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General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Chloration, Chlorination, Clorinación, Composé aromatique, Aromatic compound, Compuesto aromático, Composé benzénique, Benzenic compound, Compuesto bencénico, Etude expérimentale, Experimental study, Estudio experimental, Hydrocarbure, Hydrocarbon, Hidrocarburo, Réaction catalytique, Catalytic reaction, Reacción catalítica, Sulfuryle Chlorure, Sulfuryl Chlorides, Sulfurilo Cloruro, Tamis moléculaire, Molecular sieve, Tamiz molecular, Toluène, Toluene, Tolueno, Zéolite, Zeolite, Zeolita, Zéolite Y, and Zéolite ZSM5

The catalytic decomposition of sulfuryl chloride was studied over dried sodium forms of zeolites ZSM-5, L, and Y. NaZSM-5 did not catalyze the decomposition, whereas NaKL and NaY did. During the chlorination of aromatic hydrocarbons using NaKL or NaY, the chlorinating agent sulfuryl chloride must compete with molecular chlorine produced by its own decomposition. The rate of reaction with molecular chlorine alone is much faster than that with sulfuryl chloride. In the presence of sulfuryl chloride, however, the rate of chlorination by molecular chlorine is greatly reduced. Both chlorinating agents use Lewis acid sites, suggesting that these sites are predominantly covered by sulfuryl chloride. Sulfuryl chloride is slightly more selective for para-chlorotoluene than is molecular chlorine. NaZSM-5 catalyzes chlorination using either molecular chlorine or sulfuryl chloride alone, but the latter reactant is not simultaneously decomposed by NaZSM-5. The decomposition may require a basic site adjacent to the Lewis acid site, and NaZSM-5 may not possess basic sites of sufficient strength.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Complexe ammino, Ammino complex, Complejo ammina, Complexe cationique, Cationic complex, Complejo catiónico, Décomposition thermique, Thermal decomposition, Descomposición térmica, Etude expérimentale, Experimental study, Estudio experimental, Faujasite, Faujasita, Platine Complexe, Platinum Complexes, Platino Complejo, Rayon X, X ray, Rayos X, Spectrométrie IR, Infrared spectrometry, Espectrometría IR, Spectrométrie photoélectron, Photoelectron spectrometry, Espectrometría fotoelectrón, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, Zéolite X, and Zéolite Y

The XPS method is employed to compare the behavior of [Pt(NH3)4]2+ ions in the surface layers of KX and KY zeolites with that in the zeolite bulk. FT i.r. and MS-t.p.d. methods are used to characterize the bulk properties. XPS and FT i.r. reveal the formation of different intermediate NHx species during the decomposition of the ammine complex in a vacuum. They are interpreted as Pt-diammine, framework ammine, and immine complexes. The maximum evolution of ammonia occurs in the temperature interval ranging from 150°C to 250°C. Positive shifts of Pt (4f) photoelectrons, observed for samples with a decomposed Pt-ammine complex, are explained by a decrease of the population of Pt 5d levels in encaged metallic clusters. The surface concentration of Pt decreases with increasing temperature due to the inward diffusion of Pt atoms.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Etude théorique, Theoretical study, Estudio teórico, Structure cristalline, Crystalline structure, Estructura cristalina, Structure, Estructura, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, and Zeolita

Symbols that specify the size and number of shortest rings at the angles of each of the 4-connected vertices of zeolite nets are given. Both the interpretation and the utility of these vertex symbols are discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Catalyseurs: préparations et propriétés, Catalysts: preparations and properties, Caractérisation, Characterization, Caracterización, Catalyseur, Catalyst, Catalizador, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Oxydation, Oxidation, Oxidación, Peroxyde, Peroxides, Peróxido, Précurseur, Precursor, Spectrométrie UV, Ultraviolet spectrometry, Espectrometría UV, Synthèse chimique, Chemical synthesis, Síntesis química, Tamis moléculaire, Molecular sieve, Tamiz molecular, Titane Composé, Titanium Compounds, Titanio Compuesto, Titane Fluorure, Titanium Fluorides, Titanio Fluoruro, Zéolite, Zeolite, Zeolita, and Silicalite 1

