Thermodynamic Properties of Liquid Toluene from Speed-of-Sound Measurements at Temperatures from 283.15 K to 473.15 K and at Pressures up to 390 MPa

Abstract

We report the speeds of sound in liquid toluene (methylbenzene) measured using double-path pulseecho apparatus independently at The University of Western Australia (UWA) and Imperial College London (ICL). The UWA data were measured at temperatures between (306 and 423) K and at pressures up to 65 MPa with standard uncertainties of between (0.02 and 0.04) %. At ICL, measurements were made at temperatures between (283.15 and 473.15) K and at pressures up to 390 MPa with standard uncertainty of 0.06 %. By means of thermodynamic integration, the measured sound-speed data were combined with initial density and isobaric heat capacity values obtained from extrapolated experimental data to derive a comprehensive set of thermodynamic properties of liquid toluene over the full measurement range. Extensive uncertainty analysis was performed by studying the response of derived properties to constant and dynamic perturbations of the sound-speed surface, as well as the initial density and heat capacity values. The relative expanded uncertainties at 95 % confidence of derived density, isobaric heat capacity, isobaric expansivity, isochoric heat capacity, isothermal compressibility, isentropic compressibility, thermal pressure coefficient and internal pressure were estimated to be (0.2, 2.2, 1.0, 2.6, 0.6, 0.2, 1.0 and 2.7) %, respectively. Due to their low uncertainty, these data and derived properties should be well-suited for developing a new and improved fundamental Helmholtz equation of state for toluene.

Thermodynamic Properties of Liquid Toluene and n-Butane Determined from Speed of Sound Data

“…, this work ( , estimated uncertainty range); , Shchamialiou et al [7]; and , Dhakal et al [8]. Experimental data: , Akhundov and Abdullaev [22]; , Glen and Johns [32]; , Ihmels and Gmehling [35]; , Masui [34]; , McGregor [39]; , McLinden and Splett [5]; , Shchamialiou et al [7]; , Segovia et al [27]; , Sommer et al [31]; and , Tay and Trusler [30] Except for the data of McLinden and Splett [5] and Sommer et al [31], no other data set agrees with our derived densities completely within their uncertainty.…”

“…, this work ( , estimated uncertainty range); , Muringer et al [40]; , Shchamialiou et al [7]; and , Dhakal et al [8]. Experimental data: , Akhundov and Abdullaev [22]; , Avelino et al [23]; , Chylinski and Gregorowicz [38]; , Comuñas et al [36]; , Glen and Johns [32]; , Ihmels and Gmehling [35]; , Magee and Bruno [37]; , Masui [34]; , McLinden and Splett [5]; , Shchamialiou et al [7]; , Sommer et al [31]; , Tay and Trusler [30]; , Valencia et al [28]; , Watson et al [26]; , Zéberg-Mikkelsen and Andersen [33]; and , Zéberg-Mikkelsen et al [24] magnetic suspension coupling with a relative uncertainty of 0.015 %.…”

“…The grey-shaded region denotes the region of thermodynamic integration. The dashed lines encircle the regions of thermodynamic integration of other authors: (red), Muringer et al [40]; (blue), Shchamialiou et al [7]; and (green), Dhakal et al [8]. Experimental data: , Akhundov and Abdullaev [22]; , Avelino et al [23]; , Chylinski and Gregorowicz [38]; , Comuñas et al [36]; , Glen and Johns [32]; , Ihmels and Gmehling [35]; , Magee and Bruno [37]; , Masui [34]; , McGregor [39]; , McLinden and Splett [5]; , Morávková et al [25]; , Segovia et al [27]; , Shchamialiou et al [7]; , Sommer et al [31]; , Tay and Trusler [30]; , Valencia et al [28]; , Watson et al [26]; , Zéberg-Mikkelsen and Andersen [33]; and , Zéberg-Mikkelsen et al [24].…”

“…7 Relative uncertainties in derived densities and isobaric heat capacities of n-butane as a function of pressure for all calculated isotherms Table 3 Derived values for the density , the isobaric heat capacity c p , and the isochoric heat capacity c v of n-butane determined by thermodynamic integration as a function of temperature T and pressure p [31], Glen and Johns [32], Zéberg-Mikkelsen and Andersen [33], Masui [34], Ihmels and Gmehling [35], Comuñas et al [36], Magee and Bruno [37], Chyliński and Gregorowicz [38], and McGregor [39]. Besides these experimental data sets, Muringer et al [40] and Dhakal et al [8] obtained densities from speed of sound measurements by the method of thermodynamic integration in large parts of the liquid region. Shchamialiou et al [7] applied a method of thermodynamic integration, which can be viewed as inverse to our method, to derive speeds of sound, isobaric and isochoric heat capacities and further properties from experimental density data.…”

“…Shchamialiou et al [7] measured the speed of sound between 298.15 K and 433.15 K with pressures up to 100 MPa and a relative uncertainty of 0.05 %. In the work of Dhakal et al [8], two data sets are reported. One was measured at the University of Western Australia in the temperature range from 306 K to 423 K at pressures up to 65 MPa with a relative uncertainty of 0.04 % to 0.08 %.…”