简介：

简介：

简介：

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.

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.

简介：

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：N-nitrosaminesarestrongcarcinogensforhumans.Thispapergivesanoverviewofthenitrosmainesincigarettesmokeincludingtheformation,theharmfulness,theanalyticalmethodsofthenitrosmainesandtheadsorptionsanddegradationsofN-nitrosamines.

简介：Bythereactionofpoly(bromoacetylstyrene)(EBPS)withthiaurea(TU),akindofnovelchelatingresinwithheterocyaclicringofsulfurandnitrogen,poly[4-(2-amino)thiazoleyl-4-vinylben=ene],wassynthesized.ItsstructurewascharacterizedbyFTIRandelementalanalysis.Thefactorswhichhaveinfluenceonthereactionsuchasreactiontime,solvents,andmolarratioofreactantswereinvestigated.

简介：

简介：

简介：Fourkindsofpalladiumcatalystsdispersedonpoly-N-vinyl-2-pyrrolidonewerepreparedbyusingCH3OH-NaOH,NaBH4,H2OorCH3OH-H2Oasthereducingagentintheprocessofcatalystpreparation.ThecatalystswerecharacterizedbyXPS,TEM,XRDandusedforthehydrogenationofmethylacrylate.Itwasfoundthatthevalencestateofpalladiumanddistributionofpalladiumparticlesaswellasthehydrogenationrateweregreatlyaffectedbythereducingagent.ThebestevenlydispersedpalladiumcatalystshowinghighhydrogenationactivitywaspreparedusingCH3OH-NaOHasthereducingagent.

简介：PolystyreneN-hydroxylsulfonamideresin1waspreparedandusedtocatalyzetheesterificationofn-butanolandaceticanhydride.ThemechanismofcatalyticesterificationprovedbyIRspectraoftheresinswasfoundthatO-HandN-HoftheN-hydroxylsulfonamideresinreactedwiththeaceticanhydriderespectivelytoformtheactiveintermediatepolystyreneN,O-diacetylsulfonamatewhichwascleavedbyn-butanoltoproducebutylacetate.Thecatalyticesterificationbyresin1wasingoodagreementwiththekineticmodelof"bi-bi-ping-pong"mechanism.

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.

简介：

简介：

简介：Animprovedmethodisdevelopedbyusingstronglyacidiccationexchangeresin(001×1，H^+form)asacatalystforthesynthesisofdiphenyl1-(N-benzyloxycarbonyl-amino)alkanephosphonatesand1-(N-benzyloxycarbonylamino)alkanephenylphosphinicacidsinhighyields.

简介：Acrylateterpolymer-boundSe,Nbidentateligandwassynthesizedfromthesidechainchlorineofcopolymerandβ-dimethylamino-β′-hydroxyl-diethylselenoether.Thepolymer-supportedplatinumcomplexexhibitedhighcatalyticactivityinthehydrosilylationofolefinswithtriethoxysilane.

简介：CrosslinkedN,O-carboxymethylchitosanresinswhichcanselectivelyadsorbtriglyceride,werepreparedbythereactionofN,O-carboxymethylchitosanwithglutaraldehydesolution.Adsorptionexperimentswereperformedbyaddingtheresinstotheserum.Theresultsshowedthatthistypeofadsoirbentcouldcutdowntheconcentrationoftriglycerideinserumby56.4%(3.35mg/gresin)atmost,whileconcentrationofthetotalprotein(TP)decreasedonlyby10.9%atleast,sothisnoveladsorbentcanbeusedtocurehypertriglyceridemiabyhemoperfusioninthefuture.

简介：六新光学地活跃并且flame-retardant(amide-imide)poly，在主要的链作为一个flame-retardant单位包含磷化氢氧化物一半的s白族5a鈥?f从六chiralN的直接polycondensation反应被综合，有二度(3-aminophenyl)的N鈥?(pyromellitoyl)-bis-L-amino酸3a鈥?f在中等在于的苯基磷化氢氧化物4N-methyl-2-pyrrolidone(NMP)，triphenyl亚磷酸盐(TPP)，钙氯化物(CaCl2)和pyridine。生产的聚合反应一系列光学地活跃poly(amide-imide)有好产量和0.34鈥?.70dLg的好固有的粘性的s?1。结果的聚合物充分借助于FTIR和1H-NMR光谱学，胶化浸透层析(GPC)，元素的分析，固有的粘性和溶解度测试被描绘。热性质和白族5a鈥?f的flame-retardant行为被调查使用热gravimetric分析(TGA和DTG)并且限制氧索引(LOI)。热分析(TGA和DTG)获得的数据表明这些聚合物显示出好热稳定性。而且，在TGA的高字符产量和好LOI值显示产生聚合物能够展出好火焰retardant性质。N，N鈥?(pyromellitoyl)-bis-L-amino酸3a鈥?f被pyromelliticdianhydride(1,2,4,5-benzenetetracarboxylicacid-1,2,4,5-dianhydride)的冷凝作用反应在量的收益准备1与L丙氨酸2a，L缬氨酸2b，L白氨酸2c，L异白氨酸2d，L苯基丙氨酸2e和L-2-aminobutyric在醋酸的酸2f答案。关键词光学地活跃-Flame-retardant聚合物-Poly(amide-imide)s-限制氧索引