The low-temperature heat capacity and thermodynamic functions of propyl tert-butyl ethers

The heat capacities of n-propyl tert-butyl and isopropyl tert-butyl ethers were measured in the temperature range 10-353 K by adiabatic calorimetry. S olid phases of both compounds were found to contain metastable and stable p olymorphs. Solid n-propyl tert-butyl ether also contained a vitreous compon ent. The temperatures and enthalpies of fusion of the ethers were determine d. The S-m(o) (T) - S-m(o) (0), H-m(o) (T) - H-m(o) (0), and G(m)(o) (T) - H-m(o) (0) molar thermodynamic functions and the entropies of formation of the substances in the ideal gas state at 298.15 K were calculated.