Dataset Information

Theoretical investigation on degradation of CH[triple bond, length as m-dash]CCH₂OH by NO₃ radicals in the atmosphere.

ABSTRACT: A detailed computational investigation is executed on the reaction between NO₃ and CH[triple bond, length as m-dash]CCH₂OH at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level. Addition/elimination and H-abstraction mechanisms are found for the NO₃ + CH[triple bond, length as m-dash]CCH₂OH reaction, and they could compete with each other. The most feasible addition/elimination pathway through a series of central-C addition, 1,4-H migration to generate intermediates IM1 (CHCONO₂CH₂OH) and IM3 (CH₂CONO₂CH₂O), and then IM3 directly decompose into product P2 (CH₂CONO₂CHO + H). The dominant H-abstraction pathway is abstracting the H atom of the -CH₂- group to generate h-P1 (CHCCHOH + HNO₃). RRKM-TST theory was used to compute the kinetics and product branching ratios of the NO₃ + CH[triple bond, length as m-dash]CCH₂OH reaction at 200-3000 K. The rate constants at 298 K are consistent with the experimental values. The lifetime of CH[triple bond, length as m-dash]CCH₂OH is estimated to be 59.72 days at 298 K. The implicit solvent model was used to examine the solvent effect on the total reaction. Based on the quantitative structure-activity relationship (QSAR) model, the toxicity during the degradation process is increased towards fish, and decreased towards daphnia and green algae.

SUBMITTER: Gao J

PROVIDER: S-EPMC11341969 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Theoretical investigation on degradation of CH[triple bond, length as m-dash]CCH2OH by NO3 radicals in the atmosphere.

Gao Jikang J Zhao Meilian M Wang Yaru Y Liao Junchao J Zhang Yunju Y

RSC advances 20240823 35

A detailed computational investigation is executed on the reaction between NO3 and CH[triple bond, length as m-dash]CCH2OH at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level. Addition/elimination and H-abstraction mechanisms are found for the NO3 + CH[triple bond, length as m-dash]CCH2OH reaction, and they could compete with each other. The most feasible addition/elimination pathway through a series of central-C addition, 1,4-H migration to generate int ...[more]

PMID: 39184547

Similar Datasets

Project description:The reaction of excited nitrogen atoms N(2D) with CH3CCH (methylacetylene) was investigated under single-collision conditions by the crossed molecular beams (CMB) scattering method with mass spectrometric detection and time-of-flight analysis at the collision energy (Ec) of 31.0 kJ/mol. Synergistic electronic structure calculations of the doublet potential energy surface (PES) were performed to assist the interpretation of the experimental results and characterize the overall reaction micromechanism. Theoretically, the reaction is found to proceed via a barrierless addition of N(2D) to the carbon-carbon triple bond of CH3CCH and an insertion of N(2D) into the CH bond of the methyl group, followed by the formation of cyclic and linear intermediates that can undergo H, CH3, and C2H elimination or isomerize to other intermediates before unimolecularly decaying to a variety of products. Kinetic calculations for addition and insertion mechanisms and statistical (Rice-Ramsperger-Kassel-Marcus) computations of product branching fractions (BFs) on the theoretical PES were performed at different values of total energy, including the one corresponding to the temperature (175 K) of Titan's stratosphere and that of the CMB experiment. Up to 14 competing product channels were statistically predicted, with the main ones, at Ec = 31.0 kJ/mol, being the formation of CH2NH (methanimine) + C2H (ethylidyne) (BF = 0.41), c-C(N)CH + CH3 (BF = 0.32), CH2CHCN (acrylonitrile) + H (BF = 0.12), and c-CH2C(N)CH + H (BF = 0.04). Of the 14 possible channels, seven correspond to H displacement channels of different exothermicity, for a total H channel BF of ∼0.25 at Ec = 31.0 kJ/mol. Experimentally, dynamical information could only be obtained about the overall H channels. In particular, the experiment corroborates the formation of acrylonitrile + H, which is the most exothermic of all 14 reaction channels and is theoretically calculated to be the dominant H-forming channel (BF = 0.12). The products containing a novel C-N bond could be potential precursors to form other nitriles (C2N2, C3N) or more complex organic species containing N atoms in planetary atmospheres, such as those of Titan and Pluto. Overall, the results are expected to have a potentially significant impact on the understanding of the gas-phase chemistry of Titan's atmosphere and the modeling of that atmosphere.

Project description:In a natural environment, Fe(ii) adsorbed onto the surfaces of natural particles to form various surface complex species can influence the transformation of contaminants. The reductive reactivity of the [[triple bond, length as m-dash]Fe(iii)]/[[triple bond, length as m-dash]Fe(ii)] couples are close correlated with the surrounding conditions. In this study, we investigated the effects of Si(iv) on the reductive reactivity of [[triple bond, length as m-dash]Fe(iii)]/[[triple bond, length as m-dash]Fe(ii)] couples adsorbed onto γ-Al2O3. Experiments were conducted under different conditions to investigate the effects of Si(iv) on the reactivity of [[triple bond, length as m-dash]Fe(iii)]/[[triple bond, length as m-dash]Fe(ii)] couples for 2-nitrophenol (2-NP, selected as the model pollutant) reduction in γ-Al2O3 suspensions. Kinetics results revealed that chemical adsorption is the rate limiting step in Fe(ii) and Si(iv) adsorption processes and the reduction of 2-NP is an endothermic reaction. The linear correlations between the reduced peak oxidation potential (E p) (versus SCE) and 2-NP reduction rate (ln k), and between the adsorbed Fe(ii) density (ρ Fe(II)) and ln k, illustrated that E p and ρ Fe(II) are two key factors in the inhibiting effects of Si(iv) on the reductive reactivity of Fe(iii)/Fe(ii) couples on γ-Al2O3. The results of Fe K-edge X-ray absorption spectroscopy revealed that the increase of Si(iv) concentration resulted in the gradual change in the composition of the adsorbed Fe species from pure [triple bond, length as m-dash]AlOFe+ (γ-Al2O3 surface-bound Fe(ii) species with higher reductive reactivity) to a mixture of [triple bond, length as m-dash]AlOFe+ and [triple bond, length as m-dash]SiOFe+ (SiO2 surface-bound Fe(ii) species with lower reductive reactivity), leading to the decrease in ρ Fe(II), the positive shift in E p, the increase in activation energy (E a), and consequently the decrease in the reduction rate (ln k) of 2-NP.

Dataset Information

Theoretical investigation on degradation of CH[triple bond, length as m-dash]CCH₂OH by NO₃ radicals in the atmosphere.

Publications

Theoretical investigation on degradation of CH[triple bond, length as m-dash]CCH<sub>2</sub>OH by NO<sub>3</sub> radicals in the atmosphere.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets