介孔氧化铝负载Ni-Co氧化物催化剂上丙烷氧化脱氢制丙烯

以非离子型三嵌段共聚物作为模板剂, 异丙醇铝为氧化铝的前驱物, 采用一锅法合成了一系列介孔氧化铝负载镍氧化物、钴氧化物以及镍-钴双金属氧化物催化剂, 并以介孔氧化铝为载体, 采用浸渍法制备了负载Ni-Co 氧化物催化剂. 采用N₂吸附-脱附、高分辨透射电镜(HRTEM)、X射线粉末衍射(XRD)、H₂程序升温还原(H₂-TPR)以及激光拉曼光谱(LRS)等技术对催化剂的结构与性质进行表征, 并考察了催化剂的丙烷氧化脱氢反应性能. 结果表明: 一锅法制备的各催化剂均有大的比表面积和规整的孔道结构, 且负载的金属氧化物高度分散; 而浸渍法制备的催化剂, 其载体的介孔结构被破坏并有Co₃O₄晶相生成. 在考察的催化剂中, 一锅法合成的介孔氧化铝负载Ni-Co 氧化物催化剂表现出最佳的丙烷氧化脱氢性能. 在450 °C、C₃H₈:O₂:N₂的摩尔比为1:1:4和空速(GHSV)为10000 mL·g^-1·h^-1条件下, 该催化剂上丙烯产率为10.3%, 远高于浸渍法制备的催化剂上所获得的丙烯产率(2.4%). 关联催化剂表征和反应结果, 讨论了催化剂结构与性能之间的关系.     

非对称陀螺自由基分子光谱的标识分析——NO2基振动态纯转动光谱分析

系统阐述了非对称陀螺分子光谱的标识分析工作涉及的一些关键理论问题,包括有效Hamilton量、表象和基矢、能级识别、跃迁选择规则、相对强度和Zeeman调制率等,并在有效Hamilton量中引入高阶离心畸变项,大大提高了计算精度,并使高转动量子数跃迁的标识分析成为可能.作为应用实例,对¹⁴N¹⁶O₂基振动态的零场和磁共振谱进行了统一分析(global analysis),获得了迄今为止最精确、最完整的¹⁴N¹⁶O₂基振动态分子结构参数,并对Curl和Brown等人过去未能标识的¹⁴N¹⁶O₂高转动量子数跃迁远红外激光磁共振谱线进行了成功标识.     

新的cis-Pt(diphos)(Ⅹ)2配合物的合成和谱学表征

本文合成了三个新的双膦螯合配体和一系列新的cis-Pt(diphos)X₂(diphos=R₂PCH₂CH₂PR₂,R=Et,n-Pr,n-Bu,i-Bu;X=Cl^-,Br^-,I^-,CN^-,SCN^-,NO₂^-)配合物,经过IR、³¹PNMR和元素分析表征了它们的结构,并观察到³¹P化学位移δ_p、铂-磷偶合常数J_p1-p与配体X的反位效应和双膦配体的σ-供电性质有关。此外,根据谱学研究,发现SCN^-和NO₂^-配体存在键合异构现象,并对谱带进行了归属。     

双核铜Schiff碱新配合物的合成及其催化和生物活性

合成了新型四甘醇醛缩苯丙氨酸Schiff碱与铜的双核配合物. 以元素分析、红外光谱、磁化率、热分析、¹H NMR及EPR谱等方法确定配合物组成为[Cu₂L(NO₃)]NO₃. 此配合物可单独催化聚合甲基丙烯酸甲酯(MMA), 并考察了催化剂的浓度、溶剂以及聚合温度和时间对聚合反应的影响. 结果表明, 在聚合条件为: MMA/催化剂= 500(摩尔比), [催化剂] = 7.5×10^–3 mol•L^–1, 1,4-二氧六环为溶剂, 80℃, 6 h, 具有良好的催化性能, 可以获得转化率为80%, 粘均分子量为72万, 间同立构含量为60.5% 的聚甲基丙烯酸甲酯. 此外, 研究表明该配合物具有十分显著的清除的作用.     

