Synthesis, Characterization and Catalytic Activities of Mesoporous AlMSU-X with Wormhole-Like Framework Structure

Mesoporous AlMSU-X molecular sieves with high acidity have been prepared from preformed beta nanoclusters under strong acidic conditions in the presence of nonionic TX-100 as structure directors. These materials were characterized by XRD, HRTEM, N₂-adsorption, ²⁷Al MAS NMR, NH₃-TPD, IR-pyridine adsorption and catalytic cracking of cumene and 1,3,5-triisopropylbenzene. The experimental results showed that Al heteroatoms had been successfully incorporated into the framework structure of mesoporous MSU-X, and so-produced catalysts exhibited superior catalytic properties.     

硅铝介孔分子筛的合成和表征及其催化异构化性能的研究

以正硅酸乙酯(TEOS)为硅源,十六烷基三甲基溴化铵(CTABr)为模板剂,三氯化铝为铝源在室温条件下合成了介孔硅铝分子筛A1-MCM-41。采用红外光谱(IR)、X射线衍射(XRD)、低温氮吸附等温线等方法对分子筛进行了结构表征。评价结果表明,A1-MCM-41分子筛对桥式四氢双环戊二烯(endo-TCD)具有良好的催化异构化性能。     

Optimization of Alumina and Aluminosilicate Aerogel Structure for High-Temperature Performance

Alumina and aluminosilicate aerogels offer potential for use at temperatures above 700°C, where silica aerogels begin to sinter. Stability of alumina and aluminosilicate pore structures at high temperatures is governed by the starting aerogel structure, which, in turn is controlled by the synthesis route. Structure, morphology, and crystallization behavior are compared for aerogels synthesized from AlCl₃ and propylene oxide with those synthesized from a variety of boehmite precursors. The aerogels possessing a crystalline boehmite structure in the as-synthesized condition retained mesoporous structures to temperatures of 1200°C, while the AlCl₃-derived aerogels, although exhibiting higher as-synthesized surface areas, crystallized and densified at 980–1005°C.     

水滑石类化合物的制备及其催化活性研究

通过酯交换法催化合成了甲基丙烯酸二甲氨基乙酯(DMAEMA),制备了其系列水滑石类化合物催化剂。通过扫描电镜(SEM)、X射线衍射仪(XRD)、傅里叶红外(FT IR)和热重(TG)等测试手段对催化剂形貌和性质进行了表征。同时考察了原料配比、催化剂用量、反应时间和反应温度等对产物产率的影响,评价了其催化剂性能。     

Mesostructured Sulfated Zirconia with High Catalytic Activity in n-Butane Isomerization

A mesostructured sulfated zirconia with a large surface area (189 m²/g) has been successfully prepared using a triblock copolymer as a structure-directing agent. The resulting material was characterized by XRD, TEM, nitrogen adsorption, FTIR and TG/DTA, which suggested that the mesostructured sulfated zirconia was tetragonal crystalline. Catalytic testing showed that the mesostructured sulfated zirconia was much more active than conventional sulfated zirconia for n-butane isomerization.     

Structure of Sodium Aluminosilicate Glasses

A series of sodium aluminosilicate glasses composed of varying ratios ( R ) of Al₂O₃/Na₂O (0.25 R 2.0) has been simulated with the molecular dynamics technique using a tetrahedral form of a three-body interaction potential. Extrema in the activation energies for sodium diffusion and in the diffusion constants for all of the atomic species were observed for glasses with equal concentrations of Al₂O₃ and Na₂O ( R = 1.0). These changes corresponded to the minimum observed experimentally in the activation energy for electrical conductivity and to the maximum observed in the viscosity for glasses with compositions of R = 1.0. The coordination of aluminum remained 4 over the entire compositional range, negating the need to invoke a coordination change of aluminum to explain the changes in the physical properties. The changes to the simulated physical properties as R passed through the equivalence point were attributed to the elimination of nonbridging oxygen, to the introduction of oxygen triclusters, and to changes in the distribution of ring structures within the glass networks.     

