US EPA

7955403 

Journal Article 

THERMODYNAMIC PROPERTIES OF CYCLOHEXANE-D12 - LOW-TEMPERATURE HEAT-CAPACITY AND ENTHALPIES OF TRANSITION AND FUSION FROM ACCURATE DIFFERENTIAL SCANNING CALORIMETRY, AND THE ENTROPY FROM SPECTROSCOPIC RESULTS 

Mraw, SC; Naasorourke, C 

1980 

1 

Journal of Chemical Thermodynamics
ISSN: 0021-9614 

12 

7 

691-704 

English 

10.1016/0021-9614(80)90091-9 

WOS:A1980JY61300011 

The heat capacity of cyclohexane-d1 2 was measured from 120 to 325 K by the technique of accurate differential scanning calorimetry. A parallel series of measurements on cyclohexane-h1 2 was found to be accurate to approximately ±2 per cent from 120 to 200 K and to ±1 per cent from 200 to 325 K by comparison with accepted literature values. The enthalpy of the solid-to-solid phase transition in cyclohexane-d1 2 was found to be (6810±100) J mol-1 at (186.0±0.5) K and that of fusion to be (2620±80) J mol-1 at (277.2±0.5) K. The entropy of ideal gaseous cyclohexane-d1 2 at 298.15 K was calculated from spectroscopic results to be (322.1±2.8) J K-1 mol-1. This value was used with the results of the present work and literature data on the enthalpies of vaporization and combustion to tabulate complete thermodynamic properties of cyclohexane-d1 2 from 120 to 323.15 K, including the standard enthalpies and standard Gibbs free energies of formation in both the liquid and ideal-gaseous states at 298.15 K. These latter values are: liquid, ΔHfo(298.15 K) = -(221.5±4.8) kJ mol-1, ΔGfo(298.15 K) = -(20.1±6.2) kJ mol-1; ideal gas, ΔHfo(298.15 K) = -(188.6±5.0) kJ mol-1, ΔGfo(298.15 K) = -(15.3±6.3) kJ mol-1. 1980.