Theoretical study of the reaction kinetics of atomic bromine with tetrahydropyran

Handle URI:
http://hdl.handle.net/10754/564056
Title:
Theoretical study of the reaction kinetics of atomic bromine with tetrahydropyran
Authors:
Giri, Binod; Lo, John M H; Roscoe, John M.; Alquaity, Awad ( 0000-0002-9306-0154 ) ; Farooq, Aamir ( 0000-0001-5296-2197 )
Abstract:
A detailed theoretical analysis of the reaction of atomic bromine with tetrahydropyran (THP, C5H10O) was performed using several ab initio methods and statistical rate theory calculations. Initial geometries of all species involved in the potential energy surface of the title reaction were obtained at the B3LYP/cc-pVTZ level of theory. These molecular geometries were reoptimized using three different meta-generalized gradient approximation (meta-GGA) functionals. Single-point energies of the stationary points were obtained by employing the coupled-cluster with single and double excitations (CCSD) and fourth-order Møller-Plesset (MP4 SDQ) levels of theory. The computed CCSD and MP4(SDQ) energies for optimized structures at various DFT functionals were found to be consistent within 2 kJ mol-1. For a more accurate energetic description, single-point calculations at the CCSD(T)/CBS level of theory were performed for the minimum structures and transition states optimized at the B3LYP/cc-pVTZ level of theory. Similar to other ether + Br reactions, it was found that the tetrahydropyran + Br reaction proceeds in an overall endothermic addition-elimination mechanism via a number of intermediates. However, the reactivity of various ethers with atomic bromine was found to vary substantially. In contrast with the 1,4-dioxane + Br reaction, the chair form of the addition complex (c-C5H10O-Br) for THP + Br does not need to undergo ring inversion to form a boat conformer (b-C4H8O2-Br) before the intramolecular H-shift can occur to eventually release HBr. Instead, a direct, yet more favorable route was mapped out on the potential energy surface of the THP + Br reaction. The rate coefficients for all relevant steps involved in the reaction mechanism were computed using the energetics of coupled cluster calculations. On the basis of the results of the CCSD(T)/CBS//B3LYP/cc-pVTZ level of theory, the calculated overall rate coefficients can be expressed as kov.,calc.(T) = 4.60 × 10-10 exp[-20.4 kJ mol-1/(RT)] cm3 molecule-1 s-1 for the temperature range of 273-393 K. The calculated values are found to be in excellent agreement with the experimental data published previously.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Chemical Kinetics & Laser Sensors Laboratory
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry A
Issue Date:
12-Feb-2015
DOI:
10.1021/jp510987q
Type:
Article
ISSN:
10895639
Sponsors:
The computations described in this work were performed on the computing facilities of the department of Academic Information and Communication Technologies (AICT) and the High-Performance Computing (HPC) facilities within the research computing services of the University of Calgary and the Western Canada Research Grid. We are grateful to Dr. Matthias Olzmann for helpful discussions and also for providing the program script for the SACM calculations. The work of KAUST authors was supported by funding from King Abdullah University of Science and Technology.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorGiri, Binoden
dc.contributor.authorLo, John M Hen
dc.contributor.authorRoscoe, John M.en
dc.contributor.authorAlquaity, Awaden
dc.contributor.authorFarooq, Aamiren
dc.date.accessioned2015-08-03T12:30:07Zen
dc.date.available2015-08-03T12:30:07Zen
dc.date.issued2015-02-12en
dc.identifier.issn10895639en
dc.identifier.doi10.1021/jp510987qen
dc.identifier.urihttp://hdl.handle.net/10754/564056en
dc.description.abstractA detailed theoretical analysis of the reaction of atomic bromine with tetrahydropyran (THP, C5H10O) was performed using several ab initio methods and statistical rate theory calculations. Initial geometries of all species involved in the potential energy surface of the title reaction were obtained at the B3LYP/cc-pVTZ level of theory. These molecular geometries were reoptimized using three different meta-generalized gradient approximation (meta-GGA) functionals. Single-point energies of the stationary points were obtained by employing the coupled-cluster with single and double excitations (CCSD) and fourth-order Møller-Plesset (MP4 SDQ) levels of theory. The computed CCSD and MP4(SDQ) energies for optimized structures at various DFT functionals were found to be consistent within 2 kJ mol-1. For a more accurate energetic description, single-point calculations at the CCSD(T)/CBS level of theory were performed for the minimum structures and transition states optimized at the B3LYP/cc-pVTZ level of theory. Similar to other ether + Br reactions, it was found that the tetrahydropyran + Br reaction proceeds in an overall endothermic addition-elimination mechanism via a number of intermediates. However, the reactivity of various ethers with atomic bromine was found to vary substantially. In contrast with the 1,4-dioxane + Br reaction, the chair form of the addition complex (c-C5H10O-Br) for THP + Br does not need to undergo ring inversion to form a boat conformer (b-C4H8O2-Br) before the intramolecular H-shift can occur to eventually release HBr. Instead, a direct, yet more favorable route was mapped out on the potential energy surface of the THP + Br reaction. The rate coefficients for all relevant steps involved in the reaction mechanism were computed using the energetics of coupled cluster calculations. On the basis of the results of the CCSD(T)/CBS//B3LYP/cc-pVTZ level of theory, the calculated overall rate coefficients can be expressed as kov.,calc.(T) = 4.60 × 10-10 exp[-20.4 kJ mol-1/(RT)] cm3 molecule-1 s-1 for the temperature range of 273-393 K. The calculated values are found to be in excellent agreement with the experimental data published previously.en
dc.description.sponsorshipThe computations described in this work were performed on the computing facilities of the department of Academic Information and Communication Technologies (AICT) and the High-Performance Computing (HPC) facilities within the research computing services of the University of Calgary and the Western Canada Research Grid. We are grateful to Dr. Matthias Olzmann for helpful discussions and also for providing the program script for the SACM calculations. The work of KAUST authors was supported by funding from King Abdullah University of Science and Technology.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleTheoretical study of the reaction kinetics of atomic bromine with tetrahydropyranen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentChemical Kinetics & Laser Sensors Laboratoryen
dc.identifier.journalThe Journal of Physical Chemistry Aen
dc.contributor.institutionDepartment of Chemistry, University of Calgary, 2500 University Drive NWCalgary, AB, Canadaen
dc.contributor.institutionDepartment of Chemistry, Acadia University, 6 University AvenueWolfville, NS, Canadaen
kaust.authorGiri, Binoden
kaust.authorFarooq, Aamiren
kaust.authorAlquaity, Awaden
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