A theoretical study on the methanol to propene mechanism catalyzed by a phosphorus-modified acidic FAU zeolite

Xia, Mengya; Tong, Qiaoxian; Sun, Huai; Sun, Yi; Han, Sheng; Li, Qianggen

doi:10.1039/d2nj04863a

Cited by 3 publications

(10 citation statements)

References 81 publications

(123 reference statements)

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“…On the basis of the previous theoretical studies, , we investigated the MTP reaction mechanisms on gallium-modified FAU (Ga-FAU) zeolite and have proposed four possible reaction pathways. The whole MTP mechanism includes two cycles: polyMB cycle (Schemes –) and alkene cycle (Scheme ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…The alkene cycle is another possible mechanism for the production of propene. According to the previous study, , we proposed the alkene cycle mechanism on the Ga-FAU zeolite as given in Scheme . A series of elementary steps, such as methylation, deprotonation, proton transfer, and β-scission steps are involved to produce propene molecule.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The Bro̷nsted acid site is then formed by adding one acid proton (H) directly to the bridging oxygen atom (O1 position) bonded to the Ga atom. Finally, the terminal Si atoms in the Ga-FAU model are saturated by the Si–H bonds with a fixed bond length of 1.47 Å. , The DFT method with M06-2X functional and universal force field (UFF) is employed to describe the QM and MM atoms, respectively. − It is well-known that the M06-2X functional developed by Zhao et al could accurately predict the thermochemistry, noncovalent interactions, electronic excitation energies, and aromatic–aromatic stacking interactions of main-group elements. ,− The UFF force field developed by Rappe et al is often used to describe the nonbonded interactions in the zeolitic catalytic reactions. ,, …”

Section: Computational Modeling and Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Methanol to Propene over Gallium-Modified FAU Zeolite: Theoretical Study on the Polymethylbenzene and Alkene Cycles

Miao,

Sun,

Han

et al. 2024

J. Phys. Chem. C

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The catalytic performance of gallium-modified acidic FAU (Ga-FAU) zeolite in the methanol to propene (MTP) process was theoretically investigated by a two-layer ONIOM (our own N-layered integrated molecular orbital and molecular Mechanics) method. The whole MTP mechanism includes two cycles: the polymethylbenzene (polyMB) cycle and the alkene cycle. The polyMB cycle consists of the direct internal H-shift pathway, spiro pathway, methyl-transfer pathway, and paring pathway. Compared with the previous theoretical results on the MTP process on the pure acidic Si/Al FAU, the addition of Ga atoms into the Si/Al H-FAU could reduce the contribution of the polyMB cycle and increase the reactivity of the alkene cycle on the MTP process. A careful analysis of activation free energy barriers on the transition states (TSs) shows that the internal H-shift step is the ratedetermining step for the direct internal H-shift pathway and the paring pathway. The ratedetermining step for the spiro and methyl-transfer pathways is the methylation of the PMB molecule. The methylation of the propene molecule is the rate-determining step for the alkene cycle. The polyMB and alkene cycles have almost the same reactivity on the Ga-FAU zeolite. For the polyMB cycle, the different elementary steps are in the following order of reactivity: internal methyl transfer > deprotonation > C−C bond cracking > ring contraction > methylation > internal H-shift. The order in the alkene cycle is different: deprotonation > proton transfer > beta-scission > methylation. The differential charge density (DCD), local orbital locator (LOL), and reduced density gradient (RDG) revealed the direction of electron flow in different fragments in the TS structures and the nature of interactions between the fragments in the TSs.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Computational Modeling and Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Methanol to Propene over Gallium-Modified FAU Zeolite: Theoretical Study on the Polymethylbenzene and Alkene Cycles

Miao,

Sun,

Han

et al. 2024

J. Phys. Chem. C

Self Cite

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“…ONIOM calculation was used on zeolite due to its faster calculation and reliable results. [31][32][33][34][35][36][37] The protogenic group, consisting of sulfonic acid groups, terminal À CH 2 groups and water molecules, was set as the high layer, while the rest of the atoms in the fragments were set as low layer. All atoms in the backbone except for the hydrogen atoms were fixed in Cartesian coordinates.…”

Section: Methodsmentioning

confidence: 99%

“…Two propylsulfonic acid side chains were attached to each of the adjacent designated Si/Al atom forming fragments with the molecular formula: Si 9 AlO 12 H 18 (OC 3 H 6 SO 3 H) 2 and Si 10 O 12 H 18 (OC 3 H 6 SO 3 H) 2 , respectively for both systems. ONIOM calculation was used on zeolite due to its faster calculation and reliable results [31–37] . The protogenic group, consisting of sulfonic acid groups, terminal −CH 2 groups and water molecules, was set as the high layer, while the rest of the atoms in the fragments were set as low layer.…”

Section: Methodsmentioning

confidence: 99%

ONIOM Study on the Influence of Aluminium in Propylsulfonic Acid‐functionalized ZSM‐5 for Proton Transfer

et al. 2023

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Proton exchange membrane fuel cells (PEMFCs) are promising candidates for clean and efficient power sources. Zeolite nanoparticle membranes have been introduced as potential new membrane materials to improve the performance of PEMFCs. Understanding the proton transport mechanism on zeolite nanoparticle membranes at the atomic level is crucial in developing more efficient PEMFCs. We investigated the influence of aluminium to initiate proton transfer within zeolite fragments by performing geometry conformation of hydrated propylsulfonic acid‐functionalized zeolite ZSM‐5 clusters from one to six water molecules using four different ONIOM schemes; ONIOM(B3LYP:HF) and ONIOM(B3LYP:PM3) in gas phase and within polarizable continuum model (PCM) of water system. Results show that four water molecules are required for second proton dissociation to occur in Al systems, whereas at least five water molecules are needed in their counterpart systems. Analysis of the results suggests that the presence of Al atom in the zeolite backbone increases the electronegativity of the oxygen atom of the sulfonic acid. The oxygen provides an active site for the acidic proton to participate and increased the ability of hydrogen to dissociate itself and form hydronium cations. Our ONIOM calculation proves that ONIOM(B3LYP:PM3) method of calculation provides a reliable result with minimal computational cost.

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OEEFs precisely regulating the propane oxidation reaction catalyzed by O–Fe-corrolazine

Song,

Yang,

Yang

et al. 2024

New J. Chem.

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A theoretical study on the methanol to propene mechanism catalyzed by a phosphorus-modified acidic FAU zeolite

Abstract: The reaction mechanisms of methanol to propene (MTP) on phosphorus modified acidic FAU (H-FAU) zeolite have been theoretically investigated by a two-layer ONIOM (our Own N-layered Integrated molecular Orbital and...

Cited by 3 publications

References 81 publications

Methanol to Propene over Gallium-Modified FAU Zeolite: Theoretical Study on the Polymethylbenzene and Alkene Cycles

Methanol to Propene over Gallium-Modified FAU Zeolite: Theoretical Study on the Polymethylbenzene and Alkene Cycles

ONIOM Study on the Influence of Aluminium in Propylsulfonic Acid‐functionalized ZSM‐5 for Proton Transfer

OEEFs precisely regulating the propane oxidation reaction catalyzed by O–Fe-corrolazine

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