Catalytic ketonisation of acetic acid over modified zirconia

Parida, Kulamani; Mishra, H.K.

doi:10.1016/s1381-1169(98)00184-8

Cited by 74 publications

(43 citation statements)

References 13 publications

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“…Also important is that the alkaline treatment does not significantly change the equilibrium concentration of both acids on the KOH treated zirconia compared to the untreated zirconia, and only makes a slight change of that for titania (Fig. 9), which is in full agreement with literature data [30].…”

Section: Concentration Of Active Sitessupporting

confidence: 90%

“…Evidently, alkaline treatment did not cause a substantial change of the surface area of zirconia and titania. This conclusion is also supported by the literature data showing that zirconia doped with Na, K, or Cs has almost the same surface area as pure untreated zirconia [30]. Therefore, the surface area factor can be excluded from consideration when analyzing the difference in catalyst behavior.…”

Section: Catalysts Surface Areasupporting

confidence: 72%

“…It has been reported in literature that doping zirconia with Cs and K had no effect on the concentration and the strength of basic sites on surface [30]. In fact, zirconia doped with Na, indicated a decline in the number of both the strongly basic sites found by adsorption of phenol, and the moderately basic sites found by adsorption of acrylic acid.…”

Section: Concentration Of Active Sitesmentioning

confidence: 87%

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Cross-selectivity in the catalytic ketonization of carboxylic acids

Ignatchenko

DeRaddo

Marino

et al. 2015

Applied Catalysis A: General

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a b s t r a c tA mixture of acetic and 2-methylpropanoic (isobutyric) acids representing non-branched and branched acids, respectively, was catalytically converted to a mixture of ketones in a set of statistically designed experiments (DOE). The selectivity toward the cross-ketonization product was analyzed depending on (a) temperature within 300-450 • C range, (b) molar fraction of each acid in the mixture, from 10% to 90%, and (c) liquid hourly space velocity (LHSV) within 2-12 h −1 , and compared against the selectivity toward two symmetrical ketones. Six metal oxide catalysts were tested and ranked on their ability to yield the cross-product as opposed to the self-condensation product. The catalysts were based on either the anatase form of titania or monoclinic form of zirconia and treated with either KOH or K 2 HPO 4 . The titania catalyst treated by KOH outperformed all other catalysts by providing the cross-selectivity above the statistically expected binomial distribution. The criterion for having a high cross-selectivity in the decarboxylative ketonization is formulated mathematically as the separation of roles of two acids, one being a more active enolic component, and the other being the preferred carbonyl component. According to the suggested criterion, the less branched acetic acid reacts as both the preferred carbonyl and enolic component with untreated catalysts. Therefore, untreated catalysts promote selective formation of the symmetrical ketone, acetone, thereby decreasing the selectivity to the cross-ketone. After alkaline treatment, both the anatase form of titania and monoclinic form of zirconia increase the isobutyric acid participation as the carbonyl component. Acetic acid remains as the preferred enolic component with all treated catalysts, thus increasing the selectivity toward the cross-product in the ketonization of a mixture of carboxylic acids. The condition for achieving a high cross-selectivity by polarizing roles of the two reactants can be extended to other types of cross-condensations.

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Section: Concentration Of Active Sitessupporting

confidence: 90%

Section: Catalysts Surface Areasupporting

confidence: 72%

Section: Concentration Of Active Sitesmentioning

confidence: 87%

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Cross-selectivity in the catalytic ketonization of carboxylic acids

Ignatchenko

DeRaddo

Marino

et al. 2015

Applied Catalysis A: General

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“…Over ZrO 2 , acetone and CO 2 were the major products and almost no hydrogen was observed. Oxides, such as ZrO 2 , are known [10,11] to catalyze the ketonization of AcOH to acetone (Eq. 5) and the results shown in Table 1 are thus not surprising.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Aspects of Catalytic Steam Reforming of Biomass-related Oxygenates

et al. 2008

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Catalytic steam reforming of acetic acid, as a model oxygenate derived from biomass, was studied over supported Pt catalysts. It is suggested that both Pt and the support are involved in the activation of acetic acid and water, respectively. This manifests in different intrinsic activity for Pt when anchored on different supports. Accordingly, the reforming proceeds most likely at the boundary between the Pt and the support and the number of Pt sites that are in the close proximity of the support determine hydrogen formation rates.

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“…The effect of K on surface acetate species was proven in the work of Parida and Mishara [8], who examined the catalytic ketonization of acetic acid over alkali metal doped ZrO 2 catalysts. Comparing the yield of acetone at 573 K they found that in the presence of an alkali metal the amount of this product increased, except Li, where less acetone formed than over pure ZrO 2 .…”

Section: Introductionmentioning

confidence: 99%

Promoting Mechanism of Potassium in the Reforming of Ethanol on Pt/Al2O3 Catalyst

et al. 2008

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The reaction of ethanol and water has been investigated over K doped 1% Pt/Al 2 O 3 catalysts. The presence of K resulted at room temperature in upward shift of the IR band of CO formed in the ethanol adsorption. At higher temperature the presence of surface acetate species was also detected which, according to the TPD results decomposed above 600 K to form CH 4 and CO 2 . The K destabilized these forms. In the catalytic reaction the H 2 selectivities were similar and much higher over all promoted Pt/Al 2 O 3 than on the pure catalyst. In this study it was proved that the K had a destabilizing effect onto the surface acetate groups and thus improved the steam reforming activity of 1% Pt/Al 2 O 3 .

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Catalytic ketonisation of acetic acid over modified zirconia

Cited by 74 publications

References 13 publications

Cross-selectivity in the catalytic ketonization of carboxylic acids

Cross-selectivity in the catalytic ketonization of carboxylic acids

Mechanistic Aspects of Catalytic Steam Reforming of Biomass-related Oxygenates

Promoting Mechanism of Potassium in the Reforming of Ethanol on Pt/Al2O3 Catalyst

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