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

A detailed computational investigation is executed on the reaction between NO ₃ and CH[triple bond, length as m-dash]CCH ₂ OH at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level. Addition/elimination and H-abstraction mechanisms are found for the NO ₃ + CH[triple bond, length as m-dash]CCH ₂ OH 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 (CHCONO ₂ CH ₂ OH) and IM3 (CH ₂ CONO ₂ CH ₂ O), and then IM3 directly decompose into product P2 (CH ₂ CONO ₂ CHO + H). The dominant H-abstraction pathway is abstracting the H atom of the -CH ₂ - group to generate h-P1 (CHCCHOH + HNO ₃ ). RRKM-TST theory was used to compute the kinetics and product branching ratios of the NO ₃ + CH[triple bond, length as m-dash]CCH ₂ OH 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]CCH ₂ OH 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.
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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