The Effect of Water on the Heterogeneously Catalyzed Selective Oxidation of Acrolein: An Isotope Study

Petzold, Theodor Dierk; Blickhan, Nina; Drochner, Alfons; Vogel, Herbert

doi:10.1002/cctc.201400099

Cited by 19 publications

(36 citation statements)

References 55 publications

(43 reference statements)

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“…From previous works, the individual reaction steps (reversible adsorption of ACR by the formation of a surface acetal, conversion of the surface acetal into a surface acrylate (redox step), and desorption of AA) are known , , but are of less importance in a first approach for modeling of the activity hysteresis. Nevertheless, such details are required for the explanation of the results from the steady‐state isotopic transient kinetic analysis experiments or the activity‐enhancing effects of water , , , , . In addition to selective oxidation of ACR (Eqs.…”

Section: Models and Simulationmentioning

confidence: 99%

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Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

et al. 2017

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Dedicated to Professor Rüdiger Lange on the occasion of his 65th birthdayOxidation of acrolein to acrylic acid on a Mo/V/W mixed oxide catalyst was studied by transient (cyclic temperature-programmed (TP)) as well as steady-state methods. TP reactions (TPReactions) exhibit an activity hysteresis of the catalyst with respect to temperature. As a result of the steady-state measurements, the activity hysteresis is not related to multiple steady states and is exclusively a transient phenomenon. Generally, the dynamics of bulk oxygen plays a key role leading to a reversible oxidation/reduction of the catalyst surface which influences the activity. This means the bulk acts as oxygen buffer. In this context, a reaction model, which involves the participation of bulk oxygen, was deduced and verified by modeling.

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Section: Models and Simulationmentioning

confidence: 99%

“…However, at elementary level, the mechanism is still not fully understood. For this purpose, additional aspects, such as the effect of water , , , or the participation of oxygen from the bulk phase of the mixed oxide have to be considered .…”

Section: Introductionmentioning

confidence: 99%

Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

et al. 2017

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“…At the present temperature (150 °C), no conversion of the ACR occurs (also no O 2 was fed). Nevertheless, an interchange of oxygen between H 2 18 O and ACR can occur over the shown adsorption equilibria (Figure ) . The oxygen exchange rate correlates with the adsorption or desorption rates and thus also indirectly with the adsorption constant (

K \sim \frac{k_{a d}}{k_{d e}}

).…”

Section: Resultsmentioning

confidence: 97%

“…It should be noted that the combustion of ACR‐D 4 results consequently in CO x and D 2 O. It is known that water enhances the activity of a mixed oxide . Thus, a KIE, which is caused by the exchange of H 2 O to D 2 O, is conceivable.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Study on the Selective Oxidation of Acrolein to Acrylic Acid: Identification of the Rate‐Limiting Step via Perdeuterated Acrolein

et al. 2019

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Gas phase oxidation of acrolein to acrylic acid on hydrothermally prepared Mo/V/W mixed oxides was investigated by isotopic labeling of acrolein. In this context, perdeuterated acrolein was synthesized for the first time and subsequently used for mechanistic studies. A clear kinetic isotopic effect (KIE) is observed referring to the α‐hydrogen‐abstraction as the rate‐determining step in the selective acrolein oxidation. Furthermore, no change in the selectivity patterns is observed due to the perdeuteration, which confirms that the α‐hydrogen‐abstraction also acts as the rate‐limiting step in the total oxidation of acrolein. Based on these KIE studies combined with additional experiments including D2O‐SSITKA and temperature‐programmed desorption, a detailed reaction mechanism for acrolein oxidation is proposed.

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“…Vogel et al . described the problem of isotope scrambling with H 2 O even for the selective oxidation of acrolein to acrylic acid, where only small amounts of H 2 O are formed due to the high selectivity of the reaction. In our case, the effect of oxygen exchange of H 2 O with MAN must be considered due to the significant formation of H 2 O in both selective and unselective reaction pathways.…”

Section: Resultsmentioning

confidence: 99%

Selective Oxidation of n‐Butane over Vanadium‐Phosphorus Oxide: Oxygen Activation and Dynamics

et al. 2018

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The complex microkinetics of the selective oxidation of n‐butane to maleic anhydride (MAN) over vanadyl pyrophosphate‐based (VPP) catalysts has been widely investigated so far, however, they are still under debate. We present novel results of kinetic analyses and isotope labeling to shed light on the activation of gas‐phase oxygen and the dynamics of oxygen species on the catalyst surface and in the bulk. We suggest the existence of at least two catalytically relevant surface oxygen species responsible for selective and unselective activation of n‐butane, which are formed by adsorption and consecutive dissociation of O2 at the active site. The formation of selective [O] from unselective [O2] is likely promoted by co‐fed H2O, which increases the MAN selectivity. Regarding the VPP bulk serving as a reservoir for active [O] species it is concluded that the dynamic exchange is limited to the amorphous surface layer forming under reaction conditions, whereas the crystalline bulk is not involved into the reaction. Labelling studies are heavily influenced by vital 16O/18O scrambling of MAN isotopes with the reaction product H2O.

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The Effect of Water on the Heterogeneously Catalyzed Selective Oxidation of Acrolein: An Isotope Study

Cited by 19 publications

References 55 publications

Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

Activity Hysteresis during Cyclic Temperature‐Programmed Reactions in the Partial Oxidation of Acrolein to Acrylic Acid

Mechanistic Study on the Selective Oxidation of Acrolein to Acrylic Acid: Identification of the Rate‐Limiting Step via Perdeuterated Acrolein

Selective Oxidation of n‐Butane over Vanadium‐Phosphorus Oxide: Oxygen Activation and Dynamics

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