Thermal conductivities are reported for a series of 1-alkyl-3-methylimidazolium hexafluorophosphates having butyl, hexyl, and octyl groups, which are expressed by [bmim][PF6], [hmim][PF6], and [omim][PF6], respectively. The experimental method used was a transient short-hot-wire method. Since only a small amount of sample liquid is required, this method was found to be effective for the thermal-conductivity measurements of ionic liquids (ILs). The experimental temperatures ranged from 294 to 335 K at pressures up to 20 MPa. The values of the thermal conductivities of ILs at normal pressure are similar to those of benzene. It was found that an effect of the length of the alkyl chain on the thermal conductivities in ILs is negligible. From the data for the thermal conductivity and viscosity at 293.15 K and 0.1 MPa of ILs and normal alkanes, a simple correlation was developed based on the Mohanty theory. From comparisons between the thermal conductivities of ILs and those of organic liquids (n-hexane, benzene, and methanol), the temperature and pressure dependences of the thermal conductivity of ILs are relatively weak.

Thermal Conductivities of [bmim][PF 6 ], [hmim][PF 6 ], and [omim][PF 6 ] from 294 to 335 K at Pressures up to 20 MPa

Mutual diffusion coefficients of all 20 binary liquid mixtures that can be formed out of methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride without a miscibility gap are studied at ambient conditions of temperature and pressure in the entire composition range. The considered mixtures show a varying mixing behavior from almost ideal to strongly non-ideal. Predictive molecular dynamics simulations employing the Green-Kubo formalism are carried out. Radial distribution functions are analyzed to gain an understanding of the liquid structure influencing the diffusion processes. It is shown that cluster formation in mixtures containing one alcoholic component has a significant impact on the diffusion process. The estimation of the thermodynamic factor from experimental vapor-liquid equilibrium data is investigated, considering three excess Gibbs energy models, i.e., Wilson, NRTL, and UNIQUAC. It is found that the Wilson model yields the thermodynamic factor that best suits the simulation results for the prediction of the Fick diffusion coefficient. Four semi-empirical methods for the prediction of the self-diffusion coefficients and nine predictive equations for the Fick diffusion coefficient are assessed and it is found that methods based on local composition models are more reliable. Finally, the shear viscosity and thermal conductivity are predicted and in most cases favorably compared with experimental literature values.

Mutual diffusion of binary liquid mixtures containing methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride

A new group contribution method for estimating the heat capacity of pure organic liquids, as a function of temperature in the range from the melting temperature to the normal boiling temperature, w...

Estimation of the Heat Capacity of Organic Liquids as a Function of Temperature by a Three-Level Group Contribution Method

Atomic versus molecular description of transport properties in polyatomic fluids: n-butane as an illustration

The density and viscosity of $$n$$
 -heptane have been simultaneously measured over the temperature range from 298 K to 470 K and at pressures up to 245 MPa using the hydrostatic weighing and falling-body techniques, respectively. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95 % confidence level with a coverage factor of $$k= 2$$
 is estimated to be 0.15 % to 0.30 %, 0.05 %, 0.02 K, and 1.5 % to 2.0 % (depending on temperature and pressure ranges), respectively. The measured densities were used to develop a Tait-type equation of state for liquid $$n$$
 -heptane. Theoretically based Arrhenius–Andrade and Vogel–Tamman–Fulcher type equations with pressure-dependent coefficients were used to describe the temperature and pressure dependences of the measured viscosities for liquid $$n$$
 -heptane. The measured values of the density and viscosity were compared in detail with reported data and with the values calculated from a reference EOS and correlation models for the viscosity.

Experimental Study of the Density and Viscosity of $$n$$ -Heptane at Temperatures from 298 K to 470 K and Pressure upto 245 MPa

The thermal conductivities of ten pure liquid alcohols and four of their binary mixtures were measured by use of the relative horizontal parallel-plate method (steady-state type) under atmospheric pressures Measurements for pure alcohols were carried out at temperatures from 20 to 70°C and for binary mixtures at 250 and 500°C A previous correlation model developed for the thermal conductivities of nonpolar liquids on the basis of the lattice model coupled with the hole theory concept has been successfully extended to polar liquids such as alcohols by the introduction of a new empirical parameter to represent the polar effect Reduced values of the potential parameters and the empirical parameter, needed in the calculation of thermal conductivities, could be correlated by quadratic functions of Pitzer''s acentric factor and Stiel''s polar factor The present model is also extended to alcohol mixtures by use of binary interaction parameters

Thermal conductivities of liquid alcohols and their binary mixtures

Thermal Conductivities of Liquid Hydrocarbons and Their Binary Mixtures

Resultats de mesures a 25 et 40 o C des conductivites thermiques de 4 melanges binaires d'alcool et d'hydrocarbure: toluene-ethanol, n-heptane-1-heptanol-benzene-2 butanol et toluene-1-heptanol. Proposition d'une methode de correlation generalisee pour le calcul des conductivites thermiques de liquides polaires et non polaire

Thermal conductivities of liquids and their mixtures for hydrocarbons and alcohols

http://www.jstage.jst.go.jp/article/jcej1968/14/2/14_2_156/_pdf

Kojiro Ogiwara

Papers

Thermal conductivities of liquid alcohols and their binary mixtures

Thermal Conductivities of Liquid Hydrocarbons and Their Binary Mixtures

Thermal conductivities of liquids and their mixtures for hydrocarbons and alcohols

Correlation of the constant-volume heat capacity of liquid organic compounds by the group contribution method