合成皂石及其交联物在偏三甲苯歧化反应中的催化行为

以羟基铝低聚物与其交联制得柱撑皂石,并在偏三甲苯歧化反应中考察了它们的催化性能.结果表明,催化活性随柱撑皂石表面酸量增加而增加;四甲苯中均四甲苯和二甲苯中邻二甲苯的百分含量皆高于热力学平衡值.催化特性与柱撑皂石的柱密度相关.     

层柱皂石的合成、表征及正癸烷临氢异构催化性能

采用高温水热合成法在强碱性条件下,成功制备了有序性很高的三八面体结构的皂石,同时对其进行铝柱柱撑,通过XRD、27Al MAS-NMR、N2吸附脱附、吡啶红外、TGA-DTA、TEM等技术对材料进行了物化表征,并用临氢异构表征了材料的催化性能. 结果表明：层柱皂石具有很好的层柱结构,热稳定性可达800℃以上,且具有较好的正癸烷临氢异构转化率和异构产物收率.     

M?ssbauer Spectroscopy Study of Alumina-Supported Iron-Containing Catalysts for Hydrogen Sulfide Oxidation

The pillared clay catalyst, which was obtained by exposing activated clay powder to sulfuric acid and aluminium salts and calcining in air at 373 – 673 K, was found to be highly active for the title reaction. The activity is mainly attributed to the Lewis acid sites and also to a small number of Brönsted acid sites, whose number and strength increases with the extent of pillaring. The kinetic equation of surface esterification is y = 2.57x - 1.47.     

镓皂石的合成和交联及其催化性能

用水热法合成了Ｇａ取代皂石（ＧａＳ，并用羟基铝低聚物与其交换制得了ＰＧａＳ。用ＸＲＤ，＾２７Ａｌ、＾２９Ｓｉ ＭＡＳ ＮＭＲ和ＮＨ３－ＴＰＤ表征了ＧａＳ，ＰＧａＳ和ＣＰＧａＳ。在１，２，４－三甲苯歧化反应中观察了ＰＳ（交联皂石）和ＰＧａＳ的催化性能。结果表明ＧａＳ的结晶度很高，Ｇａ确实进入了皂石的骨架，与ＰＳ相比，ＰＧａＳ的活性和活性衰减低，歧化选择性高。这可能与ＰＧａＳ表面Ｌ酸所占表面酸份额高有     

层柱人工水热合成皂石的制备与表征(英)

利用具有理想皂石结构的人工水热合成蒙皂石为层原料，通过与羟基聚合铝离子（[Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺）交换反应合成得到了一种层柱粘土。实验对于该铝柱皂石进行了粉末XRD，FT-IR和TG-DTA表征。氮气吸附实验说明其高温活化（773K，2 h）产物具有很高的BET比表面（360 m²·g^-1）。相对于层柱蒙脱土，层柱皂石显示了更高的催化裂解性能和热稳定性。层柱皂石的异丙苯裂解转化率达到了65%；而层柱蒙脱土的转化率只有4%。这说明层材料的四面体取代对于层柱粘土Br?nsted酸位的形成具有重要的决定作用。氨程序升温脱附实验发现铝柱皂石在350～650 ℃区间具有较强的氨脱附量，表明层柱皂石具有层柱蒙脱土所没有的强酸中心。     

铝交联皂石的合成和表征及催化性能

用XRD、化学分析、IR、MASNMR、TPD等手段表征了合成皂石及其铝交联物的结构。结果表明:皂石的交联密度与四面体层电荷和交联条件(Al/土比)有关。在乙醇氨化反应中,交联皂石显示了较好的催化活性和选择性。皂石的交联密度与液相产物分布的关系表明层柱材料对此反应具有择形催化作用。醇氨化反应可能是在吸附态NH_3和气相醇分子间进行的。     

新型层柱材料Zn2Al-SiW9M3的合成、表征及催化性能研究

杂多阴离子柱撑粘土是一类新型层柱催化材料.本文采用水热合成与离子交换方法首次将三取代Keggin结构杂多阴离子α-[SiW9O37M3(H2O)3]n-(简写为SiW9M3,M＝Mn2+,Cr3+,Ti3+,Fe3+)嵌入到Zn-Al型阴离子粘土层间,并通过XRD、IR、DTA和元素分析等手段对其结构进行了表征,考察了它们在顺丁烯二酸环氧化反应中的催化活性.     

