The heat capacities and volumes of some low molecular weight amides, ketones, esters, and ethers in water over the whole solubility range

1978 ◽  
Vol 56 (22) ◽  
pp. 2808-2814 ◽  
Author(s):  
Geneviève Roux ◽  
Gérald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
Hydrophobic Interactions ◽  
Heat Capacities ◽  
Initial Slope ◽  
Pure Liquid ◽  
Factors Affecting ◽  
Solubility Range ◽  
Low Concentrations ◽  
Hydrophobic Solutes ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

The densities and heat capacities per unit volume of aqueous solutions of propionamide, methylacetate, ethylacetate, methylethylketone and diethylketone, and bis(2-ethoxyethyl)ether were measured over the whole solubility range with a flow densimeter and a flow microcalorimeter. Most systems were studied at 10, 25, and 40 °C. Properties of the pure liquids were also measured whenever possible. The derived apparent molal volumes [Formula: see text] all decrease with concentration in the water-rich region, except with ethyl acetate which increases at high temperature. In general the more hydrophobic the solute the more negative the initial slope. All apparent molal heat capacities [Formula: see text] decrease as a function of concentration and the decrease is more important for more hydrophobic solutes. The apparent molal expansibilities [Formula: see text] are obtained from [Formula: see text]. They are positive for all solutes but, at low concentrations, they are smaller than the corresponding molar value of the pure liquid. Various factors affecting hydrophobic interactions are examined.

Aqueous solutions of azoniaspiroalkane halides. VI. Apparent molal volumes and apparent molal heat capacities of chlorides and iodides

1979 ◽  
Vol 8 (6) ◽  
pp. 449-460 ◽  
Author(s):  
Antonio Lo Surdo ◽  
Wen-Yang Wen ◽  
Carmel Jolicoeur
Keyword(s):  
Aqueous Solutions ◽  
Heat Capacities ◽  
Apparent Molal Volumes ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

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.

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 Heat Capacities and Volumes of Tetrabutylammonium Carboxylates and Related Solutes in Water at 25 °C

1973 ◽  
Vol 51 (17) ◽  
pp. 2993-2998 ◽  
Author(s):  
Paul-André Leduc ◽  
Jacques E. Desnoyers
Keyword(s):  
Concentration Dependence ◽  
Sodium Acetate ◽  
Ammonium Acetate ◽  
Tetrabutylammonium Bromide ◽  
Heat Capacities ◽  
Ammonium Bromide ◽  
Sodium Octanoate ◽  
Apparent Molal Volumes ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

The apparent molal volumes and heat capacities were measured in water at 25 °C with a flow digital densimeter and a flow microcalorimeter for the following salts: tetrabutylammonium octanoate, tetrabutylammonium butanoate, tetrabutylammonium bromide, ammonium acetate, ammonium chloride, ammonium bromide, sodium octanoate, and sodium acetate. The tetrabutylammonium octanoate and butanoate and sodium octanoate form micelles at 0.13, 0.6, and 0.35 M, respectively. The concentration dependence of the apparent molal volumes of the carboxylate salts is similar to that of typical hydrophobic or hydrophilic electrolytes. On the other hand, in the submicellar region, the concentration dependence of their apparent molal heat capacities is abnormal when compared with model electrolytes. It seems that the heat capacities may be reflecting interactions involving a hydrogen bonding of the carboxylate group with water.

Ultrasonic vibration potentials, apparent molal volumes, and apparent molal heat capacities of 1:1 electrolytes in acetonitrile

1979 ◽  
Vol 8 (10) ◽  
pp. 729-753 ◽  
Author(s):  
Raoul Zana ◽  
G�rald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
Ultrasonic Vibration ◽  
Heat Capacities ◽  
Apparent Molal Volumes ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

Interactions between cations and sugars. II. Enthalpies, heat capacities, and volumes of aqueous solutions of Ca2+–D-ribose and Ca2+–D-arabinose at 25 °C

1986 ◽  
Vol 64 (5) ◽  
pp. 996-1001 ◽  
Author(s):  
Jean-Pierre Morel ◽  
Claude Lhermet ◽  
Nicole Morel-Desrosiers
Keyword(s):  
Thermodynamic Properties ◽  
Aqueous Solutions ◽  
Association Constant ◽  
Pair Interaction ◽  
Heat Capacities ◽  
Enthalpies Of Solution ◽  
Weak Association ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities ◽  
Entropy Of Reaction

