A mechanistic study of ethanol transformation into ethene and acetaldehyde on an oxygenated Au-exchanged ZSM-5 zeolite

Injongkol, Yuwanda; Maihom, Thana; Choomwattana, Saowapak; Boekfa, Bundet; Limtrakul, Jumras

doi:10.1039/c7ra06313j

Cited by 7 publications

(3 citation statements)

References 67 publications

(74 reference statements)

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“…All calculations were performed with the M06-L density functional as implemented in the Gaussian 09 code . Previous studies of adsorption and reaction mechanisms on zeolites − and also on other materials such as metals-organic frameworks − have confirmed its usability. The 6-31G(d,p) basis set is employed for the Si, C, O, Li, Na, K, and H atoms, while Sn, Zr, and Hf atoms are described by the Stuttgart Effective Core Potential basis (ECP) .…”

Section: Model and Methodsmentioning

confidence: 85%

Furfural to Furfuryl Alcohol: Computational Study of the Hydrogen Transfer on Lewis Acidic BEA Zeolites and Effects of Cation Exchange and Tetravalent Metal Substitution

et al. 2018

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The hydrogen transfer of furfural to furfuryl alcohol with i-propanol as the hydrogen source over cation-exchanged Lewis acidic BEA zeolite has been investigated by means of density functional calculations. The reaction proceeds in three steps. First the O-H bond of i-propanol is broken to form a propoxide intermediate. After that, the furylmethoxy intermediate is formed via hydrogen transfer process, and finally furylmethoxy abstracts the proton to form the furfuryl alcohol product. The second step is rate-determining by requiring the highest activation energy (23.8 kcal/mol) if the reaction takes place on Li-Sn-BEA zeolite. We find that the catalytic activity of various cation-exchanged Sn-BEA zeolites is in the order Li-Sn-BEA > Na-Sn-BEA > K-Sn-BEA. The lower activation energy for Li-Sn-BEA compared to Na-Sn-BEA and K-Sn-BEA can be explained by the larger charge transfer from the carbonyl bond to the catalyst, leading to its activation and to the attraction of the hydrogen being transferred. The larger charge transfer in turn is due to the smaller gap between the energies of furfural HOMO and the zeolite LUMO in Li-Sn-BEA, compared to both Na-Sn-BEA and K-Sn-BEA. In a similar way, we also compare the catalytic activity of tetravalent metal centers (Sn, Zr, and Hf) substituted into BEA and find in the order Zr ≥ Hf > Sn, based on activation energies. Finally we investigate statistically which property of the reactants is a suitable descriptor for an approximative prediction of the reaction rate in order to be able to quickly screen promising catalytic materials for this reaction.

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Section: Model and Methodsmentioning

confidence: 85%

Furfural to Furfuryl Alcohol: Computational Study of the Hydrogen Transfer on Lewis Acidic BEA Zeolites and Effects of Cation Exchange and Tetravalent Metal Substitution

et al. 2018

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“…[27][28][29][30][31] In particular, zeolite and porous silica materials have become an area of considerable interest as favourable supports for metal species owing to their ability to stabilize metal ions and direct metal cluster size. 24,[32][33][34][35][36] One such example is the direct production of acetaldehyde from ethanol over Fe-exchanged mordenite (Fe-MOR) zeolites prepared by both solution-state and solid-state ion-exchange methods. 36 In this report, acetaldehyde was formed with 7-25% selectivity over Fe-MOR materials at reaction temperatures between 200 to 400 C. Notably, an acetaldehyde selectivity of 79% was reported at a reaction temperature of 100 C over an Fe-MOR catalyst prepared by solid-sate ion-exchange, albeit at very low ethanol conversion values (0.72%).…”

Section: Introductionmentioning

confidence: 99%

Zinc oxide-modified mordenite as an effective catalyst for the dehydrogenation of (bio)ethanol to acetaldehyde

Raynes

Taylor

2021

Sustainable Energy Fuels

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“…[38] These effects on unsaturated aliphatic, aromatic and heterocyclic compounds were theoretically examined by a combination of second order Møller-Plesset perturbation theory (MP2) and hybrid density functional M06-2X. [39] The M06 functionals [40] developed by the Truhlar group had also been successfully used for studying adsorption and reactions on acidic Zeolites [39,41,42], on Lewis-acid zeolites [43,44], on metallic catalysts [45][46][47][48][49], and on organic molecules [50,51]. Recently they have been applied to determine P-NMR chemical shifts of phosphorus-modi ed CHA zeolite.…”

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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A mechanistic study of ethanol transformation into ethene and acetaldehyde on an oxygenated Au-exchanged ZSM-5 zeolite

Abstract: Ethanol transformation to ethene and acetaldehyde over low- and high-spin state oxygenated Au-exchanged ZSM-5 zeolite have been investigated by means of density functional calculations with the M06-L functional.

Cited by 7 publications

References 67 publications

Furfural to Furfuryl Alcohol: Computational Study of the Hydrogen Transfer on Lewis Acidic BEA Zeolites and Effects of Cation Exchange and Tetravalent Metal Substitution

Furfural to Furfuryl Alcohol: Computational Study of the Hydrogen Transfer on Lewis Acidic BEA Zeolites and Effects of Cation Exchange and Tetravalent Metal Substitution

Zinc oxide-modified mordenite as an effective catalyst for the dehydrogenation of (bio)ethanol to acetaldehyde

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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