Eight Constants in the Benedict-Webb-Rubin Equation of State for 1-Pentyne and Their Validity for Bubble Point Pressure with Propane or Dimethyl Ether

Saturated vapor pressure was measured for pentane and 1-pentyne using a static apparatus at temperatures in the range 273.15 to 463.58 K. The P-V-T relationship was measured for 1-pentyne by a constant volume method up to 4.0919 MPa at 485.00 K, where the inner volume of the cell was calibrated with the mass and pressure of gaseous pentane at the same temperature. Bubble point pressures were also investigated for two binaries, propane or dimethyl ether with 1-pentyne, using the static apparatus at 303.15 K and 313.15 K. The eight constants of the Benedict-Webb-Rubin (BWR) equation of state were determined for 1-pentyne by assuming functions where the critical pressure and the acentric factor depend on the critical temperature. The average relative deviations for saturated vapor pressure and P-V-T relationship were -5.813 % and 3.321 %, respectively. Using mixing rules with a binary parameter in the BWR equation, the average relative deviation was 0.231 % for the bubble point pressures of the two binaries.