学科分类
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29 个结果
  • 简介:Polystyrenemacromonomerswithdifferentmolecularweightwerepreparedbyradicalpolymerizationofstyrene(St)inbenzeneusingβ-methacryloxylethyl2-N,N-diethyldithiocarbamylacetate(MAEDCA)asamonomer-iniferter.Characterizationofthemacromonomerby~1H-NMRshowedthattheendgroupswereα-methacrylyoxylethyloxycarbonyl-methylandω-(N,N-diethyldithiocarbamyl).Themacromonomerwasdifficulttohomopolymerize,butitwaseasilycopolymerizedwithmethylmethacrylate(MMA)initiatedbyAIBNtoformgraftcopolymers(PMMA-g-PSt)withPStbranchesrandomlydistributedalongthePMMAbackbone.CopolymerizationreactionandthestructureofthegraftcopolymerswerestronglyaffectedbyM_nandconcentrationofthemacromonomer.ThecompositionandM_nofthepurifiedgraftcopolymerweredeterminedby~1H-NMRandGPCanalysis.

  • 标签: Monomer-iniferter Photoiniferter MACROMONOMER Living radical POLYMERIZATION
  • 简介:AnewkindofpolysiloxanecontainingN,N’-bis(diphenylsilyl)tetraphenylcyclodisilazanewaspreparedbyanionicnon-equilibriumpolymerizationwitha"seedsolution"asinitiator.Themonomer,N,N’-bis(hydroxydiphenylsilyl)-tetraphenyl-cyclodisilazane(BHPTPC),wassynthesizedviathehydrolysisofN,N’-bis(chlorodiphenylsilyl)tetraphenyl-cyclodisilazane(BCPTPC).AnewmethodforthepreparationofBCPTPCisalsoreportedherewithhighyieldandsimplermanipulation.ThesynthesizedpolysiloxanecontainingN,N’-bis(diphenylsilyl)tetraphenylcyclodisilazanewascharacterizedby1H-NMR,29Si-NMR,gelpermeationchromatography(GPC)andintrinsicviscosity.

  • 标签: POLYSILOXANE N N’-Bis(diphenylsilyl)tetraphenylcyclodisilazane SYNTHESIS
  • 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.

  • 标签: L-蛋氨酸 N-乙酰基-D-蛋氨酸 N-乙酰基-DL-蛋氨酸 分离 纯化 脱酰作用
  • 简介:N-nitrosaminesarestrongcarcinogensforhumans.Thispapergivesanoverviewofthenitrosmainesincigarettesmokeincludingtheformation,theharmfulness,theanalyticalmethodsofthenitrosmainesandtheadsorptionsanddegradationsofN-nitrosamines.

  • 标签: N-亚硝酸 烟草 解析方法 吸附降解
  • 简介:Bythereactionofpoly(bromoacetylstyrene)(EBPS)withthiaurea(TU),akindofnovelchelatingresinwithheterocyaclicringofsulfurandnitrogen,poly[4-(2-amino)thiazoleyl-4-vinylben=ene],wassynthesized.ItsstructurewascharacterizedbyFTIRandelementalanalysis.Thefactorswhichhaveinfluenceonthereactionsuchasreactiontime,solvents,andmolarratioofreactantswereinvestigated.

  • 标签: 合成 螯合树脂 含硫含氮杂环化合物 | 反应时间
  • 简介:Inthispaper,MPt/C(M=La,Nd)catalystsofPEMFCweresynthesizedbymicrowaveradiationprocess.ThecrystallinityandstructureofcatalystswererespectivelyanalyzedbyXRDandnitrogenadsorptiontests.Theactivityofcatalystswasinvestigatedbyelectrochemistryexperiment.Theresultsshowedthat:1)comparedwithPt/Ccatalystpreparedbytypicalimpregnation-reductionprocess,thesizeofMPt/CcatalystparticledecreasedandtheavailablecrystalforO2reductionincreased;2)theMPt/CcatalystshadrelativelyhighBETsurfaceareas;and3)thesecrystaltransformationsoftheMPt/Ccatalystbroughthightheelectrocatalyticactivity,andasaresult,improvedthepowerofPEMFC.