The synthesis of pillared nickel-substituted saponite and its hydroisomerization activity

Nickel-substituted saponite clays (NiS) were synthesized. The pillared clays notedPNiS were prepared from the NiS intercalated with large inorganic cations such as [Al_(13)O_4(OH)_(24).(H_2O)_(12)]~(7+). It is found that the pillar density is correlative with aluminium content in the tetra-hedral sheet of NiS. The results from TPR indicate that the palladium loaded on samples promotesthe reduction of the nickel ion in the octahedral sheet. The pillared clays impregnated with Pd~(2+)noted PdPNiS show excellent hydroisomerization property which is much better than that of nickelsubstituted mica-montmorillonite pillared with silicon oxide oligomer noted PdPSMM. The hexaneconversion increases with the content of aluminium ion in the tetrahedral sheet, whereas the changeof the selectivity of isomerization is not obvious.     

Acidity studies on pillared clays (PILCs) by pyridine adsorption and 1-butanol dehydration

A study was made on the acidic properties of clays, from different parent materials, pillared with aluminium or zirconium species. In conjunction with the well known method of pyridine desorption followed by infrared spectroscopy, the reaction test of 1-butanol dehydration was carried out. Also the heats of adsorption and the amounts of adsorbed pyridine, were determined by a thermogravimetry coupled with Differential Scanning Calorimetry (TG-DSC). The information on the acidic properties of the materials, obtained by the three methods, is discussed and it is concluded that the latter method (TG/DSC), although not currently used as one could expect, is sufficiently expedite and appropriate for this purpose.     

Montmorillonite intercalated with SiO2, SiO2-Al2O3 or SiO2-TiO2 pillars by surfactant-directed method as catalytic supports for DeNOx process

The intercalation of natural montmorillonite with SiO₂, SiO₂-Al₂O₃ or SiO₂-TiO₂ pillars by the surfactant-directed method resulted in the formation of high surface area porous materials; these were tested as catalytic supports for the process of selective catalytic reduction of NO (DeNOx). The incorporation of titanium or aluminium into the structure of the silica pillars significantly increased the surface acidity of the clay samples. Iron and copper were deposited onto the surface of the pillared clays mainly in the form of monomeric isolated cations and oligomeric metal oxide species. The contribution of the latter species was higher in the clay intercalated with SiO₂-TiO₂ pillars than in the samples modified with SiO₂ and SiO₂-Al₂O₃ pillars. The pillared clay-based catalysts were active in the DeNOx process but, in this group, the best results were obtained for the clay intercalated with SiO₂-TiO₂ pillars and doped with iron and copper. The catalytic performance of the samples is discussed in respect of their surface acidity and active forms of transition metal species deposited.     

A Lamellar MWW Zeolite With Silicon and Niobium Oxide Pillars: A Catalyst for the Oxidation of Volatile Organic Compounds

In this work, an MWW-type zeolite with pillars containing silicon and niobium oxide was synthesized to obtain a hierarchical zeolite. The effect of niobium insertion in the pillaring process was determined by combining a controllable acidity and accessibility in the final material. All pillared materials had niobium occupying framework positions in pillars and extra-framework positions. The pillared material, Pil-Nb-4.5 with 4.5 wt % niobium, did not compromise the mesoporosity formed by pillaring, while the increase of niobium in the structure gradually decreased the mesoporosity and ordering of lamellar stacking. The morphology of the pillared zeolites and the niobium content were found to directly affect the catalytic activity. Specifically, we report on the activity of the MWW-type zeolites with niobium catalyzing the gas-phase oxidation of volatile organic compounds (VOCs), which is an important reaction for clean environmental. All produced MWW-type zeolites with niobium were catalytically active, even at low temperatures and low niobium loading, and provided excellent conversion efficiencies.     

Sorption of cobalt on organic and inorganic intercalated clays

A Mexican montmorillonite clay was intercalated on the one hand with aluminium or zirconium polyhydroxications, and on the other with two organic compounds. Radioactive cobalt was used to study the Co²⁺ sorption curves in the original and pillared clays. It was found that pillaring in general does not favour the diffusion of cobalt between the layers specially the organic pillared clays. In equilibrium, the cobalt retention reached the highest level, around 0.7 meq/g in the Zr pillared clay.     

