caa a22 4500 605513848 CHVBK 20210128100702.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00894-015-2839-2 doi (NATIONALLICENCE)springer-10.1007/s00894-015-2839-2 Theoretical study of the oxidation mechanisms of thiophene initiated by hydroxyl radicals [Elektronische Daten] [Abolfazl Shiroudi, Michael Deleuze] The mechanisms for the oxidation of thiophene by OH radicals under inert conditions (Ar) have been studied using density functional theory in conjunction with various exchange-correlation functionals. These results were compared with benchmark CBS-QB3 theoretical results. Kinetic rate constants were estimated by means of variational transition state theory (VTST) and the statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Effective rate constants were calculated via a steady-state analysis based upon a two-step model reaction mechanism. In line with experimental results, the computed branching ratios indicate that the most kinetically efficient process involves OH addition to a carbon atom adjacent to the sulfur atom. Due to the presence of negative activation energies, pressures larger than 104bar are required to reach the high-pressure limit. Nucleus-independent chemical shift indices and natural bond orbital analysis show that the computed activation energies are dictated by changes in aromaticity and charge-transfer effects due to the delocalization of lone pairs from sulfur to empty π* orbitals. Graphical Abstract CBS-QB3 energy profiles for the reaction pathways 1-3 characterizing the oxidation of thiophene by hydroxyl radicals into the related products. Springer-Verlag Berlin Heidelberg, 2015 Thiophene nationallicence Hydroxyl radical nationallicence Oxidation processes nationallicence Rate constants nationallicence OH addition nationallicence Reaction mechanisms nationallicence Chemical kinetics nationallicence RRKM theory nationallicence Shiroudi Abolfazl Center of Molecular and Materials Modelling, Hasselt University, Agoralaan, Gebouw D, B-3590, Diepenbeek, Belgium aut Deleuze Michael Center of Molecular and Materials Modelling, Hasselt University, Agoralaan, Gebouw D, B-3590, Diepenbeek, Belgium aut Journal of Molecular Modeling Springer Berlin Heidelberg 21/11(2015-11-01), 1-20 1610-2940 21:11<1 2015 21 894 https://doi.org/10.1007/s00894-015-2839-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00894-015-2839-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shiroudi Abolfazl Center of Molecular and Materials Modelling, Hasselt University, Agoralaan, Gebouw D, B-3590, Diepenbeek, Belgium aut NATIONALLICENCE 700 1- Deleuze Michael Center of Molecular and Materials Modelling, Hasselt University, Agoralaan, Gebouw D, B-3590, Diepenbeek, Belgium aut NATIONALLICENCE 773 0- Journal of Molecular Modeling Springer Berlin Heidelberg 21/11(2015-11-01), 1-20 1610-2940 21:11<1 2015 21 894