Abstract
Freezing-point depressions and enthalpies of dilution for aqueous solutions of the straight chain, aliphatic carboxylic acids, C1 through C4, have been measured. These data, together with the corresponding apparent molal heat capacities, have been used to calculate the pairwise free energy and enthalpy of interaction of undissociated acid molecules at 298.150K. As expected, the effect of dimer and triplet interaction increases with chain length, reflecting the hydrophobic nature of the hydrocarbon portion of the molecules. The group-interaction additivity principle of Savage and Wood applied to these results gives an excellent correlation and yields values of the group interaction parameters, Gi,j and Hi,j for the CH2 and COOH groups. These parameters confirm previous results for the interaction of polar and hydrophobic groups in water. The primary data have been fitted to the activity expansion equations of Wood, Lilley, and Thompson to yield values of dimer and trimer "sociation" constants and their temperature derivatives. This procedure allows for the simultaneous treatment of the dissociation effects of these acids as weak electrolytes together with their tendency to form associated clusters.
| Original language | English |
|---|---|
| Pages (from-to) | 305-324 |
| Number of pages | 20 |
| Journal | Journal of Solution Chemistry |
| Volume | 9 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 1980 |
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Keywords
- activity expansion
- carboxylic acids
- enthalpies of dilution
- Freezing points
- group additivity principle
- sociation constants
- solute-solute interaction
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
Cite this
Freezing points and enthalpies of dilution of aqueous formic, acetic, propionic, and butyric acids. Free energies and enthalpies of solute-Solute interactions. / Harris, Alex; Thompson, Peter T.; Wood, Robert H.
In: Journal of Solution Chemistry, Vol. 9, No. 5, 05.1980, p. 305-324.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Freezing points and enthalpies of dilution of aqueous formic, acetic, propionic, and butyric acids. Free energies and enthalpies of solute-Solute interactions
AU - Harris, Alex
AU - Thompson, Peter T.
AU - Wood, Robert H.
PY - 1980/5
Y1 - 1980/5
N2 - Freezing-point depressions and enthalpies of dilution for aqueous solutions of the straight chain, aliphatic carboxylic acids, C1 through C4, have been measured. These data, together with the corresponding apparent molal heat capacities, have been used to calculate the pairwise free energy and enthalpy of interaction of undissociated acid molecules at 298.150K. As expected, the effect of dimer and triplet interaction increases with chain length, reflecting the hydrophobic nature of the hydrocarbon portion of the molecules. The group-interaction additivity principle of Savage and Wood applied to these results gives an excellent correlation and yields values of the group interaction parameters, Gi,j and Hi,j for the CH2 and COOH groups. These parameters confirm previous results for the interaction of polar and hydrophobic groups in water. The primary data have been fitted to the activity expansion equations of Wood, Lilley, and Thompson to yield values of dimer and trimer "sociation" constants and their temperature derivatives. This procedure allows for the simultaneous treatment of the dissociation effects of these acids as weak electrolytes together with their tendency to form associated clusters.
AB - Freezing-point depressions and enthalpies of dilution for aqueous solutions of the straight chain, aliphatic carboxylic acids, C1 through C4, have been measured. These data, together with the corresponding apparent molal heat capacities, have been used to calculate the pairwise free energy and enthalpy of interaction of undissociated acid molecules at 298.150K. As expected, the effect of dimer and triplet interaction increases with chain length, reflecting the hydrophobic nature of the hydrocarbon portion of the molecules. The group-interaction additivity principle of Savage and Wood applied to these results gives an excellent correlation and yields values of the group interaction parameters, Gi,j and Hi,j for the CH2 and COOH groups. These parameters confirm previous results for the interaction of polar and hydrophobic groups in water. The primary data have been fitted to the activity expansion equations of Wood, Lilley, and Thompson to yield values of dimer and trimer "sociation" constants and their temperature derivatives. This procedure allows for the simultaneous treatment of the dissociation effects of these acids as weak electrolytes together with their tendency to form associated clusters.
KW - activity expansion
KW - carboxylic acids
KW - enthalpies of dilution
KW - Freezing points
KW - group additivity principle
KW - sociation constants
KW - solute-solute interaction
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UR - http://www.scopus.com/inward/citedby.url?scp=0001501636&partnerID=8YFLogxK
U2 - 10.1007/BF00651538
DO - 10.1007/BF00651538
M3 - Article
VL - 9
SP - 305
EP - 324
JO - Journal of Solution Chemistry
JF - Journal of Solution Chemistry
SN - 0095-9782
IS - 5
ER -