Abstract
The apparent molar heat capacities, ϕ C p , of ethanol, n-propanol, n-butanol, and tetraethylammonium, tetra-n-propylammonium, tetra-n-butylammonium and tetra-n-pentylammonium bromides have been measured measured using a Picker flow calorimeter (Sodev, Canada, Model CP-Cpr) at 298.15 K in water–N,N-dimethylformamide (DMF) mixtures. The contribution of the CH2 moiety, ϕ C p (CH2), was estimated from these data as the change in ϕ C p per additional CH2 unit. The values of ϕ C p (CH2) in water (ca. 100 J·K−1·mol−1) are two to three times those in neat organic solvents (ca. 30–40 J·K−1·mol−1), consistent with a substantial contribution from hydrophobic solvation in water. In water-rich aqueous DMF solutions, ϕ C p (CH2) decreases monotonically with increasing DMF concentration, the decrease being more rapid for the n-alcohols. This trend differs significantly from that reported in the literature for highly aqueous mixtures of t-butanol, where ϕ C p (CH2) passes through a maximum.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
McStravick, I., Flynn, K., Lambert, J., Teahan, N., Waghorne, W.E.: Enthalpy of transfer of –CH2– between water and organic solvents. J. Mol. Liq. 94, 145–153 (2001)
McStravick, I., Duffy, E., Waghorne, W.E.: Enthalpies of transfer of –CH2– between water and nonaqueous or mixed aqueous solvents. Comparison of values from n-alcohols and tetraalkylammonium halides. J. Mol. Liq. 103–104, 121–131 (2003)
Noban, S., Donohue, P., Waghorne, W.E.: Enthalpies of transfer of the –CH2– moiety into aqueous amide solvent systems. J. Phys. Chem. 107, 13188–13191 (2003)
Hora, J., McCarthy, R., Waghorne, W.E.: Enthalpies of transfer of the CH2 moiety into aqueous acetonitrile mixtures; Comparison of values from n-alcohols and tetraalkylammonium ions; Effect of temperature. J. Chem. Thermodyn. 37, 83–88 (2005)
Hefter, G.T., Marcus, Y.: A critical review of methods for obtaining ionic volumes in solution. J. Solution Chem. 26, 249–266 (1997)
Hefter, G.T., Grolier, J.-P.E., Roux, A.H.: Apparent molar heat capacities and volumes of electrolytes and ions in t-butanol–water mixtures. J. Solution Chem. 18, 229–248 (1989)
Philip, P.R., Desnoyers, J.E.: Apparent molal heat capacities of transfer from H2O to D2O of tetraalkylammonium bromides. J. Solution Chem. 1, 353–367 (1972)
Magalhaes, M.C.F., Königsberger, E., May, P.M., Hefter, G.: Heat capacities of concentrated aqueous solutions of sodium sulfate, sodium carbonate, and sodium hydroxide at 25 °C. J. Chem. Eng. Data 47, 590–598 (2002)
Płaczek, A., Grzybkowski, W., Hefter, G.T.: Molar volumes and heat capacities of electrolytes and ions in N,N-dimethylformamide. J. Phys. Chem. B 112, 12366–12373 (2008)
Archer, D.G.: Thermodynamic properties of the sodium chloride + water system. II. Thermodynamic properties of NaCl(aq), NaCl·2H2O(cr), and phase equilibria. J. Phys. Chem. Ref. Data 21, 793–829 (1992)
Stimson, H.F.: Heat units and temperature scales for calorimetry. Am. J. Phys. 23, 614–622 (1955)
Fenclová, D., Perez-Casas, S., Costas, M., Dohnal, V.: Partial molar heat capacities and partial molar volumes of all of the isomeric (C3 to C5) alkanols at infinite dilution in water at 298.15 K. J. Chem. Eng. Data 49, 1833–1838 (2004)
Origlia-Lust, M.L., Woolley, E.M.: Apparent molar volumes and apparent molar heat capacities of dilute aqueous solutions of ethanol, 1-propanol, and 2-propanol at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa. J. Chem. Thermodyn. 35, 1101–1118 (2003)
Marcus, Y., Hefter, G.: Ionic partial molar heat capacities in non-aqueous solvents. J. Chem. Soc. 92, 757–761 (1996)
Avédikian, L., Perron, G., Desnoyers, J.E.: Apparent molal heat volumes and heat capacities of some alkali halides and tetraalkylammonium bromides in aqueous tert-butanol solutions. J. Solution Chem. 4, 331–345 (1975)
Benson, G.C., D’Arcy, P.J., Kiyohara, O.: Thermodynamics of aqueous mixtures of nenelectrolytes II. Isobaric heat capacities of water–n-alcohol mixtures at 25 °C. J. Solution Chem. 9, 931–938 (1980)
Grolier, J.-P.E., Wilhelm, E.: Excess volumes and excess heat capacities of water + ethanol at 298.15 K. Fluid Phase Equilib. 6(3), 283–287 (1981)
De Visser, C., Perron, G., Desnoyers, J.E., Heuvelsland, W.J.M., Somsen, G.: Volumes and heat capacities of mixtures of N,N-dimethylformamide and water at 298.15 K. J. Chem. Eng. Data 22, 74–79 (1977)
Miyai, L., Nakamura, M., Tamura, K., Murakami, S.: Isotope effects on thermodynamic properties in four binary systems: Water (or heavy water) + dimethylsulfoxide (or N,N-dimethylformamide). J. Solution Chem. 26, 973–988 (1997)
Hefter, G.T., Grolier, J.-P.E., Roux, A.H., Roux-Desranges, G.: Apparent molar heat capacities and volumes of electrolytes and ions in acetonitrile–water mixtures. J. Solution Chem. 19, 207–223 (1980)
Fuchs, K., Kaatzr, U.: Dielectric spectra of mono- and disaccharide aqueous solutions. J. Chem. Phys. 116, 7137–7144 (2002)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Waghorne, W.E., Riveros, D.C., Vargas, E.F. et al. Apparent Molar Heat Capacities of n-Alcohols (C2 to C4) and Symmetric Tetraalkylammonium Bromides (C2 to C5) in Water–N,N-Dimethylformamide Mixtures: Methylene Group Contribution and Hydrophobic Hydration. J Solution Chem 45, 1303–1312 (2016). https://doi.org/10.1007/s10953-016-0498-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10953-016-0498-2