Theoretical study on the gas phase hydroxyl radical reaction with tetrahydrothiophene, tetrahydrofuran, thiophene and furan

Upadhyaya, Hari P.

doi:10.1016/j.cplett.2023.140385

Cited by 2 publications

(3 citation statements)

References 43 publications

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“…The authors in their study calculated the energy using a simple DFT method whereas in the present study a more refined and accurate method, namely, B2PLYP-D method which is a hybrid density functional with perturbative second order correction consisting a mixture of DFT components and the MP2 correlation energy calculated with the DFT orbitals has been applied. In our earlier publication, we have successfully used the B2PLYP-D method for energy evaluation and rate constant determination study even in the molecular systems showing multireference character [47]. Hence, the theoretical study in the present study is believed to be more accurate and hence the energetics and the rate constants evaluation.…”

Section: Quincloracmentioning

confidence: 85%

“…The structure of such complex can be also seen in Figure 1. In general, these intermediate complexes shows similar structure wherein the • OH radical is almost equidistance from the two carbon atom depending upon their local reactivity parameter [47,51]. The stabilization energy of the intermediate complexes (reference cluster) for C8 and C5 addition reaction are 2.88 and 2.48 kcal/mol, respectively.…”

Section: Ecotoxicity Assessmentsmentioning

confidence: 95%

“…The energy of these various structures was then refined by performing the single point energy calculation at higher level of theory using a hybrid density functional with perturbative second order MP2 correction known as B2PLYP-D method [45,46]. In our earlier study, it has been shown that the B2PLYP-D method has a good reproducibility even in some molecular system showing multireference character owing to the electron correlation [47].…”

Section: Electronic Structure Calculationsmentioning

confidence: 99%

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Theoretical studies on the kinetics and mechanism of hydroxyl radical reaction with quinclorac and quinmerac herbicides in aqueous media

Upadhyaya

2024

Int J of Quantum Chemistry

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The kinetic and mechanistic studies for the reaction of hydroxyl radical with two quinoline based herbicides, namely, quinclorac and quinmerac has been performed using various computational methods in aqueous media. Geometry optimizations were performed using Density Functional Theory (DFT) methods including water as the solvent. Local reactivity parameters of these herbicides towards the •OH radical are predicted using condensed Fukui function. Single point energies of various species were calculated using double hybrid method, namely, B2PLYP–D for better accuracy. The pKa values for these acid based herbicides allow them to exist in deprotonated form in aqueous condition. Hence, the calculations are also performed for the deprotonated or the anionic form apart from the neutral species. Individual rate coefficients for •OH radical addition reaction with each carbon atoms were evaluated using conventional transition state theory using one–dimensional tunneling corrections. The solvent effect on reaction is implemented through Collins–Kimball formulations. Both the approaches, namely, the Fukui index and individual rate constant determination confirms that the most reactive site for the •OH radical addition in these two herbicide is the carbon atom attached to the COOH group. The total rate constant for the •OH radical reaction with both neutral and anionic forms of these two herbicides are relatively high and equal to its diffusion‐limit value. Evaluation of the ecotoxicities of the parent herbicides and their OH adducts is estimated using the structure–activity relationship concept.

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Section: Quincloracmentioning

confidence: 85%

Section: Ecotoxicity Assessmentsmentioning

confidence: 95%

Section: Electronic Structure Calculationsmentioning

confidence: 99%

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Theoretical studies on the kinetics and mechanism of hydroxyl radical reaction with quinclorac and quinmerac herbicides in aqueous media

Upadhyaya

2024

Int J of Quantum Chemistry

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Predicting pressure-dependent rate constants for the furan + OH reactions and their impact under tropospheric conditions

Nascimento,

Queiroz,

Rivelino

et al. 2024

The Journal of Chemical Physics

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In this work, we have evaluated the influence of temperature and pressure on the mechanism of furan oxidation by the OH radical. The stationary points on the potential energy surface were described at the M06-2X/aug-cc-pVTZ level of theory. In the kinetic treatment at the high-pressure limit (HPL), we have combined the multistructural canonical variational theory with multidimensional small-curvature tunneling corrections and long-range transition state theory. The system-specific quantum Rice–Ramsperger–Kassel theory was employed to estimate the pressure-dependent rate. In the HPL, the OH addition on the α carbon is the dominant pathway in the mechanism, producing a product via the ring-opening process, also confirmed by the product branching ratio calculations. The overall rate constant, obtained by a kinetic Monte Carlo simulation, reads the form koverall=5.22×10−13T/3001.10⁡exp1247(K/T) and indicates that the furan oxidation by OH radicals is a pressure-independent reaction under tropospheric conditions.

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Theoretical study on the gas phase hydroxyl radical reaction with tetrahydrothiophene, tetrahydrofuran, thiophene and furan

Cited by 2 publications

References 43 publications

Theoretical studies on the kinetics and mechanism of hydroxyl radical reaction with quinclorac and quinmerac herbicides in aqueous media

Theoretical studies on the kinetics and mechanism of hydroxyl radical reaction with quinclorac and quinmerac herbicides in aqueous media

Predicting pressure-dependent rate constants for the furan + OH reactions and their impact under tropospheric conditions

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