Thermodynamic parameters of phase transitions of perfluoro-N-(4-methylcyclohexyl)piperidine

Abstract

The heat capacity of perfluoro-N-(4-methylcyclohexyl)piperidine (PMCP) was measured by low-temperature adiabatic calorimetry. The purity of the substance (N 1 = 99.66 mol %), triple point temperature (T tp = 293.26 K), and enthalpy of fusion (Δfus H m ° = 8.32 kJ/mol) were determined. The enthalpy of vaporization was measured by calorimetry at 298.15 K (Δvap H m ° (298.15 K) = 56.56 kJ/mol). The temperature dependence of the saturated vapor pressure of PMCP over the pressure range 6.2–101.6 kPa was determined by comparative ebulliometry. The normal boiling point (T n.b. = 460.74 K), ehthalpies of vaporization (at various temperatures), and critical parameters of PMCP were calculated. The calculated and experimental values of Δvap H m ° (298.15 K) agree to within measurement errors, which proves the reliability of these values and pT parameters used in calculations.