Revisiting the Tropospheric OH-Initiated Unimolecular Decomposition of Chlorpyrifos and Chlorpyrifos-Methyl: A Theoretical Perspective

Quintano, Mateus; Rodrigues, Gabriel L. S.; Chagas, Marcelo A.; Rocha, Willian R.

doi:10.1021/acs.jpca.0c02006

Cited by 3 publications

(2 citation statements)

References 52 publications

(93 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, ·OH and SO 4 •− have strong oxidizing properties, and they can easily undergo addition reactions with unsaturated bonds and abstraction reactions with H atoms [ 28 , 29 ]. Therefore, it is considered that the addition reactions of radicals with the P=S bond and pyridine ring, as well as the abstraction reactions with H atoms.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Persulfate–Based Advanced Oxidation Process for Chlorpyrifos Degradation: Mechanism, Kinetics, and Toxicity Assessment

Xu,

Zhang,

Zou

et al. 2024

Toxics

View full text Add to dashboard Cite

Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address this issue, density functional theory was used to analyze the degradation mechanism of CPY at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level, and computational toxicology methods were employed to explore the toxicity of CPY and its degradation products. Results show that hydroxyl radicals (·OH) and sulfate radicals (SO4•−) initiate the degradation reactions by adding to the P=S bond and abstracting the H atom on the ethyl group, rather than undergoing α-elimination of the pyridine ring in the persulfate oxidation process. Moreover, the addition products were attracted and degraded by breaking the P–O bond, while the abstraction products were degraded through dealkylation reactions. The transformation products, including 3,5,6-trichloro-2-pyridynol, O,O-diethyl phosphorothioate, chlorpyrifos oxon, and acetaldehyde, obtained through theoretical calculations have been detected in previous experimental studies. The reaction rate constants of CPY with ·OH and SO4•− were 6.32 × 108 and 9.14 × 108 M−1·s−1 at room temperature, respectively, which was consistent with the experimental values of 4.42 × 109 and 4.5 × 109 M−1 s−1. Toxicity evaluation results indicated that the acute and chronic toxicity to aquatic organisms gradually decreased during the degradation process. However, some products still possess toxic or highly toxic levels, which may pose risks to human health. These research findings contribute to understanding the transformation behavior and risk assessment of CPY in practical wastewater treatment.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Density functional theory (DFT) has been widely applied to study the chemical reaction mechanisms through elementary reactions [ 28 , 29 ]. DFT calculations can verify the existence of short-lived intermediates during the reaction process.…”

Section: Introductionmentioning

confidence: 99%