| Autor: |
Kandpal SC; Tata Institute of Fundamental Research, Hyderabad 500046, India. ramakrishnan@tifrh.res.in., Otukile KP; Department of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa. moskaleval@ufs.ac.za., Jindal S; Tata Institute of Fundamental Research, Hyderabad 500046, India. ramakrishnan@tifrh.res.in., Senthil S; Tata Institute of Fundamental Research, Hyderabad 500046, India. ramakrishnan@tifrh.res.in., Matthews C; Department of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa. moskaleval@ufs.ac.za., Chakraborty S; Tata Institute of Fundamental Research, Hyderabad 500046, India. ramakrishnan@tifrh.res.in., Moskaleva LV; Department of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa. moskaleval@ufs.ac.za., Ramakrishnan R; Tata Institute of Fundamental Research, Hyderabad 500046, India. ramakrishnan@tifrh.res.in. |
| Jazyk: |
angličtina |
| Zdroj: |
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2023 Oct 18; Vol. 25 (40), pp. 27302-27320. Date of Electronic Publication: 2023 Oct 18. |
| DOI: |
10.1039/d3cp03598k |
| Abstrakt: |
The hydroperoxyalkyl radicals (˙QOOH) are known to play a significant role in combustion and tropospheric processes, yet their direct spectroscopic detection remains challenging. In this study, we investigate molecular stereo-electronic effects influencing the kinetic and thermodynamic stability of a ˙QOOH along its formation path from the precursor, alkylperoxyl radical (ROO˙), and the depletion path resulting in the formation of cyclic ether + ˙OH. We focus on reactive intermediates encountered in the oxidation of acyclic hydrocarbon radicals: ethyl, isopropyl, isobutyl, tert -butyl, neopentyl, and their alicyclic counterparts: cyclohexyl, cyclohexenyl, and cyclohexadienyl. We report reaction energies and barriers calculated with the highly accurate method Weizmann-1 (W1) for the channels: ROO˙ ⇌ ˙QOOH, ROO˙ ⇌ alkene + ˙OOH, ˙QOOH ⇌ alkene + ˙OOH, and ˙QOOH ⇌ cyclic ether + ˙OH. Using W1 results as a reference, we have systematically benchmarked the accuracy of popular density functional theory (DFT), composite thermochemistry methods, and an explicitly correlated coupled-cluster method. We ascertain inductive, resonance, and steric effects on the overall stability of ˙QOOH and computationally investigate the possibility of forming more stable species. With new reactions as test cases, we probe the capacity of various ab initio methods to yield quantitative insights on the elementary steps of combustion. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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