A new titanium precursor, TiF4, has been used to synthesize titanium silicalite-1 (TS-1). In contrast to the commonly used alkoxides, TiF4 is stable in air, water, and even basic TPAOH solutions, which offers considerable advantages as compared to conventional synthesis routes. In particular, TS-1 can be obtained with commercial TPAOH solutions, containing alkali cations, without formation of extraframework species. For samples synthesized with alkali-free TPAOH solutions, the maximum Ti incorporation that can be achieved corresponds to about 2.05 Ti/u.c., and TS-1 samples are similar to previously reported solids prepared with titanium alkoxides. In particular, they are very active in the ammoximation of cyclohexanone and the hydroxylation of phenol with hydrogen peroxide. When TS-1 is prepared with commercial TPAOH solutions, alkali cations can be removed by washing the solid with dilute acid, and the catalytic performance of the washed zeolite is similar to that of samples synthesized with alkali-free TPAOH.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Etude expérimentale, Experimental study, Estudio experimental, Kaolin, Caolín, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Résonance magnétique nucléaire, Nuclear magnetic resonance, Resonancia magnética nuclear, Spectrométrie Fourier, Fourier spectrometry, Espectrometría Fourier, Tamis moléculaire, Molecular sieve, Tamiz molecular, Traitement thermique, Heat treatment, Tratamiento térmico, Transformation phase, Phase transformation, Transformación fase, Zéolite, Zeolite, Zeolita, and Zéolite X

The thermal transformation of kaolin extrudates to metakaolin and the subsequent crystallization of low-silica X extrudates has been investigated by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy, N2-adsorption, 27Al and 29Si MAS NMR, and surface analysis. Kaolin transforms to metakaolin at 973 K. The macroporous metakaolin extrudates are converted to zeolite X plus a small amount of zeolite A in alkaline solution at 324 K. The 27Al NMR signals of octahedral and pentacoordinated aluminium in metakaolin are removed after 30 min at 324 K, whereas the first XRD features of zeolites X and A are not detected until 48 h. Likewise, 29Si NMR and FTIR spectra show that zeolite is first present at 48 h synthesis time. The amount of zeolite A decreases with increasing synthesis time, but there is an overall increase in product crystallinity and surface area up to 240 h. SEM analyses show that zeolite crystals first form in the interior of extrudates at the edges of macropores; with time the metakaolin matrix is consumed to produce well-crystalline zeolite extrudates consisting of ca. 95% low-silica X and 5% zeolite A.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Catalyseurs: préparations et propriétés, Catalysts: preparations and properties, Catalyseur, Catalyst, Catalizador, Cristallisation, Crystallization, Cristalización, Etude expérimentale, Experimental study, Estudio experimental, Gel colloïdal, Colloidal gel, Gel coloidal, Hydrogène Fluorure, Hydrogen Fluorides, Hidrógeno Fluoruro, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Oxalique acide, Oxalic acid, Oxálico ácido, Précurseur, Precursor, Préparation, Preparation, Preparación, Silice, Silica, Sílice, Synthèse chimique, Chemical synthesis, Síntesis química, Titane Silicate, Titanium Silicates, Titanio Silicato, Titane ion, Titanium ion, and Titanio ión

A new synthesis route for MFI-type titanosilicates (TS-1) using methylamine along with tetrapropylammonium bromide (TPABr), silica or silicon tetrachloride and titanium tetrachloride, thus avoiding the use of costly TPAOH and Ti-alkoxide, has been investigated. The presence of titanium ions in the reaction gel slowed down the crystallization of MFI zeolites, while addition of hydrogen fluoride as a co-mineralizer into the gel dramatically improved the crystallization kinetics. Ti was readily incorporated into the zeolite framework, as confirmed by IR, XRD (unit cell expansion), and UV-vis spectroscopy. Reduced initial amounts of methylamine in the gel led to an increase of the apparent crystallization rate of the zeolite and to a remarkable decrease of the amount of framework Ti, suggesting that high concentration of methylamine is needed for the Ti incorporation into the growing MFI crystallites.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Adsorption, Adsorción, Azote, Nitrogen, Nitrógeno, Cuivre Complexe, Copper Complexes, Cobre Complejo, Etude expérimentale, Experimental study, Estudio experimental, Mésoporosité, Mesoporosity, Mesoporosidad, Pyridine, Piridina, Résonance paramagnétique électronique, Electron paramagnetic resonance, Resonancia paramagnética electrónica, Spectrométrie photoélectron, Photoelectron spectrometry, Espectrometría fotoelectrón, Synthèse chimique, Chemical synthesis, Síntesis química, Tamis moléculaire, Molecular sieve, Tamiz molecular, and Tamis MCM41