  • 标签: 合成 微波辐射 聚合物电解质膜燃料电池 催化剂 X射线衍射 氮吸附试验
  • 简介:Fourkindsofpalladiumcatalystsdispersedonpoly-N-vinyl-2-pyrrolidonewerepreparedbyusingCH3OH-NaOH,NaBH4,H2OorCH3OH-H2Oasthereducingagentintheprocessofcatalystpreparation.ThecatalystswerecharacterizedbyXPS,TEM,XRDandusedforthehydrogenationofmethylacrylate.Itwasfoundthatthevalencestateofpalladiumanddistributionofpalladiumparticlesaswellasthehydrogenationrateweregreatlyaffectedbythereducingagent.ThebestevenlydispersedpalladiumcatalystshowinghighhydrogenationactivitywaspreparedusingCH3OH-NaOHasthereducingagent.

  • 标签: 高分散钯催化剂 聚N-乙烯基-2-吡咯烷酮 制备 性质
  • 简介:PolystyreneN-hydroxylsulfonamideresin1waspreparedandusedtocatalyzetheesterificationofn-butanolandaceticanhydride.ThemechanismofcatalyticesterificationprovedbyIRspectraoftheresinswasfoundthatO-HandN-HoftheN-hydroxylsulfonamideresinreactedwiththeaceticanhydriderespectivelytoformtheactiveintermediatepolystyreneN,O-diacetylsulfonamatewhichwascleavedbyn-butanoltoproducebutylacetate.Thecatalyticesterificationbyresin1wasingoodagreementwiththekineticmodelof"bi-bi-ping-pong"mechanism.

  • 标签: 催化剂 聚苯乙烯N-羟基磺胺类药物 酯化作用 丁醇 醋酸酐 酰基转移作用
  • 简介:Inthispaper,sixkindsofactivatedcarbonssuchasAg^+-activatedcarbon,Cu^2+activatedcarbon,Fe^3+-activatedcarbon,activatedcarbon,Ba^2+-activatedcarbonandCa^2+activatedcarbonwereprepared.Themodelforestimatingactivatedenergyofdesorptionwasestablished.Temperature-programmeddesorption(TPD)experimentswereconductedtomeasuretheTPDcurvesofn-hexanolandthenestimatetheactivationenergyfordesorptionofn-hexanolontheactivatedcarbons.Resultsshowedthattheactivationenergyforthedesorptionofn-hexanolontheAg^+-activatedcarbon,theCu^2+-activatedcarbonandtheFe^3+-activatedcarbonwerehigherthanthoseofn-hexanolontheactivatedcarbon,theCa^2+-activatedcarbonandtheBa^2+-activatedcarbon.

  • 标签: 有机化合物 解吸 n-乙烷
  • 简介:Acrylateterpolymer-boundSe,Nbidentateligandwassynthesizedfromthesidechainchlorineofcopolymerandβ-dimethylamino-β′-hydroxyl-diethylselenoether.Thepolymer-supportedplatinumcomplexexhibitedhighcatalyticactivityinthehydrosilylationofolefinswithtriethoxysilane.

  • 标签: 合成 催化活性 铂络合物 双配位基
  • 简介:CrosslinkedN,O-carboxymethylchitosanresinswhichcanselectivelyadsorbtriglyceride,werepreparedbythereactionofN,O-carboxymethylchitosanwithglutaraldehydesolution.Adsorptionexperimentswereperformedbyaddingtheresinstotheserum.Theresultsshowedthatthistypeofadsoirbentcouldcutdowntheconcentrationoftriglycerideinserumby56.4%(3.35mg/gresin)atmost,whileconcentrationofthetotalprotein(TP)decreasedonlyby10.9%atleast,sothisnoveladsorbentcanbeusedtocurehypertriglyceridemiabyhemoperfusioninthefuture.

  • 标签: 合成树酯 甘油三酯 吸附特性