核壳型聚丙烯酰胺纳米微球的制备及其性能

以丙烯酰胺(AM)和丙烯酸(AA)为聚合单体,以2-丙烯酰胺-2-甲基丙磺酸(AMPS)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为功能性单体,通过反相乳液二次聚合制备出核壳型微球乳液PMPAM。利用红外光谱、热重分析仪、透射电镜、激光粒度分析仪、流变分析仪、稳定性分析仪等对微球乳液PMPAM进行了表征。结果显示:PMPAM热稳定性良好,微球呈表面光滑、分布均匀的核壳型结构,其乳液存放6个月仍稳定。通过测定不同温度下和不同矿化度的盐水中PMPAM微球膨胀率表征了其耐温、耐盐性。结果表明:PMPAM微球溶胀5 d后,微球粒径从260 nm膨胀至1 168 nm,与初始粒径相比,溶胀率高达4.49倍;在60℃下,PMPAM微球老化5 d后的膨胀率在蒸馏水中达到4.56倍,在矿化度为1.45×103mg/L(Na+)盐水中达到2.48倍,说明其具有较好的抗盐性能;随着温度的升高,PMPAM微球膨胀率呈逐渐增大的趋势,从20℃下的1.27倍增加到60℃下的3.63倍。随剪切速率的增大,乳液呈剪切变稀的特性,且具有一定的黏弹性。     

纳米氧化铁的制备方法及其应用

综述了国内外纳米氧化铁的制备方法及其研究现状,详述了纳米氧化铁在催化剂方面的应用,并对其发展进行了展望。     

介孔SO_4~(2-)/ZrO_2的制备、表征及性能

以正丙醇锆为锆前躯体,硫酸铵为硫源,十六烷基三甲基溴化铵(CTAB)为模板剂,溴化钾为添加剂,按n(Zr4+)∶n(CTAB)∶n(SO24-)=2∶1∶2,在水热条件、酸性介质中合成了介孔ZrO2/SO24-。通过X射线衍射(XRD),N2物理吸附,扫描电镜(SEM),FTIR分析手段对其结构进行了表征;并以乙酸正丁酯的酯化反应为探针反应,考察了其催化活性。结果表明,采用两步焙烧法去除模板剂后,该样品的介孔结构类似于MCM-41,d值为3.85nm;在500℃焙烧后,该样品仍具有274m2/g的比表面积及3.2nm的平均孔径;SEM显示焙烧后的样品形貌为球形颗粒;FTIR分析得出,焙烧产物ZrO2/SO42-中S=O键对Zr4+有强的吸电子作用,产生强的Lewis酸中心。当催化剂用量为正丁醇质量的2.5%,n(乙酸)∶n(正丁醇)=1∶2,反应3h后,乙酸的转化率达91.48%。     

无粘结剂MCM-22分子筛催化剂制备及其催化性能

采用NaOH溶液对含粘结剂的成型工业MCM-22分子筛催化剂进行后处理以脱除粘结剂,制备无粘结剂MCM-22分子筛催化剂,并实验考察了碱浓度、处理时间对催化剂的强度、活性组分的含量、酸量及催化性能的影响。结果表明:在NaOH溶液的质量分数为0.3%、150℃的条件下对圆柱形含粘结剂MCM-22分子筛催化剂处理4h,即可制得无粘结MCM-22分子筛催化剂。在苯与乙烯液相烷基化反应中,在苯与乙烯物质的量比为3.0,乙烯质量空速为9.0h~(-1),温度200℃,压力3.5 MPa的反应条件下,无粘结剂MCM-22分子筛催化剂的乙烯转化率维持在60%以上,催化性能与分子筛原粉相当,明显优于含粘结剂的催化剂(低于40%),且其强度能够满足工业应用的要求。     

二氧化锰纳米棒的制备和催化性能研究

采用水热法140 ℃下制备了二氧化锰的棒状结构.XRD和扫描电子显微镜研究了二氧化锰的晶相和形貌,对棒状二氧化锰降解品红催化性能进行了测试,实验表明,催化剂的加入量,双氧水的加入量和溶液的pH值对品红的脱色效果产生重要的影响,在催化剂的加入量为0.02 g时,双氧水的加入量为4 mL,溶液的pH值为6.2时有较佳的脱色...     

MCM-41分子筛的制备及催化性能研究

用微波法合成MCM-41中孔分子筛.并采用液相沉积法制备了以MCM-41分子筛为载体负载TiO2/S2O82-的同体酸催化剂,以乙酸与异戊醇的酯化反应作为探针反应,考察了焙烧温度、焙烧时间、浸渍溶液的浓度、浸渍时间以及钛硅比等制备条件对催化剂催化活性的影响,得到了最佳的制备条件.最佳条件是:n(Ti)/n(Si)=2,...     

