The Relation between the Efficiency of an Adsorbent in a Refrigeration System and Its Hydration Isotherm

The efficiencies of various types of silica gels, zeolites, and crystalline microporous aluminophosphates in adsorption systems of refrigeration have been determined. On the basis of the results obtained a method is proposed for the determination of the efficiency of an adsorbent from its hydration isotherm without experimental determination of the temperature dependence of the adsorption equilibrium parameters.     

数据挖掘辅助定向合成(Ⅰ)具有特定孔道结构的微孔磷酸铝

采用决策树方法对微孔磷酸铝的合成反应数据库进行了数据挖掘研究, 结果表明, 有机胺模板剂的属性对特定孔道的生成起着至关重要的作用. 进一步分析得到合成十二元环AlPO4-5微孔磷酸铝的约束条件, 并从理论上预测出用于合成十二元环AlPO4-5微孔磷酸铝的一系列新的有机胺模板剂. 部分理论分析结果得到了分子力学计算的有力支持, 并被合成实验所验证.     

The Syntheses of 1-Dimensional(1-D)Chain, 2-D Layered, and 3-D Microporous Alumino-phosphates with Occluded Amine or Ammonium Templates from Alcoholic Systems

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Calorimetric Study of the Acidity of a New Family of Mesoporous Catalysts

Thermally stable mesoporous aluminophosphates (AIPO) and silicoaluminophosphates (SAPO) were prepared at room temperature in the presence of a cationic surfactant and an organic base. These materials possess high surface areas and regular mesopores of approximately 35 Å diameter. By contrast to microporous crystalline aluminophosphate molecular sieves, mesoporous compounds are amorphous and characterized by Al/P ratios greater than 1. These particularities are responsible for a strong Lewis acidity, as evidenced by ammonia adsorption microcalorimetry. Mesoporous materials are more acidic than the microporous analogues and the amount of strong acid sites increases with the silicon content. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis of molecular sieve AlPO4-12

A member of the novel family of crystalline microporous aluminophosphates, AlPO₄-12, was synthesized by hydrothermal crystallization using different aluminum-containing compounds. Three new crystalline phases were obtained by varying the composition of the reaction mixture. The effect of the synthesis conditions on the hudrothermal process and the kinetics of crystallization are discussed. The apparent activation energies obtained for AlPO₄-12 are 20.9 and 14.6 kcal/mol for nucleation and crystallization, respectively. The adsorption isotherms of one AlPO₄-12 product were measured.     

Expressiveness of Adsorption Measurements for Characterization of Zeolitic Materials—A Review

This critical review concerns the author's results and experience in adsorption studies on molecular sieves comprising crystalline microporous aluminosilicates and aluminophosphates as well as amorphous mesoporous aluminosilicates. The discussion is mainly based on three distinctly different standard adsorbates: nitrogen, benzene, and water. The highlights or advantages and the shortcomings or limitations are considered from the points of view of the experimental procedures and expressiveness or concluding. The results are compared to several other zeolitic materials and adsorbates. Adsorption technique is a valuable tool for characterization of the molecular sieves. Since the measurements are very sensitive to modification of the materials, the investigations require sufficiently thorough procedures and the results a careful interpretation. A comparison between the results for larger series of materials yields valuable conclusions that are much more expressive than those from a single measurement or material. Dedicated to the memory of Professor Wolfgang Schirmer.     

用分子动力学模拟方法研究层孔与微孔磷酸铝化合 物中有机胺的模板作用: 指 导定向合成的有效途径

用分子动力学方法,研究了有机胺模板剂对二维层孔与三维微孔磷酸铝化合物的模板作用。依据主-客体间的非键相互作用能量,可以有效地预测出适于某一特定结构的有机胺模板剂。通过选择理论预测的有机胺分子作模板剂,在溶剂热体系中可以定向地合成出具有特定结构的化合物。这一工作对于微孔功能体系的分子工程学研究具有一定的指导意义。     

Molecular Model for Aluminophosphates Containing Fluoride as a Structure-Directing and Mineralizing Agent

Two tricyclic capped six-rings (C6R), a double four-ring (D4R), and an Al(μ-F)₂Al unit are among the structural features of 1 (see picture for structure) that are closely related to motifs found in layered and three-dimensional alumino- and gallophosphates. Several reactive centers can render 1 a viable precursor for the synthesis of microporous aluminophosphates.     

