本文關(guān)鍵詞： 超微孔 氧化鋁 脂肪醇聚氧乙烯醚 選擇性催化還原反應(yīng)　出處：《太原理工大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：氧化鋁作為催化劑或催化劑載體，在石油化工、有機(jī)合成、精細(xì)化工等領(lǐng)域具有廣泛的用途。傳統(tǒng)的γ-Al2O3比表面較低且孔徑較大、孔分布較寬而不能充分滿足在催化過程中對(duì)選擇性、穩(wěn)定性、反應(yīng)接觸面積等有特殊要求的反應(yīng)。因此，合成具有更大比表面積、較小孔徑和較窄孔分布的氧化鋁分子篩具有重要意義和廣闊的應(yīng)用前景。 文獻(xiàn)所報(bào)道的采用溶膠凝膠法、水熱合成法、沉淀法、微乳液法、雙水解法、硬模板法等得到氧化鋁前驅(qū)體，然后通過煅燒或者溶劑萃取的方法除去模板劑分子后得到氧化鋁孔材料，其合成路線大多比較復(fù)雜，成本較高不易工業(yè)放大或生產(chǎn)。目前國(guó)內(nèi)外鮮有軟模板合成微孔級(jí)氧化鋁的報(bào)道和應(yīng)用。我們通過采用溶膠凝膠溶劑揮發(fā)誘導(dǎo)自組裝法，以廉價(jià)的表面活性劑脂肪醇聚氧乙烯醚為模板劑，制備出超微孔級(jí)（孔徑1-2nm）氧化鋁材料突破了傳統(tǒng)氧化鋁材料孔徑尺寸的限制，通過簡(jiǎn)單改變有限的反應(yīng)條件就能有效地控制前軀體的聚集形態(tài)，而產(chǎn)生超微孔結(jié)構(gòu)，從而改變氧化鋁的孔徑尺寸和性能，以擴(kuò)大其應(yīng)用范圍。 超微孔(super-microporous)氧化鋁基材料的孔徑介于微孔和介孔之間，其所特有分子擇形性能，將會(huì)在包括重油精制處理、新特種化學(xué)品發(fā)展、分子反應(yīng)有特殊要求的催化反應(yīng)和制藥前驅(qū)體的合成等方面發(fā)揮其特有的優(yōu)越性。但目前對(duì)于此方面的研究尚處于起步階段，如合成所用的模板劑較昂貴不易獲得或環(huán)境非友好；很難合成出具有熱穩(wěn)定性和催化活性兼?zhèn)涞奈⒖准?jí)氧化鋁基材料等。因此，，尋找價(jià)格適宜、性能優(yōu)越、環(huán)境友好的模板劑，不斷地優(yōu)化和完善其合成工藝和合成路線已成為當(dāng)前亟待解決的問題，以使其最終能達(dá)到實(shí)際生產(chǎn)應(yīng)用的目的。 本論文以非離子表面活性劑脂肪醇聚氧乙烯醚AEO-7為模板劑，采用溶劑揮發(fā)自組裝方法，成功制備出超微孔高比表面積微晶氧化鋁材料。該材料比表面積超過650m2/g，孔分布相對(duì)集中，平均孔徑在1.0-2.0nm之間，且具有較強(qiáng)的路易斯酸性，選區(qū)電子衍射顯示其為晶體結(jié)構(gòu)。合成所用模板劑原料廉價(jià)易得，且合成路徑簡(jiǎn)便直接，環(huán)境友好。同時(shí)，較系統(tǒng)的考察了模板劑添加量、無機(jī)酸量、有機(jī)羧酸類型等因素對(duì)材料制備和孔結(jié)構(gòu)的影響。 在成功制備出微孔級(jí)氧化鋁基礎(chǔ)上，運(yùn)用一鍋法將Zr組分引入Al2O3的結(jié)構(gòu)中，形成復(fù)合金屬氧化物微孔材料。由于Zr組分的引入，抑制了氧化鋁的晶相轉(zhuǎn)變和晶粒團(tuán)聚，使氧化鋁的晶相在1200℃才轉(zhuǎn)變?yōu)棣?Al2O3，相對(duì)于普通γ-Al2O3在500℃左右晶相的生成，較大幅度的延遲了氧化鋁晶相的轉(zhuǎn)變溫度。微孔氧化鋁材料在600℃焙燒后，即轉(zhuǎn)變?yōu)榻榭撞牧�，而添加適量的鋯組分后，即使經(jīng)過900℃焙燒，仍然能保持具有微孔結(jié)構(gòu)，從而提高了其熱穩(wěn)定性能。 同時(shí)，本文運(yùn)用P123和AEO-7復(fù)合模板劑成功制備出含有中微孔的氧化鋁基材料，并詳細(xì)考察了各模板劑不同含量對(duì)材料孔結(jié)構(gòu)的影響變化規(guī)律。同單一模板劑相比，復(fù)合模板劑所制備材料的熱穩(wěn)定性大大提高，900℃焙燒后，比表面積仍然有188m2/g。并能根據(jù)實(shí)際需要通過改變不同模板劑的含量對(duì)其孔徑和孔分布進(jìn)行有效的調(diào)變。 采用原位合成法或浸漬法引入活性組分CuO,成功制備出超微孔基銅鋁基脫硝催化劑。并系統(tǒng)考察了不同活性組分含量催化劑的結(jié)構(gòu)和性能，及其在甲烷選擇性催化還原NO反應(yīng)中的活性及規(guī)律。氮吸附結(jié)果顯示兩種制備方法的銅鋁基催化劑主體都是微孔材料，具有高的且穩(wěn)定的催化活性。原位合成引入銅的摩爾分率不低于15%或浸漬法銅的摩爾分率不低于5%時(shí)，以甲烷（CH4）為還原劑，反應(yīng)溫度超過400°C，轉(zhuǎn)化率隨溫度的增加而明顯提高，當(dāng)溫度達(dá)到600°C時(shí)，NO的轉(zhuǎn)化率接近100%。并且在無還原劑甲烷參與的條件下，該催化反應(yīng)能將部分NO直接分解轉(zhuǎn)化為N2，是目前鋁基脫硝催化劑鮮有報(bào)道的。
