HOBr and HOCl are important oxidants in a variety of aqueous solutions, including drinking water, wastewater, and sites of inflammation in mammals (where specific white blood cells can produce HOBr and HOCl by oxidizing bromide and chloride, respectively). In each of these systems, HOBr and HOCl are of potential concern because they can react with nucleophilic organic compounds to generate brominated and chlorinated products, which are commonly referred to as disinfection by-products (DBPs) in the environmental literature. Salicylic acid is significant in that it is has been detected in drinking water influent and is present in human blood following dietary consumption. Previous studies have generally overlooked halogenating agents other than HOCl and HOBr during reactions with micropollutants, including salicylic acid. This research examined regiospecific rates of aqueous halogenation of the salicylic acid to produce halogenated products (e.g., 3-chlorosalicylic acid, 5-chlorosalicylic acid, 3,5-dichlorosalicylic acid, 3-bromosalicylic acid, 5-bromosalicylic acid, and 3,5-dibromosalicylic acid). Time course experiments were carried out as a function of pH, [Br-], and [Cl-]. Aliquots from reactors were analyzed by high performance liquid chromatography with UV-vis detection. Herein, we discuss the effects of pH, [Br-], and [Cl-] on overall rates of salicylic acid chlorination/bromination. These results are then used to determine the contributions of individual halogenating agents (e.g., HOCl, HOBr, Cl2, Br2, BrCl, Cl2O, and BrOCl) on net halogenation rates.

Influence of often-overlooked free chlorine and free bromine species on regiospecific halogenation rates of salicylic acid

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.