Chlorination and bromination of 1,3-diphenylguanidine and 1,3-di-o-tolylguanidine: Kinetics, transformation products and toxicity assessment

JOURNAL OF HAZARDOUS MATERIALS

卷:385

Article

Sieira, Benigno J.¹  Montes, Rosa¹  Touffet, Arnaud²  Rodil, Rosario¹  Cela, Rafael¹  Gallard, Herve²  Benito Quintana, Jose¹ 

[1] Univ Santiago de Compostela, Inst Food Anal & Res IIAA, Dept Analyt Chem Nutr & Food Sci, R Constantino Candeira S N, Santiago De Compostela 15782, Spain

[2] Univ Poitiers, ENSIP, IC2MP, 1 Rue Marcel Dore,TSA 41105, F-86073 Poitiers, France

关键词: Halogenation;    Transformation products;    High-resolution mass spectrometry (HRMS);    Ecotoxicity;    Disinfection by-products;   

DOI  :  10.1016/j.jhazmat.2019.121590

来源: Elsevier

【 摘 要 】

This works investigates the chlorination and bromination of two rubber and polymer related chemicals, which have emerged as relevant water contaminants, i.e. 1,3-di-o-tolylguanidine (DTG) and 1,3-diphenylguanidine (DPG). Kinetic constants at different pH values were obtained and modelled, taking into account the pK(a) values of DTG/DPG and HClO, showing that the maximum reaction rate (k(app) > 10(4 )M(-1) s(-1)) is obtained at pH values 8.8 for DPG and 9.1 for DTG. Bromination is also very fast, although unlike chlorination, deviation from the model was observed at neutral pH, which was attributed to formation of metastable transformation product (TP). A total of 35 TPs, corresponding to halogenation, hydroxylation, formation of monophenylguanidine derivatives and cyclization reactions, were tentatively identified. Furthermore it was found that chloroform can be formed up to a 25% molar yield, while dichloroacetonitrile was formed into less than a 3% yield. Several ecotoxicological endpoints were predicted by quantitative structure-activity relationship models (QSAR) for the TPs, some of which were predicted to be more toxic than DPG/DTG. Also a chlorinated solution investigated by a Vibrio Fisheri acute toxicity test, confirmed that toxicity increases with chlorination.

【 授权许可】

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