Excess Enthalpies of Liquid α,ω-Dichloroalkane + n-Hexane Mixtures. A Group Contribution Study of the Cl  Cl Proximity Effect

1980 ◽  
Vol 84 (6) ◽  
pp. 525-529 ◽  
Author(s):  
Carmelo Polo ◽  
Celso Gutierrez-Losa ◽  
Mohammad-Reza Kechavarz ◽  
Henry V. Kehiaian
Keyword(s):  
Proximity Effect ◽  
Group Contribution ◽  
Excess Enthalpies

Measurements and analysis of the excess enthalpies of some dichloroalkane + 2-ketone systems using UNIFAC group-contribution model

1994 ◽  
Vol 72 (2) ◽  
pp. 304-307 ◽  
Author(s):  
Consolación P. Menaut ◽  
José M. Pico ◽  
Josefa Fernández ◽  
José L. Legido ◽  
M. Inmaculada Paz Andrade
Keyword(s):  
Binary Mixtures ◽  
Proximity Effect ◽  
Atmospheric Pressure ◽  
Group Contribution ◽  
Experimental Results ◽  
Excess Enthalpies ◽  
Calvet Microcalorimeter ◽  
Group Contribution Model ◽  
Normal Atmospheric Pressure ◽  
Unifac Group Contribution Model

Experimental excess molar enthalpies hE at 298.15 K and normal atmospheric pressure were obtained for the binary mixtures 1,2-dichloropropane + (2-propanone, 2-butanone, or 2-pentanone), 1,3-dichloropropane + (2-butanone or 2-pentanone), 1,4-dichlorobutane + (2-butanone or 2-pentanone) using a Calvet microcalorimeter. The hE values for all the mixtures were negative. The experimental results used to test the capability of the interaction parameters of two versions of the UNIFAC group-contribution model to predict the proximity effect in these kind of mixtures.

Heats of mixing of the ternary systems 1-propanol-n-alkane-cyclohexane

1982 ◽  
Vol 47 (4) ◽  
pp. 1045-1059 ◽  
Author(s):  
František Veselý ◽  
Vladimír Dohnal ◽  
Miloslav Prchal
Keyword(s):  
Ternary Systems ◽  
Group Contribution ◽  
Polar Component ◽  
Excess Enthalpies ◽  
Group Contribution Method ◽  
Heats Of Mixing ◽  
Scatchard Equation ◽  
System 1 ◽  
Associated Solution ◽  
Good Agreement

Heats of mixing HE were measured at the temperature of 298 15 K in the ternary system 1-propanol-n-hexane-cyclohexane, 1-propanol-n-heptane-cyclohexane and 1-propanol-n-octane cyclohexane along three pseudobinary chorids and in the binary system 1-propanol-n-hexane. The measured values of the ternary excess enthalpies were correlated by the Scatchard equation for one polar component and by the SSF equation in pseudobinary mixtures. A very good agreement with the experiments was attained on computing the enthalpies of mixing by the group-contribution method. Qualitatively the same results were found on applying the modified Renon-Prausnitz model of continuously associated solution. The combination of the Renon-Prausnitz model with the group-contribution method did not yield a more conspicuous improvement.

Intramolecular-proximity effect on the excess enthalpies of (a dichloroalkane + an alkan-2-one)

1994 ◽  
Vol 26 (1) ◽  
pp. 53-59 ◽  
Author(s):  
J. Garcı́a ◽  
E.R. López ◽  
J. Fernández ◽  
A. Amigo ◽  
M.I.Paz Andrade
Keyword(s):  
Proximity Effect ◽  
Excess Enthalpies

Analysis of excess enthalpies of ethyl formate + n-alkane or 1-alkanol with two group contribution models

1990 ◽  
Vol 56 ◽  
pp. 219-234 ◽  
Author(s):  
J. Ortega ◽  
J.L. Legido ◽  
J. Fernandez ◽  
M. Lopez ◽  
L. Pias ◽  
...  
Keyword(s):  
Ethyl Formate ◽  
Group Contribution ◽  
Excess Enthalpies

Potential of group contribution methods for the prediction of phase equilibria and excess properties of complex mixtures

2003 ◽  
Vol 75 (7) ◽  
pp. 875-888 ◽  
Author(s):  
Jürgen Gmehling
Keyword(s):  
Equation Of State ◽  
Phase Equilibria ◽  
Equations Of State ◽  
Data Bank ◽  
Group Contribution ◽  
Proximity Effects ◽  
Excess Properties ◽  
Excess Enthalpies ◽  
Separation Processes ◽  
Group Contribution Methods

Reliable knowledge of the thermophysical properties of pure compounds and their mixtures in the whole composition and a wide temperature and pressure range is a vital prerequisite for computer-aided synthesis, design, and optimization of chemical processes. Knowledge of the various phase equilibria is most important for the development of thermal separation processes (but also for other applications,such as the design of multiphase reactors, the prediction of the fate of a chemical in the environment,etc.).Whereas 25 years ago, the main interest was directed to the development of predictive tools for vapor–liquid equilibria of subcritical compounds of similar size (ASOG, UNIFAC), 15 years later a proper description of the temperature dependence (excess enthalpies), the activity coefficients at infinite dilution, and solid–liquid equilibria of eutectic mixtures (including strong asymmetric systems) was achieved. After the combination with cubic equations of state [Soave–Redlich–Kwong (SRK), Peng–Robinson (PR)], the group contribution concept was extended to supercritical compounds [predictive SRK (PSRK)]. With the development of an adequate electrolyte model (LIFAC), the equation-of-state approach can even be used for systems with strong electrolytes. With the revision of the group interaction parameters, the extension of the parameter matrix (introduction of new structural groups, filling of parameter gaps), and the help of a large database (Dortmund Data Bank), the predicted results of group contribution methods were significantly improved and the range of applicability greatly extended. Furthermore, still-existing problems with the group contribution approach (proximity effects,etc.) were reduced.With the help of a volume-translated PR equation of state and application of temperature-dependent and improved mixing rules, the remaining weaknesses of group contribution equations of state (such as poor results for liquid densities, excess enthalpies, and the problems with asymmetric systems) were minimized.

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