Thermodynamic properties of 1-aminoadamantane

The heat capacity of crystalline 1-aminoadamantane over the temperature range from (5 to 370) K, the temperatures and the enthalpies of its solid-to-solid phase transitions, Ttrs,1 = (241.4 ± 0.2) K and Δtrs,1Hm∘=(1716±10)J·mol-1; Ttrs,2 = (284.6 ± 0.1) K and Δtrs,2Hm∘=(5309±5)J·mol-1, were obtained by the adiabatic calorimetry. The thermodynamic functions of the compound in the crystalline state were derived. The saturated vapour pressure and the sublimation enthalpy {ΔsubHm∘(298.15K)=(61.65±0.63)kJ·mol-1} were determined from the results of the measurements by the effusion Knudsen method and by the transpiration method. The enthalpy of combustion and the enthalpy of formation for crystalline 1-aminoadamantane were measured in a static-bomb isoperibol combustion calorimeter: ΔcHm∘(cr,298.15K)=(-6169.2±1.9)kJ·mol-1andΔfHm∘(cr,298.15K)=(-195.4±2.3)kJ·mol-1. The thermodynamic properties in the ideal gaseous state were calculated by the statistical thermodynamics method. The molecular and spectral data for 1-aminoadamantane were obtained from quantum-chemical calculations (B3LYP/6-31+G∗) and from Raman and i.r. spectroscopic studies.