnewpolymerhasgoodsolubility,thermalstabilityetc.Itsspecificrotationwasfoundtobe+174°,anditschiropticalpropertywasalsostudied.