INVESTIGADORES
QUERINI carlos Alberto
artículos
Título:
Skeletal isomerization of 1-butene on WOx/Y-AI2O3
Autor/es:
BENITEZ, VIVIANA M; QUERINI, CARLOS A; FIGOLI, NORA; COMELLI, RAÚL A
Revista:
APPLIED CATALYSIS A-GENERAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 1999 vol. 178 p. 205 - 218
ISSN:
0926-860X
Resumen:
The catalytic behavior of WOx/g-Al2O3 (having different tungsten loading) during the 1-butene skeletal isomerization at
3808C, atmospheric pressure, and 0.15 atm 1-butene partial pressure was measured. Catalysts were prepared by impregnation
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
3808C, atmospheric pressure, and 0.15 atm 1-butene partial pressure was measured. Catalysts were prepared by impregnation
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
3808C, atmospheric pressure, and 0.15 atm 1-butene partial pressure was measured. Catalysts were prepared by impregnation
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
3808C, atmospheric pressure, and 0.15 atm 1-butene partial pressure was measured. Catalysts were prepared by impregnation
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis indicated that the coke deposited during the reaction burns at high temperature independently of both tungsten
loading and calcination conditions, mainly differing in the total amount. Product distribution shows the absence of C1 and C2
using an equilibrium±adsorption technique, being characterized by speci®c surface area and cumulative pore volume
measurements, temperature-programmed reduction (TPR), ammonia temperature-programmed desorption (NH3-TPD), X-ray
photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), and microcalorimetric measurements. After a standard
calcination procedure the isobutene production (which was practically constant with time-on-stream) reached a maximum
when increasing the tungsten loading. After 240 min of reaction the catalytic bed showed two layers: the upper part of the bed
is completely black and the bottom is light brown. By modifying the calcination conditions, the isobutene production is
decreased with time and the catalyst ®nished completely black all along the bed. Temperature-programmed oxidation (TPO)
analysis i