Calorimetric investigations of the self-association of aliphatic carboxylic acids in organic solvents
A calorimetric enthalpy of dilution technique was applied to the investigation of carboxylic acid self-association in organic solvents at 25°C. Data were analyzed in terms of the apparent relative molar enthalpy, Φ_L, and were found to fit adequately a monomer-dimer model. Values of the thermodynamic dimerization parameters K_2 and ΔH°_2 were obtained for several methyl-, halo-, and phenyl-substituted acetic and propionic acids in benzene. Some of the acids were also studied in toluene and carbon tetrachloride. Substituent effects on K_2 and ΔH°_2 were in general small and were explained adequately by an electrostatic model of the monomer-dimer interaction. Solvent effects were explained by considering an acid-solvent interaction. The effect on the results of small amounts of water in the solvent was found to be a function of aqueous acid strength. Acetic acid and other weak acids were unaffected by water in the solvent, but a significant affect was observed with stronger acids, such as the haloacetic acids.
College and Department
Chemistry and Biochemistry
BYU ScholarsArchive Citation
Zaugg, Noel S., "Calorimetric investigations of the self-association of aliphatic carboxylic acids in organic solvents" (1975). Theses and Dissertations. 8505.
Carboxylic acids, Aliphatic compounds