新型层柱材料ZnAl─CuW11In的合成、表征及催化活性

本文用水热离子交换法首次将中心原子为铜的钨系取代型杂多阴离子［ＣｕＷ１１Ｏ３９Ｉｎ（Ｈ２Ｏ）］７－嵌入ＺｎＡｌ型阴离子粘土层间，通过ＸＲＤ、ＩＲ及ＥＳＲ等对柱撑产物进行了表征。ＸＲＤ研究表明柱撑产物的底面间距为１．７５ｎｍ，通道高度达１．２８ｎｍ。ＥＳＲ结果显示杂多阴离子进入粘土层间后ＣｕＯ４四面体中Ｃｕ－Ｏ键的共价性减弱。催化实验则表明柱撑产物对邻苯二甲酸二辛酯（ＤＯＰ）的合成反应有较高的催化活性     

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。     

过氧杂多阴离子柱撑水滑石类层状化合物的合成与表征

以硝酸根型水滑石作交换前驱体，通过离子交换法合成了过渡金属离子一、三钛取代的Ｋｅｇｇｉｎ结构过氧钨硅杂多阴离子柱撑水滑石Ｚｎ２Ａｌ（ＯＨ）６－［ＳｉＷ１１（ＴｉＯ２）Ｏ３９］及Ｚｎ２Ａｌ（ＯＨ）６－［ＳｉＷ９（ＴｉＯ２）３Ｏ３７］，用元素分析、ＸＲＤ、ＩＲ、ＸＰＳ、化学分析等手段对产物的组成和结构进行了表征。结果表明，过氧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。     

钨硅系列三元杂多阴离柱撑阴离子粘土的合成及表征

采用离子交换法将过渡金属离了三元取代钨杂多阴离子引入Ｚｎ２Ａｌ型阴离子粘土层内，得到柱撑水滑石Ｚｎ２Ａｌ（ＯＨ）６－ＳｉＷ９Ｚ３Ｏ４０（Ｚ＝Ｔｉ＾４＋，Ｍｏ＾６＋）及Ｚｎ２Ａｌ（ＯＨ）６－ＳｉＷ９Ｆｅ３（Ｈ２Ｏ２）３Ｏ３７。ＺＲＤ及ＩＲ表明，杂多阴离子引入水滑石层间后，水滑石层内高度为１．０ｎｍ。     

Keggin结构磷钨钒杂多阴离子柱撑水滑石的合成、表征与热稳定性研究

采用水浴液中阴离子直接交换法合成了具有不同钒含量的Ｋｅｇｇｉｎ结构磷钨钒杂多阴离子ＰＷ（１２－ｎ）ＶｎＯ（４０）（ｎ＝１—５）柱撑水滑石，用元素分析、ＸＲＤ和ＩＲ对柱撑产物的组成和结构进行了表征．ＸＲＤ结果给出柱撑产物的底面间距达１．４７Ｍ．ＤＴＡ结果表明柱撑产物的热稳定性高于水滑石前驱体，且与杂多阴离子中Ｖ含量相关．由不同温度下焙烧样品的ＸＲＤ和ＩＲ研究可知，柱撑产物的热分解过程为：＜２５０℃时脱除物理吸附水和层间水；２５０～４００℃范围内脱羟基（同时伴随着层间Ｋｅｇｇｉｎ离子结构的破坏）；４００℃以上生成ＷＯ３和Ｍｇ２Ｖ２Ｏ７，后者在７５０℃以上分解为ＭｇＯ和Ｖ２Ｏ５．     

P—W系杂多阴离子柱水滑石的制备及表征

本文采用微波法，首次制了第四周期系过滤金属取代三元杂多阴离子（ＰＺＷ１１）柱水滑石。经ＸＲＤ、ＤＴＡ、ＩＲ、ＵＶ－ＤＲＳ和ＥＳＲ表征。结果表明插入层间的柱高约为１．０ｎｍ，进入水滑石层间的杂多阴离子与其盐的ＩＲ振动类型和振动频率很相近，并且在水滑石层间ＰＷ１２基团不能稳定存在，可能已部分发生降解，而ＰＺＷ１１则能稳定的存在于水滑石层间。ＵＶ结果表明，进入水滑石层间的杂多阴离子的桥氧与钨（Ｏｂ／Ｏｃ     

新的柱撑阴离子粘土的合成,表征和催化性能研究

用水热合成和离子交换方法合成了新的柱撑阴离子粘土Ｚｎ２Ａｌ－ＳｉＷ９Ｍｎ３,通过ＸＲＤ,ＩＲ,ＤＴＡ,元素分析等手段对其进行了表征。研究表明,合成的杂多阴离子柱撑粘土的通道高度为１．００ｎｍ,红外光谱显示了Ｋｅｇｇｉｎ结构阴离子的特征振动、柱撑产物的热稳定性高于其前驱体,在马来酸环氧化反应中显示了较高的催化活性。     

