简介:AseriesofcarboxylicacidswasesterifiedtothecorrespondingesterswithTiCl_4ascatalystatroomtemperature,inhighyields.Thiscatalystwashighlyeffectivefortheselectiveesterificationofprimaryalcoholswithcarboxylicacids,inthepresenceofsecondaryalcohols,andfortheselectiveesterificationofsaturatedacidwithalcoholinthepresenceofconjugatedacidoraromaticacid.Onaccountofthehighyield,highchemoselectivity,mildcondition,andbeingfreeofotherdehydrants,thisisanefficientmethod.
简介:Theresearchworkonpreparationprocessofactivematerialsoftherareearthionselectiveelectrodesandthevalenceoftheelectrodemembranewerereported.Theactivematerialswerechacterizedbyinfraredspectrum,elementalanalysisandXPS.Wehadstudiedtherareearthionselectiveelectrodesinwhichtheactivematerialsconsistoffunctionalpolymers.Inthispaper,theresearchworkonpreparationprocessandthevalenceoftheelectrodemembranewerereported,whichhasnotbeenseeninliteratureyet.
简介:三3,3-di(4-substituted-phenyl)-1,1-isophthaloylbis(thiourea)混合物作为新奇中立阴离子受体被设计,并且在好收益由简单步骤综合了。受体1的单个晶体结构证明一个溶剂分子被主人分子通过分子间的氢结合捕获。而且,它作为为存在的一个超分子的系统自我装配丰富内部--并且intramolecular氢结合并且-在苯基组之间的相互作用。他们阴离子受体被检验了由的申请紫外力并且1HNMR光谱学,证明他们比另外的卤化物为氟化物有一种更高的选择。主人和客人在第一个步骤通过氢结合相互作用形成了1:1stoichiometry建筑群,然后在F的过量的存在跟随deprotonation的一个过程吗?在DMF的溶剂。
简介:IntroductionMoleculeimprintingtechnologyhasmadegreatprogressinmakingchiralstationaryphasewithpredeterminedchiralselectivityagainstenantiomerssuchasaminoacidandtheirderivatives;sugarandtheirderivatives;naproxenandmethylbenZylamine’-’.Functionalmonomer...
简介:Phosphorylatedmesoporouscarbons(PMCs)wereinvestigatedascatalystsinthedehydrationoffructosetohydroxymethylfurfural(HMF).TheacidicPMCsshowbetterselectivitytoHMFcomparedtosulfonatedcarboncatalyst(SC)despiteloweractivity.TheconcentrationofP-OgroupsonthePMCwascorrelatedwiththeactivity/selectivityofthecatalysts;thehighertheP-Oconcentration,thehighertheactivity.However,thehighertheP-Ocontent,thelowertheselectivitytoHMF.Indeed,alowerconcentrationoftheP-OgroupsminimizedthedegradationofHMFtolevulinicacidandtheformationofby-products,suchashumines.Stabilitytestsshowedthatthesesystemsdeactivateduetotheformationofhuminesandwaterinsolubleby-productsderivedfromthedehydrationoffructosewhichblockedthecatalyticallyactivesites.
简介:Theactivationandselectiveconversionofenergy-relatedmoleculesisanimportantresearchareaofenergychemistry.Thedepletionofpetroleumhasstimulatedresearchactivitiesintotheutilizationofnon-petroleumcarbonresourcessuchasnaturalgas(includingconventionaland
简介:Thispaperpresentsanequalizationalgorithmforcontinuousphasemodulation(CPM)overfrequency-selectivechannels.Aspecifictrainingsequenceisfirstembeddedineachdatapacket.Byrecursiveleast-squares(RLS)estimation,thechannelinformationparameterscanbeacquired,andafractionallyspacedequalizerperformsjointdecodingandequalization.Simulationresultsshowthattheproposedalgorithmcanacquirethechannelinformationparametersrapidlyandaccurately,andthatthefractionallyspacedequalizercaneliminatetheintersymbolinterference(ISI)effectively,andisnotsensitivetotiminginaccuracy,sothisalgorithmcanbeexploitedfordemodulationsysteminburstmode.
简介:ThispaperdealswiththetransportpropertiesofoligomerofpolythioetherPSAusedasmoblecarrierinbulkliquidmembraneforgold(Ⅲ).ItwasfoundthatAu(Ⅲ)canbetransportedbyPSAfromsourcephasetoreceivingphasecompletelyunderappropriateconditionsandonlyAu(Ⅲ)canbetransferredthroughtheliquidmembranetoreceivingphasefromamixtureofNa(I)-Cu(Ⅱ)-Au(Ⅲ)-Fe(Ⅲ)-Pt(Ⅳ)inthefollowingsystem:HAuCl4-HCl(aq.)/PSA-ClCH2-CH2Cl/(NH2)2CS-HCl(aq.).ThetransportrateofAu(Ⅲ)dependedontheconcentrationofcarrier,thethicknessofliquidmembrane,theconcentrationofAu(Ⅲ)insourcephaseandtheacidityofthemedia.
简介:AseriesofCoMo/Al2O3catalystsforselectivehydrodesulfurization(HDS)ofgasolinewerestudiedwithRamanspectroscopy,apowerfulmethodthatcreatesspecifcsignalsforthestatesandthedistributionsofoxidicprecursorsandsulfdedactivephases.ThehighertheMoandCo,thelowerthetetrahedrallycoordinatedmolybdate,andthehigherthepolymolybdate.ButtheamountofpolymolybdatedecreasedwhenCoMoO4appeared.Cobalt-promotedpolymolybdatewastheprecursor,anditsrelativecontentcorrelatedwellwiththeHDSselectivity.Forsulfdedcatalysts,addingthecobalt-promoterledtolocaldistortion-disorderoftheMoS2structureandtheformationofaCoMoSphase.Thismethodcanprovideimportantinformationfordesigningnewindustrialselective-HDScatalysts.
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简介:Glycerolcanbeobtainedasaby-productduringbiodieselmanufacture.Itisimportanttoconvertglyceroltovalue-addedproducts.Glycerolesterificationwithaceticacidisoneofthemostpromisingapproachesforglycerolutilization.Itisusuallydifficulttoobtaindiacetinwithgoodactivityandselectivity.Inthiswork,glycerolesterificationwithaceticacidoverdifferentmetaloxides,suchasBi2O3,Sb2O3,SnO2,TiO2,Nb2O5andSb2O5,wasinvestigated.Itwasfoundthatinthesixinvestigatedmetaloxides,onlySb2O5resultedingoodactivityandselectivitytodiacetin.Undertheoptimizedconditions,theglycerolconversionreached96.8%,andtheselectivitytodiacetinreached54.2%,whiletheselectivitytomonoacetinandtriacetinwas33.2%and12.6%,respectively.ThecatalystswerecharacterizedwithFT-IRspectraofadsorbedpyridine,whichindicatedthatinthesixinvestigatedmetaloxides,onlySb2O5possessedBr?nstedacidsitesstrongenoughtoprotonateadsorbedpyridine.ThegoodcatalyticactivityandselectivitytodiacetinmightbemainlyattributabletotheBr?nstedacidsitesofSb2O5.ReusabilitytestsshowedthatwithSb2O5ascatalyst,aftersixreactioncycles,nosignificantchangeintheglycerolconversionandtheselectivitytodiacetinwasobserved.