Lippa, K. A. published the artcileNucleophilic Aromatic Substitution Reactions of Chloroazines with Bisulfide (HS-) and Polysulfides (Sn2-), Quality Control of 25983-14-6, the main research area is chloroazine nucleophilic aromatic substitution reaction bisulfide polysulfide; seawater pollution chloroazine natural remediation nucleophilic reaction bisulfide polysulfide.
Reactions of bisulfide and polysulfides with chloroazines (important constituents of agrochems. and textile dyes) were examined in aqueous solution at 25°. For atrazine, rates are first-order in polysulfide concentration, and polysulfide dianions are the principal reactive nucleophiles; no measurable reaction occurs with HS-. Second-order rate constants for reactions of an array of chloroazines with polysulfides are several orders of magnitude greater than for reactions with HS-. Transformation products indicate the substitution of halogen(s) by sulfur. Ring aza nitrogens substantially enhance reactivity through a combination of inductive and mesomeric effects, and electron-withdrawing or electron-donating substituents markedly enhance or diminish reactivity, resp. The overall second-order nature of the reaction, the products observed, and reactivity trends are all consistent with a nucleophilic aromatic substitution (SNAr) mechanism. Rate constants for reactions with HS- and Sn2- (n = 2-5) correlate only weakly with LUMO (LUMO) energies, suggesting that the electrophilicity of a chloroazine is not the sole determinant of its reactivity. When second-order rate constants are extrapolated to HS- and Sn2- concentrations reported in salt marsh pore waters, half-lives of minutes to years are obtained. Polysulfides in particular could play an important role in effecting abiotic transformations of chloroazines in hypoxic marine waters.
Environmental Science and Technology published new progress about Aquatic sediment pore water (salt marsh). 25983-14-6 belongs to class quinoxaline, name is 2,3,6,7-Tetrachloroquinoxaline, and the molecular formula is C8H2Cl4N2, Quality Control of 25983-14-6.
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider