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Kinetics and mechanisms of chlorine transfer from chloramine to amines in aqueous medium

1991; Wiley; Volume: 23; Issue: 4 Linguagem: Inglês

10.1002/kin.550230404

1097-4601

Michel Ferriol, Josette Gazet, Marie‐thérèse Saugier‐cohen Adad,

Chemical Analysis and Environmental Impact

Abstract The kinetics and the equilibrium constant of the chlorine transfer reaction between monochloramine NH 2 Cl and the amines: C 2 H 5 NH 2 , (CH 3 ) 2 CHNH 2 , (CH 3 ) 2 NH, and (C 2 H 5 ) 2 NH are investigated by spectrophotometry in aqueous medium at 25°C, in the pH range from 8 to 13 and for an ionic strength equal to 1.03 ± 0.05 M . For a concentration of total ammonia equal to 1 M , the observed rate constant is pH independent below 8 and above 12.8 and reaches a maximum located between the pK a s of NH 4 + and RR'NH 2 + . From these results and those obtained earlier for NH 2 Cl and CH 3 NH 2 , the reaction is shown to involve an interaction between neutral molecules NH 2 Cl and RR'NH, subject to general acid catalysis. The ability of an interaction corresponding to a specific catalysis and involving NH 3 Cl + and RR'NH rather than NH 2 Cl and RR'NH 2 + is also discussed. The activation parameters are given for each reaction.