Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

The low-temperature heat capacities, phase transitions and thermodynamic properties of 1,3-dimethyladamantane and 1-ethyladamantane

Varushchenko, R. M., Druzhinina, A. I., Senyavin, V. M., Sarkisova, V.S.
J. Chem. Thermodyn. 2005, 37, 2, 141-151
ABSTRACT
The heat capacity of the crystalline and liquid phases of 1,3-dimethyladamantane (1,3-DMA) and 1-ethyladamantane (1-EA) have been measured by vacuum adiabatic calorimetry over the temperature range (8 to 373) K. 1,3-DMA and 1-EA were found to exist in two and one crystalline phases, respectively. The temperatures, enthalpies and entropies of solid-to-solid transition and fusions have been determined. The ?fusS is less than the gas constant for 1,3-dimethyladamantane, indicates that this compound, as well as 1,3,5-trimethyladamantane (1,3,5-TMA) studied previously, forms a plastic crystalline phase before being fused. The temperature dependencies of the lattice modes were determined with Raman spectroscopy for all three substances. The thermodynamic functions obtained calorimetrically for 1,3-DMA, 1-EA and 1,3,5-TMA were corroborated through adequate accord between the calorimetric and spectroscopically determined entropy.
Compounds
# Formula Name
1 C12H20 1,3-dimethyladamantane
2 C12H20 1-ethyladamantane
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1
  • Crystal 1
  • Liquid
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 1
  • Crystal 1
  • Liquid
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:4
  • 199
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • VADIAC:UFactor:4
  • 17
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 78
  • POMD
  • 1
  • Molar enthalpy, kJ/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 1
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 1
  • POMD
  • 2
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 2
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Gas
  • ADIACA:UFactor:4:FP
  • 1
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • VADIAC:UFactor:4
  • 167
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 109
  • POMD
  • 2
  • Molar enthalpy, kJ/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 1
  • POMD
  • 2
  • Molar entropy, J/K/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • VADIAC:UFactor:4
  • 1