杂多阴离子柱撑锰铝水滑石的合成、表征及催化性能

杂多阴离子柱撑锰铝水滑石的合成、表征及催化性能刘继广，孙铁，蒋大振（吉林大学化学系，长春１３００２３）关键词杂多阴离子，柱撑，锰铝水滑石，异丁烷，烷基化类水滑石化合物属于阴离子型粘土‘’‘，其中心金属离子Ｍ２＋或Ｍ３＋及平衡阴离子可根据需要进行改变．...     

杂多阴离子柱撑水滑石层柱相互作用的XPS研究(II)

水滑石（LayeredDoubleHydroxides，简称LDHs）作为一类重要的柱层材料已引起人们的重视[1，2]．人们利用水滑石间柱阴离子的可交换性的特点[3].将各种阴离子如无机和有机阴离子[4]、同多和杂多阴离子（Polyoxometalates；简称POMs）[5]相继被引入水滑石层间．因此得到了具有高     

硅钨系列三元杂多阴离子柱撑水滑石的合成、表征及其酸碱催化性能

从ＮＯ_３－ＬＤＨ出发，通过直接交换反应合成了具有Ｋｅｇｇｉｎ结构的杂多阴离子ＳｉＷ_（１１）Ｍ·（Ｈ_２Ｏ）Ｏ　（Ｍ为第一系列过渡金属）柱撑水滑石，用元素分析、ＸＲＤ、ＩＲ和ＤＴＡ对产物的组成和结构进行了表征。结果表明，杂多阴离子进入水滑石层间，使水滑石的层间距从０．９２ｎｍ增加到１．４７ｎｍ，且热稳定性有所提高。柱撑产物在异丙醇反应中表现出酸碱双功能催化作用，但酸催化占明显优势。     

水滑石类阴离子黏土的合成及催化应用研究进展

水滑石类阴离子黏土具有一些独特的性能,作为催化材料应用广泛。本文就水滑石类阴离子黏土的合成现状进行了概述,对其各种不同的合成方法进行了比较。给出了它作为碱催化剂、氧化还原催化剂以及催化剂载体的应用实例,共引用文献60篇。     

类水滑石及其杂多阴离子柱撑物的合成与表面酸性研究

合成了一些类水滑石和过渡金属取代型杂多酸盐，并由此制备了相应杂多阴离子柱撑水滑石层柱材料。用ＸＲＤ，ＩＲ和元素分析等手段对合成产物进行组成和结构表征，用ＮＨ３－ＴＰＤ，Ｐｙ－ＩＲ研究了合成产物的表面酸性和酸类型，并在异丙醇反应中考察了合成物的酸碱催化行为，结果表明，水滑石和柱撑水滑石均同时存在酸碱中心，且酸碱相对强度与柱阴离子类型密切相关。杂多阴离子进入水滑石层，同时改变了水滑石和杂多酸盐的酸强度     

锌铝类水滑石的复原及表征(英)

本文采用焙烧复原法，在70 ℃以80%的乙醇溶液为分散介质，有机酸阴离子与煅烧后的锌铝类水滑石的物质的量之比为1∶9的条件下，实现了苯甲酸及苯二甲酸异构阴离子与锌铝类水滑石的插层反应，同时，还进行了等物质的量的两种酸与锌铝类水滑石（1∶1∶9）的插层反应。利用XRD和IR测试技术对样品结构进行表征，UV及HPLC对有机酸的反应量进行定量，并采用Gaussian-98软件包中ab initio分子轨道法（HF/6-31G）计算了各有机酸阴离子的分子结构，分析了其结构与插层行为的关系，并理论结合实验给出了各有机酸阴离子在锌铝类水滑石层间可能的空间构型。研究结果表明，苯甲酸及苯二甲酸异构阴离子在插层过程中表现出选择性，其优先进入锌铝类水滑石层间的顺序是：对苯二甲酸>邻苯二甲酸>间苯二甲酸>苯甲酸，且锌铝类水滑石对对苯二甲酸表现出较高的选择性，是环境友好的分离方法。     

己二酸柱撑水滑石的制备及表征

水滑石（Layered Double Hydroxidex,简称LDHs）是一类具有层状结构的阴离子型粘土^[1]。水滑石的一个重要性质是层间阴离子具有可交换性,引入不同的阴离子,能够得到不同结构和功能和柱撑水石滑,因而阴离子插层是水滑石研究的一个重要方向。各类阴离子如有机和无机阴离子、同多和杂多阴离子以及金属配合物阴离子的柱撑水滑石在文献中都有报道^[2-5]。其中有机阴离子由于在结构上的多样性,使有机阴离子柱撑水滑石具有巨大的应用开发潜力,已经引起了人们的广泛关注^[6-12]。     

P-Cu-Mo杂多阴离子柱撑水滑石的制备

杂多阴离子柱撑水滑石作为一类新型的催化材料,近年来日益受到人们的关注。但由于杂多化合物对碱不稳定及水滑石在酸性条件下层结构易被破环,故文献中仅有制得钨硅系杂多阴离子柱水滑石的报道。作者将过渡金属引入钼磷酸的Keggin结构骨架中,提高了其溶液稳定性,并在微波场中快速地制得了P-Cu-Mo杂多阴离子柱撑水滑石。     

