10480.改性微孔介孔zsm5mcm41分子篩的合成及其催化多元醇酯化性能研究

1、孫運(yùn)林改性微孔介孔ZSM5／MCM41分子篩的合成及其催化多元醇酯化性能研究I摘要微孔介孔復(fù)合分子篩結(jié)合了微孔分子篩與介孔分子篩的優(yōu)點(diǎn)，具有比表面積大、酸強(qiáng)度以及熱穩(wěn)定性高等優(yōu)勢(shì)，在化工生產(chǎn)以及環(huán)境保護(hù)等方面具有比較廣闊的應(yīng)用前景。本文采用二次水熱晶化法合成了具有微孔與介孔復(fù)合結(jié)構(gòu)的ZSM5／MCM41分子篩，并采用離子交換法和浸漬負(fù)載法對(duì)其進(jìn)行了改性，以多元醇與乙酸的酯化反應(yīng)為探針，對(duì)復(fù)合分子篩催化劑的催化性能進(jìn)行了考察。一、HZSM

2、一5／MCM41的制備、表征及催化性能研究本文以硅酸鈉和堿液處理后的ZSM5料漿作硅鋁源，以十六烷基三甲基溴化銨作為模板劑，采用二次水熱晶化法制備出ZSM5／MCM一41分子篩(zM)，并對(duì)其酸性進(jìn)行了調(diào)變并制備出HZM，采用XRD、FTIR、BET、TEM、NH3TPD等分析測(cè)試技術(shù)對(duì)合成的微孔介孔復(fù)合分子篩進(jìn)行了表征。結(jié)果表明，制各出的ZM分子篩為含有ZSM一5的微孔結(jié)構(gòu)和MCM一41的介孔結(jié)構(gòu)的微孔介孔復(fù)合分子篩，經(jīng)氫離子交換后的

3、HZM分子篩擁有很強(qiáng)的酸性，為強(qiáng)酸性復(fù)合分子篩。以甘油和乙酸的酯化為探針，對(duì)HZM分子篩的催化性能進(jìn)行了考察，探究了反應(yīng)時(shí)間、催化劑用量以及乙酸與甘油摩爾比對(duì)酯化反應(yīng)的影響。實(shí)驗(yàn)發(fā)現(xiàn)在酸醇摩爾比為6：1、催化劑用量為反應(yīng)物量的22％、反應(yīng)時(shí)間為32h，以及反應(yīng)過(guò)程中精餾出副產(chǎn)物水的條件下，酯化反應(yīng)效果最佳，此時(shí)甘油的轉(zhuǎn)化率接近100％，三乙酸甘油酯的選擇性達(dá)87％。二、改性ZSM5／MCM41的制備、表征及催化性能研究以HZM作催化劑時(shí)

4、，酯化反應(yīng)速度較慢，三乙酸甘油酯的選擇性不高，催化劑的活性有待提高；另外，由于H—ZM分子篩的酸性較強(qiáng)，導(dǎo)致催化劑比較容易積碳而失活，因此以SnCl4、Zn(AC)2、Fe(N03)3和Fe2(S04)3為活性前驅(qū)體，采用離子交換法或浸漬負(fù)載法對(duì)ZM分子篩進(jìn)行了改性，制備出Fe—ZM、Zn—ZM、SnZM、ZnO／ZM和Fe2(S04)3／ZM，采用XRD、FTIR、BET、NH3TPD等分析測(cè)試技術(shù)對(duì)改性后的復(fù)合分子篩進(jìn)行了表征。結(jié)果

5、表明，活性組分高度分散于復(fù)合分子篩上；另外，與離子交換改性相比，浸漬負(fù)載改性對(duì)復(fù)合分子篩的介孔結(jié)構(gòu)影響較??；復(fù)合分子篩改性后酸性與HZM復(fù)合分子篩相比普遍降低。最后，分別以甘油與乙酸、乙二醇與乙酸的酯化為探針，對(duì)改性后復(fù)合分子篩的催化性能進(jìn)行了考察。孫運(yùn)林改性微孔介孔ZSM5／MCM41分了篩的合成及其催化多元醇酯化性能研究1IAbstractMicromesoporouscompositemolecularsieveswhichcom

6、binetheadvantagesofmicroporousmolecularsievesandmesporousmolecularsieveswithlargespecificsufacearea，highacidstrengthandhydrothermalstabilityarewidelyusedinthefiledsofchemicalproductionandenvironmentalprotectionInthisthes

7、is，ZSM5／MCM一41compositesweresynthesizedbyatwostepcrystallizationprocess，andtheyweremodifiedbyionexchangeprocessandimpregnationThecatalyticactivityofthecompositeswasinvestigatedbythereactionofpolyhydricalcoholswithacetica

8、cid1Preparation，characterizationandcatalyticperformanceofHZSM5／MCM一41compositesZSM5／MCM41compositesweresynthesizedbytwostephydrothennalcrystallizationprocessusingCTABastemplate，Na2Si03andtheslurryofalkalitreatedZSM5zeoli

9、teasstuffTheacidityofZSM5／MCM41compositeswasmodifiedbyionexchangeprocess，then，HZSM一5／MCM一41compositeswerepreparedThecatalystswerecharacterizedbyX—raydiffraction，infraredspectroscopyNH3chemicaladsorptionandN2physicaladsor

10、ptionandSOonTheresultsshowedthatZSM5／MCM一41possessthecharacteristicsofbothZSM一5andMCM一41，andNH3一TPDresultssuggestedthattheacidityofHZSM一5／MCM一41compositeswereverystrongTheircatalyticactivitywasevaluatedintheesterificatio

11、nreactionofglycerolwithaceticacid，andtheexperimentalconditionsincludingreactiontime，thedosageofcatalystwasinvestigatedTheresultsindicatedthatundertheoptimalconditionsoftheamountofcatalystwas22％，theratioofaceticacid／glyce

12、rolwas6：1，thereactiontimewas32h，andduringthereactionthewaterwasseparatedbydistillation，theconversionofglycerolandtheselectivityoftriacetinwereupto100％and87％respectively2Preparation，characterizationandcatalyticperformance

13、ofmodifiedZSM5／MCM一41ThereactionspeedlSslowandtheselectivityoftriacetinlSlOWwhenHZSM’5／MCM_41compositswefeusedasthecatalystsInadditionbecauseofthestrongacidityofHZSM一5／MCM41composites，whichareeasyleadingtocarbondepositio

14、noncatalystsurfaceandcatalystdeactivationTherefore，SnCl4，Zn(AC)2，re(N03)3andFe2(S04)3wereselectedastheactiveprecursortomodifyZSM5／MCM41composits，andFeZM，ZnZM，SnZM，ZnO／ZMandFe2(S04)3／ZMweresynthesizedbyionexchangeandimpre