Hydration of the halide ions in certain organic solvents

Abstract

LBL-1630The amount of water co-extracted by the halide anions into several solvents has been determined. The order was always Gl-> Br-> I-, and at high organic..;.phase salt concentrations, the hydration numbers increased with increasing concentration, apparently paralleling the formation of ion pairs and higher ion aggregates. In nitrobenzene· the lower, limiting values are 3. 3, 1. 8, and 1. 0 moles of water per anion for Cl-, Br-, and I~, respectively.With dichloroethane as solvent, and more particularly with chloroform, solvation of the anion by the (weakly) acid proton of the diluent replaces part of the hydration, and the hydration number observed decreases markedly. For a number of reasons, the hydration numbers observed are lower limits to the first-shell hydration or coordination number of the anion.

Hydrated Ion Clusters in Hydrophobic Liquid: Equilibrium Distribution, Kinetics, and Implications

“…The average hydration number of Cl – in liquid DCM at saturated water conditions is estimated to be 0.43 in the present calculation. This is qualitatively comparable to the previous experimental estimate of the hydration numbers of Cl – in other solvents, 3.3 in nitrobenzene, 2.4 in dichloroethane, and 1.0 in chloroform, though the present estimate is somewhat smaller than these previous values. Figure shows that the Cl – ion becomes less hydrated with deceasing water concentration in the liquid DCM.…”

Hydration to Benzo-15-crown-5, Benzo-18-crown-6 and the Benzo-18-crown-6-Potassium Ion Complex in the Low-Polar Organic Solvents

“…[1][2][3][4][5][6][7][8][9][10] Particularly, in the solvent extraction study, since the solutes in the water-saturated organic solution are discussed, hydration of the solutes in the organic phase is a very important subject. It has been demonstrated that the water molecules are coextracted with the metal ions, [11][12][13][14] the metal complexes, [14][15][16][17] and the inorganic anions 2,3,[18][19][20] into the organic solvents, and the mean hydration numbers of these solutes in the organic phase were determined.…”

“…[1][2][3][4][5][6][7][8][9][10] Particularly, in the solvent extraction study, since the solutes in the water-saturated organic solution are discussed, hydration of the solutes in the organic phase is a very important subject. It has been demonstrated that the water molecules are coextracted with the metal ions, 11-14 the metal complexes, [14][15][16][17] and the inorganic anions 2,3,[18][19][20] into the organic solvents, and the mean hydration numbers of these solutes in the organic phase were determined.There have been numerous studies about the ion-pair extraction of the crown ether complexes; extractability and selectivity of the metal ions have been discussed by using the overall extraction equilibrium constant and its component equilibrium constants. 21,22 On the other hand, in recent years, hydration of the crown ether molecules and complexes has been also studied by both the theoretical 23-31 and experimental [32][33][34][35][36][37] approaches, but most of these studies were in aqueous solution.…”

Temperature Effect on the Selective Hydration of Sodium Ion in Nitrobenzene

“…For many years much attention has been directed towards the co-extraction of water to water immiscible organic solvents with hydrophilic inorganic ions, [1][2][3][4][5][6][7][8][9] including Li + , Na + , Ca 2+ , and Cland also with organic ions [9][10][11] having dissociated groups, such as -CO2and -NH3 + . Even water-immiscible organic solvents, such as nitrobenzene (NB), usually dissolve a considerable amount of water (e.g.…”

“…In recent years the co-transport of water by ions has been dealt with by molecular dynamic simulations. [13][14][15] In solvent-extraction studies, [1][2][3][4][5][6][7][8]10,11 the number (n) of water molecules co-extracted with an ion was determined by the Karl Fischer method. However, it has frequently been asked whether the ion is really bound to water molecules in organic solvents.…”