阳离子掺杂水滑石的制备及其性质研究

研究了掺杂阳离子水滑石的制备及阳离子对水滑石性质的影响. 分别制备了掺杂Zn2+、Ni2+、Fe3+型的水滑石, 考察了掺杂阳离子对水滑石晶相结构、层间距、层间阴离子含量、水滑石表面形态、水滑石碱性的影响, 结果表明, 由于阳离子的引入, 导致水滑石层间距减小及层间阴离子结合量降低, 且使水滑石培烧产物电负性提高, 并最终降低其碱性. 以上述水滑石培烧产物作为固体碱催化剂促进苯甲醛和丙醛缩合, 合成α-甲基肉桂醛, 关联了水滑石培烧产物碱性与反应活性的关系.     

过氧杂多阴离子柱撑水滑石的合成、表征及催化性能的研究

通过离子交换法, 将含钛过渡金属离子一、三取代钨硅、钨磷过氧杂多配合物嵌入Zn2Al类水滑石中, 获得了柱撑化合物, 并用XRD, IR, XPS, 元素分析等手段对产物的结构和组成进行了表征。结果表明, 过氧杂多阴离子进入水滑石层间后, 水滑石的层间距从0.92nm增大到1.47nm, 且O2^2^-链没有被破坏。柱撑产物在环己烯氧化反应中显示优良的催化性能。     

Manufacture of opal-matrix functional nanocomposites by catalytic dehydrogenation of isopropanol under supercritical conditions

The products of redox reactions that occur during the manufacture of opal-matrix nanocomposites in isopropanol under supercritical conditions are studied. Experimental data, thermodynamic calculations, and reaction yield values imply that hydrogen is formed in the catalytic dehydrogenation of isopropanol to acetone under supercritical conditions. The alcohol dehydrogenation catalysts are ultrafine d-element oxides encapsulated in the pore space of an ordered opal matrix; in a closed experimental system (an autoclave), these oxides are reduced by hydrogen to metals or to lower oxides (or the oxygen stoichiometry of higher oxides changes).     

Décomposition de l'isopropanol sur les apatites mixtes calcium-argent

Decomposition of isopropanol on mixed calcium-silver apatites. A new family of apatite materials Ca_10-xAg_x(PO₄)₆(OH)_2-x□_x were synthesized, then studied using the decomposition reaction of isopropanol. The catalytic activity of the mixed apatites was observed to correspond mainly to dehydrogenation reaction features (the formation of acetone). This phenomenon has been tentatively related to the migration of Ag⁺ ions towards the surface and to their reduction to metallic silver under catalytic reaction conditions. The catalytic tests for the isopropanol decomposition reaction show that silver substituted hydroxyapatites were more actives than pure hydroxyapatite.     

Physicochemical and catalytic characterizations of materials prepared from copper malonate by thermal decomposition or chemical reduction

Results of Carr and Galwey [1] concerning copper malonate (CM) decomposition in vacuo at 510 K prompted present studies on the utility of CM as a low-temperature precursor of oxide-supported copper catalysts. CM deposited upon metal oxides has been converted to copper particles by vacuum thermal decomposition or reduction with aqueous hydrazine. Using the dehydrogenation of isopropanol to acetone as a catalytic probe reaction, comparisons are made between levels of catalytic activity and selectivity induced in TiO₂, MgO and Ca(OH)₂ supports by copper deposited thereon. Effects of particle size, prereduction temperature, and support reducibility are described and evidence is given for a strong metal support interaction (SMSI)-like inhibition of activity of Cu/TiO₂ by prior high temperature reduction.     

碱金属助剂类型及前驱物对改性NiAl复合氧化物催化分解N2O活性的影响

制备了不同Ni/Al原子比的NiAl类水滑石样品,焙烧获得NiAl复合氧化物,用于N₂O分解反应,研究了NiAl复合氧化物组成对催化活性的影响。在活性较高的NiAl复合氧化物表面浸渍碱金属碳酸盐溶液,制备改性NiAl复合氧化物,考察了碱金属类型（Na、K、Cs）和钾前驱物（K₂CO₃、K₂C₂O₄、CH₃COOK、KNO₃）对改性催化剂活性的影响。用XRD、ICP-AES、FT-IR、BET、H₂-TPR、XPS技术表征了催化剂的组成结构。结果表明,Ni/Al原子比为2.7的NiAl复合氧化物催化活性较高;Na、K、Cs碳酸盐改性NiAl复合氧化物均提高了催化剂活性,其中K的助剂效应最强。钾前驱物对K改性NiAl复合氧化物的催化活性有显著影响,其中碳酸钾、醋酸钾、草酸钾的加入明显提高了改性催化剂的催化活性,而加入硝酸钾反而降低了催化剂活性。     

One-pot synthesis of VO x /Al 2 O 3 as efficient catalysts for propane dehydrogenation