The thermodynamic parameters characterizing the interaction between Ca2+ and the suitably positioned sequences of hydroxyls of some sugar isomers have been determined. This was done by comparing the properties of D-ribose which bears such sequences of hydroxyls with the properties of D-arabinose chosen as an inactive reference. The enthalpies of solution and of dilution, the apparent molal heat capacities, and the apparent molal volumes of the two pentoses have been first measured in water at 25 °C. The measurement of these properties for the transfer of the sugars from water to CaCl2 solutions (and, conversely, for the transfer of CaCl2 from water to the sugar solutions) directly gives access to the Ca2+–hydroxyls pair interaction parameters. The thermodynamic properties of this reaction of association may then be estimated: [Formula: see text][Formula: see text] The analysis of these data shows that the weak association constant results from a large compensation between the favourable enthalpy and the unfavourable entropy of reaction.

Aqueous solutions of azoniaspiroalkane halides. II. Apparent molal volumes and apparent molal heat capacities

1976 ◽  
Vol 80 (5) ◽  
pp. 466-470 ◽  
Author(s):  
Wen-Yang Wen ◽  
Antonio LoSurdo ◽  
Carmel Jolicoeur ◽  
Jeanine Boileau
Keyword(s):  
Aqueous Solutions ◽  
Heat Capacities ◽  
Apparent Molal Volumes ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

Apparent Molal Volumes and Heat Capacities of some Sulfates and Carbonates in Water at 25 °C

1975 ◽  
Vol 53 (8) ◽  
pp. 1134-1138 ◽  
Author(s):  
Gérald Perron ◽  
Jacques E. Desnoyers ◽  
Frank J. Millero
Keyword(s):  
Heat Capacity ◽  
Ionic Strength ◽  
Ion Pair ◽  
Heat Capacities ◽  
Anomalous Increase ◽  
Low Concentration ◽  
Apparent Molal Volumes ◽  
Specific Heats ◽  
Molal Volumes ◽  
Apparent Molal Heat Capacities

The densities and volumetric specific heats of Na2SO4, K2SO4, MgSO4, Na2CO3, NaHCO3, and NaOH were measured up to an ionic strength of 1 in water at 25 °C with a flow densimeter and a flow microcalorimeter. From these data, the heat capacity for the formation of the ion pair MgSO40was evaluated as 84.9 J K−1 mol−1. There is an anomalous increase in the apparent molal heat capacities of Na2CO3 at low concentration but the apparent molal volumes are normal. This anomaly can be suppressed with NaOH. Attempts to account quantitatively for this behavior by an hydrolysis correction were not successful.

Apparent molal heat capacities of transfer from H2O to D2O of tetraalkylammonium bromides

1972 ◽  
Vol 1 (4) ◽  
pp. 353-367 ◽  
Author(s):  
P. R. Philip ◽  
J. E. Desnoyers
Keyword(s):  
Heat Capacities ◽  
Tetraalkylammonium Bromides ◽  
Apparent Molal Heat Capacities

Heat capacities and volumes of some non-electrolytes in N,N-dimethylformamide at 298.15 K

1987 ◽  
Vol 65 (12) ◽  
pp. 2810-2814 ◽  
Author(s):  
Henryk Piekarski
Keyword(s):  
Ethylene Glycol ◽  
Heat Capacities ◽  
Scaled Particle Theory ◽  
Partial Molal Volume ◽  
Cavity Formation ◽  
Particle Theory ◽  
Molal Volume ◽  
Analogous Data ◽  
Other Substances ◽  
Apparent Molal Heat Capacities

Heat capacities and densities of dilute solutions of formamide, acetone, tetrahydrofuran, ethylene glycol, 2-methoxyethanol, and 2-ethoxyethanol in N,N-dimethylformamide were determined at 298.15 K. Apparent molal heat capacities and volumes for these solutes in DMF were calculated and compared with the analogous data for other substances in DMF solution as well as with the data concerning solutions in methanol and water. Heat capacities of cavity formation (ΔCcav) in DMF were calculated on the basis of the Scaled Particle Theory. ΔCcav appeared to be linearly correlated with the standard partial molal volume of corresponding solutes in DMF. Similar dependences were also found for aqueous and methanolic solutions of the non-electrolytes.

Sign in / Sign up

Export Citation Format

Share Document