Mesoporous MCM-41 materials have been synthesized and loaded with copper pyridine complexes by an ion-exchange procedure. Nitrogen adsorption and X-ray diffraction studies of the parent and loaded MCM-41 materials confirm the incorporation of the copper complexes into the mesopores of the MCM-41 structure. The incorporation status of the organometallic copper complexes is monitored by electron spin resonance and electron spin echo envelope modulation spectroscopy during the preparation procedure. Immobilized isolated copper pyridine complexes as well as agglomerates of complexes have been found in the ion-exchanged mesoporous material.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Adsorption, Adsorción, Caractérisation, Characterization, Caracterización, Chaleur adsorption, Heat of adsorption, Calor adsorción, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Isotherme désorption, Desorption isotherm, Isotermo desorpción, Synthèse chimique, Chemical synthesis, Síntesis química, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, and Zéolite A

The adsorption properties of the clathrasil Deca-dodecasil 3R (DD3R) have been studied. This porous tectosilicate becomes microporous when the organic template 1-adamantanamine is removed by calcination, which gives this clathrasil zeolitical properties. By means of adsorption of water, DD3R has been proven to be very hydrophobic. These adsorption data, together with the isosteric heats of adsorption of carbon dioxide at different loadings, reveal the absence of strong adsorption sites for polar or polarizable molecules, in contrast to the adsorbent zeolite A.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Cobalt Gallium Phosphate, Cobalt Gallium Phosphates, Cobalto Galio Fosfato, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Fer Gallium Phosphate, Iron Gallium Phosphates, Hierro Galio Fosfato, Gallium Manganèse Phosphate, Gallium Manganese Phosphates, Galio Manganeso Fosfato, Matériau poreux, Porous material, Material poroso, Microporosité, Microporosity, Microporosidad, Paramètre cristallin, Lattice parameters, Parámetro cristalino, Structure cristalline, Crystalline structure, Estructura cristalina, Susceptibilité magnétique, Magnetic susceptibility, Susceptibilidad magnética, Tamis moléculaire, Molecular sieve, and Tamiz molecular

Three novel metal-substituted gallium phosphates, (C3N2H5)8[Me8Ga16P24O96] (Me = Co, Fe, Mn), have been synthesised under solvothermal conditions and their structures determined using single-crystal X-ray diffraction. They are isostructural, with monoclinic symmetry, space group C 2/c and unit-cell dimensions ca. 15 x 13 x 15 Å, β ca. 111°. The materials all have frameworks with the laumontite topology (structure type code LAU), constructed from alternating PO4 and MO4 tetrahedra (M = Me and Ga) with imidazole cations occupying sites within the channels of the framework. Magnetic susceptibility measurements show that the materials exhibit Curie-Weiss behaviour over wide ranges of temperature and that the transition metals are present as divalent cations.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Etude expérimentale, Experimental study, Estudio experimental, Milieu acide, Acid medium, Medio ácido, Milieu basique, Basic medium, Medio básico, Résonance magnétique nucléaire, Nuclear magnetic resonance, Resonancia magnética nuclear, Spectrométrie IR, Infrared spectrometry, Espectrometría IR, Structure, Estructura, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, and Zéolite bêta

