Ionic Solvation in Nonaqueous and Mixed Solvents

Padova, J.

doi:10.1007/978-1-4684-3003-5_1

Cited by 3 publications

(6 citation statements)

References 261 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…( Tübingen, 7400 Tübingen, West Germany. Received January 23,1984 Abstract: The geometric structure of dimethyl peroxide, CH30-0CH3, was studied by gas electron diffraction. The molecular intensities were analyzed by applying a large amplitude model with a double minimum potential for the 0-0 torsion.…”

Section: Resultsmentioning

confidence: 99%

Solvation of the halide anions in dimethyl sulfoxide. Factors involved in enhanced reactivity of negative ions in dipolar aprotic solvents

Magnera¹,

Caldwell²,

Sunner³

et al. 1984

J. Am. Chem. Soc.

View full text Add to dashboard Cite

The equilibrium constants K,l,n for the gas-phase equilibria (n -1,n) X-(Me2SO),, + Me2S0 = X-(Me,SO),, X = CI-, Br-, I-(n = 1 to n = 3 or 4) were measured with a pulsed high-pressure mass spectrometer. van't Hoff plots of these data lead to AHo,l,n, ASo,l,n, and AGon-l,r These data represent information on the inner-shell solvation of X-to Me2S0. Comparison with work in the preceding paper, this issue, on K+ (Me,SO), shows that the positive isoelectronic ion K' bonds to Me2S0 much more strongly than Cl-. MO calculations at the 4-3 1G level for these systems and improved electrostatic calculations are used to show that this is due to electrostatic reasons, Le., the location of the dipole in Me2S0 is largely on the S'O-group. This dipole can be approached easily by K+ but not by C1-since the methyl groups interfere in the latter case. Comparing the inner-shell solvation of C1-by Me2S0 and H 2 0 one finds that, in spite of the above effect, Me2S0 bonds more strongly, a consequence of the much higher dipole moment of Me2S0. However, in the liquid solvents H 2 0 provides better solvation. This is a consequence of the much larger radius of the CI-Me2S0 inner-shell cluster when compared with the C1-, H 2 0 cluster, Le., significant solvation beyond the inner shell occurs for C1-, H 2 0 but not for CI-Me2S0. Comparison of the data for C1-, Br-, I-in Me2S0 and water shows that both the inner-shell solvation and more importantly the solvation in the liquid solvents decreases for Me2S0 and H 2 0 in the order C1-, Br-, I-, Le., with increasing ion size; however, the decrease in the dipolar aprotic solvents is appreciably less. The smaller decrease of solvation with an increase of ion radius is the principal reason for the much higher rates of reactions A-+ B = (AB-)* -C-+ D in dipolar aprotic solvents. The reaction C1-+ CH3Br = CICH3 + Br-is examined in detail on the basis of its reaction coordinate in the gas phase and in solution. It is shown on the basis of sound thermochemical data for the relative solvation energies of X-that good predictions of the activation energy in protic and aprotic solvents can be made.Dipolar aprotic solvents like dimdthyl sulfoxide (Me2SO), dimethylformamide (DMF), acetonitrile, and acetone are used extensively in organic synthetic work. Of particular importance is their ability to accelerate reactions involving anionic reactants and transition states. A simple example is the sN2 reaction 1 which in D M F has a rate that is lo5 times higher than that in water.l The reasons for observing higher rates in dipolar aprotic H -CICH3 + Br-(I) CIt CHSBr -C I ---C ---B r -

show abstract

Section: Resultsmentioning

confidence: 99%

Solvation of the halide anions in dimethyl sulfoxide. Factors involved in enhanced reactivity of negative ions in dipolar aprotic solvents

Magnera¹,

Caldwell²,

Sunner³

et al. 1984

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Since for a given mixed-solvent system the importance of the above-mentioned parameters varies between different electrolytes, a dissimilar behavior of electrolytes (or individual ions) is expected and has a reasonable explanation if these differences in properties are taken into account. 1,[8][9][10][11][12][98][99][100][101][102] However, as observed in so many systems considered in this investigation, the existence of universal curves of Λ 0 (x) which include electrolytes having different properties (e.g., structurebreaking and structure-breaking electrolytes) is rather surprising and therefore requires some interpretation. Probably, the most plausible explanation is that the influence of the mixture properties on the mobility of electrolytes is only of secondary importance.…”

