Diagrams of existence of chloramines and bromamines in aqueous solution
| Autor: | François Bloc, André Hatterer, Michel Soulard |
|---|---|
| Rok vydání: | 1981 |
| Předmět: | |
| Zdroj: | Journal of the Chemical Society, Dalton Transactions. :2300 |
| ISSN: | 1364-5447 0300-9246 |
| DOI: | 10.1039/dt9810002300 |
| Popis: | Ultraviolet spectrophotometric analysis of haloamines produced by mixing aqueous helogen and ammonia solutions allowed distribution diagrams for the various species to be established as a function of pH and log R(R=[initial halogen]/[initial ammonia]). These diagrams are interpreted by using a model involving reversible reactions between the different compounds, whilst neglecting their decomposition. The reactions (equilibrium constants in parentheses) controlling concentrations of the species are as shown in equations (1)–(6). These equilibria and X2+ H2O ⇄ HXO + H++ X–(1), HXO ⇄ H++ XO–(2), NH3+ H+⇄ NH4+(3), NH2X + H2O ⇄ NH4++ XO–(Khm)(4), 2NH2X + H+⇄ NHX2+ NH4+(Kmd)(5), 3NHX2+ H+⇄ 2NX3+ NH4+(Kdt)(6) the law of N and X+ mass conservation led to a non-linear system of eight equations with eight unknowns, solved by iteration. Experimental values of the constants, derived from isocontent curves between two species, are (at 25 °C): Khm(Cl)= 4 × 10–7 mol dm–3, Khm(Br)= 1 × 10–7 mol dm–3, Kmd(Cl)= 5.2 × 106 dm3 mol–1, Kmd(Br)= 8 × 107 dm3 mol–1, Kdt(Cl)= 1.7 × 104 dm3 mol–1, Kdt(Br)= 1.5 × 105 dm3 mol–1. Satisfactory agreement was found between calculated and measured values for the various species. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|