基于咪唑型离子液体微介孔Y分子筛的制备与性能研究

发布时间：2018-04-22 01:32

本文选题：微介孔Y分子筛 + 离子液体　；参考：《东南大学》2016年硕士论文

【摘要】：微孔Y型分子筛由于具有较大的比表面积、较强的酸性、良好的水热稳定性,被广泛地用在催化、吸附和分离等领域。但其狭窄的的孔径(～0.74nm)阻碍了反应物和产物的扩散与分离,从而限制了其在大分子反应中的应用。与微孔分子筛相比,介孔材料具有较大的孔径,能够加快扩散速度。易于反应物通过介孔到达反应活性位,相应地,反应产物能够快速地从催化剂孔道内部扩散出来。但是介孔材料的水热稳定性和耐酸性均较差。因此将介孔引入到Y型分子筛中,可以有效地避免二者的缺点,优势互补,协同作用。这种新型的微介孔Y型分子筛既具有传统的沸石分子筛的性能,又能够降低扩散阻力,极其有利于含有大分子的催化反应。二芳基乙烷(PXE)是生产压敏复写纸显色剂的优良溶剂,主要通过邻二甲苯和苯乙烯的烷基化反应获得。本论文以离子液体1-甲基-3-(3-三甲氧基硅基丙基)咪唑氯摀(MTPI)为介孔模板剂,硅酸钠为硅源,偏铝酸钠、十八水硫酸铝为铝源,制备了一种新型的微介孔Y型分子筛。将制备的Na型Y分子筛进行离子交换得到H型微介孔Y型分子筛,并考察其在邻二甲苯和苯乙烯制备二芳基乙烷(PXE)的烷基化反应中的催化性能。采用离子液体MTPI为介孔模板剂,在不加入任何助剂的条件下,一步水热法制备了结晶度较好的微介孔NaY型分子筛。考察了离子液体MTPI与溶液中Na2O的摩尔比(n)、晶化温度(x)对分子筛NaY-nMTPI-x的影响。研究表明：当x为100℃、n为0.15时,制备的NaY-0.15MTPI分子筛样品的比表面积最大,达到690 m2/g(其中介孔比表面占76 m2/g)；孔体积为0.39 cm3/g(其中介孔孔体积为0.11 cm3/g)。通过离子交换法制备系列的微介孔HY-nMTPI分子筛作为烷基化催化剂。对比发现,所有的微介孔HY-nMTPI分子筛都比微孔分子筛HY的催化性能好。其中HY-0.15 MTPI由于具有较多的介孔结构和最多的酸量,在PXE产率和催化剂循环使用方面均表现出良好的催化性能。以离子液体MTPI为介孔模板剂,硅酸钠为硅源,偏铝酸钠、十八水硫酸铝为铝源,通过不同的方法制备了微介孔NaY分子筛。考察了传统的水热晶化法和超声微波协同辅助法对微介孔材料NaY(C)和NaY(UMSS)形成的影响。结果表明：在超声微波的辐射下,虽然合成微介孔分子筛NaY(UMSS)的晶化时间大大地缩短,但是其具有较大的比表面积与孔容、较好的结晶度、较多的介孔结构、较小的晶粒和较好的分散性。因此经过离子交换后,样品HY(UMSS)在PXE产率和催化剂寿命方面表现出最佳的催化性能。当晶化温度为100℃, n(MTPI):n(Na2O)为0.15时,进一步考察了不同的硅铝比(z)对分子筛z NaY结构的影响。研究表明：随着硅铝比的逐渐增大,所得分子筛样品的结晶度、比表面积和孔容均呈现先增大后减小的趋势；总酸量和酸位也随着铝源加入量的不同有很大的变化。在烷基化反应中,当z≤10.5时,所有的高铝含量的微介孔分子筛z HY都显示出较好的催化活性。而且分子筛9.5HY由于具有较高的比表面积,较多的介孔孔容和最多的酸量,在烷基化反应中表现出最好的催化性能。PXE的产率高达91.73%,表明了较多的介孔和酸量有利于烷基化反应的进行。综上所述,采用离子液体为模板剂制备的微介孔Y分子筛具有较高的比表面积、较大的孔径、较多的酸量,而且这些优点均有益于微介孔Y分子筛作为催化剂应用于邻二甲苯和苯乙烯制备PXE的烷基化反应中。
[Abstract]:Microporous Y molecular sieves are widely used in the fields of catalysis, adsorption and separation because of their large specific surface area, strong acidity and good hydrothermal stability. But the narrow pore size (~ 0.74nm) hinders the diffusion and separation of reactants and products, thus limiting its application in large molecular reactions. The mesoporous material has a larger aperture and can accelerate the diffusion speed. The reactant can reach the reactive potential through the mesopore. Accordingly, the reaction products can quickly spread out of the catalyst channel. However, the hydrothermal stability and acid resistance of the mesoporous materials are poor. Therefore, the introduction of mesoporous materials to the Y type molecular sieve can effectively avoid it. The new type of micro mesoporous Y type molecular sieves not only have the properties of the traditional zeolite molecular sieves, but also reduce the diffusion resistance, and are extremely beneficial to the catalytic reaction with large molecules. Two aryl ethane (PXE) is a good solvent for the production of pressure-sensitive compound paper chromogenic agent, mainly through the xylene and benzene. The alkylation of ethylene was obtained. In this paper, a new type of micro mesoporous Y molecular sieve was prepared by using the ionic liquid 1- methyl -3- (3- trimethoxy silicon propyl) imidazolium (MTPI) as a mesoporous template, sodium silicate as the silicon source, sodium aluminate, and eighteen water aluminum sulfate as the aluminum