新型层柱微孔材料──FeW_（11）NiO_（39）柱撑ZnAl阴离子粘土的合成、表征及催化性能

采用水热合成与离子交换方法，将中心原子为过渡金属（Ｆｅ）的钨系过渡金属取代型杂多阴离子ＦｅＷ_（１１）ＮｉＯ_（３９）（Ｈ_２Ｏ）￣（７－）（缩写为ＦｅＷ_（１１）Ｎｉ）嵌入ＺｎＡｌ型阴离子层状结构粘土间，获得了大层间距、通道高度达１．３２ｎｍ的新型层柱微孔化合物。通过ＸＲＤ、ＩＲ及ＥＳＲ等手段进行了表征。以ＺｎＡｌ－Ｆｅｗ_（１１）Ｎｉ为催化剂合成邻苯二甲酸二辛酯（ＤＯＰ），选择性大于９９％，转化率由嵌入前的１２％提高到近５０％，催化活性明显提高。     

杂多阴离子柱撑水滑石层柱相互作用(Ⅰ)

杂多阴离子柱撑水滑石层柱相互作用（Ⅰ）李兴林＊佘益民郭军蒋大振（中国科学院长春应用化学研究所长春１３００２２）（吉林大学化学系长春）关键词杂多阴离子，柱撑水滑石，ＸＰＳ，ＩＲ，ＸＲＤ１９９６－０６－１８收稿，１９９６－１０－１２修回国家自然科学基金资...     

柱撑阴离子粘土的合成、表征及催化性能研I．ZnAl─SiW_（11）及ZnAl—SiW_（11）Z的合成

采用水热合成及离子交换方法将缺位及单取代型Ｋｅｇｇｉｎ结构钨硅杂多含氧酸根ＳｉＷ（１１）及ＳｉＷ（１１）Ｏ（３９）Ｚ（Ｈ２Ｏ）（６－）嵌入Ｚｎ─Ａｌ型阴离子粘土层间，得到了大层间距的新型层往状微孔材料ＺｎＡｌ─ＳｉＷ（１１）及ＺｎＡｌ—ＳｉＷ（１１）Ｚ（Ｚ＝Ｃｏ（２＋）、Ｎｉ（２十）和Ｃｕ（２＋）），ＸＲＤ与ＩＲ测试结果表明，它们只有９．７　的通道高度．     

Hydrothermal synthesis, characterization and its photoactivity of CdS/Rectorite nanocomposites

CdS/Rectorite nanocomposites were prepared through hydrothermal method by using Cd[NH₂CSNH₂]₂Ac₂ complex as precursor of CdS which was derived from cadmium acetate and thiourea. The obtained nanocomposites were characterized by X-ray diffraction (XRD), Fourier transfer infrared spectra (FTIR), diffusion reflection spectra (DRS), transmission electron microscopy (TEM) and the selected area electron diffraction (SAED) patterns. Experimental results indicate that CdS exist in at least three forms: CdS adsorbed at surface, CdS pillared in montmorillonite-like layers of Rectorite and CdS pillared in the new layered structure formed during the hydrothermal process. Those CdS crystals are hexagonal symmetry. The photoactivity and photostability of the obtained CdS/Rectorite nanocomposites are improved significantly compared to that of the reference Rectorite and pure CdS.     

三元P-Cu-W杂多阴离子柱撑水滑石的制备

用微波法制备了杂多阴离子柱撑水滑石,经XRD、IR、ESR和DTA表征,证明制备的样品具有良好的层柱结构,其热稳定性比相应的杂多酸盐提高约40℃,杂多阴离子中Cu²⁺并非处于标准的八面体场中,而是处于一种近似于五配位的立方锥场,并随嵌入层间后更趋于五配位。     

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。     

Characterization of silica-supported molybdenum catalysts by ESR, XPS and thiophene hydrodesulfurization

Two Mo/SiO₂ samples have been prepared by impregnation of silica gel with aqueous solution of molybdophosphoric heteropoly acid or ammonium heptamolybdate. The catalysts were studied by ESR and IR spectroscopy, X-ray diffraction, and XPS. Their activity was measured in the reaction of thiophene hydrodesulfurization. The silica-supported P–Mo heteropoly acid, with a preserved Keggin structure of the heteropoly anion and sulfided by H₂S, exhibited two times higher steady conversion in comparison with ammonium heptamolybdate supported on silica at pH=11 and calcined and sulfided at 500°C.     

Studies of layered and channel complexes using combined thermogravimetry and mass spectrometry

The rate of removal and uptake of guests into layered and porous materials is important in many areas of materials chemistry. Here we report on the use of atmospheric thermogravimetry linked to a mass spectrometer (TG-MS) to investigate the thermal characteristics of three different solids. We show that (i) the desorption of cyclohexylamine from the surface of a pillared acid activated smectite clay occurs in two stages, indicating two possible acidic binding sites, (ii) TG-MS is an extremely sensitive technique for probing progressive anion exchange of lithium aluminium layered double hydroxides, (iii) on heating, the perhydrate 4Na₂SO₄·NH₄Cl·2H₂O₂ releases H₂O₂ intact.We are very grateful to Miss J. Bovey for supplying us with the acid activated clay and for very helpful comments. We would like to thank Rheometric Scientific Ltd. and Leda Mass Ltd. for their advice and co-operation in designing and fitting the transfer line. Financial assistance from the EPSRC through a Quota award to ICC and a CASE award with Solvay Interox Ltd. to SDC is also appreciated.     

