Amino-functionalized SBA-15 type mesoporous silica having nanostructured hexagonal platelet morphology

Sujandi,; Park, Sang-Eon; Han, Dae-Soo; Han, Sang-Cheol; Jin, Myung‐Jong; Ohsuna, Tetsu

doi:10.1039/b608463j

Cited by 120 publications

(75 citation statements)

References 24 publications

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“…[16,17] Many heterogeneous catalysts have been developed to promote this reaction, and among those with organic groups as active sites, the most commonly used are aminoalkyls. [18][19][20][21][22][23][24] While supported aminoalkyls promote the aldol condensation, their catalytic efficiency is relatively low. [20,21,[23][24][25][26][27] A way to solve this problem could be by introducing a secondary functional group in the material.…”

Section: Introductionmentioning

confidence: 99%

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Kandel

Althaus

Peeraphatdit

et al. 2012

Journal of Catalysis

137

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In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of a co-catalyst, giving activities up to two orders of magnitude larger than those of homogeneous amines. This study confirms that the optimization of a heterogeneous catalyst depends as much on obtaining organic mechanistic information as it does on controlling the structure of the support. Disciplines Materials Chemistry | Other Chemistry | Physical ChemistryComments NOTICE: this is the author's version of a work that was accepted for publication in Journal of Catalysis. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Catalysis, [291, (2012) AbstractIn this study we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of a co-catalyst, giving activities up to two orders of magnitude larger than those of homogeneous amines. This study confirms that the optimization of a heterogeneous catalyst depends as much on obtaining organic mechanistic information as it does on controlling the structure of the support.

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Section: Introductionmentioning

confidence: 99%

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Kandel

Althaus

Peeraphatdit

et al. 2012

Journal of Catalysis

137

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“…Microwave irradiation was applied as a heating source throughout the hydrothermal aging treatment in order to achieve the potential advantages of microwave synthesis such as rapid and homogeneous heating, homogeneous nucleation and fast crystallization, phase selectivity, and uniform particle size and morphological control. 20,21 As illustrated in Scheme 1, copper cyclam complex was introduced via covalently bond grafting method to ensure that the complex will not leach out during catalytic application and the copper cyclam complex should be located in the cages of SBA-16. By grafting via cyclam ligand, copper species can allow to stay as single cation in each cyclam macrocyclic and act as single site catalyst rather than bulk catalyst system.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Oxidation of Cyclohexene with Hydrogen Peroxide over Cu(II)-Cyclam-SBA-16 Catalyst

Prasetyanto¹,

Park

2008

Bulletin of the Korean Chemical Society

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A copper cyclam-type complex was successfully immobilized onto mesoporous silica SBA-16. Characterization by NIR spectroscopy and TGA analysis confirmed that copper cyclam complex is immobilized onto mesoporous SBA-16. The Cu(II)-Cyclam-SBA-16 was proven to be a good catalyst for oxidation reaction of cyclohexene with conversion up to 77.8% after 13 h reaction and providing a high selectivity to cyclohexenol and 3-hydroperoxycyclohex-1-ene. The results suggest that the copper species play a major role as catalyst via reversible redox cycles as proven by cyclic voltammetry analysis.

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“…The deterioration of mesostructural ordering with the increase of PETES content is a common phenomenon for mesoporous hybrid materials synthesizedbyco-condensationofRSi(OR′) 3 andSi(OR′) 4 . 21,[24][25][26][27][38][39][40][41] This may be due to the weakened interactions between organosilane and Brij-76 micelles with the increase of PETES. Also, the flexibility of PETES will render the framework less rigid and lower the pore regularity.…”

Section: Effects Of Inorganic Salts On the Mesostructure Of The Organmentioning

confidence: 99%

Phosphonic Acid Functionalized Periodic Mesoporous Organosilicas and Their Potential Applications in Selective Enrichment of Phosphopeptides

Wang

Zhao

et al. 2009

J. Phys. Chem. C

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Phosphonic acid functionalized periodic mesoporous organosilicas were synthesized by co-condensation of 1,2-bis(trimethoxysilyl)ethane and diethoxyphosphorylethyl-triethoxysilane in acidic medium using Brij-76 as a template. Structural characterizations showed that the mesoporous materials with 2-D hexagonal mesostructures could be obtained in the presence of an inorganic salt, NaCl. The results of transmission electron microscopy revealed that the materials synthesized with NaCl/Brij-76 mass ratios of 3 and 4 had extensive structural defect holes in the nanochannels. After coordinating metal ions (Zr 4+ and Fe 3+ ) with phosphonic acid in the mesopore, the materials were applied as the potential immobilized metal affinity chromatographic adsorbent for the selective enrichment of phosphopeptides. Because of the stronger affinity interaction between the coordinated metal ions and the phosphoryl groups of phosphopeptides, the higher surface area, and the unique mesoporous structure, the capture of the phosphopeptide on the phosphonic acid functionalized periodic mesoporous organosilicas were much more efficient than that on the commercial POROS-20 beads.

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Amino-functionalized SBA-15 type mesoporous silica having nanostructured hexagonal platelet morphology

Cited by 120 publications

References 24 publications

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Catalytic Oxidation of Cyclohexene with Hydrogen Peroxide over Cu(II)-Cyclam-SBA-16 Catalyst

Phosphonic Acid Functionalized Periodic Mesoporous Organosilicas and Their Potential Applications in Selective Enrichment of Phosphopeptides

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