Studies on ordered mesoporous materials III. Comparison of MCM-41 to mesoporous materials derived from kanemite

Chen, Cong-Yan; Xiao, S.Q.; Davis, Mark E.

doi:10.1016/0927-6513(94)00077-9

Cited by 245 publications

(163 citation statements)

References 26 publications

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“…Figure 1 shows the powder X-ray diffractograms of samples after the aging period and after hydrothermal crystallization. The patterns (Figure 1, traces b, c, and d) are similar to the hexagonal mesoporous molecular sieves of Beck et al (1992), whereas the diffractogram in Figure 1 (trace e) appears to be of non-organized silica-surfactant rods (Chen et al, 1995). Figure 1 (trace a) is the product of the aged sample where no CTABr was added.…”

Section: Experimental Methodsmentioning

confidence: 84%

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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Section: Experimental Methodsmentioning

confidence: 84%

One-Step Synthesis of Alkyltrimethylammonium-Intercalated Magadiite

Pastore

Munsignatti

Mascarenhas

2000

Clays and clay miner.

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“…We subsequently attempted delamination with acidic Zn-(NO 3 ) 2 solution on several other layered zeolite precursors and silicates, including MCM-22P, 55 Na-kanemite, 56 B-SSZ-25, 57 and B-SSZ-70. 58,59 We considered two factors when choosing these reference materials.…”

Section: +mentioning

confidence: 99%

Novel surfactant-free route to delaminated all-silica and titanosilicate zeolites derived from a layered borosilicate MWW precursor

et al. 2014

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a Layered borosilicate zeolite precursor ERB-1P (Si/B = 11) is delaminated via simultaneous deboronation and SDA removal, to yield material DZ-1 consisting of silanol nests, using a simple aqueous Zn(NO 3 ) 2 treatment. Characterization of this synthesis process by PXRD shows loss of long-range order, and transmission electron microscopy (TEM) demonstrates transformation of rectilinear layers in the layered zeolite precursor to single and curved layers in the delaminated material. N 2 physisorption confirms the expected decrease of micropore volume and increase in external surface area for delaminated materials relative to their calcined 3D zeolite counterpart. Elemental analysis shows loss of B and absence of Zn in the delaminated material. Resonances corresponding to silanol nests are evident via 29Si solid-state NMR spectroscopy in DZ-1, which should be located within 12-MR pockets near the external surface. We have successfully utilized these nests as tetrahedral recognition sites for incorporation of Ti within an isolated framework coordination environment in material Ti-DZ-1. Diffuse-reflectance ultraviolet (DR-UV) spectroscopy of Ti-DZ-1 confirms isolated framework Ti sites, which are assigned to bands in the range of 210 nm-230 nm. Infrared spectra of Ti-DZ-1 consist of a distinct absorption band at 960 cm, which is absent in DZ-1 prior to Ti incorporation and has been previously correlated with the presence of framework Ti species. Infrared spectra after pyridine adsorption demonstrate bands consistent with Lewis-acid sites in the resulting Ti-substituted delaminated zeolite. The accessibility of these Lewis-acid sites is confirmed when using Ti-DZ-1 as a catalyst for cyclohexene epoxidation using tert-butyl hydroperoxide as the organic oxidant -a reaction for which both DZ-1 and TS-1 are inactive.

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“…Y mutinaite, as above, Y tschernichite, the Al-bearing analog of the Mobil high silica zeolite Beta (59-67), which has a remarkable polytypic domain structure with a 10-ring, three-dimensional channel system, Y boggsite, with a 10-to 12-ring, three-dimensional channel system, which occurs with tschernichite in Columbia basalt (68), Y faujasite, the natural analog of Linde Type Y, the main industrial catalyst with a 12-ring, three-dimensional channel system; can be de-aluminated by various processes (not referenced in detail); known only as a very rare mineral until discovery in sedimentary beds of diagenetic tuffs in Jordan (69), Y mordenite, an easily de-aluminated, common, high silica natural zeolite, with industrial analogs, whose one-dimensional channel can be blocked by either faulting or an Al-complex , Y mesoporous silicas with nanometer channels and mainly hydrophilic surfaces but some organophilic behavior (91)(92)(93)(94)(95)(96)(97)(98)(99)(100)(101)(102)(103), Y all-silica analog (Chevron SSZ-24) of Union Carbide aluminophosphate AlPO-5, for which one might envisage unipolar segments of aluminophosphate interleaved with nonpolar silica down the 12-ring cylindrical channel (104)(105), and Y theoretical chiral frameworks in the database of the Consortium for Theoretical Frameworks, University of Chicago, being prepared for publication.…”

mentioning

confidence: 99%

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Smith

1998

Proc. Natl. Acad. Sci. U.S.A.

117

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Catalysis at mineral surfaces might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and photochemical gas reactions. Many ideas are implausible in detail because the proposed mineral surfaces strongly prefer water and other ionic species to organic ones. The molecular sieve silicalite (Union Carbide; ‫؍‬ Al-free Mobil ZSM-5 zeolite) has a three-dimensional, 10-ring channel system whose electrically neutral Si-O surface strongly adsorbs organic species over water. Three -O-Si tetrahedral bonds lie in the surface, and the fourth Si-O points inwards. In contrast, the outward Si-OH of simple quartz and feldspar crystals generates their ionic organophobicity. The ZSM-5-type zeolite mutinaite occurs in Antarctica with boggsite and tschernichite (Al-analog of Mobil Beta). Archean mutinaite might have become de-aluminated toward silicalite during hot/cold/wet/dry cycles. Catalytic activity of silicalite increases linearly with Al-OH substitution for Si, and Al atoms tend to avoid each other. Adjacent organophilic and catalytic Al-OH regions in nanometer channels might have scavenged organic species for catalytic assembly into specific polymers protected from prompt photochemical destruction. Polymer migration along weathered silicic surfaces of micrometer-wide channels of feldspars might have led to assembly of replicating catalytic biomolecules and perhaps primitive cellular organisms. Silica-rich volcanic glasses should have been abundant on the early Earth, ready for crystallization into zeolites and feldspars, as in present continental basins. Abundant chert from weakly metamorphosed Archaean rocks might retain microscopic clues to the proposed mineral adsorbent/catalysts. Other framework silicas are possible, including ones with laevo/dextro one-dimensional channels. Organic molecules, transition-metal ions, and P occur inside modern feldspars.

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Studies on ordered mesoporous materials III. Comparison of MCM-41 to mesoporous materials derived from kanemite

Cited by 245 publications

References 26 publications

One-Step Synthesis of Alkyltrimethylammonium-Intercalated Magadiite

One-Step Synthesis of Alkyltrimethylammonium-Intercalated Magadiite

Novel surfactant-free route to delaminated all-silica and titanosilicate zeolites derived from a layered borosilicate MWW precursor

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

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