Thermodynamic Properties of 1,1,1,2,2,4,5,5,5-Nonafluoro-4-(trifluoromethyl)-3-pentanone: Vapor Pressure, (p, ρ, T) Behavior, and Speed of Sound Measurements, and an Equation of State

Abstract

We report comprehensive thermodynamic property measurements of 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone. The (p, ρ, T) behavior was measured from T = (225 to 470) K with pressures up to 36 MPa with a two-sinker densimeter. These measurements include compressed-liquid states and states in the extended critical region. The vapor-phase speed of sound was measured from T = (325 to 500) K with pressures up to 1.7 MPa with a spherical acoustic resonator. The vapor pressure was measured in the spherical resonator from T = (325 to 440) K with a static technique. The density and speed of sound of the liquid was measured from T = (278 to 308) K at atmospheric pressure (p = 83 kPa) in a benchtop instrument employing a vibrating-U-tube densimeter and a time-of-flight speed-of-sound technique. These data, together with selected data from the fluid manufacturer, have been used to develop an equation of state explicit in the Helmholtz energy covering the fluid region. The equation of state represents the present experimental vapor-pressure data with an RMS deviation of 0.066 %, the (p, ρ, T) data to 0.067 %, and the speed-of-sound data to 0.029 %. This fluid is of interest as the working fluid in Rankine-cycle power applications and as a fire extinguishing agent; it is also known by the trade names Novec-649 and Novec-1230.

Measurement and Correlation of the Viscosity of 1,1,1,2,2,4,5,5,5-Nonafluoro-4-(trifluoromethyl)-3-pentanone

“…The compressed liquid densities for 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone (Novec-649) between (243 to 373) K and at pressures up to 40 MPa were obtained from the correlation proposed by McLinden et al 5 The uncertainty in the equation of state is 0.067 % in density in the liquid phase. The viscosities of compressed liquid Novec-649 were measured at pressures from (0.1 to 40) MPa, along fourteen isotherms from (243 to 373) K, and are listed in Table 2, with a total number of 90 points.…”

“…The combined expanded uncertainty of viscosity with a level of confidence of 0.95 ( k = 2) was better than 2%, considering the uncertainties of temperature, pressure, repeatability of measurement, and the density of the fluid calculated from the equation of state. 5 …”

“…An equation of state for each experimental temperature and pressure was used to calculate the density, ρ . In this work, the equation of state of McLinden et al 5 was used to calculate the density for Novec-649, which was available in the NIST REFPROP database program. 11 The critical parameters for Novec-649 are T c = 441.81 K, P c = 1.869 MPa, and ρ c = 1.92 mol·L −1 5 .…”

“…$${\mu }_{\mathrm{normalr}}=131.3\mu /{(V_{\mathrm{normalc}}{T}_{\mathrm{normalc}})}^{1/2}$$ where μ is the dipole moment, T c is the critical temperature in K. μ was estimated from B3LYP/aug-cc-pVTZ calculations using Gaussian 09, 14 ω was obtained from the NIST REFPROP database program, 11 where it was calculated from its definition using the equation of state of McLinden et al 5 Values are given in Table 3. With all the parameters known, eqs 2 to 7 can be used to calculate η 0 ( T ).…”

“…We estimated that the uncertainty of the correlation in the liquid phase over the temperature range 240 K to 400 K at pressures up to 40 MPa was the same as the experimental data it was based upon, namely 2%. The correlation may be used in an extrapolation mode over the full range of the equation of state of McLinden et al, 5 from (165 to 500) K at pressures up to 50 MPa, although the uncertainty may be greater than 2%. The smooth behavior of the correlation when extrapolated is demonstrated in Figure 6, which shows the viscosity of Novec-649 as a function of temperature at different pressures, with the temperature range from (200 to 1000) K and at pressures up to 50 MPa.…”