规则SiO2颗粒的超临界合成

:2001-05-31:(G2000048001),(No29973057)(No29625307):(1974-),,:SiO2张晔,吴东,孙予罕,彭少逸(,030001):通过正硅酸乙酯(TEOS)在超临界乙醇-水-氨介质中的反应,合成出具有规则形状和大小均匀的SiO2颗粒,并通过透射电子显微镜(TEM)和扫描电子显微镜(SEM)对颗粒进行了表征同时通过调节体系中乙醇/水的摩尔比例,改变临界温度和压力,可以调变合成产品的颗粒大小同时为避免TEOS在升温过程中与水发生反应,TEOS的加入通过液体高压进样泵来完成另外,不同组成的混合介质的临界温度和压力通过跟踪具有相同配比不同总体积的体系的压力-温度曲线的分叉点来确定:;SiO2;:TQ1272:A:1008-5548(2002)02-0001-03SynthesisofRegularSilicaParticlesinSupercriticalFluidsZHANGYe,WUDong,SUNYuhanPENGShaoyi(StateKeyLaboratoryofCoalConversion,InstituteofCoalChemistry,ChineseAcademyofSciences,Taiyuan,030001,China)Abstract:Thereactionoftetraethylorthosilicate(TEOS)wasconductedinsupercriticalmediumcomposedofethanol,waterandammoniumascatalyst.TheadditionofTEOSwascarriedoutbyusingahighpressurepumptoavoidthereactionstowardswaterduringtheheatingprocess.Asaresult,veryregularanduniformsilicaparticleswereobtainedafterthereactionconductedinthesupercriticalmediumfor24h.Theparticlesizecouldbeadjustedbychangingthemolarratioofethanoltowaterandconsequentlythecriticaltemperatureandpressure.Thecriticaltemperatureandpressureofthemixedmediumwasdeterminedfromtheseparatingpointofthep-Tcurvesthatpossesseddifferenttotalvolumebutthesamecomposition.Keywords:supercriticalsystem;regularsilicaparticles;tetraethylorthosilicateTEOS-(sol-gel)[12],TEOS-TEOS,[3]TEOS-SiO2,[4],CO2TEOS--()-,SiO21实验部分113(n(C2H5OH)n(H2O)n(NH3)=49511)--,3/min,Tp,p-T3,LB-20CTEOS,24h,,12(TEM)(SEM)H-600-28220024中国粉体技术ChinaPowderScienceandTechnologyVol.8No.2April2002,TEM2结果与讨论21BarDavidDodge[5]n(C2H5OH)n(H2O)=0.490.51()548K986bar-(n(C2H5OH)n(H2O)n(NH3)=49511),Tp,p-T(),3p-T1,,-,3,3,,,3(538K,8MPa),T=558K,p=11.5MPa,0.70.30.90.1,1(V1V2V3)--(=49511)p-T22TEOSTEOS,,TEOS,TEOS,--,TEOS,-TEOS,,TEOS558K,145MPa,24hTEM2,SiO2,,764nm,TEOS,3sol-gelSiO2SEM,2SiO2TEM3-()()SiO2SEM(下转第7页)2!TheoraticalResearch!ChinaPowderScienceandTechnology2002No.28[][1][D],,1999[2]MakishimaSI,ShiraiT.Powerrequirementsforagitatingbedofsolid[J].JChemEngJap,1968,1(2):168.[3],,,[J],2000,6(2):20(上接第2页)SiO2,23/,211,TEOS/,TEOS,TEOS1SiO2(1),,,,,,1SiO2n(C2H5OH)n(H2O)TCT/KpCT/MPad/nm0.490.5155814.57650.70.35379.55880.90.15359.43023结论(1)TEOS,,--SiO2,;(2),,SiO2;(3)p-Tp-T[][1]AndersonRArkles,LarsonCL.PetrarchSystemsSilianesandSilicones[M].PetrarchSystems,1987.[2]BrinkerCJ,SchererGW.Sol-gelScience,ThePhysicsandChemistryofSol-gelProcessing[M].AcdemicPress,Inc,1990.[3]IlerRK.TheChemistryofSilica[M].Wiley,NewYork,1979.[4],,.[J],1995,13(2):38-42[5]BarDavidF,DodgeBF.Vapor-liquidEquilibrumatHighPressures[J].JChemEngData,1959,4(2):107.[6]VoronkovMG,MileshkevichVP,YuzhelevskiYA.TheSiloxaneBond[M].ConsultantsBureau,NewYouk,1978.7∀#20022!!