Vanadium oxides, as highly efficiently catalysts, are widely applied in various catalytic reactions, such as the dehydrogenation of light alkanes and epoxidation of alkenes. In this paper, a series of VO _x /Al ₂ O ₃ catalysts were fabricated by the 1-pot method for catalytic propane dehydrogenation. The results indicated that the VO _x /Al ₂ O ₃ catalysts with loading of 10 wt.% vanadium exhibited optimized catalytic performance. The as-prepared catalysts were characterized by N ₂ adsorption-desorption, XRD, TEM, H ₂ -TPR, and XPS to explore the texture properties, morphology, and electronic environment of vanadium. In addition, several vanadium catalysts were also prepared by the incipient wetness impregnation (IWI) method to compare their catalytic performance with the 1-pot synthesized catalysts. The catalysts synthesized by the 1-pot method exhibited higher selectivity of propylene and longer catalyst lifetime at high propane conversion when compared to the counterpart synthesized by the IWI method.     

Activity and selectivity of manganese oxides in alcohols Conversion as influenced by gamma-irradiation

Manganese oxide samples obtained from thermal decomposition of manganese carbonate at 400 and 600 °C were subjected to different doses of g-irradiation within the range 0.2 to 1.6 MGy. The surface and catalytic properties of the above samples were studied using nitrogen adsorption isotherms measured at -196 °C and catalytic conversion of ethanol and isopropanol at 300-400 °C using micropulse technique. The results obtained revealed that manganese oxides obtained at 400 °C consisted of a mixture of Mn₂O₃ and MnO₂ while the samples calcined at 600 °C composed entirely of Mn₂O₃. Gamma-irradiation resulted in a decrease in the particle size of manganese oxide phases with subsequent increase in their specific surface areas. Gamma-irradiation with 0.2 and 0.8 MGy effected a measurable progressive decrease in the catalytic activity in dehydration and dehydrogenation of both alcohols. However, the treated catalyst retained their initial activity upon exposure to a dose of 1.6 MGy. Also, g-irradiation increased the selectivities of the investigated solids towards dehydrogenation of both alcohols. The catalyst samples precalcined at 600 °C exhibited higher catalytic activities than those precalcined at 400 °C.     

Physicochemical studies on the TiO2-silica gel system

The physicochemical properties (crystal structure, surface acidity, surface area, catalytic activity and electrical conductivity) of TiO₂-silica gel mixed oxides have been investigated. A series of mixed oxides of various compositions in the range of 0–100% for each component were prepared by calcining the mixed oxides in air at temperatures of 115, 300, 600 and 1000°C. The results obtained have been discussed and correlated.     

Ammonia synthesis by means of plasma over MgO catalyst

Ammonia synthesis from H₂-N₂ mixed gas was studied at room temperature in a glow-discharge plasma in the presence of metals or metal oxides. Magnesia (MgO) and calcia (CaO), which are oxides with solid basicity, revealed catalytic activity in the plasma synthesis of ammonia, although they are catalytically inactive in industrial ammonia synthesis. The acidic oxides (Al₂O₃, WO₃, and SiO₂-Al₂O₃) lead to the consumption of the reactant, i.e., the H₂-N₂ mixed gas. No ammonia was isolated. Metal catalysts showed higher activity than the above basic oxides. They have, however, different activities. The reaction was faster over the active materials than over sodium chloride (NaCl) or glass wool or in a blank reactor without any catalyst.     

Palladium activity in 3-thiolene-1,1-dioxide hydrogenation in the presence of alkalis

Surface acidity/Basicity of mixed oxides of La and Zn activated at three different temperatures were determined. The data have been correlated with the catalytic activity for liquid phase reduction of cyclohexanone in isopropanol.     

Untersuchungen an oxidischen Katalysatoren. XVII. Zum Zusammenhang zwischen elektrischen und katalytischen Eigenschaften dotierter Zinkoxidkatalysatoren

Studies on Oxide Catalysts. XVII. On the Relations between Electric and Catalytic Properties of Doped Zinc Oxide Catalysts The electric conductivity and thermo EMF of zinc oxide catalysts doped with Li₂O, Ga₂O₃ and Fe₂O₃, and, on the other hand, their activity of dehydrogenation in the catalytic decomposition of isopropanol have been studied. The electric measurements were carried out preferably in an atmosphere of isopropanol. In washed single-phase catalysts doped with Li₂O (n-type semiconductors) the relation between the catalytic activity of dehydrogenation and the FERMI level position postulated by VOL'KEN?TEJN was verified quantitatively. The absorption of the isopropanol is considered to be the rate-determining acceptor step. In unwashed zinc oxide catalysts doped with Li₂O, however, the inversion from n- to p-type (between 0.3 and 0.5 mole-% Li₂O) causes a change in the character of the rate-determining step from an acceptor to a donor step. For the two-phase and three-phase solid systems of ZnO? Ga₂O₃ and ZnO? Fe₂O₃, respectively, it was not possible to find quantitative relations according to the electron theory of catalysis.