Abstract
2-Hexyne is a potential sulfur-free odorant for liquefied petroleum gas (LPG). In this study, saturated vapor pressure of 2-hexyne at 273.14-313.14 K, and bubble point pressure for three binaries, ethane–2-hexyne, propane–2-hexyne and butane–2-hexyne were measured using a static apparatus at 273.15, 303.15 and 313.15 K. The attractive parameter in the Peng–Robinson (PR) equation of state was re-determined for 2-hexyne using the saturated vapor pressure data. The attractive parameters and the excluded volumes in the PR equation were also re-determined for ethane, propane and butane using the saturated vapor pressure and liquid density data. The binary parameters were evaluated by fitting the bubble point pressure data for the three binaries. Quaternary vapor-liquid equilibrium was estimated for 45.00 kg of LPG, with the mass ratio of ethane : propane : butane = 0.6000 : 97.07 : 1.700 containing 50.00 ppm of 2-hexyne, in a household LPG cylinder with inner volume of 117.50 L. The mole fraction of 2-hexyne was evaluated as 3.939 × 10–9 in the vapor phase at 273.15 K, and increased by 2.49 times and 3.40 times at 303.15 K and 313.15 K, respectively.
