1
|
Cho J, Rösch D, Tao Y, Osborn DL, Klippenstein SJ, Sheps L, Sivaramakrishnan R. Modeling-Experiment-Theory Analysis of Reactions Initiated from Cl + Methyl Formate. J Phys Chem A 2023; 127:9804-9819. [PMID: 37937747 DOI: 10.1021/acs.jpca.3c05085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Methyl formate (MF; CH3OCHO) is the smallest representative of esters, which are common components of biodiesel. The present study characterizes the thermal dissociation kinetics of the radicals formed by H atom abstraction from MF─CH3OCO and CH2OCHO─through a combination of modeling, experiment, and theory. For the experimental effort, excimer laser photolysis of Cl2 was used as a source of Cl atoms to initiate reactions with MF in the gas phase. Time-resolved species profiles of MF, Cl2, HCl, CO2, CH3, CH3Cl, CH2O, and CH2ClOCHO were measured and quantified using photoionization mass spectrometry at temperatures of 400-750 K and 10 Torr. The experimental data were simulated using a kinetic model, which was informed by ab initio-based theoretical kinetics calculations and included chlorine chemistry and secondary reactions of radical decomposition products. We calculated the rate coefficients for the H-abstraction reactions Cl + MF → HCl + CH3OCO (R1a) and Cl + MF → HCl + CH2OCHO (R1b): k1a,theory = 6.71 × 10-15·T1.14·exp(-606/T) cm3/molecule·s; k1b,theory = 4.67 × 10-18·T2.21·exp(-245/T) cm3/molecule·s over T = 200-2000 K. Electronic structure calculations indicate that the barriers to CH3OCO and CH2OCHO dissociation are 13.7 and 31.6 kcal/mol and lead to CH3 + CO2 (R3) and CH2O + HCO (R5), respectively. The master equation-based theoretical rate coefficients are k3,theory (P = ∞) = 2.94 × 109·T1.21·exp(-6209/T) s-1 and k5,theory (P = ∞) = 8.45 × 108·T1.39·exp(-15132/T) s-1 over T = 300-1500 K. The calculated branching fractions into R1a and R1b and the rate coefficient for R5 were validated by modeling of the experimental species time profiles and found to be in excellent agreement with theory. Additionally, we found that the bimolecular reactions CH2OCHO + Cl, CH2OCHO + Cl2, and CH3 + Cl2 were critical to accurately model the experimental data and constrain the kinetics of MF-radicals. Inclusion of the kinetic parameters determined in this study showed a significant impact on combustion simulations of larger methyl esters, which are considered as biodiesel surrogates.
Collapse
Affiliation(s)
- Jaeyoung Cho
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Daniel Rösch
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Yujie Tao
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Stephen J Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| |
Collapse
|
2
|
Espinosa-Garcia J. Global potential energy surface and product pair-correlated distributions for the F( 2P) + SiH 4 reaction - comparison with experiments. Phys Chem Chem Phys 2022; 24:2887-2900. [PMID: 35060978 DOI: 10.1039/d1cp04561j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we study the gas-phase hydrogen abstraction reaction between fluorine atoms and silane in a three-step process: potential energy surface, kinetics and dynamics. Firstly, we developed for the first time an analytical full-dimensional surface, named PES-2021, using high-level explicitly-correlated ab initio data as the input. PES-2021 represents a continuous and smooth potential with analytical gradients and includes intuitive concepts (stretching and bending nuclear motions). Based on the PES-2021 quasi-classical trajectory (QCT) calculations were performed to analyse the kinetics and dynamics. Secondly, in the kinetics study at room temperature we observed a very fast reaction with a rate constant of 3.90 × 10-10 cm3 molecule-1 s-1, reproducing the scarce experimental evidence. Finally, the third step is the dynamics study, which was performed under two different conditions, a temperature of 77 K and a collision energy of 2.5 kcal mol-1, for direct comparison with experiments. In the first case, we found the largest fraction, 44%, deposited as HF(v) vibration, where the most populated states were HF(v = 2, 3), both results reproducing the experimental evidence. The largest discrepancy with the experiment was found in the HF(j) rotational distribution, where hotter distributions were found, this discrepancy being associated with limitations of the QCT method. The second case, E = 2.5 kcal mol-1, was a state-to-state correlated study and, therefore, more difficult. The theory overestimates (again) and consequently underestimates, respectively, the rotational and vibrational fractions of the HF(v,j) product as compared with experiments. While experimentally the SiH3 product appears excited only in the umbrella mode, ν2 = 0-5, correlated with the HF(v) co-product vibrational excited in v = 3 and 4, theoretically a wider vibrational distribution is found in both products, and these distributions have, obviously, an influence on the product correlated speed distributions. However, the product correlated angular distribution is well reproduced. In general, these results allowed us to test the capacity of PES-2021 + QCT tools to simulate the experimental evidence, revealing that agreement is better when average properties are compared, making the comparison worse when state-to-state properties are compared. Different causes of the theory/experiment discrepancies were analysed, and it was found that they are due, mainly, to limitations of the QCT method.
