Upper critical solution temperatures of hydrocarbon + fluorocarbon mixtures : mixtures with specific interactions

1980 ◽  
Vol 33 (3) ◽  
pp. 465 ◽  
Author(s):  
LS Toczylkin ◽  
CL Young

The upper critical solution temperatures of a series of compounds with perfluorotributylamine and with perfluorocyclohexene are reported. From these results the interaction energy parameter, ξ, has been calculated by using a hard sphere+attractive term equation of state, together with the one-fluid model. The values of ξ for these mixtures and a few calculated from literature upper critical solution temperatures have been discussed in terms of possible specific interactions between pairs of unlike molecules.

1977 ◽  
Vol 30 (2) ◽  
pp. 401 ◽  
Author(s):  
GJ Campbell ◽  
RL Hurle ◽  
SP Lie ◽  
CL Young

The gas-liquid critical temperatures, Tcm, of some mixtures of the electron donors, triethylamine, diethyl ether and diisopropyl ether with n-alkanes, benzene and hexafluorobenzene are reported. By using the van der Waals one-fluid model, an interaction energy parameter, ξ, has been calculated for each mixture from the values of T°m. The values of ξ for the n-alkane+electron donors are fairly close to unity, indicating that, as would be expected, there are no strong specific interactions between the unlike molecules. The values of ( for the electron donors with benzene give no definite indication of specific interactions. On the other hand, values of ξ for the electron donors with hexafluorobenzene indicate a specific interaction between the unlike molecules. These conclusions are discussed in relation to those reached from a consideration of other thermodynamic data.


1978 ◽  
Vol 31 (5) ◽  
pp. 957 ◽  
Author(s):  
SD Waterson ◽  
CL Young

The gas-liquid critical temperatures of 16 binary mixtures containing an organosilicon compound have been measured by the sealed-tube method, together with the gas-liquid critical temperature and pressure of tetramethoxysilane, tetraethoxysilane and tetrapropoxysilane.��� The results for the mixtures have been used to calculate a parameter characterizing the interactions between unlike molecules. An iterative solution to the criticality condition was used together with the one-fluid model and a 'hard sphere+attractive term' equation of state. ��� The interaction parameters are discussed briefly. The one-fluid model in the form used here, at least, appears to be unsatisfactory for predicting the composition dependence of the gas-liquid critical temperatures within 5 K for mixtures of molecules of widely differing sizes (i.e. size ratios as estimated from molar volumes of greater than 1 : 4).


1984 ◽  
Vol 37 (1) ◽  
pp. 29
Author(s):  
BN Missen ◽  
CL Young

Measurements are reported of the slope of the critical locus of binary mixtures of a series of hydrocarbons, and two fluorocarbons, with hydrogen near the critical point of the hydrocarbon (or fluorocarbon).These systems exhibit gas-gas immiscibility of the first kind. The results are compared with predictions from the one-fluid model together with 'a hard sphere + attractive term' equation of state proposed by Guggenheim. The results can be predicted from the theory provided the energy interaction parameter, ξ, is allowed to be somewhat less than that calculated from the Hudson and McCoubrey rule. This is discussed in terms of values of ξ from other measurements, and possible deficiencies in the theory.


2015 ◽  
Vol 29 (13) ◽  
pp. 1550089 ◽  
Author(s):  
Minhui Shan ◽  
Jianxiang Tian

As is well-known, the structures and thermodynamic properties of fluids are determined by the complex interactions, i.e., the repulsive one and the attractive one, among particles. The simplest equation-of-state (EOS) model maybe the one of hard sphere repulsion plus or multiplying some attraction. Followed by the rapid promotion of the accuracy of hard sphere EOS in the past dozens of years, one question rises as whether more accurate hard sphere repulsion derives better prediction of the structures and properties of fluids with a special attraction. In this work, we used two repulsions with clearly different accuracy and some attractions to construct series equations of state (EOSs) for real fluids, and then we discussed the saturated properties at liquid–gas equilibrium. We found that the answer to the question aforementioned is not definitely standing.


1973 ◽  
Vol 26 (10) ◽  
pp. 2071 ◽  
Author(s):  
DK Astin ◽  
ID Watson

The excess thermodynamic functions of 12 mixtures, each representative of a certain type of system, have been calculated by means of the van der Waals, Frisch,1 and Carnahan and Starling2 equation of state, in conjunction with one-fluid and two-fluid models of conformal mixtures. In addition, the equation of state of hard sphere mixtures of Mansoori et al.3 has been used. Though none of the approaches give quantitative agreement for any of the systems considered, they all give a qualitative account which broadly reflect the trends in behaviour. In the cases where it is appropriate to comment on the qualitative accuracy the two-fluid model, used with either the Frisch or Carnahan and Starling equation of state, shows a slight superiority to the others.


1977 ◽  
Vol 30 (4) ◽  
pp. 767 ◽  
Author(s):  
LS Toczylkin ◽  
CL Young

The upper critical solution temperatures, UCST , of acetone + alkane (n- C5H12 to n-C17H36) and acetone + hexane isomers have been measured. These results are used to calculate an interaction parameter ξ by using the van der Waals one-fluid model together with the Guggenheim equation of state. Values of ξ are compared with those obtained from the gas-liquid critical temperatures. The gas-liquid critical temperatures for the n- alkane + acetone systems were taken from the literature whereas those for the hexane isomers + acetone were measured in this work. The values of ξ calculated from gas-liquid critical temperatures are slightly greater than those calculated from the UCST as has been observed previously for other systems.


1980 ◽  
Vol 33 (9) ◽  
pp. 1987 ◽  
Author(s):  
SD Waterson ◽  
J Semmens ◽  
CL Young

Upper critical solution temperatures of perfluorohexane+alkanes (C5 to C18), sulfur hexafluoride+siloxanes (Si2 to Si8) and perfluoropropane+siloxanes (Si2 to Si8) mixtures are reported. In each of the three groups of mixtures the phase behaviour type changes from type II to type III (in terms of the Scott classification). The interaction parameters, ξ, calculated by using the one-fluid model change more or less smoothly with increasing chain length of the siloxane (or alkane) even when the phase behaviour type changes.


1977 ◽  
Vol 30 (10) ◽  
pp. 2103 ◽  
Author(s):  
KN Marsh ◽  
CL Young

The gas-liquid critical temperatures, Tcm of cycloalkane + n-alkane and cycloalkane + branched alkane mixtures are reported. The interaction energy parameter, ξ(expressing the deviation from the Berthelot combining rule), has been calculated for each mixture from the values of Tcm using the van der Waals one-fluid model. The values of ξ are within 0.5% of unity.


Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 469 ◽  
Author(s):  
Mariano López de Haro ◽  
Andrés Santos ◽  
Santos B. Yuste

New proposals for the equation of state of four- and five-dimensional hard-hypersphere mixtures in terms of the equation of state of the corresponding monocomponent hard-hypersphere fluid are introduced. Such proposals (which are constructed in such a way so as to yield the exact third virial coefficient) extend, on the one hand, recent similar formulations for hard-disk and (three-dimensional) hard-sphere mixtures and, on the other hand, two of our previous proposals also linking the mixture equation of state and the one of the monocomponent fluid but unable to reproduce the exact third virial coefficient. The old and new proposals are tested by comparison with published molecular dynamics and Monte Carlo simulation results and their relative merit is evaluated.


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