Low-temperature calorimetric and vapor-pressure studies on alkanediamines

Abstract

Low-temperature calorimetric measurements were obtained on the condensed phases three alkanediamines, ethylenediamine, (dl)-1,2-propanediamine, and 2-methyl-1,2-propanediamine, as a basis for deriving their heat capacities, C s, entropies, S s, thermodynamic functions, − “G s (T) − H o (0)’ T , “H s (T) − H o (0)’ T , and H s( T) − H o(0), and the enthalpies, entropies, and temperatures of phase transitions. Vapor-pressure measurements were carried out on the above alkanediamines and (dl)-1,2-butanediamine as a means for transforming the condensed-state thermodynamic properties to the perfectgas state at 1 atm. Standard values at 298.15 K were calculated for the enthalpy, Gibbs energy, and equilibrium constant of formation.