2,6-二乙酰吡啶类双希夫碱配合物的合成和研究 Ⅱ.Cu(Ⅱ)配合物的合成和研究

合成了五个2,6-二乙酰吡啶缩肼基硫代甲酸酯双希夫碱合铜(Ⅱ)配合物,用元素分析、磁化率、红外光谱及紫外-可见光谱等对它们进行了表征,研究了配合物的电化学性质和Cu₃L₂²X₂(X=Cl^-、SCN^-)的光电子能谱。结果表明:五个Cu(Ⅱ)配合物均为三核配合物,在Cu₃L₂²(SCN)₂中存在Cu(Ⅱ)间的自旋-交换作用。     

螺吡喃衍生物在固相基质中的应用

合成了一种新的螺吡喃衍生物, 将其应用到PVC膜固相基质中, 用于Zn²⁺的荧光检测. 优化条件下, 该敏感膜对Zn²⁺的响应范围为4.94×10^−7~4.15×10^−4 mol·L^−1, 检测限为1.51×10^−7 mol·L^−1. 实验发现, 该敏感膜具有很好的光学稳定性、重现性和可逆性, 而且与其他过渡金属离子如Hg²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Fe³⁺或碱金属和碱土金属离子相比, 该敏感膜对Zn²⁺的荧光增强具有高选择性.     

质子导体(Ce0.8La0.2)1－xCaxO2－δ 在合成氨中的应用

利用溶胶-凝胶法合成了萤石型稀土复合氧化物(Ce_0.8La_0.2)_1－xCa_xO_2－δ, 利用XRD、TEM和SEM对样品进行表征. 电化学方法研究表明, 合成样品在400～800 ℃温度范围内具有质子导电特性. 将(Ce_0.8La_0.2)_1－xCa_xO>_2－δ高温烧结体用于固态质子传导电池, 在常压下以氮气和氢气为原料合成氨气, 并确定了合成氨的适宜条件. 650 ℃时Ce_0.8La_0.2O_2－δ和(Ce_0.8La_0.2)_0.975Ca_0.025O_2－δ对应的氨产率分别达7.2×10^－9和7.5×10^－9 mol•s^－9•cm^－9.     

合成气制液化石油气复合催化剂的性能

 将甲醇合成催化剂与负载 Pd 的分子筛颗粒混合制得复合催化剂, 在连续固定床反应器上考察了该催化剂对合成气一步法制液化石油气 (LPG) 的性能. 采用 N₂ 吸附-脱附、_NH3 程序升温脱附和程序升温氧化对催化剂进行了表征. 结果表明, 分子筛孔径对 LPG 选择性影响显著, 当采用孔径为 0.74 nm × 0.74 nm 的 Y 型分子筛时 LPG 选择性最高. 在 300 ^oC, 2.1 MPa 和空速 1 500 h^-1 条件下, 含有 Y 型分子筛的复合催化剂上 CO 转化率达 80.2%, LPG 占烃类产物的 73.8%. 在一步法合成 LPG 反应中, 催化剂表面积炭是导致 CO 转化率和 LPG 选择性下降的主要原因.     

多C== N—基不对称Schiff碱及其稀土配合物的合成和催化

研究与探讨了多C==N—基空间不对称Schiff碱的合成, 合成了含有2个以上不同位置C==N— 基团的Schiff碱, 即四甘醇醛和2,4-二羟基苯甲醛缩双赖氨酸(TBLY)与稀土的配合物, 经元素分析、磁化率、光谱及¹H NMR, ¹H,¹H COSY, ¹³C NMR谱等表征, 确定其组成为Ln₃(TBLY)(NO₃)₃·nH₂O (Ln = La, n= 3; Ln = Nd, n= 5; Ln = Gd, Dy, Yb, Y, n= 7). 以半经验量子化学AM1法计算并探讨了在红外光谱和核磁共振谱中所观察到的烯胺键的存在. 该类新Schiff碱配合物不需助催化剂即可单独催化聚合甲基丙烯酸甲酯(MMA), 转化率可达80%, 黏均分子量约为22万.     

含三苯胺聚希夫碱的三阶光学非线性极化率

设计合成并表征了新颖的具有三阶非线性光学性能的含有富电子结构单元的共轭聚希夫碱(PolySchiff base, PSB), 用Z-扫描技术研究了目标产物的三阶非线性特性, 测定了目标产物吡咯烷酮(NMP)溶液的三阶非线性折射率及非线性吸收率, 在波长为532 nm的Nd-YAG激光作用下, 得到非线性折射率n₂ = -1.23×10^-10 esu; Reχ⁽³⁾ = -3.06×10^-12 esu. 非线性吸收系数b = 3.63 10^-10 m/W, Imχ⁽³⁾ = 1.15 10^-11 esu, χ⁽³⁾ = 1.19 10^-11 esu, 在已知的材料中显示出较大的值. 由于n₂值为负数, PSB是自散焦材料. 表明PSB具有较强的三阶非线性光学性能, 有较大的应用前景. 用量子化学计算的方法对其电子结构, 前线分子轨道, χ⁽³⁾进行了理论计算, 并讨论了之间的关系.     

