Predicting the Templating Ability of Organic Additives for the Synthesis of Microporous Materials

Lewis, Dewi W.; Freeman, C. M.; Catlow, C. Richard A.

doi:10.1021/j100028a022

Cited by 199 publications

(129 citation statements)

References 2 publications

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“…[43] The force field by Kiselev et al [44] was selected for the intermolecular SDA-zeolite and SDA-SDA interactions, and the intramolecular SDA interactions were modelled with the force field by Oie et al [45] More details on the computational methods can be found elsewhere. [46][47][48][49][50][51] First-Principles Techniques: Calculations were performed using the GAUSSIAN-98 [52] code at the density functional level of theory using the 6-31G basis set for the Si, Ge and H atoms, 6-31G(2d) for the O atoms and 6-311GA C H T U N G T R E N N U N G (2df) for the F atoms. The B3 [53] LYP [54] hybrid functional was selected.…”

Section: Methodsmentioning

confidence: 99%

Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

2006

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(19)F NMR chemical shifts are calculated in order to study the F(-) environment in double four ring (D4R) containing Si/Ge-zeolites. The calculations with the DFT/CSGT/B3PW91 methodology yielded an agreement within 2 ppm with respect to the experimental peaks corresponding to the D4R units containing 8Si0Ge, 7Si1Ge and 0Si8Ge of the octadecasil zeolite. The optimisation of the 7Si1Ge-, 6Si2Ge-, 5Si3Ge- and 4Si4Ge-D4R units with DFT/B3LYP methodology shows that a covalent Ge-F bond is formed and therefore a Ge atom in the D4R is pentacoordinated. The displacement of the fluoride ion towards a Ge atom in the Ge-containing D4R units locates four Si/Ge atoms in the close vicinity of the F(-) and this makes possible a rationalization of the (19)F NMR signals in groups according to the number of Si (n) and Ge (m) atoms in the nearest F(-) environment, F-Si(n)Ge(m) (where n+m=4). Thus, the calculated chemical shifts show that higher values are observed when the number of Ge atoms in the nearest F(-) environment increases.

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Section: Methodsmentioning

confidence: 99%

Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

2006

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“…Zeolite science delves mainly in the understanding of shape selectivity and in the rational synthesis of new zeolite structures with tunable and desirable properties. In this sense, the use of computer simulation experiments can prove a great help, as pioneering studies have clearly shown the potential of studying the host/guest interactions (i.e., the interactions between template and the inorganic framework [79][80][81]). In summary, it is nowadays well known that different molecules can act as templates to give rise to a very wide variety of zeolite frameworks.…”

Section: Synthesis and Structurementioning

confidence: 99%

Ordered Porous Nanomaterials: The Merit of Small

Murcia

2013

ISRN Nanotechnology

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This paper will introduce the reader to some of the “classical” and “new” families of ordered porous materials which have arisen throughout the past decades and/or years. From what is perhaps the best-known family of zeolites, which even now to this day is under constant research, to the exciting new family of hierarchical porous materials, the number of strategies, structures, porous textures, and potential applications grows with every passing day. We will attempt to put these new families into perspective from a synthetic and applied point of view in order to give the reader as broad a perspective as possible into these exciting materials.

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“…The reason for these studies is to rationalize which organic molecules promote the formation of a given zeolite framework or, better yet, to predict which SDA makes a hypothetical structure. Using Monte Carlo and energy minimization calculations, Lewis et al have calculated the stability and location of the SDAs in a number of zeolites [121]. The effects of aluminum content on the effect of SDA-zeolite interactions and the SDA-SDA interactions in the zeolite pores have also been studied by Sastre et al [122] using the General Utility Lattice Program (GULP) energy minimization code.…”

Section: Sda Modelingmentioning

confidence: 99%

Synthesis Approaches

Strohmaier

2010

Zeolites and Catalysis

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Zeolites were first identified as natural minerals having unique physical absorption properties. Early researchers tried to reproduce the geological conditions in an attempt to make them synthetically. From the years 1845 to 1937 many researchers investigated the hydrothermal conversion and synthesis of silicates. Although there were a number of claims that zeolites had been made synthetically, they were unsubstantiated as identification was based upon chemical analysis and optical observations. Later attempts at reproducing these early experiments did not give identifiable zeolites. It was not until the 1940s that Professor Richard M. Barrer found the necessary conditions for making zeolites synthetically and he identified them by powder X-ray diffraction. By reacting the powder minerals leucite and analcime with aqueous solutions of barium chloride at temperatures of 180-270 • C for two to six days, a synthetic chabazite was obtained. In 1948, Professor Barrer was able to synthesize zeolites entirely from synthetic solutions of sodium aluminate, silicic acid, and sodium carbonate [1]. A dry powdered gel was first obtained by drying the mixture at 110 • C, and then crystallizing it to a synthetic mordenite by reacting the gel with water at higher temperatures. In the 1950s, Donald Breck and researchers at the Union Carbide Company began to synthesize zeolites from reactive aluminosilicate gels prepared from sodium aluminate and sodium silicate solutions. This led directly to the discovery of the first two new synthetic zeolites, Linde A [2] and Linde X (Si/Al = 1.0-1.5) [3], both having new framework structures, LTA and FAU, respectively. Linde A was found to have excellent ion exchange and gas separation properties. Later, a new, higher silica containing composition of FAU, designated Linde Y [4] (Si/Al = 1.5-3.0), was synthesized and was found to be an excellent cracking catalyst for the conversion of distilled crude oil to gasoline products. The discovery of these two industrially important zeolites caught the attention of many scientists and kick started the field of zeolite synthesis research.

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Predicting the Templating Ability of Organic Additives for the Synthesis of Microporous Materials

Cited by 199 publications

References 2 publications

Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

Ordered Porous Nanomaterials: The Merit of Small

Synthesis Approaches

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Predicting the Templating Ability of Organic Additives for the Synthesis of Microporous Materials

Cited by 199 publications

References 2 publications

Computational Study of 19F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

Computational Study of 19F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

Ordered Porous Nanomaterials: The Merit of Small

Synthesis Approaches

Contact Info

Product

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Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites

Computational Study of ¹⁹F NMR Spectra of Double Four Ring‐Containing Si/Ge‐Zeolites