CHAPTER 7: Aqueous Equilibrium Constants of Formation for Bromamines, Chloramines, and Bromochloramines: Quantum Chemistry Estimates.

Chloramines, bromamines, and bromochloramines are halogen-containing species that can be formed from the reaction between ammonia and hypohalous acids in water. These species are halogen oxidants implicated in the formation of potentially dangerous disinfection byproducts during water disinfection treatments. Despite these concerns, halamine speciation is not fully understood and halamine reactivities towards naturally-occurring compounds is difficult to investigate by experimental means only. Thus, we assessed the aqueous equilibrium constants for the formation of halamines by exploiting quantum chemical modeling. A benchmark-level composite method, termed TA14, was employed to obtain accurate estimates of thermodynamic equilibria of halamine formation in aqueous systems.