Insights into Structure Direction of Microporous Aluminophosphates: Competition between Organic Molecules and Water

A combination of experimental characterisation techniques and computational modelling has allowed us to gain insight into the molecular features governing structure direction in the synthesis of microporous aluminophosphates. The occlusion of three different structure‐directing agents (SDAs), triethylamine (TEA), benzylpyrrolidine (BP) and (S )‐(?)‐N‐benzylpyrrolidine‐2‐methanol (BPM), within the AFI structure during its crystallisation, together with the simultaneous incorporation of water, has been experimentally measured. We found a higher incorporation of organic molecules in the structure obtained with BPM, while a higher water (and lower organic) content is found for the ones obtained with TEA and BP as SDAs. The computational study provides a thermodynamic explanation for the observed behaviour in terms of the relative stabilisation energy of the SDAs and water molecules within the AFI framework compared with when they are in aqueous solution, and demonstrates that a competition for preferential occupation exists between water and organic SDAs, which is a function of the interaction with the inorganic framework. The lower interaction of TEA and BP molecules with the AFI structure promotes the simultaneous incorporation of water molecules in the 12‐membered‐ring (MR) channel, to increase the host–guest interaction energy and thus the thermodynamic stability. The presence of strongly interacting methanol groups in the BPM molecules leads to the incorporation of only organic molecules within the 12‐MR channels. Our results demonstrate the essential role that water molecules play in the stabilisation of hydrophilic microporous aluminophosphates; a minimum amount of organic SDA is, however, essential for a templating role of the microporous architecture.     

Microporous Crystalline γ‐Al2O3 Replicated from Microporous Covalent Triazine Framework and Its Application as Support for Catalytic Hydrolysis of Ammonia Borane

Significant progress has been made on the synthesis and application of mesoporous γ‐alumina. To date, little attention has been paid to the synthesis of microporous crystalline alumina. Here, fabrication of microporous crystalline γ‐alumina using a microporous covalent triazine framework (CTF‐1) as a template is described. Microporous crystalline γ‐alumina with a micro‐meso binary pore system was replicated by infiltration of aluminum nitrate into the micropores of the CTF‐1 template through a NH₃/water‐vapor‐induced internal hydrolysis method, followed by thermal treatment, and subsequent removal of the CTF‐1 template with a 30 % H₂O₂ aqueous solution. The obtained crystalline γ‐alumina material exhibits a large surface area (349 m² g⁻¹) with micropore distribution centered at about 1.27 nm. Ru supported on microporous γ‐Al₂O₃ can be employed as catalyst for hydrolytic dehydrogenation of ammonia borane, and it exhibits high catalytic activity and good durability. This finding provides a new benchmark for preparing well‐defined crystalline microporous alumina materials by a template method, which can be applied in a wide range of fields.     

用计算模拟方法研究Al_3P_4O_(16)~(3-)计量比的二维层状磷酸铝中的有机胺模板能力

将快速 Monte Carlo方法与分子动力学方法相结合 ,研究了不同种类有机分子在 Al3P4 O3- 1 6 计量比的二维层状磷酸铝形成中的模板能力 .依据主 -客体之间非键相互作用能 (包括范德华能、氢键能和库仑能 ) ,可合理地解释已知实验现象 ,并能有效地预测出适于形成某一特定无机层结构的有机胺模板剂 .通过选择理论预测的有机胺分子作为模板剂 ,成功地合成了二维层状磷酸铝化合物 Al3P4 O1 6 · 1 .5 H3NC6 H1 0 NH3.     

Substitution of transition metal ions into aluminophosphates and silicoaluminophosphates: characterization and relation to catalysis

The literature related to the incorporation of transition metal ions (TMI) into aluminophosphate (AlPO) and silicoaluminophosphate (SAPO) molecular sieves is reviewed. Microporous crystalline metal aluminophosphates (MeAPOs) and metal silicoaluminophosphates (MeAPSOs) represent an important group of inorganic materials because of their high potential as adsorbents and catalysts. This review focuses mainly on the spectroscopic characterization of TMI containing MeAPOs and MeAPSOs covering the literature through 2000. The characterization of these materials is summarized and discussed in the light of possible isomorphous substitution of transition metal ions into the aluminophosphate framework. Moreover, the literature devoted to the use of these materials in catalysis and adsorption is reviewed.     

