Ethanol dehydration pathways in H-ZSM-5: Insights from temporal analysis of products

Batchu, Rakesh; Galvita, Vladimir; Alexopoulos, Konstantinos; Glazneva, Tatiana S.; Poelman, Hilde; Reyniers, Marie Françoise; Marin, Guy

doi:10.1016/j.cattod.2019.04.018

Cited by 30 publications

(20 citation statements)

References 34 publications

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“…It was concluded from Figure 4a that acetaldehyde decomposition, yielding CO, C*, CH 3 * and H* adsorbates as per Equation ( 6), is very fast so that a condensation reaction of two acetaldehyde molecules possibly yielding acetic acid, butanol isomers or ethyl acetate is not likely to proceed under these reaction conditions. It is known from the literature [62] that strongly acidic catalysts like H-ZSM-5 must be applied for the dehydration of ethanol to form ethene and diethyl ether. The above-described trends and phenomena at 200 • C for the transient responses of the different components of the ethanol dehydrogenation/acetaldehyde decomposition reaction network are qualitatively highly comparable to those at the other investigated reaction temperatures of 100 • C, 150 • C and 250 • C, and so these will not be presented here.…”

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confidence: 99%

Ethanol Dehydrogenation: A Reaction Path Study by Means of Temporal Analysis of Products

et al. 2020

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Conventional fossil fuels such as gasoline or diesel should be substituted in the future by environmentally-friendly alternatives in order to reduce emissions in the transport sector and thus mitigate global warming. In this regard, iso-butanol is very promising as its chemical and physical properties are very similar to those of gasoline. Therefore, ongoing research deals with the development of catalytically-supported synthesis routes to iso-butanol, starting from renewably-generated methanol. This research has already revealed that the dehydrogenation of ethanol plays an important role in the reaction sequence from methanol to iso-butanol. To improve the fundamental understanding of the ethanol dehydrogenation step, the Temporal Analysis of Products (TAP) methodology was applied to illuminate that the catalysts used, Pt/C, Ir/C and Cu/C, are very active in ethanol adsorption. H2 and acetaldehyde are formed on the catalyst surfaces, with the latter quickly decomposing into CO and CH4 under the given reaction conditions. Based on the TAP results, this paper proposes a reaction scheme for ethanol dehydrogenation and acetaldehyde decomposition on the respective catalysts. The samples are characterized by means of N2 sorption and Scanning Transmission Electron Microscopy (STEM).

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Ethanol Dehydrogenation: A Reaction Path Study by Means of Temporal Analysis of Products

et al. 2020

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“…An appropriately selected probe reaction can then be used as a "pragmatic scale" of the acid-base properties of the zeolitic catalyst. Unfortunately, there is no one universal or generally accepted probe reaction and many reactions have been tested for this purpose-e.g., cracking of alkanes [11,13,22,23], dehydration of alcohols (methanol [4,9,24,25] or ethanol [14,[26][27][28][29]), and isotopic exchange reaction [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Influence of Substrate Concentration on Kinetic Parameters of Ethanol Dehydration in MFI and CHA Zeolites and Relation of These Kinetic Parameters to Acid–Base Properties

et al. 2022

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The catalytic activity of zeolites is often related to their acid–base properties. In this work, the relationship between the value of apparent activation energy of ethanol dehydration, measured in a fixed bed reactor and by means of a temperature-programmed surface reaction (TPSR) depending on the amount of ethanol in the zeolite lattice and the value of activation energy of H/D exchange as a measure of acid–base properties of MFI and CHA zeolites, was studied. Tests in a fixed bed reactor were unable to provide reliable reaction kinetics data due to internal diffusion limitations and rapid catalyst deactivation. Only the TPSR method was able to provide activation energy values comparable to the activation energy values obtained from the H/D exchange rate measurements. In addition, for CHA zeolite, it has been shown that the values of ethanol dehydration activation energies depend on the amount of ethanol in the CHA framework, and this effect can be attributed to the substrate clustering effects supporting the deprotonation of zeolite Brønsted centers.

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“…[10][11][12] There were several experimental studies on the dehydration of ethanol to ethylene with H-[Al]-ZSM-5 zeolite. [13][14][15] The dehydration reaction of ethanol were also studied over Sn-Beta zeolite [16], Ni-ZSM-5 [17]. The ethoxy group was considered to be an intermediate for the dehydration of ethanol to ethylene.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Dehydration Reaction of Ethanol to Ethylene on Isomorphous B, Al, and Ga Substitution of H-ZSM-5 Zeolite: An Embedded ONIOM Study

Maeboonruan¹,

Boekfa²,

Maihom³

et al. 2021

Preprint

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Dehydration reactions are important in the petroleum and petrochemical industries, especially for the feedstock production. In this work, the catalytic activity of zeolites with different acidities for the dehydration of ethanol to ethylene was investigated by calculations on cluster models of three isomorphous B, Al, and Ga substitution of H-ZSM-5 zeolites. Detailed reaction profiles for the dehydration reaction, assuming either a stepwise or a concerted mechanism, were calculated by using the ONIOM(MP2:M06-2X) + SCREEP method. The adsorption energies of ethanol are -21.6, -28.1 and -27.7 kcal/mol on H-[B]-ZSM-5, H-[Al]-ZSM-5, H-[Ga]-ZSM-5 zeolites, respectively. The stepwise mechanism was preferred on all isomorphous zeolites. The activation energies for the ethoxy formation as the rate-determining step are in range of 40.0 to 42.3 kcal/mol. The results indicated that the order of catalytic activity were H-[Al]-ZSM-5 > H-[Ga]-ZSM-5 > H-[B]-ZSM-5 for catalyzing the dehydration of ethanol to ethylene. Besides the acid strength, the zeolite framework affected the reaction by stabilizing the reaction intermediates leading to more stable adsorption complexes and lower activation barriers.

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Ethanol dehydration pathways in H-ZSM-5: Insights from temporal analysis of products

Cited by 30 publications

References 34 publications

Ethanol Dehydrogenation: A Reaction Path Study by Means of Temporal Analysis of Products

Ethanol Dehydrogenation: A Reaction Path Study by Means of Temporal Analysis of Products

Influence of Substrate Concentration on Kinetic Parameters of Ethanol Dehydration in MFI and CHA Zeolites and Relation of These Kinetic Parameters to Acid–Base Properties

Adsorption and Dehydration Reaction of Ethanol to Ethylene on Isomorphous B, Al, and Ga Substitution of H-ZSM-5 Zeolite: An Embedded ONIOM Study

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