Facile synthesis for ordered mesoporous gamma-aluminas with high thermal stability

The facile synthesis of highly ordered mesoporous aluminas with high thermal stability and tunable pore sizes is systematically investigated. The general synthesis strategy is based on a sol-gel process associated with nonionic block copolymer as templates in ethanol solvent. Small-angle XRD, TEM, and nitrogen adsorption and desorption results show that these mesoporous aluminas possess a highly ordered 2D hexagonal mesostructure, which is resistant to high temperature up to 1000 degrees C. Ordered mesoporous structures with tunable pore sizes are obtained with various precursors, different acids as pH adjustors, and different block copolymers as templates. These mesoporous aluminas have large surface areas (ca. 400 m2/g), pore volumes (ca. 0.70 cm3/g), and narrow pore-size distributions. The influence of the complexation ability of anions and hydro-carboxylic acid, acid volatility, and other important synthesis conditions are discussed in detail. Utilizing this simple strategy, we also obtained partly ordered mesoporous alumina with hydrous aluminum nitrate as the precursor. FTIR pyridine adsorption measurements indicate that a large amount of Lewis acid sites exist in these mesoporous aluminas. These materials are expected to be good candidates in catalysis due to the uniform pore structures, large surface areas, tunable pore sizes, and large amounts of surface Lewis acid sites. Loaded with ruthenium, the representative mesoporous alumina exhibits reactant size selectivity in hydrogenation of acetone, D-glucose, and D-(+)-cellobiose as a test reaction, indicating the potential applications in shape-selective catalysis.     

介孔氧化铝的制备及其在甲醇脱水制二甲醚反应中的应用

以硝酸铝为铝源,以十六烷基三甲基溴化铵为阳离子模板剂,采用均匀沉淀法成功制得热稳定性较高和高度有序的介孔Al2O3(其比表面积179.8 m2/g,孔径5.4 am,孔体积0.3 cm3/g),并用于甲醇脱水制二甲醚反应中.结果表明,在280℃,液时空速为30 h-1条件下,甲醇转化率为90.2%,二甲醚时空收率最高可...     

高比表面积有序介孔氧化铝的制备与表征

采用溶胶-凝胶法以非离子表面活性剂PEO-PPO-PEO三嵌段共聚物F127为模板剂, 以异丙醇铝为铝源, 以异丙醇为溶剂, 成功地制备出比表面积为485 m2/g、孔径分布窄(2~20 nm)、孔容在1.2 cm3/g以上和孔道呈蠕虫状且具有一定有序性的介孔氧化铝. 采用BET, TEM, XRD和TG多种测试技术对产物性能进行了表征. 探讨了水铝比、醇水混合溶液的滴加速度、反应时间、水浴温度、陈化温度及陈化时间等条件对合成的有序介孔氧化铝结构的影响.     

High surface area, mesoporous, glassy alumina with a controllable pore size by nanocasting from carbon aerogels

A strategy to synthesize amorphous, mesoporous alumina by nanocasting has been developed, involving carbon aerogel as a hard template and aluminum nitrate solution as an alumina precursor. The alumina generated exhibits small, transparent granules with a 3-6 mm diameter and has inherited the three-dimensional network structure of the carbon template. The mesopore surface area of the alumina can be as high as 365 m2 g(-1), and the pore volume reaches 1.55 cm3 g(-1) after calcination at 600 degrees C in air for 8 h. The pore parameters can be varied within a certain range by variation of the carbon aerogel template and the loading amount of the alumina precursor. At high loadings, the obtained glassy alumina clearly has a bimodal pore size distribution in the mesopore range.     

