Volumes and Heat Capacities of Transfer of Tetraalkylammonium Bromides from Water to Aqueous Urea Solutions at 25 °C

1973 ◽  
Vol 51 (2) ◽  
pp. 187-191 ◽  
Author(s):  
P. R. Philip ◽  
J. E. Desnoyers ◽  
A. Hade
Keyword(s):  
Transfer Functions ◽  
Pure Water ◽  
Heat Capacities ◽  
Tetraalkylammonium Bromides ◽  
Apparent Molal Volumes ◽  
Aqueous Urea ◽  
Molal Volumes

The apparent molal volumes and heat capacities of tetraalkylammonium bromides were measured in urea–water mixtures at 25 °C. The volumes and heat capacities of transfer from water to urea-water mixtures indicate that structural hydration effects are smaller in urea–water mixtures than in water. Also a comparison with the corresponding transfer functions from H2O to D2O suggests that urea–water mixtures are less structured than pure water.

Volumes and Heat Capacities of Cyclic Ethers and Amines in Water and of some Electrolytes in these Mixed Aqueous Solvents

1975 ◽  
Vol 53 (17) ◽  
pp. 2591-2597 ◽  
Author(s):  
Osamu Klyohara ◽  
Gérald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
Mixed Solvent ◽  
Transfer Functions ◽  
Heat Capacities ◽  
Cyclic Ethers ◽  
Apparent Molal Volumes ◽  
Cyclic Amines ◽  
Specific Heats ◽  
Molal Volumes ◽  
Mixed Aqueous Solvents ◽  
Structural Influence

The densities and volumetric specific heats of p-dioxane, tetrahydropyran, morpholine, piperidine, and piperazine were measured in water at 25 °C with a flow densimeter and a flow microcalorimeter. The same properties were also determined for LiCl, NaCl, Me4NBr, and Bu4NBr at 0.1 m in dioxane–water, morpholine–water, and piperidine–water mixtures. The derived apparent molal volumes and heat capacities of the nonelectrolytes in water and the transfer functions of the electrolytes from water to the mixed solvent suggest that all the present cyclic amines and ethers are hydrophobic; the overall structural influence is very small with dioxane and large with piperidine.

Thermodynamic properties of tetraalkylammonium halides: volumes, heat capacities, and expansibilities in H2O, D2O and urea–water mixtures from 278 to 328 K

1976 ◽  
Vol 54 (14) ◽  
pp. 2163-2183 ◽  
Author(s):  
Gérald Perron ◽  
Nicole Desrosiers ◽  
Jacques E. Desnoyers
Keyword(s):  
Transfer Functions ◽  
Heat Capacities ◽  
Excess Functions ◽  
Free Energies ◽  
Aqueous Urea ◽  
Hydrophobic Bond ◽  
Hydrophobic Solutes ◽  
Molal Volumes ◽  
The Difference ◽  
Tetraalkylammonium Halides

The densities and heat capacities per unit volume of the symmetrical tetraalkylammonium bromides (R4NBr) were measured in H2O, D2O, and 3 m aqueous urea from 0.01 to 1 mol kg−1 and from 5 to 55 °C with a flow digital densimeter and a flow microcalorimeter. Expansibilities were also measured at 25 °C for the same electrolytes in H2O and urea–water mixtures with a dilatometer. Apparent molal volumes [Formula: see text] heat capacities [Formula: see text] and expansibilities [Formula: see text] were derived. The [Formula: see text] of R4NCl and R4NI were also measured in H2O at 25 °C. The effect of urea concentration was investigated at 25 °C in the case of Bu4NBr.Once allowance is made for the anion, the properties of the larger R4N+ behave essentially as hydrophobic nonelectrolytes in water. The transfer functions from H2O to D2O have the same sign as the hydration functions and the transfer functions from H2O to urea–water mixtures the opposite sign. Whatever is the origin of the interactions giving rise to the peculiar behavior of hydrophobic R4N+ in water, these interactions are larger in D2O and smaller in the presence of urea.The excess volumes, heat capacities, and expansibilities of Bu4NBr and Pen4NBr, once corrected for the long-range Debye–Hückel interactions, all have the same sign as the hydration functions at infinite dilution, in contrast with excess free energies and enthalpies. This suggests some kind of cooperative effect as two hydrophobic solutes interact with each other without the formation of a hydrophobic bond. No conclusions can be drawn from the difference in excess functions in the various aqueous solvents.