Section: Conclusion and Remarksmentioning

confidence: 97%

“…Since the limiting conductances Λ 0 and viscosities η are, to various extents, reflecting the size of the ions in solution, a natural interpretation of conductivities has been formulated in terms of the Walden and Stokes laws as applied to mixed solvents with and without water. [7][8][9][10][11][12] Since 1906 when Paul Walden 13 observed that the product of the molar conductance at infinite dilution Λ 0 (T) and viscosity of pure water η(T) is nearly independent of temperature, Λ 0 (T)η(T) ) constant, the so-called Walden rule or Walden product had a considerable practical importance. The Walden product is used to obtain the limiting conductances because the viscosities of water or other solvents as a function of temperature are supposed to be easier to measure than the corresponding Λ 0 (T) values.…”

Section: Introductionmentioning

confidence: 99%

“…Evidently, in the case of mixed solvents, the composition, which is usually expressed in weight fractions of the solvent w or in molar fractions x , is an additional variable. Since the limiting conductances Λ 0 and viscosities η are, to various extents, reflecting the size of the ions in solution, a natural interpretation of conductivities has been formulated in terms of the Walden and Stokes laws as applied to mixed solvents with and without water. – …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Limiting Conductances of Electrolytes and the Walden Product in Mixed Solvents in a Phenomenological Approach

Apelblat

2008

J. Phys. Chem. B

View full text Add to dashboard Cite

The applicability of the Quint-Viallard conductivity equation to the representation of electrical conductivities in mixed solvents is examined. The concept of the modified Walden product is introduced, and the benefits compared with the ordinary Walden product are discussed. The universal curve of limiting conductances for all electrolytes (or for all ions) in a given pair of solvents is introduced and examined in a number of mixtures which include methanol, ethanol, 1-propanol, tert-butyl alcohol, 1,4-dioxane, N, N-dimethylformamide, sulfolane, tetrahydrofuran, and ethylene carbonate with water. Also examined are nonaqueous mixtures of acetone-ethanol, acetone-1-propanol, dimethyl sulfoxide-propylene carbonate, acetonitrile-methanol, acetonitrile-carbon tetrachloride, and acetonitrile-propylene carbonate. Many electrolytes were involved in the evaluation of the universal curves, but the majority are alkali-metal halides, tetraalkylammonium halides, tetraalkylammonium tetraphenylborides, and potassium xanthates (inorganic and organic acids are treated separately). If in a given mixed solvent system the limiting conductance of electrolyte is unknown, the universal curve permits estimating its value and gives an indication about the quality of performed conductivity measurements. The existence of universal curves of limiting conductances indicates that the properties of electrolytes in pure solvents are, to a great extent, preserved also in the mixture of solvents due to the simple dilution effect.

show abstract

“…In the cases where DO alcohol was added to solution (DAC-water solutions), much lower times of flow ware obtained in the experiments and a more adequate viscometer was used. For these cases, the general equation relating dynamic viscosity to time of flow, n p (at -bIt) (2) was employed to account for the kinetic energy corrections. increases with concentration, this increase being higher for the tertbutyl alcohol.…”

Section: Exper Ijilentalmentioning

confidence: 99%

THB EFFECT OF TEMPERATURE AND ALCOHOL COHCEHTRATIOH OH THE VISCOSITY OF MIXTURES (n-, sec-, tert-) BUTYL ALCOHOL- -AQUEOUS SOLUTIOH OF n-DODECYLAKKOHIUM CHLORIDE

González‐Caballero

Bruque

Gálvez

1987

Journal of Dispersion Science and Technology

View full text Add to dashboard Cite

Ionic Solvation in Nonaqueous and Mixed Solvents

Cited by 3 publications

References 261 publications

Solvation of the halide anions in dimethyl sulfoxide. Factors involved in enhanced reactivity of negative ions in dipolar aprotic solvents

Solvation of the halide anions in dimethyl sulfoxide. Factors involved in enhanced reactivity of negative ions in dipolar aprotic solvents

Limiting Conductances of Electrolytes and the Walden Product in Mixed Solvents in a Phenomenological Approach

THB EFFECT OF TEMPERATURE AND ALCOHOL COHCEHTRATIOH OH THE VISCOSITY OF MIXTURES (n-, sec-, tert-) BUTYL ALCOHOL- -AQUEOUS SOLUTIOH OF n-DODECYLAKKOHIUM CHLORIDE

Contact Info

Product

Resources

About