The states of aluminum in zeolites β were investigated in detail with FTIR spectroscopy. Three kinds of aluminum-framework, nonframework, and transient-state aluminum-were detected in template-removed zeolite β. The states of aluminum in our samples intensely depends on the nature of compensating cation, consistent with the conclusion of Brougeat-Lami et al. But some new assignments of aluminum species and new opinions about the states of aluminum and their transformation are proposed. From the experimental results, we suggest that, because the framework of zeolite β is deformable, the distortion and the tension of zeolite lattice occur when protons, which possess high electron affinity, are located at cationic sites, leading to the breakage of Al-O bond and the removal of aluminum. Therefore, zeolite β is subjected to dealumination in acidic medium. On the other hand, the high deformability also results in the relaxation of zeolite structure when H+ is replaced by other cations (e.g., Na+) so that transient-state aluminum and even nonframework aluminum can go back into the framework. Owing to ion-exchange, the cationic nonframework aluminum species enter the solution; moreover, it can also reinsert into the framework after hydroxylation in basic medium.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Catalyseurs: préparations et propriétés, Catalysts: preparations and properties, Activité catalytique, Catalyst activity, Actividad catalítica, Alcane, Alkane, Alcano, Alcène, Alkene, Alqueno, Aluminium Phosphate, Aluminium Phosphates, Aluminio Fosfato, Butane, Butano, Butène, Butene, Buteno, Catalyse, Catalysis, Catálisis, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Gallium, Galio, Hydrocarbure, Hydrocarbon, Hidrocarburo, Matériau modifié, Modified material, Material modificado, Polyèdre coordination, Coordination polyhedron, Poliedro coordinación, Résonance magnétique nucléaire, Nuclear magnetic resonance, Resonancia magnética nuclear, Tamis moléculaire, Molecular sieve, Tamiz molecular, Tamis APO11, and Tamis APSO11

71Ga MAS n.m.r. analysis and the catalytic behavior during the transformation of 1-butene and n-butane strongly suggest the incorporation of Ga into the AlPO4-11 (AEL) framework during the synthesis of GaAPSO-11. A unique clear signal at around +120 ppm is proposed to be associated with the presence of tetrahedral Ga in the AEL framework of the unmodified GaAPSO-11. Migration of structural Ga atoms to the silicon domain of the AEL framework seems to occur as a result of a mild hydrothermal treatment, giving rise to an additional signal at +156 ppm, previously associated with tetrahedral gallium in gallosilicates with the MFI topology. The fact that GaAPO-11 and GaAPSO-11 behaved in a way similar to their counterparts AlPO4-11 and SAPO-11 during the skeletal isomerization of n-butenes reinforces the idea of an isomorphous substitution of Al(III) by Ga(III) in the AEL framework. The transformation of n-butane was shown to be a valuable test for detecting the presence of small amounts of hydro-dehydrogenating extraframework gallium species (EFGS) in Ga-supported SAPO-11 (Ga/SAPO-11). The fact that the sample of GaAPSO-11 was completely inactive for this transformation leads us to believe that the incorporation of gallium into the tetrahedral positions of the AEL framework was almost complete.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Diffraction RX, X ray diffraction, Difracción RX, Echange ion, Ion exchange, Cambio iónico, Etude expérimentale, Experimental study, Estudio experimental, Faujasite, Faujasita, Lanthane Chlorure, Lanthanum Chlorides, Lantano Cloruro, Lanthane III, Lanthanum III, Lantano III, Matériau modifié, Modified material, Material modificado, Mordénite, Mordenite, Mordenita, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, and Zéolite Y

Interaction of lanthanum(III) chloride with hydrogen forms of ferrierite, mordenite, zeolite L, and faujasite, under completely anhydrous conditions, is described. The course of the interaction has been studied by in situ i.r. and XRD techniques. No evidence of interaction between LaCl3 and small-pore H-ferrierite was found. The other three structures investigated do interact with LaCl3 even under the complete exclusion of water or water vapor from the surroundings. Plausible mechanisms of the solid-state ion exchange in zeolites are also discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Autres échangeurs d'ions: préparations et propriétés, Other ion exchangers: preparations and properties, Etude expérimentale, Experimental study, Estudio experimental, Mésoporosité, Mesoporosity, Mesoporosidad, Structure moléculaire, Molecular structure, Estructura molecular, Surface minimale, Minimal surface, Superficie mínima, Tamis moléculaire, Molecular sieve, Tamiz molecular, and Tamis MCM-48

A simplified pictorial description is given for the mesoporous inorganic structure MCM-48. Structure, symmetry, and pore architecture are all described in terms of this model.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Aluminium composé, Aluminium compound, Aluminio compuesto, Cristallinité, Crystallinity, Cristalinidad, Cristallisation, Crystallization, Cristalización, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Oxydation, Oxidation, Oxidación, Synthèse chimique, Chemical synthesis, Síntesis química, Tamis moléculaire, Molecular sieve, Tamiz molecular, Titane composé, Titanium compound, Titanio compuesto, Zéolite, Zeolite, Zeolita, and Zéolite bêta