source. The prepared Na type Y molecular sieve was exchanged for H micromedium by ion exchange. The catalytic properties of pore Y molecular sieves were investigated in the alkylation of two aryl ethane (PXE) prepared by o-xylene and styrene. Using ionic liquid MTPI as a mesoporous template, the micro mesoporous NaY zeolite with better crystallinity was prepared by one step hydrothermal method without any additives. The MTPI and solution of ionic liquid were investigated. The effect of crystallization temperature (x) on the molecular sieve NaY-nMTPI-x of medium Na2O (n) shows that when x is 100 and N is 0.15, the specific surface area of the prepared NaY-0.15MTPI molecular sieve is the largest, reaching 690 m2/g (which the mesoporous surface is 76 m2/g), and the pore volume of 0.39 cm3/g (including the mesoporous pore volume of 0.11 cm3/g). A series of micro mesoporous HY-nMTPI molecular sieves were prepared as a catalyst for alkylation. It was found that all microporous HY-nMTPI molecular sieves have better catalytic properties than microporous molecular sieves. Among them, HY-0.15 MTPI has a good catalytic performance in the yield of PXE and the use of catalytic agents because of the more mesoporous structure and the most acid content. Properties. Using ionic liquid MTPI as a mesoporous template, sodium silicate as a silicon source, sodium aluminate, eighteen water aluminum sulfate as the aluminum source, micro mesoporous NaY zeolite was prepared by different methods. The influence of the traditional hydrothermal crystallization method and ultrasonic microwave co assisted method on the formation of NaY (C) and NaY (UMSS) of micro mesoporous materials was investigated. The crystallization time of the synthetic mesoporous molecular sieve NaY (UMSS) is greatly shortened, but it has a larger specific surface area and pore volume, better crystallinity, more mesoporous structure, smaller grain size and better dispersibility. Therefore, after ion exchange, the sample HY (UMSS) shows the PXE yield and the life of the catalyst. The optimum catalytic performance. When the crystallization temperature is 100, n (MTPI) and n (Na2O) is 0.15, the effect of different Si / Al ratio (z) on the structure of Z NaY is further investigated. In alkylation, all the microporous mesoporous molecular sieves Z HY with high aluminum content showed good catalytic activity in the alkylation reaction, and the molecular sieve 9.5HY showed a high specific surface area, more mesoporous Kong Kong volume and the most acid content in alkylation. The best catalytic performance of.PXE is up to 91.73%, indicating that more mesoporous and acid content is beneficial to alkylation. To sum up, the micro mesoporous Y zeolite prepared by ionic liquid as a template has higher specific surface area, larger aperture and more acid content, and these advantages are beneficial to micro mesoporous Y molecular sieves. Alkylation of PXE with o-xylene and styrene was used as catalyst.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;O645.1

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