Impact of Organic Templates on the Selective Formation of Zeolite Oligomers

Ciantar, Marine; Trinh, Thuat T.; Michel, Carine; Sautet, Philippe; Mellot‐Draznieks, Caroline; Nieto‐Draghi, Carlos

doi:10.1002/ange.202014027

Cited by 11 publications

(9 citation statements)

References 40 publications

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“…The calculation finely reproduced previous results on thermostability of PAs. Consistent with recent investigations, Δ G f of t2 is slightly positive and nearly thermal neutral, suggesting that t2 would be slightly less plausible with respect to OA (Figure ) and its concentration would be lower than OA at steady state. − ,− However, the energy barriers for t2 formation and hydrolysis into t1(OA) are similar and higher than ∼60 kJ/mol, showing that a large portion of t2 may exist for further evolution. − The calculated Δ G f of t3 and c3-3-1 are −13.5 and −16.9 kJ/mol, respectively, at 298.15 K (Table ) and are in reasonable agreement with the reported Δ G when the formed H 2 O was treated explicitly. ,, The slight difference can be attributed to the theoretical implementation and computational setups.…”

Section: Resultssupporting

confidence: 84%

“…With the promotion of amines, the reaction switches to a two-step S N 2-like mechanism with five-coordinated Si species stabilized as intermediates and the barriers also change to ∼60 kJ/mol . Similar barriers were also reported by Trinh et al in their ab initio molecular dynamics simulations on the condensation of PAs in the existence of organic amines. − These, consistent with early investigations on oligomerization of PAs, ,− evidenced dependence of the reaction thermodynamics and product selectivity of condensation on thermostability of PAs.…”

Section: Introductionsupporting

confidence: 81%

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Superior Thermostability of Poly-Silicic Acid Analogues of Zeolite Composite/Secondary Building Units: A Theoretical Investigation

Liu

Meng

2023

J. Phys. Chem. C

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Secondary building units and composite building units (S/CBUs) are recognized in zeolite frameworks and built up by tetrahedron TO4 units. They were not only identified in the precursor gel for zeolite synthesis but also proposed to be of great significance in interzeolite conversion. Poly-silicic acids of S/CBU structures (S/CBU PAs) are precursors and structural analogues of S/CBUs in zeolites. We performed an exhaustive density functional theory (DFT)-based investigation on thermostability and reaction thermodynamics along potential pathways for the formation and evolution of PAs containing 1–7 T atoms. We showed that most intermolecular condensations (IECs) are exergonic and IECs are among the major mechanisms for the growth and evolution of PAs. The exergonicity of an intramolecular condensation (IAC) depends strongly on the degree of condensation of the reactant PA and it can be even endergonic if the TO4 tetrahedrons are distorted by the T–O–T connection formed. Although S/CBU PAs can only be formed on specific pathways, it is general that the exergonicity for their formation is always superior over that for their non-S/CBU counterparts originated from the same PA. Evolution of S/CBU PAs to non-S/CBU PAs would be less exergonic or even endergonic as compared with the competing formation of S/CBU PA. These data suggest the superior thermostability of S/CBU PAs over non-S/CBU PAs formed by competing IECs and IACs. We expect these findings would help to understand the hydrothermal, solvothermal, and interzeolite conversion processes for the synthesis of zeolites.

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Section: Resultssupporting

confidence: 84%

Section: Introductionsupporting

confidence: 81%

Superior Thermostability of Poly-Silicic Acid Analogues of Zeolite Composite/Secondary Building Units: A Theoretical Investigation

Liu

Meng

2023

J. Phys. Chem. C

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“…It is well-established in the literature ,, that the presence of ions can significantly influence the reaction kinetics and energetics. In this study, the obtained results indicate that the presence of Cl – has a noticeable effect on the overall activation barrier of the dimerization reaction.…”

Section: Resultsmentioning

confidence: 99%

“…The impacts of the charged ion have an important role in the silicate condensation reaction. For example, the organic cations (such as tetramethylamine (TMA + ), tetraethylamine (TEA + ), tetrapropyl amine (TPA + )) were shown to have a decisive role in the formation of dominating silicate spices during the initial state of zeolite formation. , A detailed picture of the interaction of inorganic cations (such as Li + , Na + , normalN normalH 4 + ) was also reported to have great impacts on the activation barrier of the condensation reaction.…”

Section: Introductionmentioning

confidence: 99%

The Role of Chloride ion in the Silicate Condensation Reaction from ab Initio Molecular Dynamics Simulations

Ho,

Do,

Tong

et al. 2023

J. Phys. Chem. B

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The comprehension of silicate oligomer formation during the initial stage of zeolite synthesis is of significant importance. In this study, we investigated the effect of chloride ions (Cl–) on silicate oligomerization using ab initio molecular dynamics simulations with explicit water molecules. The results show that the presence of Cl– increases the free energy barriers of all reactions compared to the case without the anion. The formation of the 4-ring structure has the lowest free energy barrier (73 kJ/mol), while the formation of the 3-ring structure has the highest barrier (98 kJ/mol) in the presence of Cl–. These findings suggest that Cl– suppresses the formation of 3-rings and favors the formation of larger oligomers in the process of zeolite synthesis. Our study provides important insights into the directing role of Cl– in silicate oligomerization by regulating thermodynamic and kinetic parameters. An important point to consider is the impact of the anion on aqueous reactions, particularly in altering the hydrogen bond network around reactive species. These results also provide a basis for further studies of the formations of larger silicate oligomers in solution.

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“…For example, organic cations (such as tetramethylamine (TMA + ), tetraethylamine (TEA + ) and tetrapropylamine (TPA + )) were shown to have a decisive role in the formation of dominating silicate species during the initial stage of zeolite formation. 33,34 Computational studies indicated that inorganic cations (such as Li + , Na + and NH 4 + ) also have a substantial impact on the activation barrier of the condensation reaction. 25,28 Furthermore, pH is recognized as one of the most important parameters for controlling the kinetic and structural aspects of silicate oligomerization.…”

Section: Introductionmentioning

confidence: 99%

Insight into the role of excess hydroxide ions in silicate condensation reactions

Tong

Tran

et al. 2023

Phys. Chem. Chem. Phys.

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Impact of Organic Templates on the Selective Formation of Zeolite Oligomers

Abstract: Supporting information for this article is given via a link at the end of the document.

Cited by 11 publications

References 40 publications

Superior Thermostability of Poly-Silicic Acid Analogues of Zeolite Composite/Secondary Building Units: A Theoretical Investigation

Superior Thermostability of Poly-Silicic Acid Analogues of Zeolite Composite/Secondary Building Units: A Theoretical Investigation

The Role of Chloride ion in the Silicate Condensation Reaction from ab Initio Molecular Dynamics Simulations

Insight into the role of excess hydroxide ions in silicate condensation reactions

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