Platinum catalysed aqueous alcohol oxidation: model-based investigation of reaction conditions and catalyst design

Gangwal, VR Vikrant; Wachem, van Bgm Berend; Kuster, Bfm Ben; Schouten, JC Jaap

doi:10.1016/s0009-2509(02)00434-7

Cited by 24 publications

(25 citation statements)

References 14 publications

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“…Similar results supporting the low adsorption of carboxylic acids onto activated carbon supports can be found in the literature [28]. To take into account effects like surface over-oxidation of platinum [29,30], leaching, platinum particle growth, and site coverage [31], an empirical deactivation function a, defined as the fraction of nondeactivated sites [32,33] can be considered. In this respect, some authors claim that over-oxidation is a slow and reversible process that occurs under oxidation conditions [34,35], which can be described by a reversible transformation of oxygen adatoms into inactive subsurface oxygen [34].…”

Section: Cwao Experimentssupporting

confidence: 66%

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

et al. 2005

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Carbon supported platinum (1% wt) catalysts were prepared by the incipient wetness impregnation method and by organometallic chemical vapor deposition. Catalyst characterization was carried out by means of adsorption and thermogravimetric techniques, and by electron microscopy. The catalyst with higher metal dispersion was produced by incipient wetness impregnation. The catalysts were tested in the catalytic wet air oxidation (200°C and 6.9 bar of oxygen partial pressure) of aqueous solutions containing low molecular weight (C 2 to C 4 ) carboxylic acids. Significant conversions (greater than 60% over 2 h) and 100% selectivity towards water and non-carboxylic acid products were observed for both systems. The initial reaction rate was used to compare the performance of the two catalytic materials and direct correspondence to the metal dispersion was found. No metal leaching was observed during reaction and no significant deactivation occurred in three successive catalytic oxidation runs. A kinetic model based on the Langmuir-Hinshelwood formulation was applied and the results were analyzed in terms of a heterogeneously catalyzed free radical mechanism.KEY WORDS: catalytic wet air oxidation (CWAO); carbon supported platinum catalysts; incipient wetness impregnation; organometallic chemical vapor deposition (OMCVD)

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Section: Cwao Experimentssupporting

confidence: 66%

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

et al. 2005

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“…On the other hand, a high amount of dissolved oxygen might also slow down aniline oxidation as reported in the literature. [13] This deactivation due to a saturation of all available adsorption sites on the catalyst might prevent access to aniline monomers. [14] However, aniline oxidation efficiency and rate are also certainly depending on the temperature too.…”

Section: Resultsmentioning

confidence: 99%

Electroless deposition of polyaniline: synthesis and characterization

Attout

Yunus

Bertrand

2008

Surface & Interface Analysis

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Polyaniline (PANi), as conductive polymer, constitutes an attractive material for electronic and optical applications. Different from electropolymerization and chemical oxidative polymerization, electroless deposition is another method for synthesizing PANi. Aniline can polymerize slowly and spontaneously on platinum or palladium surface in an aqueous acid solution of the monomer. This reaction proceeds via an electrochemical mechanism that involves the reduction of dissolved oxygen as cathodic and oxidation of aniline as anodic half-reactions at the metal/solution interface. PANi, obtained by electroless synthesis, was compared to chemical oxidative and electropolymerized ones by XPS and SEM. The product of electroless deposition is found to be chemically similar to the others but its morphology is different. The PANi film growth and morphology are studied as a function of time and temperature.

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“…According to this model, with increase in oxygen concentration, the electrochemical potential of the catalyst increases, which leads to an increase in the oxidation rate as well as to catalyst deactivation due to over-oxidation. The electrochemical kinetic model is presented in Table 1, a detailed description is given elsewhere [9]. It was found that for the methyl a-Dglucopyranoside oxidation a new set of kinetic parameters improved the performance of the kinetic model, now being suited for intrinsic kinetic as well as for mass transport limited conditions [10].…”

Section: Reaction-engineering Modelmentioning

confidence: 99%

“…The liquid reactant alcohol is in a batch mode and continuously converting to the product as reaction pro- Table 2 List of values of kinetic parameters Symbol Description Old parameters Pt/Gr [8,9] New parameters Pt/Gr [10] Adopted Pt/carbon k 1 (m 3 mol À1 s À1 ) Oxygen adsorption rate constant 6.5 Â 10 3…”

Section: Materials Balance For Liquid Reactant and Productsmentioning

confidence: 99%

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Catalyst performance for noble metal catalysed alcohol oxidation: reaction-engineering modelling and experiments

et al. 2004

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Platinum catalysed aqueous alcohol oxidation: model-based investigation of reaction conditions and catalyst design

Cited by 24 publications

References 14 publications

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

Electroless deposition of polyaniline: synthesis and characterization

Catalyst performance for noble metal catalysed alcohol oxidation: reaction-engineering modelling and experiments

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