Vapor pressures and boiling points of mono- and dimethylanilines and mono- and diethylanilines

Benchmark Thermochemistry of N-Methylaniline

“…For this reason our own data and the original published experimental p–T results were fitted in this work using eq , and Δ l g H m (298.15 K) values were derived with eq (see Table ) for comparison. To our surprise, experimental vaporization enthalpies available from the literature ,,, spread from 52.2 to 58.6 kJ·mol –1 (see Table ). The lowest value of vaporization enthalpy, 52.2 kJ·mol –1 as determined from solution calorimetry data, is based on the vague assumption that solvation enthalpies of aniline, N -methylaniline, and N , N -dimethylaniline in carbon tetrachloride are equal.…”

“…Vapor pressures of N -methylaniline have been measured in this work by transpiration (see Table ) in the temperature range 284.3–320.3 K. Two other experimental data sets available in the literature , were measured by the static method at significantly higher temperatures that were close to the normal boiling point (see Table ). Our new vapor pressures at different temperatures are generally consistent with the data available from the static method (see Figure ), except for the three lowest points reported by Nelson and Wales . Provided that only these three points were omitted, we fitted remaining data in eq to obtain the following approximation: ln false( p / p 0 false) = 301.72 R − 80026.70 R · false( T , normalK false) − 78.4 R ln true( T , normalK 298.15 normalK true) Equation is valid in the broad temperature range 284–473 K. We recommend eq for interpolation of vapor pressures of N -methylaniline for thermochemical calculations.…”

“…The lowest value of vaporization enthalpy, 52.2 kJ·mol –1 as determined from solution calorimetry data, is based on the vague assumption that solvation enthalpies of aniline, N -methylaniline, and N , N -dimethylaniline in carbon tetrachloride are equal. There are also two estimates of Δ l g H m (298.15 K) of N -methylaniline available in the literature. , The value Δ l g H m (298.15 K) = 53.1 kJ·mol –1 (broadly used in the literature earlier) was estimated by simple approximation of experimental vapor pressures from the static method using the Clausius–Clapeyron equation. But it should be pointed out that we have revealed some inconsistency of the lower data points of this data set in chapter .…”

“…8 (see Table 6) for comparison. To our surprise, experimental vaporization enthalpies available from the literature 35,36,38,39 spread from 52.2 to 58.6 kJ⋅mol -1 (see Table 6). The lowest value of vaporization enthalpy 52.…”

“…Our new vapor pressures at different temperatures are generally consistent with the data available from the static method (see Figure 5), except for three lowest points reported by Nelson and Wales. 35 Provided that, only these three points were omitted, we fitted remaining data by eq 6 in order to obtain the following approximation:…”