有序介孔材料: 历史、 现状与发展趋势

有序介孔材料是指孔径在2~50 nm之间的多孔材料, 是一类具有均匀孔径、 高有序度纳米孔道和高比表面积的新材料. 在过去30年里, 有序介孔材料的研究取得了长足的进步, 在可控合成、 结构设计和调控及功能化等方面形成了系统的理论. 同时, 其应用领域也不断被拓展, 包括能源存储与转化、 催化、 生物医药和传感等方面. 本文首先回顾了有序介孔材料的发展历史, 简要介绍发展过程中“里程碑式”的研究工作; 然后根据构效关系总结了其在不同领域应用的最新进展; 最后讨论了有序介孔材料领域进一步发展所面临的挑战与机遇, 并对未来前景进行了展望.     

Study on the capacity of mesoporous alumina with different pore sizes absorb silane inhibitors

By modifying and optimizing the procedures, which were well described and understood for the synthesis of macroporous alumina, mesoporous alumina–based film has been successfully prepared, In this paper, the orderly mesoporous Al₂O₃ thin film was prepared by electrochemical workstation, and via supported N‐octyltriethoxysilane (NOS) coupling agent, corrosion inhibitors be loaded into the different pore sizes of mesoporous alumina films. The physicochemical properties of this thin inhibitors carrier film were characterized. Corrosion resistance of mesoporous alumina and honeycomb ceramic macroporous alumina were compared; the conclusion shows that mesoporous alumina film can be used as good corrosion inhibitors carrier and bring out a high‐efficiency inhibition result. Simultaneously, by compared with corrosion inhibition of different pore sizes (20‐50 nm) mesoporous alumina who absorbed NOS, and a general relationship between the different mesoporous alumina pore sizes and the adsorption capacity of NOS was obtained.     

One‐Step Grafting of Al2O3 onto Acid‐Made Mesoporous Silica

We report a one‐step convenient chemical coating method of high alumina content onto mesoporous silicas. Aluminia‐coated mesoporous silica with high surface area (?900 m²/g), tuneable pore size (2.0–3.0 nm) and high hydrothermal stability (> 60 h) is obtained. The method may also be generalized for grafting other metal oxides onto mesoporous silica in future work.     

Mesoporous metal-organic framework materials

Metal-organic frameworks (MOFs) have emerged as a new type of porous materials for diverse applications. Most open MOFs reported to date are microporous (pore sizes <2 nm), and only a small fraction of MOFs with ordered mesoscale domains (2-50 nm) is reported. This tutorial review covers recent advances in the field of mesoporous MOFs (mesoMOFs), including their design and synthesis, porosity activation and surface modification, and potential applications in storage and separation, catalysis, drug delivery and imaging. Their specificities are dependent on the pore shape, size, and chemical environments of the cages or channels. The relationship between the structures and functions is discussed. The future outlook for the field is discussed in the context of current challenges in applications of mesoporous materials.     

Incorporation of chemical functionalities in the framework of mesoporous silica

Mesoporous silica, which shows well-defined pore systems, tunable pore diameters (2-30 nm), narrow pore size distributions and high surface areas (>600 m(2) g(-1)), is frequently modified using different methodologies (including in situ and post-synthetic strategies) to introduce various chemical functionalities useful in applications like catalysis, separation, drug delivery, and sensing. This contribution aims to provide a critical overview of the various strategies to incorporate chemical functionalities in mesoporous silica highlighting the advantages of the in situ methods based on the bottom-up construction of mesoporous silica containing various chemical functionalities in its structure.     

Facile synthesis of highly ordered mesoporous ZnTiO3 with crystalline walls by self-adjusting method

Highly ordered mesoporous ZnTiO(3) with crystalline walls was directly prepared by a sol-gel process combined with evaporation induced self-assembly in ethanol, using amphiphilic triblock copolymers as structure directing agents. The whole process is self-adjusting to organize the network-forming metal oxide species without additional acid or base. The mesoporous material is pure cubic-phase ZnTiO(3) and has large surface area (up to 134 m(2)/g), large pore volume (0.17 cm(3)/g), and narrow pore size distribution (3-4.5 nm). The optic behavior was systematically studied, which is very helpful to understand the mesoporous ZnTiO(3) material either in fundamental study or for potential applications in optics and catalysis. This work provides a "self-adjusting" approach to fabricate the mesoporous functional materials with diverse compositions: the diverse hydrolysis-condensation kinetics of various metal oxides is homogenized to yield stable multicomponent precursors. The development of such a simple, versatile, and reproducible method is important for applications in practice.