Chlorination of isothiazolinone biocides: kinetics, reactive species, pathway, and toxicity evolution was written by Wang, Wen-Long;Nong, Yu-Jia;Yang, Zheng-Wei;Wu, Qian-Yuan;Hubner, Uwe. And the article was included in Water Research in 2022.Name: Isothiazol-3(2H)-one This article mentions the following:
Due to the Covid-19 pandemic, the worldwide biocides application has been increased, which will eventually result in enhanced residuals in treated wastewater. At the same time, chlorine disinfection of secondary effluents and hospital wastewaters has been intensified. With respect to predicted elevated exposure in wastewater, the chlorination kinetics, transformation pathways and toxicity evolution were investigated in this study for two typical isothiazolinone biocides, methyl-isothiazolinone (MIT) and chloro-methyl-isothiazolinone (CMIT). Second-order rate constants of 0.13 M-1·s-1, 1.95 x 105 M-1·s-1 and 5.14 x 105 M-1·s-1 were determined for the reaction of MIT with HOCl, Cl2O and Cl2, resp., while reactivity of CMIT was around 1-2 orders of magnitude lower. While chlorination of isothiazolinone biocides at pH 7.1 was dominated by Cl2O-oxidation, acidic pH and elevated Cl- concentration favored free active chlorine (FAC) speciation into Cl2 and increased overall isothiazolinone removal. Regardless of the dominant FAC species, the elimination of MIT and CMIT resulted in an immediate loss of acute toxicity under all exptl. conditions, which was attributed to a preferential attack at the S-atom resulting in subsequent formation of sulfoxides and sulfones and eventually an S-elimination. However, chlorination of isothiazolinone biocides in secondary effluent only achieved <10% elimination at typical disinfection chlorine exposure 200 mg·L-1·min, but was predicted to be remarkably increased by acidizing solution to pH 5.5. Alternative measures might be needed to minimize the discharge of these toxic chems. into the aquatic environment. In the experiment, the researchers used many compounds, for example, Isothiazol-3(2H)-one (cas: 1003-07-2Name: Isothiazol-3(2H)-one).
Isothiazol-3(2H)-one (cas: 1003-07-2) belongs to isothiazole derivatives. Similar to other five-membered heterocycles, isothiazoles react with a wide range of electrophilic and nucleophilic reagents to form diverse products. It has been found that isothiazole-based compounds show synergistic effects when used with other biocidal compounds.Name: Isothiazol-3(2H)-one
Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com