The effects of pressure on the density, dielectric constant, and viscosity of several hydrocarbons and other organic liquids

Abstract

The effects of pressures up to 4 kbar on the density, dielectric constant, and viscosity of n-pentane, trl-iexane, n-octane, cyclopentane, methylcyclohexane, and 2,2-dimethylbutane (DMB) were measured at 30 "C. The pressure effects on the viscosities of n-hexane and n-octane were also determined at 0 and 60". The densities of diethyl ether and cyclopentanone and the dielectric constant of carbon tetrachloride at high pressures are a!so recorded. The densities of the hydrocarbons increased by 20-30% and the dielectric constants increased by 11-16 % as the pressure was increased from 1 to 4000 bars at 305, but the viscosities increased by 695-2352 % over the same pressure range. Carbon tetrachloride froze at 1500 bars at 30°, and cyclopentanone froze at 3500 bars at about 20'. In agreement with earlier work on other liquids, the value of the Clausius-Mosotti function (E -1) V/(E f 2) for the present compounds decreased slightly with increasing pressure. The viscosity at a given pressure decreased slightly with increasing temperature, and temperature effect increased with increasing pressure. In general, the slnaller the compressibility of the liquid, the greater was the effect of pressure on the viscosity; DMB was a n exception because its viscosity increased abnormally rapidly with pressure. Molecular structure and liquid structure have greater influences on the pressure dependence of viscosity than on that of density or dielectric constant.

On the behaviour of solutions of xenon in liquid cycloalkanes: Solubility of xenon in cyclopentane

“…[35] and the molar volume calculated from Refs. [36][37][38][39]. The second virial coefficients for pure cyclopentane were taken from Dymond et al [40] and for pure xenon from the compilation of Dymond and Smith [41].…”

Models for viscosity, thermal conductivity, and surface tension of selected pure fluids as implemented in REFPROP v10.0

“…Lennard-Jones parameters were calculated by the method of Chung et al (Chung et al, 1988); values are presented in Table 1. Liquid-phase data from Chavanne and Van Risseghem (Chavanne, 1922), Brazier and Freeman (Brazier, 1969), and Lambert et al (Lambert et al, 1955) were fit to obtain the coefficients in Table 2. Lambert et al (Lambert et al, 1955) give data in the gas phase.…”

“…Deviations with viscosity data as a function of temperature are shown in Figure 13, and as a function of pressure in Figure 14. The data of Brazier and Freeman (Brazier, 1969) extend to 400 MPa, but we limit the use of the correlation to 100 MPa. The estimated uncertainty for the liquid phase at pressures to 100 MPa is 5 %.…”

Correlation and Prediction of Dense Fluid Transport Coefficients. VIII. Mixtures of Alkyl Benzenes with Other Hydrocarbons

“…In Table 1, the experimental measurements [12][13][14][15], T. Makita, Personal communication (1985), [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] used to compute the aforementioned equations for the parameters a i , b i , and C and the experimental temperature ranges and maximum pressures considered are shown. It should be noted that the maximum pressure shown in the table refers to the point above which deviations started to increase considerably, i.e., the correlation is valid up to the maximum pressure quoted in the table.…”