Microkinetic modeling of cis-cyclooctene oxidation on heterogeneous Mn–tmtacn complexes

Bjorkman, Kathryn R.; Schoenfeldt, Nicholas J.; Notestein, Justin M.; Broadbelt, Linda J.

doi:10.1016/j.jcat.2012.03.026

Cited by 10 publications

(10 citation statements)

References 27 publications

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“…By introducing eq 2-7 into eq 2-6, the rate constant of surface reactions becomes (2)(3)(4)(5)(6)(7)(8) and the pre-exponential factor of surface reactions (ν sr ) is…”

Section: Methodsmentioning

confidence: 99%

“…TS IS (2)(3)(4)(5)(6)(7)(8)(9) Because the rate equations of all the elementary reactions are defined, the following step in the microkinetic modeling is set up as ordinary differential equations (ODEs). On the basis of the mass balance, each ODE describes the relationship between the coverage (θ) and time (t) of each surface species in the microkinetic model.…”

Section: Methodsmentioning

confidence: 99%

“…ads des (2)(3)(4)(5)(6)(7)(8)(9)(10)(11) In eq 2-10, E A is the energy of a single adsorbate in the gas phase, E RuO 2 is the energy of the clean surface, and E A/RuO 2 is the total energy of the adsorption system. A positive value of E des indicates an endothermic desorption process.…”

Section: Methodsmentioning

confidence: 99%

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Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Wang

Pham

et al. 2014

ACS Catal.

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The investigation by microkinetic simulations provide detailed reaction mechanisms about the NH 3 oxidation on the RuO 2 (110) surface. There are 41 elementary reactions involved in the microkinetic model in which all the thermodynamic and kinetic parameters are obtained from density functional theory (DFT) calculations, and the entropy effects of each reaction are considered in the simulation. The differences in reaction mechanisms between the batch type and the steady state were characterized in this study. The selectivities to the oxidation products, including N 2 , NO, and N 2 O, depend on the oxidation conditions. The simulated results show that the O 2 /NH 3 ratio, system temperature, and pressure are the controlling factors that could alter the results of the oxidation. The microkinetic modeling demonstrates how these parameters affect the NH 3 conversion and the selectivities. The simulations showed that N 2 and NO could be a primary product under different oxidizing conditions; however, N 2 O could only be a minor product because of the nature of its formation mechanism. The highest N 2 O selectivity obtained in the simulations is 30%.

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“…By introducing eq 2-7 into eq 2-6, the rate constant of surface reactions becomes (2)(3)(4)(5)(6)(7)(8) and the pre-exponential factor of surface reactions (ν sr ) is…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Wang

Pham

et al. 2014

ACS Catal.

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“…Nevertheless, X-ray absorption spectroscopy and UV/Vis diffuse reflectance spectroscopy are particularly suited to studying the oxidation states of manganese and were applied in this case, demonstrating that 81 As for the homogenous systems discussed above, in the case of the heterogenised catalyst, recycling was limited and tentatively ascribed to the effect of build-up of cis-diol in the reaction mixture. 81 Recently Bjorkman et al 82 reported a microkinetic study of the heterogenised system with extensive use of modelling and concluded that the rate determining step was activation of the complex with H 2 O 2 . While direct extension of the conclusions of their study to the homogeneous system cannot be made, it is nevertheless consistent with the observation that the resting state for the catalyst is the complex [Mn III,III 2 (m-O)-(m-RCO 2 ) 2 (TMTACN) 2 ] 2+ .…”

Section: Trimethyl-triazacyclononane Based Ligands For Manganese Catamentioning

confidence: 99%

Mechanisms in manganese catalysed oxidation of alkenes with H₂O₂

Saisaha

Böer²,

Browne³

2013

Chem. Soc. Rev.

148

114

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The development of new catalytic systems for cis-dihydroxylation and epoxidation of alkenes, based on atom economic and environmentally friendly concepts, is a major contemporary challenge. In recent years, several systems based on manganese catalysts using H(2)O(2) as the terminal oxidant have been developed. In this review, selected homogeneous manganese catalytic systems, including 'ligand free' and pyridyl amine ligand based systems, that have been applied to alkene oxidation will be discussed with a strong focus on the mechanistic studies that have been carried out.

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“…The use of microkinetic models, − which explicitly treat all elementary steps and make no approximations or assumptions of which may be rate-limiting, has been successful at determining such information. These methods have been applied to a number of systems relevant to biofuels and green chemical processes, based on parameters found from experimental data, , first-principles density functional theory calculations, − or QM/MM molecular dynamics …”

Section: Introductionmentioning

confidence: 99%

Effects of Substituents on the S_N2 Free Energy of Activation for α-O-4 Lignin Model Compounds

Pelzer

Broadbelt

2017

J. Phys. Chem. C

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Current methods for processing lignocellulosic biomass fail to take full advantage of the phenolic chemicals available in lignin, the third most common polymer on the planet. The complexity of the lignin polymer structure, the lack of knowledge of the mechanisms by which it breaks down, and the difficulties in predicting and controlling the reaction product distribution make improvement in processing methods challenging. The use of model compounds, which contain only a few key features of the native polymer, allow the reactivity of the overall polymer to be investigated more simply by isolating key elements. In our previous work, we examined the mechanism of acidolysis for two α-O-4 lignin model compounds, benzylphenyl ether (BPE) and 1-(phenoxyethyl)benzene (PEB). In the present work, we examine the rate-limiting step of this mechanism, a nucleophilic attack on the α-carbon commensurate with protonation of the ether oxygen, for other α-O-4 model compounds that contain features more reminiscent of native lignin, including compounds based on native model dimers. The effects of individual substituents and combinations of substituents are also examined in order to determine their contributions to the reactivity of native lignin dimers. Simple relationships are examined between ground-state properties and reactivity. The results of these calculations show that the effects of substituents on the reactivity of BPE-based compounds are quite different from those of PEB-based compounds. While reasonable correlations can be found for BPE reactivity and properties across substituents, PEB shows much less predictable reactivity except among small subsets of substituents. Overall, the trends observed here provide useful information about the reactivity of α-O-4 bonds in lignin during acidolysis as a function of the local chemical environment.

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Microkinetic modeling of cis-cyclooctene oxidation on heterogeneous Mn–tmtacn complexes

Cited by 10 publications

References 27 publications

Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Mechanisms in manganese catalysed oxidation of alkenes with H₂O₂

Effects of Substituents on the S_N2 Free Energy of Activation for α-O-4 Lignin Model Compounds

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Microkinetic modeling of cis-cyclooctene oxidation on heterogeneous Mn–tmtacn complexes

Cited by 10 publications

References 27 publications

Microkinetic Simulation of Ammonia Oxidation on the RuO2(110) Surface

Microkinetic Simulation of Ammonia Oxidation on the RuO2(110) Surface

Mechanisms in manganese catalysed oxidation of alkenes with H2O2

Effects of Substituents on the SN2 Free Energy of Activation for α-O-4 Lignin Model Compounds

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Product

Resources

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Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Mechanisms in manganese catalysed oxidation of alkenes with H₂O₂

Effects of Substituents on the S_N2 Free Energy of Activation for α-O-4 Lignin Model Compounds