Measurement and correlation of the (p,ρ,T) relation of liquid cyclohexane, toluene, and ethanol in the temperature range from 233.15 K to 473.15 K at pressures up to 30 MPa for use as density reference liquids

Density measurements on binary mixtures (nitrogen + carbon dioxide and argon + carbon dioxide) at temperatures from (298.15 to 423.15) K with pressures from (11 to 31) MPa using a single-sinker densimeter

“…It basically consisted of a high-pressure measuring cell, which was installed inside a vacuum-insulated two-stage thermostat, a magnetic-suspension coupling incorporated in the measuring cell, and an analytical balance at the top of the apparatus. Both [29], C 2 H 6 [30], N 2 [28], CH 4 [31], natural gases [8,9,15,32,33] 5.0 mK [9] 0.01% of (40 or 200) MPa [28] 0.1% [9] Chamorro (250 to 400) K [25] Up to 20 MPa [25] 0 to 2000 kg/m 3 [25] CH 4 ÀN 2 [34], CO 2 ÀN 2 [10,35], CH 4 ÀCO 2 [36], COÀN 2 [37] 3.9 mK [25] (0.007 to 0.015)% of 20 MPa [25] (0.020 to 0.155)% [25] Kuramoto (293.15 to 473.15) K [22] Designed up to 20 MPa [22] n/a iso-Octane, n-nonane, n-tridecane, water, 2,4-dichlorotoluene, 3,4-dichlorotoluene, bromobenzene [22] 3.0 mK [22] n/a (6.7 to 11.7) ppm [22] Wagner (235 to 520) K [38] Up to 30 MPa [39] (2 to 2000) kg/m 3 [39] Cyclohexane, toluene, and ethanol [39], n-heptane, n-nonane, 2,4-dichlorotoluene, and bromobenzene [40], Ethylene, ethane, and sulfur hexafluoride [38], Ar and N 2 [41], CH 4 and CO 2 [42] 8.0 mK [39] 0 a The uncertainties listed, are just for information purposes and especially those estimated before 1990 are from a current point of view possibly not reliable because (i) the confidence probability was not provided in the original paper; (ii) there was no general standard to declare the measurement uncertainty at that time; or (iii) no complete analysis on the measurement uncertainty was done for these apparatuses. The...…”

CHAPTER 4. Density Standards and Traceability

“…In a companion work, Sommer et al 18 used the same instrument to measure cyclohexane, toluene, and ethanol over similar ranges of temperature and pressure. Together these fluids cover a density range of 718 to 1494 kg m À3 .…”

“…The purities of these fluids were 98% for bromobenzene; 99% for n-nonane and bromobenzene; 99.3% for n-heptane; and 99.9% for toluene, cyclohexane, and ethanol. Both Schilling et al 17 and Sommer et al 18 compared their densities to literature values and found differences of up to 0.2% in density, indicating that the source and uncertainty of data must be carefully considered. Schilling et al 17 compared their data to the high-accuracy data of Kuramoto et al 16 for the three fluids they measured in common and noted differences of up to 0.068%; this is much more than the mutual uncertainties and was attributed to variations in the samples.…”

“…Schilling et al 17 compared their data to the high-accuracy data of Kuramoto et al 16 for the three fluids they measured in common and noted differences of up to 0.068%; this is much more than the mutual uncertainties and was attributed to variations in the samples. Sommer et al 18 also compared their own density measurements on two different batches of toluene from the same supplier (which were measured as received), together with the toluene data of McLinden and Splett 19 and found differences of up to 0.02%; thus, even for relatively high-purity material, batch-to-batch variations can be significant. This factor is circumvented when using certified density standards, as discussed in Section 4.5.…”

Derived thermodynamic properties for the (ethanol + decane) and (carbon dioxide + ethanol + decane) systems at high pressures

“…The density of ethanol q 1 and decane q 2 were obtained by applying the multiparameter equations used by Sommer et al [13] and Lemmon and Span [14], in that order. As can be observed in figure 2, the excess molar volumes of the binary system are positive and exhibit the maximum values at equimolar composition, dashed lines represent the trends of data sets at 1 MPa.…”