Collect. Czech. Chem. Commun. 1982, 47, 2692-2701

Heat capacities of monomer models of some hydrophilic polymers in an aqueous solution from 20° to 60 °C

Ján Biroš, Antonín Sikora, Antonín Živný and Julius Pouchlý

Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6


The apparent molar heat capacities of propionic and isobutyric acids and of 2-hydroxyethyl pivalate and 2-(2'-hydroxyethoxy)ethyl pivalate in a dilute aqueous solution were determined with a DASM-1 m calorimeter. Moreover, the apparent specific volumes of these compounds in the aqueous solution and their molar heat capacities in the bulk liquid state were also determined. In the range 20° - 60 °C the apparent heat capacity in the aqueous solution is temperature-independent, or (in the case of propionic acid) increases slightly with temperature. The apparent heat capacities measured at 25 °C were compared with values estimated using various reported additivity schemes. Good agreement was observed for both acids; the other two compounds with more complicated molecules showed significant deviations from additivity.