Kinetics of acetic acid esterification with 2-ethoxyethanol over an Al-pillared clay catalyst

The Al-pillared clay catalyst obtained by exposing activated clay powder to sulfuric acid and aluminium salts and calcining in air at 373 - 673 K, was found to be highly active for the title reaction. The results indicated that pillared layer clay of the mixed oxide has been employed as parent catalysts for their definite structure and special properties which can be modified by the substitution of L and B acid sites cations. Solid acid catalyst of supported aluminium was found to be highly active and selective at the 373 - 473 K temperature range for heterogeneous esterification. The activity is mainly attributed to the Lewis (and a considerably small number of Br?nsted) acid sites whose number and strength increased due to pillaring. The water produced in the esterification can be induced by Al³⁺, which makes the catalyst surface to form strong B acid. Their acidities are obtained by pH measurement. If only B acid sites are > 70%, and pH < 1 in the 2-ethoxyethanol, there exists an activity of esterification. The used catalyst gave identical results with that of the fresh one. X-ray diffraction spectra show that the composition and active phase of the used catalysts are the same as the fresh ones. The kinetic study of the reaction was carried out by an integral method of analysis. The kinetic equation of surface esterification is y = 2.36x - 0.98. This revised version was published online in June 2006 with corrections to the Cover Date.     

对苯乙烯磺酸在水滑石层间的柱撑及聚合

对苯乙烯磺酸在水滑石层间的柱撑及聚合;水滑石;对苯乙烯磺酸;柱撑;聚合     

Characterization of a delaminated clay and pillared clays by adsorption of probe molecules

Characterization of the textural and structural properties of a sodium form of a delaminated calcic montmorillonite, and of aluminium pillared materials prepared with and without amine pre-adsorption, was made using the adsorption of different probe molecules (nitrogen, toluene, methyl ethyl ketone and 1,1,1-trichloroethane). Due to the delaminated character of the prepared solids, the characterization by X-ray diffraction of the pillared materials was not possible. In this context, the adsorption of probe molecules revealed to be informative since, although the prepared materials were mainly mesoporous solids in consequence of their delaminated nature, when the amine pre-adsorption was used before the pillaring, microporosity was also formed.     

过氧杂多阴离子型层柱化合物的合成、表征及催化活性

通过离子交换法,将含Zr过渡金属离子1,3取代钨硅、钨磷过氧杂多酸盐嵌入Zn2Al类水滑石中,获得了层柱化合物,并用XRD,IR,UV等手段对产物的结构进行了表征.结果表明过氧杂多阴离子进入水滑石层间后,水滑石的层间距从0.92增大到1.47 nm,且过氧链没被破坏.层柱化合物在酯化反应中显示优良的催化性能.     

镓取代皂石的合成与交联的研究

以XRD、MAS NMR、IR和化学分析等方法研究了镓取代皂石及其羟基铝低聚物交联物。结果表明,Ga占据骨架四面体位置,影响四面体层电荷及Al柱的交联密度。交联物经焙烧后,Al柱与层形成Ga—O—Al_p键,实现了层与柱的交联,而Al_(13)基本结构不变。     

新型层柱化合物合成、表征及催化活性

将含过氧铌一、三取代钨硅、钨磷过氧杂多阴离子利用离子交换法嵌入Zn2Al类水滑石中制得层柱化合物,利用XRD,IR,UV等方法对产物的结构进行了表征。结果表明在层柱化合物中过氧杂多阴离子仍然保持Keggin结构,并且过氧键没被破坏。层柱化合物在酯化反应中显示优良的催化性能。     

交联镓皂石表面酸性及催化性能的研究

用水热法合成出两种不同镓含量的镓皂石，并用羟基铝低聚物对其进行了交联。对其表面酸性的考察发现，样品的酸量随嫁含量的增加而增大；样品均含有Ｂ酸和Ｌ酸中心，交联样品的Ｂ酸中心比交联前少。对样品催化性能的研究发现，催化活性与镓含量及酸量呈顺变关系。     

Solvent extraction separation of iron(III) and aluminium(III) from other elements with Cyanex 302

A rapid method was developed for the solvent extraction separation of iron(III) and aluminium(III) from other elements with Cyanex 302 in chloroform as the diluent. Iron(III) was quantitatively extracted at pH 2.0-2.5 with 5 x 10(-3) M Cyanex 302 in chloroform whereas the extraction of aluminium(III) was quantitative in the pH range 3.0-4.0 with 10 x 10(-3) M Cyanex 302 in chloroform. Iron(III) was stripped from the organic phase with 1.0 M and aluminium(III) with 2.0 M hydrochloric acid. Both metals were separated from multicomponent mixtures. The method was applied to the separation of iron and aluminium from real samples.