Synthesis of Mesoporous Materials: Liquid-Crystal Templating versus Intercalation of Layered Silicates

Vartuli, J.C.; Kresge, Charles T.; Leonowicz, M. E.; Chu, Alice; McCullen, S.B.; Johnson, Ivy D.; Sheppard, E. W.

doi:10.1021/cm00047a029

Cited by 133 publications

(96 citation statements)

References 2 publications

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“…[25] If particles aggregate, one could observe a solid phase formed upon reaching the cac, a phase that may or may not have periodic order. [44] This is plainly what is observed in the synthesis of M41S [45,46] -type materials with organic cations such as cetyltrimethylammonium. There is then a fundamental connection between silica nanoparticles detected in zeolite synthesis and the synthesis of mesoporous materials.…”

Section: From Nanoparticles To Extended Structuressupporting

confidence: 58%

Silica Self‐Assembly and Synthesis of Microporous and Mesoporous Silicates

Rimer

Fedeyko

Vlachos

et al. 2006

Chemistry A European J

131

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The microstructure of silica in basic aqueous solutions containing organic cations and prepared from monomeric precursors is reviewed and interpreted within the context of classical ideas of self-assembly of molecular aggregates. The solution properties can be understood by using the pseudo-phase separation approach coupled to the acid-base chemistry of silanol groups and the Poisson-Boltzmann equation. The silica nanoparticles frequently observed in these systems have a core-shell structure with silica in the core and the organic cations at the shell. Individual particles are observed when the forces between particles are repulsive-as is the case for small cations such as tetramethylammonium or tetrapropylammonium-and extended structures such as M41S materials are formed when the forces are attractive--as is the case for surfactants such as cetyltrimethylammonium. These ideas are useful to understand the evolution of zeolite synthesis gels from nucleation to crystal growth. Although at room temperature the silica and the organic cations are segregated, upon heating the organic cations are embedded within the particles. This transformation signals the onset of structure direction whereby the size and geometry of the organic cation induce changes in the structure of silica that may lead to zeolite nuclei.

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Section: From Nanoparticles To Extended Structuressupporting

confidence: 58%

Silica Self‐Assembly and Synthesis of Microporous and Mesoporous Silicates

Rimer

Fedeyko

Vlachos

et al. 2006

Chemistry A European J

131

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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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“…It was seen that the MCM-41 diffractogram exhibits two peaks at 2θ = 1.77-2º which can be indexed as 100 and 110 and ± 57 Å of lattice parameter (a o calculated by formula of a o = 2d 100 /√3). According to the previous research, the main peak at 2θ = 2-3° assigned the ordered hexagonal structure of MCM-41, while the other weak peaks at 2θ = 4-7º assigned the highly ordered structure of MCM-41 [9,18]. Fig.…”

Section: Extraction Of Silica From Sidoarjo Mudmentioning

confidence: 68%

Transesterification of Waste Cooking Oil Using NH2/MCM-41 Base Catalyst: Effect of Methanol/Oil Mole Ratio and Catalyst/Oil Weight Ratio towards Conversion of Ester

Triyono¹,

Trisunaryanti²,

Putri³

et al. 2018

Asian J. Chem.

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Transesterification of waste cooking oil (WCO) using NH2/MCM-41 base catalyst has been carried out. The MCM-41 was synthesized by hydrothermal method using the silica from Sidoarjo mud and cetyltrimethylammonium bromide (CTAB) as a template and calcined at 540 °C for 5 h. The MCM-41 was modified by adding (3-aminopropyl) trimethoxysilane using 5 mol percent of N/Si to produce NH2/MCM-41 base catalyst. Transesterification of waste cooking oil was carried out under variation of methanol/WCO mole ratio of 6, 9, 12, 15 and 18 using 10 wt. % of catalyst towards oil and weight ratio of catalyst/WCO of 2, 4, 6, 8, 10 wt. % using methanol/waste cooking oil mole ratio of 15. The result showed that the purity of silica from Sidoarjo mud was 93.40 wt. %. The highest product of methyl ester was 49.98 wt. % obtained using 4 wt. % of catalyst/WCO weight ratio in methanol/oil mole ratio of 15.

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Synthesis of Mesoporous Materials: Liquid-Crystal Templating versus Intercalation of Layered Silicates

Cited by 133 publications

References 2 publications

Silica Self‐Assembly and Synthesis of Microporous and Mesoporous Silicates

Silica Self‐Assembly and Synthesis of Microporous and Mesoporous Silicates

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

Transesterification of Waste Cooking Oil Using NH2/MCM-41 Base Catalyst: Effect of Methanol/Oil Mole Ratio and Catalyst/Oil Weight Ratio towards Conversion of Ester

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