Crystallization curves of [Ti,Al]-Beta were obtained from reaction mixtures having Si/Ti ratios between 20 and 125 and Si/Al approx. 200. It was observed that practically all aluminum is incorporated into the solid during the first hours of reaction, whereas titanium and silicon are continuously incorporated. Increasing Ti content in the reaction mixture results in an increase in particle size, indicating that the presence of Ti reduces the nucleation rate. X-ray diffraction and diffuse reflectance spectra show that when the Ti content is less than 4% of the tetrahedral atoms, this element is incorporated in the sieve framework in isolated form.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Composé nitro, Nitro compound, Compuesto nitro, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Matériau poreux, Porous material, Material poroso, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Mésoporosité, Mesoporosity, Mesoporosidad, Optique non linéaire, Non linear optics, Optica no lineal, Propriété optique, Optical properties, Propiedad óptica, Tamis moléculaire, Molecular sieve, Tamiz molecular, Aniline(4-nitro), and Tamis MCM41

Para-nitroaniline (pNA) has been incorporated into the one-dimensional channels of mesoporous MCM-41, the hexagonal member of the M41S family of ordered mesoporous silicate materials. The composite material shows a number of remarkable features, depending on the sorption procedure for the organic component, the after treatment, and the annealing time of the composite. In X-ray diffraction experiments different states of one-dimensional ordering of the sorbate molecules in the channel pores are observed. In agreement with the molecular dipole, chain-like coherent domains with the long axis of the sorbate molecule parallel as well as perpendicular to the host channel axis show up. In aged samples the periodic ordering of the pNA molecules is lost, and nonlinear optical properties of the composite have been measured in second harmonic generation experiments indicating the presence of a polar direction in the sample.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Clathrate, Clatrato, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Méthode hydrothermale, Hydrothermal growth, Método hidrotermal, Nitrate, Nitrates, Nitrato, Résonance magnétique nucléaire, Nuclear magnetic resonance, Resonancia magnética nuclear, Sodalite, Sodalita, Solvant organique, Organic solvent, Solvente orgánico, Synthèse chimique, Chemical synthesis, Síntesis química, Tamis moléculaire, Molecular sieve, and Tamiz molecular

Hydrothermal synthesis of sodalite has been investigated in the system NaOCH3-2SiO2-Al2O3-NaNO3-(CH3OH, C5H11OH) at temperatures of 423 K and 473 K. For the first time the organic solvents methanol or pentanol together with sodium methylate as base were used besides common inorganic educts as Si/Al source and sodium nitrate salt. The sodalites have been characterized by X-ray powder diffraction, as well as by 29Si, 23Na MAS NMR, and 23Na DOR NMR measurements. IR-FT spectroscopy shows the successful enclathration of nitrate anions in the β-cages of sodalite. Reaction products of the solvent/base have been identified by (1H) 13C CPMAS NMR and 1H MAS NMR. Scanning-electron micrographs show crystals larger than 15 μm grown at 473 K in pentanol.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Acide Brönsted, Brönsted acid, Acido Bronsted, Acide Lewis, Lewis acid, Acido Lewis, Acidité, Acidity, Acidez, Aluminium Composé, Aluminium Compounds, Aluminio Compuesto, Caractérisation, Characterization, Caracterización, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Résonance magnétique nucléaire, Nuclear magnetic resonance, Resonancia magnética nuclear, Site Brönsted, Bronsted site, Sitio Bronsted, Site Lewis, Lewis site, Sitio Lewis, Site acide, Acidic site, Sitio ácido, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, and Zéolite ZSM5

