Study of preferential solvation of lithium chloride in hydroxylamine-water mixtures by Monte Carlo simulation

Abstract

Monte Carlo studies have been carried out for the system consisting of 2LiC1 in 4 compositions, namely 4.5, 25.0, 50.0 and 75.2 weight % of hydroxylamine in water at 305 Kelvin and 1 atmospheric pressure, using pair potentials derived from ab initio calculations . The simulation results show that a mixture containing 4.5% hydroxylamine in the solvent displays an ideal configuration as for pure aqueous solution, [Li (H [subcript2]O)6] ⁺ and [C1 (H[subcript2]O)8] ⁻ . The increase 0f hydroxylamine content to 25.0%, 50.0% and 75.2% the average compositions become [Li(H[subcript2]O)4 (NH[subcript2]OH2] ⁺ and [C1(H[subcript2]O)7(NH[subcript2]OH)4.5] ⁻ ,[Li(H[subcript2]O)2.5 (NH[subcript2]OH3] ⁺ and [C1 (H[subcript2]O)4(NH[subcript2]OH)4] ⁻ and [Li(H[subcript2]O)1.5 (NH[subcript2]OH )5] ⁺ and [C1(H[subcript2]O)4.5 (NH[subcript2]OH)8] ⁻ , respectively. In addition, the results are also analysed in terms of coordination number distribution. These results indicate that the determined salvation numbers are the average number of the actual composition. For example, the average number of NH[subcript2]OH molecules of 2 in [Li(H[subcript2]O)4(NH[subcript2]OH)2] ⁺ for 25% hydroxylamine in water, but the actual composition is 1 and 3.