Synthesis of Kenyaite and Magadiite in the Presence of Various Anions

Fletcher, Ross A.

doi:10.1346/ccmn.1987.0350410

Cited by 79 publications

(42 citation statements)

References 6 publications

(2 reference statements)

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“…It is important to point out that the crystallization was achieved in absence of structure directing agents in only one hydrothermal step, avoiding swelling, pillarization and extraction post-synthesis treatments of the previously synthesized inorganic layered precursors. inorganic sheets, as for instance makatite-type, which are forming conventional inorganic layered silicates such as magadiite or kenyaite, 48,49 and silicoaluminates obtained from synthesis gels with high aluminum content. 50 Probably, these types of thin sheets are structured by effective covalent connection between silicon and aluminum tetrahedron, forming intralayer six member rings (6MR) which are along the plane bc of the inorganic layers, such as it was indicated for ECS-type materials.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

One-pot synthesis of hierarchical porous layered hybrid materials based on aluminosilicate sheets and organic functional pillars

et al. 2014

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Layered hybrid materials (LHMs) based on ordered silicoaluminate sheets linked with organic fragments, perpendicularly located and stabilized in the interlayer space, were synthesized by one-pot direct hydrothermal process, in absence of structural directing agents (SDAs), and using bridged silsesquioxanes as organosilicon precursors. By following the synthesis described here, the preliminary preparation of inorganic layered precursors, post-synthesis swelling and/or pillaring treatments can be avoided. The physico-chemical and structural characteristics of the materials were studied by chemical and thermogravimetrical analyses, X-ray diffraction, TEM microscopy, spectroscopic techniques (NMR and FTIR) and textural measurements. The complete exchange of intracrystalline sodium cations by protons, without substantial structural alteration of hybrid materials, facilitated the generation of hybrid materials, which contained acid and base sites located in the inorganic (silicoaluminate layers) and in the organic interlayer linkers, respectively, being the resultant acid-base materials active and selective catalysts.

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Section: Synthesis and Characterizationmentioning

confidence: 99%

One-pot synthesis of hierarchical porous layered hybrid materials based on aluminosilicate sheets and organic functional pillars

et al. 2014

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“…Magadiite is a naturally occurring crystalline silicate Lagaly, 1977, 1983;Eugster, 1967;Fletcher and Bibby, 1987;Iler, 1964), although it can also be synthesized (Schwieger et al, 1988(Schwieger et al, , 1991. Magadiite is a member of a family of silicic acids comprising also makatite [the only member whose structure is known (Annehed et aI., 1982)], kanemite, octosilicate, and kenyaite.…”

Section: Introductionmentioning

confidence: 99%

One-Step Synthesis of Alkyltrimethylammonium-Intercalated Magadiite

Pastore

Munsignatti

Mascarenhas

2000

Clays and clay miner.

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Abstraet--Cetyltrimethylammonium-and tetradecyltrimethylammonium-intercalated magadiites were prepared by direct syntheses, starting from sodium metasilieate (NaaO/SiO2 = 1.0) and nitric acid. Total substitution of sodium by cetyltrimethylammonium or tetradecyltrimetbylammoniurn cations was not achieved in the range of surfactant : silicon molar ratios used in this study. When a phosphoniun-based surfactant replaces the ammonium surfactants in the same procedure, the result of the synthesis is a mixture of quartz and unmodified surfactant. If dodecylammonium bromide is used, an MCM-41 molecular sieve is obtained. The substitution of the silicon source by tetramethylammonium silicate or of nitric acid by hydrochloric, hydrofluoric, or acetic acids also yields MCM-41 molecular sieves, indicating that the formation of magadiite is greatly dependent on the presence of sodium cations and nitrate anions.

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“…The synthesis of this mineral was reported for the first time in 1972 by Lagaly et al The appropriate amounts of NaOH, SiO2 and H20 were mixed and heated in sealed glass vessels or ampullae at 100 ~ for at least 4 weeks. With the interest generated by these lamellar minerals in the late eighties, other synthetic approaches have been proposed, using shorter times of reaction (Fletcher and Bibby 1987;Garces et al 1988;Sprung et al 1990;Dailey and Pinnavaia 1992b). Most of these syntheses were performed in a Teflon-lined autoclave at higher temperatures for shorter periods of time (Garces et al 1988;Sprung et al 1990;Dailey and Pinnavaia 1992b).…”

Section: Introductionmentioning

confidence: 99%