Excess enthalpies for (water + ethanol) atT= 398 K toT= 548 K andp= 15 MPa

Standards in isothermal microcalorimetry (IUPAC Technical Report)

“…Taking this into account singles out (ethanol + water) as the best test system. Accurate data are available, over a wide range of temperatures (298 to 548 K) and pressures (0.4 to 15 MPa) [14,[24][25][26][27]. The values of ∆ mix H vary from exothermic at 298 K to endothermic at temperatures above 333 K. Enthalpies are strongly dependent on the concentrations and therefore provide an excellent test for mixing efficiency (cf.…”

Molar enthalpy increments for (0.5 H2O+0.5C2H5OH) at temperatures up to 573.2 K and pressures up to 11.3 MPa

“…(15) A flow mixing calorimeter for the measurement of excess enthalpies in the liquid phase at high temperatures and pressures has also been constructed. (16) It has been used to make measurements on The phase diagram for (water + ethanol) has been determined by Griswold et al (17) who measured both the critical temperature and the critical pressure over a range of compositions, and measured seven (vapour + liquid) equilibrium loops in the temperature range 423.2 K to 623.2 K. The phase diagram for the mixture is shown in figure 1a, and (vapour + liquid) equilibrium loops over the temperature range relevant to this work are shown in figure 1b. At T = 523 K and lower temperatures the pressure-composition isotherms show the presence of an azeotrope, but at T = 548 K and higher temperatures no azeotrope is formed.…”

“…Ott et al (1) used a flow mixing calorimeter firstly to measure H E m for this mixture at the temperature 298.15 K and at the pressures (0.4, 5.0, 10.0, and 15.0) MPa, and secondly (2) at the temperatures 398.15 K, 423.15 K, 448.15 K, and 473.15 K at pressures of (5.0 and 15.0) MPa. Wormald et al (3) used a differential flow mixing calorimeter to measure H E m at temperatures in the range T = 398.2 K to 548.2 K at the pressure 15 MPa. Both sets of measurements were made over a wide range of compositions.…”

Molar enthalpy increments for (0.5 H2O + 0.5 CH3OH) at temperatures up to 573.2 K and pressures up to 13.0 MPa

“…A further check on the measurements can be made in the liquid region at the temperatures T = (423.2 and 473.2) K. Liquid phase excess enthalpies have been measured at p = 7 MPa by Simonson et al (17) who made three H E m measurements at T = 423.2 K and nine measurements at T = 473.2 K. Wormald et al (12) figure 2. The agreement between the liquid phase enthalpy increments obtained by combining the H E m measurements with the mean of the pure component enthalpies, and the enthalpy increments measured using the countercurrent heat exchange calorimeter, is therefore better than 1 per cent, as it was for the ideal gas values shown in figure 5.…”

“…(11) Another flow mixing calorimeter for the measurement of excess enthalpies in the liquid phase at high temperatures and pressures has also been constructed. (12) It has been used to make measurements on (14,15) have made high pressure volumetric measurements over the range T = (278 to 323) K at pressures up to 280 MPa from which they derived excess volumes and calculated excess enthalpies. Busey et al (16) have constructed a high pressure flow mixing cell which they mounted in a Calvet microcalorimeter.…”