Sulfoxaflor is one of the widely used insecticides in agricultural lands to protect crops from insects. Due to its persistent nature, sulfoxaflor is identified as an environmental pollutant. In the present work, the mechanism and kinetics of sulfoxaflor degradation initiated by OH radical addition reaction are studied by using quantum chemical calculations. In the gas phase, the OH addition reaction at the C4 position of sulfoxaflor is found to be the favorable reaction pathway. The rate constant for the initial OH-addition reaction has been studied using canonical variational transition state theory (CVT) over the temperature range of 200-350 K. The initially formed sulfoxaflor-OH adduct intermediate transforms by reacting with O, HO, HO, and NO (x = 1-2) radicals. The excited-state calculation performed for the stationary points shows that the intermediates formed along the reaction pathway are easily photolyzed in normal sunlight. The toxicity assessment result shows that sulfoxaflor and few of its degradation products are harmful and toxic. The acidification potential of sulfoxaflor was found to be one, which shows its contribution to acid rain. This study gives an in-depth understanding of the mechanism, kinetics, and risk assessment of sulfoxaflor in the environment and aquatic system.
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http://dx.doi.org/10.1007/s11356-023-25898-6 | DOI Listing |
J Phys Chem A
December 2024
Institute of Research and Development, Duy Tan University, Da Nang 550000, VietNam.
Water Res
November 2024
Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China.
Methylisothiazolinone (MIT) and Benzisothiazolinone (BIT) are two widely used non-oxidizing biocides of isothiazolinones. Their production and usage volume have sharply increased since the pandemic of COVID-19, inevitably leading to more release into water environment. However, their photochemical behaviors in water environment are still unclear.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2024
Combustion Research Facility, Sandia National Laboratories, Livermore 94550, California, USA.
Imidazoles are present in Earth's atmosphere in both the gas-phase and in aerosol particles, and have been implicated in the formation of brown carbon aerosols. The gas-phase oxidation of imidazole (CNH) by hydroxyl radicals has been shown to be preferentially initiated OH-addition to position C5, producing the 5-hydroxyimidazolyl radical adduct. However, the fate of this adduct upon reaction with O in the atmospheric gas-phase is currently unknown.
View Article and Find Full Text PDFNat Commun
July 2024
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
The anisotropic water interfaces provide an environment to drive various chemical reactions not seen in bulk solutions. However, catalytic reactions by the aqueous interfaces are still in their infancy, with the emphasis being on the reaction rate acceleration on water. Here, we report that the oil-water interface activates and oxidizes C(sp)-H bonds in toluene, yielding benzaldehyde with high selectivity (>99%) and conversion (>99%) under mild, catalyst-free conditions.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
November 2024
Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil.
We theoretically investigate the photoionization scenarios of molecular complexes involving cyclopentadiene and cyanocyclopentadiene bound to water dimers. Using electronic structure calculations within density-functional theory (DFT) and time dependent DFT (TD-DFT), we explore the potential photochemical pathways following ionization, and determine the charge transfer excitations related to the possible subsequent reactions. Our findings suggest that the investigated photochemical pathways of the hydrated complexes take place in two well-defined ultraviolet regions: (i) 8.
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