Modification of MCM-41 by surface silylation with trimethylchlorosilane and adsorption study
Article Abstract:
The modification of siliceous mesoporous molecular sieves MCM-41 by surface silylation was described using trimethylchlorosilane. In addition, the surface coverage of functional groups as well as the role of surface silanol groups during modification were examined. Experimental results showed that the maximum degree of surface attachments of trimethylsilyl groups was estimated to be 85%, which corresponds to the density of trimethylsilyl groups of 1.9 per nm(super 2). The degree of silylation was also found to linearly increase as the pre-outgassing temperature increases prior to silylation.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Thickness and stability of adsorbed film in cylindrical mesopores
Article Abstract:
Experiments were performed on a series of MCM-41 samples of uniform cylindrical channels used as model adsorbents. The samples displayed various interior pore sizes. X-ray powder diffraction studies were performed on the MCM-41 samples from which hexagonally arranged pore structures were identified. The mesoporosity of the samples were divided into the uniform framework-confined channels and the nonuniform interparticle voids. A semiempirical equation is suggested in describing the status of stable adsorbed films in cylindrical mesopores.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Irreversible change of pore structure of MCM-41 upon hydration at room temperature
Article Abstract:
X-ray diffraction, 29Si magic angle spinning nuclear magnetic resonance, and gravimetric adsorption methods were used to investigate the pore structure stability of MCM-41 materials during hydration/dehydration. Results revealed that the hydrolysis of the bare Si-O-Si(Al) bonds in the presence of water vapor causes the pore structure to collapse upon rehydration at room temperature. The whole MCM-41 structure collapses when MCM-41 is left in air for three months.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
User Contributions:
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