Preferential solvation study: Solvation of sodium chloride in water-hydroxylamine mixtures Original Research Article

MC simulations have been carried out to determine the solvation structure of NaCl in water/hydroxylamine mixtures of different composition. Na+ prefers solvation by NH2OH over the whole concentration range studied, proving a stronger N-affinity of this ion compared to the O-preferring Li+. The chlorideʹs solvation shell is quite sensitive to the solventʹs composition and determined mainly by the possibility of forming suitable hydrogen bonds. The larger size and weaker binding energy of the Cl− first solvation shell allows a wider variety of species composition than for Na+ and makes exchange processes between molecules in the first and second solvation spheres possible, involving mainly water ligands and those hydroxylamines being coordinated to the chloride ion via the amino group. The solvent structure is slightly modified by the presence of the ions in the solution compared with the structure of the pure NH2OHH2O mixtures. Such influence is mainly observed in the hydroxylamine-water and hydroxylamine-hydroxylamine interactions, whereas the structure of water-water pairs is less disturbed by addition of the ions.