Structure of Sodium Aluminosilicate Glass Surfaces

Sodium aluminosilicate (NAS) glass surfaces with compositions containing approximately 63% SiO₂ and Al/Na ratios, R , of 0.25 R 2.0 were simulated using the molecular dynamics technique with a multibody interaction potential. There were changes to the surface structure and composition in comparison to bulk NAS glasses. The changes included an increased concentration of sodium and oxygen and the formation of nonbridging oxygen at the outermost surfaces, although the increases were smaller with increased Al concentration. In addition, the formation of small-membered rings and three-coordinated aluminum occurred in the subsurface regions. These changes were accompanied by a change in the ratio of Al/Na in the region extending to 4 Å below the surface.     

PdAg、PdAu合金纳米晶的制备及其催化性能研究

采用硼氢化钠一步还原法,首先得到PdAg和PdAu双金属合金纳米颗粒.利用XRD、TEM以及紫外可见光光谱技术对其进行了表征分析.结果表明,PdAg和PdAu两种合金都具有纳米颗粒分散均匀且颗粒尺寸小等优点.随后采用胶体沉积法将两种合金均匀地负载到Al2O3上,成功获得PdAg/Al2O3和PdAu/Al2O3两种金属纳米催化剂.在邻氯硝基苯加氢反应中,与Pd/Al2O3纳米催化剂相比,PdAg/Al2O3催化剂显示出95.5％的选择性,而PdAu/AI2O3催化剂的选择性高达98.7％,这可能归因于Pd与Ag或Au金属间的协同效应.     

氟氧化铝的制备、表征及催化性能

采用干法制备得到氟氧化铝,NH3-TPD法对其进行酸性表征,并作乙醇脱水催化活性测试。结果表明:制备得到的氟氧化铝酸强度比纯AlF3有了较大的提高,催化乙醇制乙烯的最高转化率和选择性为96.65%和99.43%。     

生物质炭基磺酸化固体酸的制备及催化性能比较

以常见的碳水化合物葡萄糖、纤维素、蔗糖、医用棉为原料,采用碳化磺化法制备得到四种碳基磺酸化固体酸催化剂.采用傅里叶转换红外光谱(FT-IR )、表面酸量的测定等手段对这四种碳基磺酸化固体酸进行了表征.同时,将其用在乙酸乙酯的合成中,比较了其催化效率、稳定性.此外,还进行了再生实验.     

Nb/USY的制备及催化氧化脱硫性能

以USY分子筛为载体,铌酸为铌源,通过浸渍法制备了Nb/USY催化剂,并采用XRD、N2吸附-脱附、FTIR和TG-DTA对其进行表征分析。以噻吩的异辛烷溶液为模拟汽油、H2O2为氧化剂进行氧化脱硫反应,考察了铌酸负载量、催化剂焙烧温度、焙烧时间对催化剂活性的影响以及催化剂的再生使用性能,通过对氧化产物的分析,探讨了氧化脱硫机理。结果表明,在铌酸的负载量为15%、催化剂焙烧温度为300℃、焙烧时间为120 min时,Nb/USY催化剂活性最高,且再生性能良好,经分析确定噻吩硫的最终的氧化产物为硫酸根。     

膜分散小型反应器制备ZrO2纳米颗粒的实验研究

在膜分散机理及传质性能研究的基础上,本文提出了采用小型膜分散反应器进行纳米颗粒的制备,以二氧化锆纳米颗粒的制备为例,对此方法进行了研究.结果表明,制得的颗粒粒度小,在10～30 nm之间,且粒度分布窄,分散性好,球形度高.颗粒粒径随体系流量的增大而减小,随分散相浓度增大有一最大值.同时该方法能耗低,易于控制,并可进行连续操作,是一种很好的制备纳米颗粒的方法.     

不同碳基磺酸化固体酸的制备及催化性能比较

以常见的碳水化合物葡萄糖、纤维素、蔗糖、医用棉为原料,采用碳化磺化法制备得到四种碳基磺酸化固体酸催化剂。采用傅里叶转换红外光谱（FT-IR）、表面酸量的测定等手段对这四种碳基磺酸化固体酸进行了表征。同时将其用在乙酸乙酯的合成中,比较了其催化效率、稳定性。此外还进行了再生实验。