Formic Acid Dehydrogenation by Ruthenium Catalyst – Computational and Kinetic Analysis with the Energy Span Model

Frenklah, Alexander; Treigerman, Ziv; Sasson, Yoel; Kozuch, Sebastian

doi:10.1002/ejoc.201801226

Cited by 9 publications

(7 citation statements)

References 46 publications

(151 reference statements)

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“…Since 0 is in fast equilibrium with the active cycles ( 7 → 18 ), and it draws most of the catalyst concentration into itself, it should be considered in the TOF calculation. A similar situation is found in Kozuch’s work …”

Section: Resultssupporting

confidence: 87%

“…A similar situation is found in Kozuch's work. 62 For path A (Figure 2), the AUTOF program identifies the TOF-determining intermediate (TDI) as 2 17 and the TOFdetermining transition state (TDTS) as 1 TS 7-14_N , corresponding to an energetic span (δE) of 22.4 kcal/mol and TOF of 0.67 h −1 . For path D (Figure 4), TDI is 2 17 and TDTS is 2 TS 12-13 , corresponding to δE = 15.2 kcal/mol and TOF = 1.1 × 10 5 h −1 .…”

Section: Preliminary Mechanistic Assessmentmentioning

confidence: 99%

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Unraveling the Mechanism of Aerobic Alcohol Oxidation by a Cu/pytl-β-Cyclodextrin/TEMPO Catalytic System under Air in Neat Water

Feng

Cheng

et al. 2021

Inorg. Chem.

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The mechanism for the oxidation of p-tolylmethanol to p-tolualdehyde catalyzed by a Cu/pytl-β-cyclodextrin/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-1-oxy) catalytic system under air in neat water is fully investigated by density functional theory (DFT). Four possible pathways (paths A → D) are presented. The calculated TOF = 0.67 h −1 for path A is consistent with the experimental TOF = 1.9 h −1 but much lower than that for path D (TOF = 1.1 × 10 5 h −1 ). The results demonstrate that path A is the dominant pathway under the optimal experimental conditions, even though path D is more kinetically favorable. This is because the concentration of precatalyst 11 [(pytl-β-CD)Cu II (OH)] in path D is too low to start path D, so p-tolylmethanol oxidation can only proceed via path A. This finding implies that the relative concentration of precatalysts in a one-pot synthesis experiment plays a vital role in the aerobic alcohol oxidation reaction. Based on this finding, we speculate that the direct use of the presynthesized precatalyst 11 or addition of an appropriate amount of NaOH to the reaction solution, but with the total amount of the base added unchanged, is a good way to improve its catalytic activity. Meanwhile, the solvent water was not found to directly participate in the catalytic active sites for the oxidation of alcohols but rather inhibited it by forming the hydrogen-bonded network.

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Section: Resultssupporting

confidence: 87%

Section: Preliminary Mechanistic Assessmentmentioning

confidence: 99%

Unraveling the Mechanism of Aerobic Alcohol Oxidation by a Cu/pytl-β-Cyclodextrin/TEMPO Catalytic System under Air in Neat Water

Feng

Cheng

et al. 2021

Inorg. Chem.

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“…Noteworthy, all previous values are for standard 1 M concentrations. A concentration correction to the Gibbs energies can be included if necessary as a RT ·ln[ C ] term, ,, and to match the low water concentrations in the experiment, this correction is a must. At approximately 10 mM (see below), it will theoretically add another 11 kJ mol –1 to T3 per water molecule.…”

Section: Resultsmentioning

confidence: 99%

Chalcogen vs Halogen Bonding Catalysis in a Water-Bridge-Cocatalyzed Nitro-Michael Reaction

et al. 2021

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Recently, a tellurium-based chalcogen-bond-catalyzed nitro-Michael reaction was reported (Angew. Chem. Int. Ed. 2019, 58, 16923), taking advantage of the strong Lewis acidity of the catalyst. This species was found to be more effective than an analogous iodine-based halogen bond organocatalyst. Herein, we present a detailed mechanistic and kinetic analysis of these catalytic cycles including the influence of the solvent (and the performance of different intrinsic solvation models). While the chalcogen bonding interaction is fundamental to activate the C−C bond formation, we found that the presence of a two-water molecular bridge is critical to allow the following, otherwise high-energy proton transfer step. Even though the iodine-based halogen bonding interaction is stronger than the tellurium-based chalcogen bonding one, which makes the former a stronger Lewis acid and hence in principle a more efficient catalyst, solvation effects explain the smaller energy span of the latter.

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“…5 Originally developed for mechanisms without branching, the ESM was extended to describe reaction networks with parallel reaction pathways using graph theory. 6 This ESM approach has been demonstrated 7 and inspired software development. 8 While strong fundamentals have been established, the ESM approach lacks rigor in its underlying assumptions and agreement with MKM results.…”

Section: Introductionmentioning

confidence: 99%

“…Mechanistic reaction networks describing a single overall reaction or selectivity between multiple reactions are ubiquitous. , Reaction flux can traverse multiple parallel pathways leading to a complex ensemble of contributions to the observed activity. Multiple softwares have been developed specifically to analyze reaction networks, , with MKMs commonly used .…”

Section: Introductionmentioning

confidence: 99%

Modified Energy Span Analysis of Catalytic Parallel Pathways and Selectivity

Cohen

Vlachos

2022

Ind. Eng. Chem. Res.

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Mechanistic modeling provides vital insights into catalytic reactions. To analyze complex reaction networks with parallel pathways, we leverage the graph theory approach of the Energy Span Model (ESM) to develop a modified energy span analysis (MESA). A new method of cycle plots is proposed to perform reaction pathways analysis visually. We demonstrate this method on two published models: one describing carbon monoxide oxidation and the other simulating ethylene conversion to propanal via hydroformylation or ethane via hydrogenation. Fundamental insights explain kinetic observables, such as a reactant’s negative reaction order. General principles are revealed, such as rate-determining surface species being outside the primary reaction flux cycle and pathway selectivity being a purely kinetic property when reaction conditions are not near equilibrium. Finally, we demonstrate MESA’s consistency with published microkinetic modeling results, highlighting this technique’s extension of the ESM to heterogeneous catalysts using collision theory to describe adsorption steps and concentration effects.

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Formic Acid Dehydrogenation by Ruthenium Catalyst – Computational and Kinetic Analysis with the Energy Span Model

Cited by 9 publications

References 46 publications

Unraveling the Mechanism of Aerobic Alcohol Oxidation by a Cu/pytl-β-Cyclodextrin/TEMPO Catalytic System under Air in Neat Water

Unraveling the Mechanism of Aerobic Alcohol Oxidation by a Cu/pytl-β-Cyclodextrin/TEMPO Catalytic System under Air in Neat Water

Chalcogen vs Halogen Bonding Catalysis in a Water-Bridge-Cocatalyzed Nitro-Michael Reaction

Modified Energy Span Analysis of Catalytic Parallel Pathways and Selectivity

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