Measurements of Vapor Pressure, Heat Capacity, and Density along the Saturation Line for Cyclopropane Carboxylic Acid, N,N-Diethylethanolamine, 2,3-Dihydrofuran, 5-Hexen-2-one, Perfluorobutanoic Acid, and 2-Phenylpropionaldehyde

This paper reports measurements made for DIPPR Research Project 821 in the 1997 Project Year. Vapor pressures were measured to a pressure limit of 270 kPa or lower decomposition point for all six compounds using a twin ebulliometric apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperatures (ambient to a maximum of 448 K). A differential scanning calorimeter was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. The results of all the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization [within the temperature range (±50 K) of the vapor pressures], solubility parameter, and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. In addition, the liquid-phase densities were compared with values derived using a four-term power series in [(1 − T r ) n /3 ]. All measured and derived values were compared with those obtained in a search of the literature.