INVESTIGADORES
SAPAG Manuel Karim
artículos
Título:
Mesoporous Silicates with Spherical Morphology Modified with Vanadium Highly Active in Oxidation of Cyclohexenewith H2O2
Autor/es:
CORINA M. CHANQUÍA; ANALÍA L. CÁNEPA; KARIM SAPAG; PATRICIO REYES; EDUARDO R. HERRERO; SANDRA G. CASUSCELLI; GRISELDA A. EIMER
Revista:
TOPICS IN CATALYSIS
Editorial:
SPRINGER/PLENUM PUBLISHERS
Referencias:
Año: 2011 vol. 54 p. 160 - 169
ISSN:
1022-5528
Resumen:
Vanadium-containing mesoporous molecular
sieves have been prepared by hydrothermal treatment at
373 K. These materials showed spherical morphology with
a narrow particle size distribution between 2 and 4 lm. The
techniques used for their physicochemical characterization
were: XRD, AAS, N2 physisorption, SEM, TEM and DR
UVVis spectroscopy. All the materials presented high
specific surface area ([900 m2/g), characteristic of MCM-
41 materials. A well-defined mesoporous structure was
observed by TEM measures although there was no onedimensional
ordering of pores characteristic of such
materials. Additionally, secondary mesoporosity domains
were determined in the BJH size distribution. The sample
synthesized with the highest content of V presented marked
differences in their structural characteristics, which were
attributed to the blockage of channels by the presence of
nano-clusters and/or VxOy nano-oxides. From the DR
UVVis analysis, a successful incorporation of V ions to
silica structure in tetrahedral coordination with oxygen of
the network could be inferred. The catalytic activity
of these materials was evaluated in the test reaction of
cyclohexene oxidation using H2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.lm. The
techniques used for their physicochemical characterization
were: XRD, AAS, N2 physisorption, SEM, TEM and DR
UVVis spectroscopy. All the materials presented high
specific surface area ([900 m2/g), characteristic of MCM-
41 materials. A well-defined mesoporous structure was
observed by TEM measures although there was no onedimensional
ordering of pores characteristic of such
materials. Additionally, secondary mesoporosity domains
were determined in the BJH size distribution. The sample
synthesized with the highest content of V presented marked
differences in their structural characteristics, which were
attributed to the blockage of channels by the presence of
nano-clusters and/or VxOy nano-oxides. From the DR
UVVis analysis, a successful incorporation of V ions to
silica structure in tetrahedral coordination with oxygen of
the network could be inferred. The catalytic activity
of these materials was evaluated in the test reaction of
cyclohexene oxidation using H2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.2 physisorption, SEM, TEM and DR
UVVis spectroscopy. All the materials presented high
specific surface area ([900 m2/g), characteristic of MCM-
41 materials. A well-defined mesoporous structure was
observed by TEM measures although there was no onedimensional
ordering of pores characteristic of such
materials. Additionally, secondary mesoporosity domains
were determined in the BJH size distribution. The sample
synthesized with the highest content of V presented marked
differences in their structural characteristics, which were
attributed to the blockage of channels by the presence of
nano-clusters and/or VxOy nano-oxides. From the DR
UVVis analysis, a successful incorporation of V ions to
silica structure in tetrahedral coordination with oxygen of
the network could be inferred. The catalytic activity
of these materials was evaluated in the test reaction of
cyclohexene oxidation using H2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.[900 m2/g), characteristic of MCM-
41 materials. A well-defined mesoporous structure was
observed by TEM measures although there was no onedimensional
ordering of pores characteristic of such
materials. Additionally, secondary mesoporosity domains
were determined in the BJH size distribution. The sample
synthesized with the highest content of V presented marked
differences in their structural characteristics, which were
attributed to the blockage of channels by the presence of
nano-clusters and/or VxOy nano-oxides. From the DR
UVVis analysis, a successful incorporation of V ions to
silica structure in tetrahedral coordination with oxygen of
the network could be inferred. The catalytic activity
of these materials was evaluated in the test reaction of
cyclohexene oxidation using H2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.xOy nano-oxides. From the DR
UVVis analysis, a successful incorporation of V ions to
silica structure in tetrahedral coordination with oxygen of
the network could be inferred. The catalytic activity
of these materials was evaluated in the test reaction of
cyclohexene oxidation using H2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.2O2 as oxidizing agent,
showing a high conversion of about 93% respect to the
maximum, resulting dominant the radicalary mechanism
over the direct oxidation mechanism. Apparently, the isolated
V ions incorporated into the silica structure would
be responsible for the high catalytic activity of these
materials.