The acidity of aluminum in a nominally 70:1 SiO2/Al2O3 ratio ZSM-5 prepared by conventional means was characterized by TPAD, 27Al and 29Si n.m.r., XRD, and FTi.r. Discrepancies observed between the amount of tetrahedral acidic aluminum measured by TPAD and i.r. versus Al n.m.r. are due to the presence of Lewis aluminum. Furthermore, it is suggested that this Lewis aluminum may be located in the zeolite framework. These sites are not thought to be inherent to the ZSM-5 structure but are probably generated during calcination, resulting in partial hydrolysis of Al-O bonds. A small percentage of octahedral aluminum was observed in hydrated HZSM-5, but was quantitatively converted to tetrahedral aluminum by treatment with ammonium nitrate solution at pH 8.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Caractérisation, Characterization, Caracterización, Composé naturel, Natural compound, Compuesto natural, Diffraction RX, X ray diffraction, Difracción RX, Etude expérimentale, Experimental study, Estudio experimental, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Minéralogie, Mineralogy, Mineralogía, Oxyde, Oxides, Óxido, Paramètre cristallin, Lattice parameters, Parámetro cristalino, Silice, Silica, Sílice, Spectrométrie IR, Infrared spectrometry, Espectrometría IR, Structure cristalline, Crystalline structure, Estructura cristalina, Tamis moléculaire, Molecular sieve, Tamiz molecular, Zéolite, Zeolite, Zeolita, Mutinaite, and Zéolite ZSM5

Mutinaite is the third new zeolite from Ferrar dolerites at Mt. Adamson (Northern Victoria Land, Antarctica). The mineral occurs as subspherical aggregates of tiny radiating lath-like fibres or as aggregates of transparent, colourless to pale-milky, tiny tabular crystals; it has vitreous luster, white streak and good (100) cleavage. Mutinaite is brittle with dmeas = 2.14(3) and dcalc = 2.17 g/cm3. Optically, it is biaxial negative with α = 1.485(2), β = 1.487(2) and γ = 1.488(2). The orientation is X = b, Y = a, Z = c. Mutinaite is orthorhombic with a = 20.223(7), b = 20.052(8), c = 13.491(5)Å, space group Pnma. The strongest powder X-ray diffraction lines are (d(Å), I, hkl): 11.20, 84, 101, 011;9.98, 35, 200,020; 3.85, 100, 501, 051; 3.75, 98, 303; 3.67, 27, 133; 3.00, 32, 503. The framework topology is that of the synthetic zeolite ZSM-5. The chemical formula is: (Na2.76K0.11Mg0.21Ca3.78)Σ=6.86(Al11.20Si84.91)Σ=96.11O192.60H2O. The Si/Al ratio, equal to 7.6, is the highest found in a natural zeolite. Thermal stability and rehydration capacity are very high. The name is from Mutina, the ancient Latin name of the city of Modena.

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Controlled desilication of ZSM-5 zeolite, using an aqueous solution of 0.8 M sodium carbonate and 0.01 M sodium hydroxide, results in a significant decrease of the Si/Al atomic ratio, with sodium orthosilicate and its dimer, sodium pyrosilicate, being selectively removed from the zeolite framework. Micropores of 0.49 nm, i.e., those significantly smaller than those of the parent zeolite, are formed during desilication at the expense of the original micropores. Such a desilicated zeolite shows an ion-exchange activity (with Ca2+) much higher than that of the parent zeolite, owing to the increase of the density of Al tetrahedral sites. Activation of the desilicated zeolite at a temperature higher than 300°C results in the enlargement of the newly formed micropores. The final system is quite homogeneous with only one type of micropore, ca. 0.56 nm in diameter. This is probably at the origin of further improvements in the ion-exchange performance. There is no significant change of the ZSM-5 zeolite structure in this method of secondary synthesis: Thus, the function of the thermal treatment is to stabilize the framework and to homogenize the pore network of the desilicated zeolite.

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Crystal structure refinements of mordenites indicate that partial (Si,AI) order in the tetrahedral sites regularly recurs within the observed range (6-9) Al/unit cell. Consequently, for a given Si/Al ratio, it is possible to determine the maximum number of OH groups that can be allocated on each framework oxygen. Assuming that only one proton can be bonded at the same time to the oxygens of a tetrahedron, structural data indicate that it is highly probable that Brønsted sites are on framework oxygens 02 and 07, heading toward the center of the 12-ring, and on 09, heading toward the center of the 8-ring, each with about the same population. The intensities of the i.r. stretching bands (around 3,600 cm-1 wavenumbers) of the hydroxyls Si(OH)Al agree well with this result.