Collapse
Affiliation(s)
- J Espinosa-Garcia
- Área de Química Física and Instituto de Computación Científica Avanzada, Universidad de Extremadura, 06071 Badajoz, Spain.
| |
Collapse
|
3
|
Espinosa-Garcia J, Corchado JC. Theoretical study of the Cl( 2P) + SiH 4 reaction: global potential energy surface and product pair-correlated distributions. Comparison with experiment. Phys Chem Chem Phys 2021; 23:21065-21077. [PMID: 34523628 DOI: 10.1039/d1cp02563e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the theoretical study of the title reaction, an analytical full-dimensional potential energy surface named PES-2021 was developed for the first time, by fitting high-level explicitly-correlated ab initio data. This reaction presented high exothermicity, (298 K) = -11.6 kcal mol-1, reproducing the experimental evidence; it is a barrierless reaction and no intermediate complexes were found. PES-2021 is a continuous and smooth potential energy surface, it includes intuitive concepts in its development and fitting, such as stretching and bending nuclear motions, and it presents analytical first energy derivatives. Based on PES-2021, kinetics and dynamics studies were carried out using quasi-classical trajectory calculations. In the kinetics study, over the temperature range 300-450 K, we observed that rate constants were practically independent of temperature, with an almost zero activation energy, as compared to 0.0 and -0.48 kcal mol-1 experimentally reported. In this kinetics study the role of the spin-orbit effect on reactivity was analysed. In the dynamics study, different product pair-correlated dynamics properties were compared with the only experimental evidence: product energy partition, product vibrational distribution, product angular distribution and product speed distribution. We observed two mechanisms of reaction, a stripping mechanism associated with large impact parameters and forward scattering, and an indirect mechanism associated with sideways-backward scattering related with "nearly-trapped" trajectories due to the product rotation. In general, theoretical results reasonably simulate the experimental measurements when they consider some rotational and vibrational constraints as well as binning techniques to mimic a quantum-mechanical behaviour. Although the agreement is not quantitative, the present results shed light on the mechanism of this difficult polyatomic reactive system.
Collapse
Affiliation(s)
- J Espinosa-Garcia
- Área de Química Física and Instituto de Computación Científica Avanzada, Universidad de Extremadura, 06071 Badajoz, Spain.
| | - J C Corchado
- Área de Química Física and Instituto de Computación Científica Avanzada, Universidad de Extremadura, 06071 Badajoz, Spain.
