Ideal-gas enthalpies of formation of methyl benzoate, ethyl benzoate, (R)-(+)-limonene, tert-amyl methyl
ether, trans-crotonaldehyde, and diethylene glycol are reported. The standard energy of combustion and
hence standard enthalpy of formation of each compound in the liquid phase has been measured using an
oxygen rotating-bomb calorimeter without rotation. Vapor pressures were measured to a pressure limit
of 270 kPa or the lower decomposition point for each of the six compounds using a twin ebulliometric
apparatus. Liquid-phase densities along the saturation line were measured for each compound over a
range of temperature (ambient to a maximum of 548 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. For methyl benzoate and tert-amyl methyl ether,
critical temperatures and critical densities were determined from the DSC results and corresponding
critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical
temperatures, critical pressures, and critical densities for each of the remaining compounds. The results
of the measurements were combined to derive a series of thermophysical properties including critical
temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to
within ±50 K of the temperature region of the experimentally determined vapor pressures), and heat
capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each
compound. All measured and derived values were compared with those obtained in a search of the
literature. Recommended critical parameters are listed for each of the compounds studied. Group-additivity
parameters, useful in the application of the Benson gas-phase group-contribution correlations, were
derived.