柱撑阴离子粘土的合成、表征及催化性能研I.ZnAl─SiW11及ZnAl—SiW11Z的合成

采用水热合成及离子交换方法将缺位及单取代型Keggin结构钨硅杂多含氧酸根SiW₁₁及SiW₁₁O₃₉Z(H₂O)^6-嵌入Zn─Al型阴离子粘土层间,得到了大层间距的新型层往状微孔材料ZnAl─SiW₁₁及ZnAl-SiW₁₁Z(Z=Co²⁺、Ni²⁺和Cu²⁺),XRD与IR测试结果表明,它们只有9.7Å 的通道高度.     

柱撑化合物Zn2Al-PW11Z的结构模型及酯化活性

杂多化合物是性能优异的酸型和氧化型或双功能催化剂[1－4]，而通式为的阴离子粘土通常具有减催化或还原催化性能[5，6]．因此，从在分子及原子水平上设计催化剂，调控催化性能观点出发，人们期望将体积较大的杂多阴离子嵌入阴离子粘土层间，合成大层间距的新型柱撑微孔材料．1988年Pinnavaia等人[7]首次报导了Zn2Al－V10O28是具有2．0nm孔径分布的中微孔材料．最近，笔者将单取代型Keggin结构杂多阴离子GeW11O39Z（H2O）6－（其中Z＝Ni2 和Cu2 ）和缺位Keggin结构的GeW11O嵌入Zn2Al－NO3层间，合成了通道高度为0．9nm的新型柱撑…     

Synthesis,Characterization and Catalytic Activity of ZnAl Anionic Clay Pillared by α-Na_6[GaW_(11)O_(39)Fe(H_2O)]·18H_2O

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｎｉｏｎｉｃｃｌａｙｉｓａｌｓｏｃａｌｅｄｌａｙｅｒｅｄｄｏｕｂｌｅｈｙｄｒｏｘｉｄｅ（ｎｏｔｅｄａｓＬＤＨ）,ｉｔｓｕｎｉｑｕｅｂａｓｉｃｃａｔａｌｙｔｉｃｆｕｎｃｔｉｏｎ,ｉｎｔｅｒｅｓｔｉｎｇ“ｍｅｍｏｒｙｅｆｅ...     

Photochemical Synthesis,Properties and X—Ray Crystal Structure of Tetrabutylammonium Dodecamolybdophosphate Heteropoly Blue

Ｈｅｔｅｒｏｐｏｌｙｂｌｕｅｉｓｔｈｅｒｅｄｕｃｅｄｐｒｏｄｕｃｔｏｆｔｈｅｐｏｌｙ ｏｘｏｍｅｔａｌａｔｅｓ.Ｉｔｈａｓａｔｔｒａｃｔｅｄｍｕｃｈａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｉｔｓｎｏｖｅｌｓｔｒｕｃｔｕｒｅ ,ｕｎｉｑｕｅｐｒｏｐｅｒｔｉｅｓａｎｄｐｏｔｅｎｔｉａｌａｐ ｐｌｉｃａｔｉｏｎｓｉｎｔｈｅｆｉｅｌｄｓｏｆｃａｔａｌｙｓｉｓ ,ｐｈａｒｍａｃｅｕｔｉｃａｌｃｈｅｍｉｓｔｒｙａｎｄｆｕｎｃｔｉｏｎａｌｍａｔｅｒｉａｌｓ .1 3 Ａｔｅａｒｌｙｓｔａｇｅ ,ｈｅｔｅｒｏｐｏｌｙｂｌｕｅｗａ…     

Silver-layered double hydroxides self-assemblies

New inorganic ensembles type layered double hydroxides enriched with silver ions were investigated in terms of thermal behavior and structural evolution by means of TG-FTIR analysis. The studies were focused on two classes of layered precursors, actually distinguished only by the nature of the divalent metal ions, in order to correlate the influence of the clay structure with the thermal behavior of the silver-anionic clay ensembles. The understanding of the thermal degradation mechanism, which is essential to advance the potential applications, requires supplementary characterization techniques such as XRD and FTIR analyses. The thermal analysis performed at three different heating rates revealed the three thermal degradation stages typical for LDHs structure, but different from sample to sample as a consequence of the different interactions between the clay layers and the interlayer anions. The interpretation of the 3D FTIR spectra of the gaseous species resulting in each stage of the thermal degradation process, by means of standard IR spectra, indicates CO₂ and H₂O as main evolved gasses. Moreover, the evolution curves of the gaseous species released by the thermal degradation in air of the studied anionic clays point out that the two gaseous components are eliminated into the temperature ranges corresponding to those given by TG–DTG. The comparative study of the silver-LDH ensembles from the perspective of the structural evolution during the controlled heating suggest a better response from the ensemble with structure consisting of magnesium as divalent cation in the clay network, meaning a better thermal stability.