Platinum catalysed wet oxidation of phenol in a stirred slurry reactor

Masende, Zpg; Kuster, Bfm Ben; Ptasinski, KJ Krzysztof; Janssen, F.J.J.G.; Katima, J.H.Y.; Schouten, JC Jaap

doi:10.1016/s0920-5861(03)00064-6

Cited by 58 publications

(53 citation statements)

References 24 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: 63%

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: 63%

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

et al. 2005

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“…In fact, whatever the palladium loading, even if it is very low, the nitrogen selectivity is strongly improved. Qin [40] has tentatively reported a detailed kinetic scheme on RuO 2 /Al 2 O 3 catalyst for ammonia oxidation (equation [8][9][10][11][12][13][14][15][16]. This hypothetic mechanism seems also adapted with metallic catalysts.…”

Section: Catalytic Wet Air Oxidation Of Ammonia Onmentioning

confidence: 96%

“…CWAO or WAO can typically be applied to effluents with medium chemical oxygen demand (COD), in the 5-100 g.L )1 range of concentration, and for treating toxic or/and non biodegradable pollutants [3][4][5][6]. CWAO is a very efficient process for treating a large range of pollutants such as carboxylic acids [7], phenol [8][9][10][11][12][13][14], polymers [15], and N,O-containing organic compounds [16]. Depending on the reaction conditions (temperature, pressure), two different objectives can be achieved: (i) a total mineralization of pollutants into CO 2 , N 2 and H 2 O or (ii) an increase of the effluent biodegradability by orientating the reaction through the formation of easily biodegradable by-products such as carboxylic acids [17].…”

Section: Introductionmentioning

confidence: 99%

Role of ceria-supported noble metal catalysts (Ru, Pd, Pt) in wet air oxidation of nitrogen and oxygen containing compounds

et al. 2005

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Catalytic Wet Air Oxidation (CWAO) of aniline, phenol, carboxylic acids and ammonia was carried out in a batch reactor over noble metals (Ru, Pd, Pt) supported on ceria. Ruthenium is very active for the conversion of a wide range of organic compounds and selective into carbon dioxide. The ability of ceria to transfer oxygen is essential for good performances in CWAO. However, Ru/CeO 2 is not selective for ammonia oxidation into N 2 . Addition of small amount of Pd enhances both activity and selectivity of Ru in this reaction. Finally, oxidation of nitrogenous organic compounds requires moderate temperature and oxygen pressure and needs to adjust the oxidizing capacity of the catalyst.

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“…The process involved the reaction of phenol with 30% H 2 O 2 , which is simple and produces no pollution. Phenol oxidation on Pt catalysts supported on graphite in a stirred tank reactor was studied, and the selectivity of its products was found to depend on the degree of oxygen coverage of the platinum surface [6]. The overoxidized Pt was considered favorable for the formation of hydroquinone, whereas the partly oxidized platinum deemed favorable for the formation of catechol.…”

Section: Introductionmentioning

confidence: 99%

Characterization of platinum–iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

Chumee

Grisdanurak

Neramittagapong

et al. 2009

Science and Technology of Advanced Materials

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Mesoporous material RH-MCM-41 was synthesized with rice husk silica by a hydrothermal method. It was used as a support for bimetallic platinum−iron catalysts Pt-Fe/RH-MCM-41 for phenol hydroxylation. The catalysts were prepared by co-impregnation with Pt and Fe at amounts of 0.5 and 5.0 wt.%, respectively. The RH-MCM-41 structure in the catalysts was studied with x-ray diffraction, and their surface areas were determined by nitrogen adsorption. The oxidation number of Fe supported on RH-MCM-41 was +3, as determined by x-ray absorption near edge structure (XANES) analysis. Transmission electron microscopy (TEM) images of all the catalysts displayed well-ordered structures, and metal nanoparticles were observed in some catalysts. All the catalysts were active for phenol hydroxylation using H 2 O 2 as the oxidant at phenol : H 2 O 2 mole ratios of 2 : 1, 2 : 2, 2 : 3 and 2 : 4. The first three ratios produced only catechol and hydroquinone, whereas the 2 : 4 ratio also produced benzoquinone. The 2 : 3 ratio gave the highest phenol conversion of 47% at 70• C. The catalyst prepared by co-impregnation with Pt and Fe was more active than that prepared using a physical mixture of Pt/RH-MCM-41 and Fe/RH-MCM-41.

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Platinum catalysed wet oxidation of phenol in a stirred slurry reactor

Cited by 58 publications

References 24 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

Role of ceria-supported noble metal catalysts (Ru, Pd, Pt) in wet air oxidation of nitrogen and oxygen containing compounds

Characterization of platinum–iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

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