Reaction and Deactivation Pathways in Xylene Isomerization on Zirconia Modified by Tungsten Oxide

Wilson, Ryan D.; Barton, David G.; Baertsch, Chelsey D.; Iglesia, Enrique

doi:10.1006/jcat.2000.2942

Cited by 82 publications

(99 citation statements)

References 24 publications

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“…Reference source not found., where side reactions resulted in other products besides propylene and ammonia. In general, the Brønsted acid densities for the tested aluminosilicate materials, found in Table 4-1, are much higher than the Brønsted acid densities for WOx/ZrO2 catalysts reported in the literature [213,216,217]. These results suggest that the difference in activity for n-dodecane cracking on a per gram basis between WOx/ZrO2 and aluminosilicate catalysts can be attributed to the difference in Brønsted acid density.…”

Section: Catalytic Testscontrasting

confidence: 43%

Solid Acid Catalysts for Endothermic Fuels

Huang

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Vehicles traveling at high supersonic and hypersonic flight speeds experience high thermal heat loads from aerodynamic heating that exceed the heat sink capacity of existing thermal management systems. Conventional thermal management systems are limited by the physical heat sink capacity of hydrocarbon fuels. One method to increase the heat sink capacity of hydrocarbon fuels is to carry out endothermic reactions on the hydrocarbon fuel near the heat load. The breaking of C-C bonds over a catalyst, otherwise known as catalytic cracking, is an endothermic reaction that can provide a substantial heat sink for so called endothermic fuels. Understanding the effects of catalyst porosity and hydrocarbon molecular structure for catalytic cracking under supercritical conditions is necessary for the rational design of catalyst/fuel pairings for endothermic fuels. In this study, reactions of linear, branched, and cyclic hydrocarbons were performed over micro-and mesoporous solid acid catalysts under supercritical conditions. Measurements of intrinsic rate parameters were used to develop a fundamental understanding of the reaction mechanism under supercritical conditions.

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Section: Catalytic Testscontrasting

confidence: 43%

Solid Acid Catalysts for Endothermic Fuels

Huang

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“…According to the standard, this steel has the following composition (wt.%): Fe (balance), Cr (18)(19)(20), Ni (8)(9)(10)(11)(12), C(<0.08), Si(<1), other elements (minor concentration). Before deposition, the substrates were subjected to conventional degreasing procedures.…”

Section: Methodsmentioning

confidence: 99%

“…Zirconia itself is a catalytic material. 8,9 In environmental catalysis, ZrO 2 has been used in catalytic selective reduction of NO x . 10 It is used in catalysis as a support, 11,12 owing to its chemical stability, high thermal expansion coefficient, low thermal conductivity and high thermomechanical resistance.…”

Section: Introductionmentioning

confidence: 99%

XPS depth profile study of porous zirconia films deposited on stainless steel by spray pyrolysis: the problem of substrate corrosion

Martı́n

López

Carrera

et al. 2004

Surface & Interface Analysis

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Zirconia (ZrO 2 ) films of tissue-like structure and narrow pore size distribution have been deposited by spray pyrolysis using aqueous zirconyl chloride octahydrate (ZrOCl 2 ·8H 2 O) precursor solutions. Stainlesssteel sheets, protected or unprotected by a ZnO barrier layer, have been used as the substrate material held at 473 K. The ZnO barrier layers have been deposited on the stainless steel held at 523 K by spray pyrolysis using a zinc acetate precursor. Their property of corrosion protection to stainless steel has been proved by electrochemical polarization measurements in 0.5 M NaCl solution. A complementary study of XPS (depth profiling, mapping) and x-ray diffraction has shown that the unprotected steel substrates were corroded during ZrO 2 film post-annealing in air at T ≥ 773 K, whereas steel substrates protected with a compact barrier layer of crystalline ZnO before ZrO 2 film deposition did not show surface corrosion even after annealing up to 997 K.

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“…The difference in the interactions between both adsorbates and AC can be associated to the difference in their dipolar moments. Indeed, the OX and PrOH molecules are characterized by different dipole moment 0.64 D and 1.68 D, respectively [27,28]. This characteristic may lead to different affinities to the AC surface sites and subsequently promotes their adsorption.…”

Section: Heats Of Adsorption Of Ox and Proh On Ac Under Adsorption Eqmentioning

confidence: 99%

Determination by Modeling of the Interactions during the Adsorption Equilibrium of N-Propanol and Ortho Xylene on Activated Carbon Surface

Hachimi¹

2014

J Chem Eng Process Technol

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Temperature Programmed Adsorption Equilibrium (TPAE) procedure was used to determine the heats of adsorption of ortho xylene and 1-propanol on activated carbon at 300 K. The evolutions of the surface coverage with the adsorption temperature (θ e =f(T a )) were compared to the Temkin model in order to determine the heats of adsorption and reveal the affinity to the surface of activated carbon regarding the polarity of each adsorbate. It has been shown that the heats of adsorption of ortho xylene were E θ0 =100 kJ/mol and E θ1 =62 kJ/mol at 185 Pa, respectively, at low and high surface coverage. Whereas the heats of adsorption of 1-propanol at the adsorption equilibrium was found to be dependent to the surface coverage with E θ0 =67 kJ/mol and E θ1 =58 kJ/mol at 475 Pa. It was shown that ortho-xylene molecules have more affinity to the activated carbon surface than 1-propanol regarding the difference in the heats of adsorption.

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Reaction and Deactivation Pathways in Xylene Isomerization on Zirconia Modified by Tungsten Oxide

Cited by 82 publications

References 24 publications

Solid Acid Catalysts for Endothermic Fuels

Solid Acid Catalysts for Endothermic Fuels

XPS depth profile study of porous zirconia films deposited on stainless steel by spray pyrolysis: the problem of substrate corrosion

Determination by Modeling of the Interactions during the Adsorption Equilibrium of N-Propanol and Ortho Xylene on Activated Carbon Surface

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