ChemInform Abstract: Kinetics and Mechanism of the Base Decomposition of Nitrogen Trichloride in Aqueous Solution.

ChemInform Abstract

The kinetics of decomposition of NCl₃ in neutral and basic solutions is investigated in the presence of several different buffers and in the presence of excess hydroxide ion (up to 0.25 M). All the reactions are first order in (NCl₃), but the rate expression based on the stoichiometry shown in the scheme contains rate terms that are zero, first, and second order in (OH-) as well as terms with significant rate contributions from buffers. In the proposed mechanism Cl₂NClOH- is a common reactive intermediate that can react with acids (H₃O+, HB, and H₂O) to form HNCl₂ and HOCl or it can react with an additional OH- to release OCl-. HNCl₂ so formed reacts rapidly with a second NCl₃ to give products. The thermodynamic stability of NCl₃ in aqueous solution is substantially greater than was previously thought, as indicated by the stability constant of 1.6·10⁸ M-1 for its formation from NHCl₂ and HOCl (second reaction in the scheme).