| |
Collapse
|
4
|
Pelucchi M, Cavallotti C, Frassoldati A, Ranzi E, Glarborg P, Faravelli T. Theoretical and kinetic modeling study of chloromethane (CH
3
Cl) pyrolysis and oxidation. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Matteo Pelucchi
- CRECK Modeling Lab Department of Chemistry Materials and Chemical Engineering “G. Natta” Politecnico di Milano Milan Italy
| | - Carlo Cavallotti
- CRECK Modeling Lab Department of Chemistry Materials and Chemical Engineering “G. Natta” Politecnico di Milano Milan Italy
| | - Alessio Frassoldati
- CRECK Modeling Lab Department of Chemistry Materials and Chemical Engineering “G. Natta” Politecnico di Milano Milan Italy
| | - Eliseo Ranzi
- CRECK Modeling Lab Department of Chemistry Materials and Chemical Engineering “G. Natta” Politecnico di Milano Milan Italy
| | - Peter Glarborg
- DTU Chemical Engineering Technical University of Denmark Lyngby Denmark
| | - Tiziano Faravelli
- CRECK Modeling Lab Department of Chemistry Materials and Chemical Engineering “G. Natta” Politecnico di Milano Milan Italy
| |
Collapse
|
5
|
Singla M, Rasmussen ML, Hashemi H, Wu H, Glarborg P, Pelucchi M, Faravelli T, Marshall P. Ab initio calculations and kinetic modeling of thermal conversion of methyl chloride: implications for gasification of biomass. Phys Chem Chem Phys 2018; 20:10741-10752. [PMID: 29364295 DOI: 10.1039/c7cp07552a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Limitations in current hot gas cleaning methods for chlorine species from biomass gasification may be a challenge for end use such as gas turbines, engines, and fuel cells, all requiring very low levels of chlorine. During devolatilization of biomass, chlorine is released partly as methyl chloride. In the present work, the thermal conversion of CH3Cl under gasification conditions was investigated. A detailed chemical kinetic model for pyrolysis and oxidation of methyl chloride was developed and validated against selected experimental data from the literature. Key reactions of CH2Cl with O2 and C2H4 for which data are scarce were studied by ab initio methods. The model was used to analyze the fate of methyl chloride in gasification processes. The results indicate that CH3Cl emissions will be negligible for most gasification technologies, but could be a concern for fluidized bed gasifiers, in particular in low-temperature gasification. The present work illustrates how ab initio theory and chemical kinetic modeling can help to resolve emission issues for thermal processes in industrial scale.
Collapse
Affiliation(s)
- Mallika Singla
- DTU Chemical Engineering, Technical University of Denmark, 2800 Lyngby, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Espinosa-Garcia J, Corchado JC, Garcia-Chamorro M, Rangel C. F(2P) + C2H6 → HF + C2H5 kinetics study based on a new analytical potential energy surface. Phys Chem Chem Phys 2018; 20:19860-19870. [DOI: 10.1039/c8cp03103g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An exhaustive kinetics study was performed for the title reaction using two theoretical approaches: variational transition-state theory and quasi-classical trajectory calculations, based on an original new analytical full-dimensional potential energy surface, named PES-2018, which has been fitted to high-level ab initio calculations.
Collapse
Affiliation(s)
- J. Espinosa-Garcia
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| | - J. C. Corchado
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| | - M. Garcia-Chamorro
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| | - C. Rangel
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| |
Collapse
|
7
|
Rangel C, Espinosa-Garcia J. Full-dimensional analytical potential energy surface describing the gas-phase Cl + C2H6 reaction and kinetics study of rate constants and kinetic isotope effects. Phys Chem Chem Phys 2018; 20:3925-3938. [DOI: 10.1039/c7cp07592h] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Within the Born–Oppenheimer approximation a full-dimensional analytical potential energy surface, PES-2017, was developed for the gas-phase hydrogen abstraction reaction between the chlorine atom and ethane, which is a nine body system.
Collapse
Affiliation(s)
- Cipriano Rangel
- Departamento de Química Física and Instituto de Computación Científica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| | - Joaquin Espinosa-Garcia
- Departamento de Química Física and Instituto de Computación Científica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| |
Collapse
|
8
|
Sangwan M, Chesnokov EN, Krasnoperov LN. Reaction CH3 + OH Studied over the 294–714 K Temperature and 1–100 bar Pressure Ranges. J Phys Chem A 2012; 116:8661-70. [DOI: 10.1021/jp305070c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuvesh Sangwan
- Department of Chemistry
and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey
07102, United States
| | | | - Lev N. Krasnoperov
- Department of Chemistry
and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey
07102, United States
| |
Collapse
|
9
|
Blitz MA, Seakins PW. Laboratory studies of photochemistry and gas phase radical reaction kinetics relevant to planetary atmospheres. Chem Soc Rev 2012; 41:6318-47. [DOI: 10.1039/c2cs35204d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
10
|
Rozanov VN, Treger YA. Kinetics of the gas-phase thermal chlorination of methane. KINETICS AND CATALYSIS 2010. [DOI: 10.1134/s0023158410050034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
11
|
Han W, Kennedy EM, Mackie JC, Dlugogorski BZ. Synthesis of Vinylidene Fluoride via Reaction of Chlorodifluoromethane (HCFC-22) with Methane. Ind Eng Chem Res 2010. [DOI: 10.1021/ie100338j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Wenfeng Han
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Eric M. Kennedy
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - John C. Mackie
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Bogdan Z. Dlugogorski
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| |
Collapse
|
12
|
|