Thermodynamics of alkali alkanoates IX. Heat capacity and thermodynamic functions of lithium 2-methylpropanoate at temperatures from 7 K to 535 K

Abstract

The heat capacity of lithium 2-methylpropanoate was measured by equilibrium adiabatic calorimetry at temperatures, T from 7 K up to 350 K and by d.s.c. from 330 K through melting to 535 K. A small diffuse hump was observed in the range T = 125 K to 250 K. A solid-to-solid (intercrystalline) transition was observed at T = 445 K, and melting to the isotropic liquid occurred at 510 K. The enthalpies [Delta]trsHom and entropies [Delta]trsSom of transition were calculated to be 903R[middle dot]K and 2.03R for the solid-to-solid transformation (assumed to be first order) and 1045R[middle dot]K and 2.05R for melting.