鈦硅分子篩催化劑的研究進(jìn)展

1、ResearchprogressoftitaniumsilicalitecatalysZhangxiaomingZhangzhaorongSoujiquanLishuben(LanzhouInstituteofChemicalPhysicsfinepetrochemicalintermediatesNationalEngineeringResearchCenter,Lanzhou730000)Theroleoftitaniumcatalystintheoxidationreactionoforganiccompoundsiswellknown1,2.Introducedinthemolecul

2、arsieveframeworkduetothemolecularsievehavingaregularporestructureandlargespecificsurfaceareacharacteristics,heteroatom,havinganoxidation-reductionabilitytopreparenovelcatalyticoxidationcatalyst,hasbeenmoreinterestingsubjectin1983ENI3theTaramassoitscollaboratorsfirstsuccessfulsynthesisofthetitanium-c

3、ontainingzeolitecatalystofTS-1,asubsequentstudyfound,Tammoniaoxidation7S-1withH2O2aqueoussolutionasoxidantandtheoxidationreactionofaseriesoforganiccompounds,suchasolefinepoxidation4,thearomatichydrocarbonringhydroxylation5,6,ketone,alkaneoxidation8,9andthealcoholoxidation10andsotheprocesshasauniques

4、hape-selectivecatalyticfunctionascomparedwithothertypesofcatalyticsystems,thesystem(1)themildreactionconditions(atmosphericpressure,0-100°C);(2)theuniquefunctionoftheshape-selectivecatalyticoxidation;(3)environmentalfriendliness.TS-1hasbeenverylimitedbecausetheapertureisonlyabout0.55nm,anditsra

5、ngeofapplicationswheretheaerodynamicdiameterisgreaterthan0.60nmsubstratemoleculescannotenterwithinitsporeswithoutreactivity.Orderovercomethislimitation,thetypeofcatalysttogetawiderrangeofapplications,themajorityofscientistshavesuccessfullysynthesizedTS-211,Ti-Beta12andaseriesoflargeaperturezeoliteca

6、talysts.Inrecentyears,withthedevelopmentofthepetroleumrefiningandfinepetrochemicaltechnologyrequirestheuseofsomereorganizationoftheoiltobeeffective.M41S13,14,HMS15andMSU16seriesofmesoporousmolecularsievesTiheteroatomderivativesTi-MCM-4117,Ti-MCM-4818,Ti-HMS19,20andofTi-theMSU16emerged,thelatterinthe

7、selectiveoxidationoforganiccompoundsshowedhighercatalyticactivity.Thispaperreviewstherecentyears,theprogressmadeintermsofmicroporousandmesoporoustitaniumsilicalitecatalystpreparation,characterization,andcatalyticreaction.TS-1isfirstsynthesized,andalsosofarbeenstudiedmost,andmorethoroughlyofaclassoft

8、itaniumsilicalitecatalyst.TS-1isaSilicalite-1isomorphouslysubstitutedderivativesthereof,havingtheMFIstructure.TS-workandtheresultsachievedmanycommentshavebeenreported10,21-24hereonlyabriefoverviewoftheTS-1preparation,characterization,andtheircorrespondingcatalyticreaction.Theclassicalmethodofprepari

9、ngazeolitecatalystisahydrothermalsynthesismethodinthetheearliestpatentliterature,Taramasso3reportedtwopreparationTS-1Themethodofoneistetraethylorthosilicate(TEOS)andtetraethylammoniumn-titanate(TEOT)assilicasourceandatitaniumsource,andtetrapropylammoniumhydroxide(TPAOH)astemplatingagent;otherisasili

10、casolasasiliconsource,andtodissolveinH2O2thetitanateastitaniumsourceTPAOHtemplatingagentinadditiontothehydrothermalsynthesismethod,theTS-1canalsobeobtainedbythemethodofsecondarysynthesisTiCl4anddealuminationofZSM-5forvaporphasereaction,togivewithhydrothermalsynthesismethodissimilartothestructure25,b

11、utthismethodiseasytocauseanatase.Huanxinetal26forthetitaniumsource,TEOSasasiliconsource,andsucceededinsynthesizingaTS-1toTiCl3Thesamecatalyticactivity,withthesamereportedintheliterature,andtheprocesscanbeeffectivelypreventedfromgenerationofanataseInaddition,TuelandTaarit,continuouscoveragepositiveio

12、nswithphosphorus27,1,6-hexamethylenediammoniumion(Di-TPA)28,tetraethylammoniumhydroxide(TEAOH)/TPAOHandTEAOH/tetrabutylammoniumhydroxide(TBAOH)29asatemplatetoprepareTS-1process.describedusingdifferentPreparationofTemplateTS-1islikelythe.PreparationofTitaniumSilicalitereagentoverNa+,K+andotheralkalim