Apparent Molal Volumes and Heat Capacities of Tetrabutylammonium Bromide in Aqueous Electrolyte Solutions

1975 ◽  
Vol 53 (21) ◽  
pp. 3206-3210 ◽  
Author(s):  
Nicole Desrosiers ◽  
Jacques E. Desnoyers
Keyword(s):  
Aqueous Solutions ◽  
Long Range ◽  
Transfer Functions ◽  
Aqueous Electrolyte ◽  
Tetrabutylammonium Bromide ◽  
Electrolyte Solutions ◽  
Heat Capacities ◽  
Apparent Molal Volumes ◽  
Flow Microcalorimeter ◽  
Molal Volumes

The apparent molal volumes and heat capacities of Bu4NBr were measured in aqueous solutions of NaF, NaCl, NaBr, KBr, NaAc, and NH4Ac at 25 °C with a flow densimeter and a flow microcalorimeter. The derived transfer functions of Bu4NBr from water to the electrolyte solutions, after correction for the long-range coulombic forces, are all negative. This suggests that the noncoulombic interactions between hydrophobic and hydrophilic ions result in negative contributions to volumes and heat capacities.

A Comparative Study of Bu4NBr, NaBPh4, Ph4PCl, and Ph4AsCl in Water and Methanol at 25 °C: Partial Molal Volumes, Heat Capacities, and Viscosities

1972 ◽  
Vol 50 (19) ◽  
pp. 3167-3178 ◽  
Author(s):  
C. Jolicoeur ◽  
P. R. Philip ◽  
G. Perron ◽  
P. A. Leduc ◽  
J. E. Desnoyers
Keyword(s):  
Comparative Study ◽  
Transfer Functions ◽  
Heat Capacities ◽  
Solvent Interactions ◽  
Apparent Molal Volumes ◽  
Partial Molal Volumes ◽  
Molal Volumes

The apparent molal volumes [Formula: see text] and heat capacities [Formula: see text] of Bu4NBr, NaBPh4, Ph4PCl, and Ph4AsCl have been measured in water and methanol at 25 °C in the concentration range 0.01–0.2 M. The viscosity of aqueous NaBPh4 and Ph4AsCl have also been measured at 25 °C and in the same concentration range. Individual ionic values have been estimated for most of these properties. A comparison of these values for the quaternary ions BU4N+, [Formula: see text], Ph4P+, Ph4As+ illustrates sizable differences in the solute–solvent interactions of alkyl and aryl substituted ions. Some specificity is also suggested in the solvation of the tetraphenyl ions, as shown by a comparison of the properties which should reflect directly the size of the ions [Formula: see text]and also in (H2O → CH3OH) transfer functions.

Apparent molal heat capacities and volumes of aqueous electrolytes at 25 °C: NaClO3, NaClO4, NaNO3, NaBrO3, NaIO3, KClO3, KBrO3, KIO3, NH4NO3, NH4Cl, and NH4ClO4

1978 ◽  
Vol 56 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Alain Roux ◽  
Goolam M. Musbally ◽  
Gérald Perron ◽  
Jacques E. Desnoyers ◽  
Prem Paul Singh ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Aqueous Electrolytes ◽  
Apparent Molal Volumes ◽  
Hückel Theory ◽  
Standard Values ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

Measurements at 25 °C with flow calorimeters and densimeters have led to heat capacities and densities of aqueous solutions of 11 1:1 electrolytes: NaClO3, NaBrO3, NaIO3, NaNO3, NaClO4, NH4NO3, KClO3, KBrO3, KIO3, NH4Cl, and NH4ClO4. The first 6 salts were studied up to near saturation. We have used results of these measurements to obtain apparent molal heat capacities and apparent molal volumes of the various solutes. Extrapolation to infinite dilution on the basis of the Debye–Hückel theory bas led to [Formula: see text]and [Formula: see text] values for each solute. We have compared these standard values with results of earlier investigations.

Volumes and heat capacities of some amino acids in water at 25 °C

1977 ◽  
Vol 55 (19) ◽  
pp. 3364-3367 ◽  
Author(s):  
JagDish C. Ahluwalia ◽  
Claude Ostiguy ◽  
Gerald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
Amino Acids ◽  
Heat Capacities ◽  
Apparent Molal Volumes ◽  
Flow Microcalorimeter ◽  
Ionic Groups ◽  
The Poor ◽  
Molal Volumes

The apparent molal volumes and heat capacities of nine amino acids were measured in water at 25 °C with a flow densimeter and a flow microcalorimeter. It is shown that the poor additivity of the standard partial molal quantities of amino acids in water are attributable to the ionization of the two groups NH2 and COOH. The hydration of these ionic groups interfere with each other when they are separated by less than three carbon atoms.

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