MICROPOROUS INORGANIC MEMBRANES

Recent development in microporous inorganic membranes represents a significant advance in materials for separation and chemical reaction applications. This paper provides an in-depth review of synthesis and properties of two groups (amorphous and crystalline) of microporous inorganic membranes. Amorphous microporous silica membranes can be prepared by the sol-gel and phase separation methods. Flat sheet, tubular and hollow fiber amorphous carbon membranes have been fabricated by various pyrolysis methods from polymer precursors. A large number of synthesis methods have been developed to prepare good quality polycrystalline zeolite membranes. Several techniques, including vapor and liquid approaches, are reviewed for pore structure modification to prepare microporous inorganic membranes from mesoporous inorganic membranes. Chemical, microstructural and permeation properties of these microporous membranes are summarized and compared among the several microporous membranes discussed in this paper. Theory for gas permeation through microporous membranes is also reviewed, with emphasis on comparison of theoretical with the experimental data. These inorganic microporous membranes offer excellent separation properties by the mechanisms of preferential adsorption, selective configurational diffusion or molecular sieving.     

芳香胺对微孔层状磷酸铝材料的剥离与嵌入

用XRD和SEM研究了芳香胺对微孔层状磷酸铝 [Al3P4O16][CH3CH2NH3]3和[Al2P3O10(OH)2]•[C6NH8]的剥离和嵌入过程, 结果发现, 芳香胺本身的碱性大小是形成新的柱撑物的关键. 卞胺是碱性较强的芳香胺, 可以很好地将磷酸铝剥离并嵌入到层间形成新的层状化合物; 而碱性较弱的苯胺却无法做到. 新柱撑物形成的速度除与介质的介电常数和芳香胺的加入量有关外, 还取决于原有磷酸铝层板间相互作用的强弱.     

ITQ-12: a new microporous silica polymorph potentially useful for light hydrocarbon separations

The new synthetic form of microporous crystalline silica, denoted as ITQ-12, shows a high potential for the separation of propane and propene from its mixtures.     

Microcalorimetric study of argon,oxygen, nitrogen and carbon monoxide adsorption on crystalline zirconia

The adsorption of argon, oxygen, nitrogen and carbon monoxide at 77 K on crystalline zirconia and microporous zirconia gels has been studied by adsorption volumetry and isothermal microcalorimetry.The microporous structure of the zirconia gel may explain the higher enthalpy of adsorption obtained for argon. Both crystalline samples are mesoporous and in each case, the polar sites on the surface give specific interactions with dipolar (CO) or quadrupolar (N₂, O₂) molecules, which can be deduced from the adsorption isotherms and the corresponding differential enthalpy curves.M. J. T. acknowledges for a 2 month invited professorship at Université de Provence.     

Advances in Synthesis of Mesostructured Aluminophosphates

More and more attention has been paid to the synthesis of mesostructured aluminophosphates for many years. A lot of valuable research results, including various synthetic approaches and structural materials, have been obtained. This paper reviews the progress in the synthesis of mesostructured aluminophosphates over the past few years, with the hope of revealing opportunities for future work.     

Advances in Synthesis of Mesostructured Aluminophosphates

More and more attention has been paid to the synthesis of mesostructured aluminophosphates for many years. A lot of valuable research results, including various synthetic approaches and structural materials, have been obtained. This paper reviews the progress in the synthesis of mesostructured aluminophosphates over the past few years, with the hope of revealing opportunities for future work.     

Comment on the applicability of the Gurvich rule for estimation of pore volume in microporous zeolites

Adsorption - This comment seeks to establish a relation between two definitions of the pore volume of a microporous crystalline material. According to the first definition based on the Gurvich...     

Realisation of truly microporous pillared clays

When pillaring a well crystalline synthetic hectorite using molecular pillars, we obtained a truly microporous material for the first time that displays long range order of the pillars and consequently a narrow pore size distribution.