13、etalionsoftheconcentrationshouldbesufficientlylow,becausethealkalimetalionswillhinderthetitaniumatominthemolecularsieveframeworkembedded;anothertheonehand,topreventthepreparationprocessdifficulttodissolvetheanataseanataseformationwillleadtosubsequentreactionofH2O2decompositionandreducethecatalyticac

14、tivityinordertopreventthegenerationofanatase,thepreparationprocessshouldbevigorouslystirred,sothattitaniumsourceinthesiliconsourceishighlyfragmented.,Thangaraj,7theslowerrateofhydrolysistheoftetrabutylammoniumpositivetitanate(TBOT)AlternateTEOT,withanhydrousisopropylalcoholasaco-solvent,andachievedg

15、oodeffect.TS-1zeolitecatalystuniqueshape-selectivecatalyticoxidationfunction,undoubtedlyhasadirectrelationshipwiththeskeletonofTi(IV)Therefore,thefocusofsuchzeolitecharacterizationistodeterminetheexistenceofTi(IV)inthemolecularsieveitsligandenvironment.characterizationofTS-1,exceptforroutinecharacte

16、rizationofX-raydiffraction(XRD),N2adsorption/desorptionmethod,Fouriertransforminfraredspectroscopy(FT-IR)29Simagicanglespinningnuclearmagneticresonancespectroscopy(29Si-MAS-NMR),diffusereflectanceUV-visiblespectrum(DRUVVis),X-rayphotoelectronspectroscopy(XPS),extendedX-rayabsorptionfinestructure(EXA

17、FS)andX-rayabsorptionnearedgestructureanalysis(XANES)andothertechnologiesexistintheformoftetrahedralcoordinationTi(IV)providedthebasisforAccordingtothenamingofIUPAC40,theaperturebetween2-50nmmolecularsievesformesoporousmolecularsieves.1990s,classzeoliteinorganicmaterialsseparation,ionexchangeandcata

18、lyticdisciplinesoneofthehottolongchainsurfactantsastemplatingagent,havebeensuccessfullysynthesizedM41S13,14,HMS15andMSU16andaseriesofmesoporousmolecularsieves.formationmechanismoftheporestructureofmesoporousmolecularsieveresearchhasbeenreported41-46Atthesametime,Ti17-20,V47,Zr48,Mn49andCr50withthere

19、doxabilityoftransitionmetalatomsintomesoporousmolecularsieveskeletonstructure,getalotofnewcatalystsforthepreparationoffinechemicalswhichTiatomisomorphoussubstitutionintheholetitaniumsilicalitehasimportantsignificanceoftheoreticalresearchandindustrialapplicationvalue.TheGontierandTuel20alsoPressTanev

20、tomethodpreparedTi-HMS,andpreparationprocessofvariousfactorssuchastheproportionofTiO2/SiO2,isopropanol,surfaceactiveagentchainlength,characteristicofthetitaniumsourceandofSurf/SiO2system.foundthatinthepreparationprocess,whenthetworeagentsismixedfor15min,theresultingproducthadwithHexagonalvariouschar

21、acteristicsofmostofSurf/SiO2thebestratioof0.3increasethisproportionoftheapertureincreases,butthespecificsurfaceareaandadsorptioncapacityisgreatlyreduced.Reviewedaboveonthesynthesis,characterizationandcatalyticoxidationpropertiesoftitaniumsilicaliteandmesoporousmolecularsievesprepareditsheteroatomder

22、ivativescanbeseen,thetitaniumsilicaliteasanewtypeofselectiveoxidationcatalystdemandisveryimportanttotheincreasingvolumeofthepreparationoffinechemicals.especiallyinrecentyears,thesuccessofaseriesofmesoporousmolecularsievessynthesisandapplication,makingtherangeofapplicationsgreatlybroadenthefieldhasat

23、tractedmoreandmoreattentionofresearchersbutweshouldalsoseethattherearestillmanyproblemsinthefield,suchasthetitaniumsilicalitecatalyticreactionmechanism,theformationmechanismofmesoporousmolecularsievesandskeletoninthepresenceofTi(IV)wayforfurtherexplorationoftheseissuesandresearchwillbecomearesearchf

24、ocusinthecomingperiod.鈦硅分子篩催化劑的研究進(jìn)展張小明張兆榮索繼栓李樹本（中國(guó)科學(xué)院蘭州化學(xué)物理研究所精細(xì)石油化工中間體國(guó)家工程研究中心蘭州730000）含鈦催化劑在有機(jī)化合物氧化反應(yīng)中的作用是眾所周知的1,2.由于分子篩具有規(guī)整的孔道結(jié)構(gòu)和較大的比表面積等特點(diǎn)，在分子篩骨架中引入具有氧化還原能力的雜原子，以制備新型的催化氧化催化劑，一直是人們比較感興趣的課題.1983年ENI3的Taramasso及其合作者首次成功地合成了含鈦的分子篩催化劑TS-1.隨后的研究發(fā)現(xiàn)，TS-1在以H2O2水溶液為氧化劑的一系列有機(jī)化合物的氧化反應(yīng)，如烯姓:的環(huán)氧化4、芳姓:環(huán)的羥基化5,6