[Abstract]:As a catalyst or a catalyst carrier , the alumina has wide application in the fields of petrochemical industry , organic synthesis , fine chemical engineering and the like . The traditional gamma - Al2O3 has low specific surface and large pore size , and has wide pore distribution , and can not fully meet the special requirements for selectivity , stability , reaction contact area and the like in the catalytic process . An alumina precursor is prepared by sol - gel method , hydrothermal synthesis method , precipitation method , microemulsion method , double hydrolysis method and hard template method . The pore size of super - microporous aluminum oxide - based material is between the micropores and the mesoporous . Its specific molecular - selective properties will exert its unique advantages in the synthesis of catalytic reactions and pharmaceutical precursors including heavy oil refining , new special chemical development , molecular reaction , special requirements for molecular reactions , etc . It is difficult to synthesize the microporous grade aluminum oxide based materials with thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the template agent with good thermal stability and catalytic activity . Therefore , it is difficult to synthesize the synthetic technology and synthetic route which is urgently needed to be solved , so that it can finally achieve the purpose of practical production application . This paper uses non - ionic surfactant fatty alcohol polyoxyethylene ether AEO - 7 as template agent , and adopts solvent volatilization self - assembly method to successfully prepare ultra - microporous high specific surface area microcrystalline alumina material . The specific surface area of this material is more than 650m2 / g , the pore distribution is relatively concentrated , the average pore diameter is between 1.0 and 2.0nm , the average pore diameter is between 1.0 and 2.0nm , and the synthetic route is simple and direct , and is environment - friendly . On the basis of the successful preparation of microporous - grade alumina , the Zr component is introduced into the structure of Al2O3 by one - pot method . As the Zr component is introduced , the phase transition and grain agglomeration of the alumina are inhibited , and the transformation temperature of the alumina crystal phase is greatly delayed by the generation of the crystal phase at 1200 DEG C . At the same time , using P123 and AEO - 7 composite template agent to successfully prepare alumina - based material containing mesoporous silica , the influence of different content of template agent on the pore structure of material is investigated in detail . Compared with single template agent , the thermal stability of the prepared material is greatly improved . After calcination at 900 鈩

本文編號(hào)：1515385