25、、酮的氨氧化7、烷姓:的氧化8,9及醇的氧化10等過程中有獨(dú)特的擇形催化功能.同其他類型的催化體系相比較，該體系有（1）反應(yīng)條件溫和（常壓,0-100C）;（2）獨(dú)特的擇形催化氧化功能;（3）環(huán)境友好等優(yōu)點(diǎn)。TS-1由于孔徑只有0.55nm左右，而使其應(yīng)用范圍受到了很大的限制.凡動(dòng)力學(xué)直徑大于0.60nm的底物分子因不能進(jìn)入其孔道內(nèi)部而無反應(yīng)活性.為了克服這一局限性，使該類催化劑能得到更為廣泛的應(yīng)用，廣大科研工作者相繼成功地合成了TS-211、Ti-Beta12等一系列孔徑較大的分子篩催化劑。近年來，隨著石油煉制及精細(xì)石油化工技術(shù)的發(fā)展，要求對(duì)一些重組分油加以有效利用.M41S13,14、HM

26、S15及MSU16等系列中孔分子篩及其Ti雜原子衍生物Ti-MCM-4117、Ti-MCM-4818、Ti-HMS19,20和Ti-MSU16等應(yīng)運(yùn)而生，后者在有機(jī)化合物選擇氧化中表現(xiàn)出較高的催化活性。本文綜述了近幾年在微孔及中孔鈦硅分子篩催化劑的制備、表征及催化反應(yīng)等方面所取得的進(jìn)展。TS-1是最早合成的、也是迄今為止人們研究得最多且比較徹底的一類鈦硅分子篩催化劑.TS-1是Silicalite-1的同品取代衍生物，具有MFI的結(jié)構(gòu).關(guān)于TS-1的工作和所取得的成果已經(jīng)有許多評(píng)述見諸報(bào)道10,21-24.這里僅就TS-1的制備、表征及其相應(yīng)的催化反應(yīng)等方面作一簡(jiǎn)要的概述。制備分子篩催化劑的經(jīng)

27、典方法是水熱合成法.在最早的專利文獻(xiàn)中，Taramasso等3報(bào)道了兩種制備TS-1的方法.一種是以四乙基正硅酸酯（TEOS）和四乙基正鈦酸酯（TEOT）為硅源和鈦源，以四丙基氫氧化錢（TPAOH）為模板劑；另一種是以硅溶膠為硅源,以溶解于H2O2中的鈦酸酯為鈦源，用TPAOH做模板劑.除了水熱合成法之外，TS-1也可以通過二次合成的方法得到.以TiCl4和脫鋁的ZSM-5S行氣相反應(yīng)，得到了與水熱合成法類似的結(jié)構(gòu)25.但這種方法易于導(dǎo)致產(chǎn)生銳鈦礦.高煥新等人26以TiCl3為鈦源，TEOS為硅源，成功地合成了TS-1,具有同文獻(xiàn)報(bào)道同樣的催化活性，并且該過程可以有效地防止銳鈦礦的產(chǎn)生.另外，

28、Tuel和Taarit連續(xù)報(bào)道了用磷正離子27、1,6-己二錢離子（Di-TPA）28、四乙基氫氧化錢（TEAOH）/TPAOH及TEAOH/四丁基氫氧化錢（TBAOH）29為模板劑制備TS-1的過程.說明用不同的模板劑制備TS-1是可能的.在鈦硅分子篩的制備中，試劑中Na+、K+等堿金屬離子的濃度應(yīng)足夠低，因?yàn)閴A金屬離子會(huì)阻礙鈦原子在分子篩骨架中的嵌入；另一方面，要防止制備過程中產(chǎn)生難溶解的銳鈦礦.銳鈦礦的形成會(huì)導(dǎo)致后續(xù)反應(yīng)中H2O2的分解而降低催化活性.為了防止銳鈦礦的產(chǎn)生，制備過程中應(yīng)該激烈攪拌，使鈦源在硅源中高度分散.另外，Thangaraj等7以水解速度較慢的四丁基正鈦酸酯（TBOT）替代TEOT,用無水異丙醇作為共溶劑，取得了較好的效果。TS-1分子篩催化劑獨(dú)特的擇形催化氧化功能，無疑與骨架中的Ti（IV）有著直接的關(guān)系.因此，該類分子篩表征的重點(diǎn)在于確定Ti（IV）在分子篩中的存在方式及