I'm going to develop a model for prediction of activity coefficients at infinite dilution of organic solutes in Ionic liquids.
In http://ilthermo.boulder.nist.gov/ website or related articles the data is reported in different phases. I mean a certain binary mixture of Organic+IL in a certain operation condition has two values for activity but in L-G and only L phase.
For example
system: 1-methyl-3-octylimidazolium tetrafluoroborate+Octane @ 298 K
1) Liquid-Gas phases
Solubilities of the Gaseous and Liquid Solutes and Their Thermodynamics of Solubilization in the Novel Room-Temperature Ionic Liquids at Infinite Dilution by Gas Chromatography
Zhang, J.; Zhang, Q.; Qiao, B.; Deng, Y. (2007) J. Chem. Eng. Data 52, 2277-2283.
A.C.=16.1 ± 1.1
2) Liquid phas:
Thermodynamic Properties of Mixtures Containing Ionic Liquids. 6. Activity Coefficients at Infinite Dilution of Hydrocarbons, Alcohols, Esters, and Aldehydes in 1-Methyl-3-octyl-imidazolium Tetrafluoroborate Using Gas-Liquid Chromatography
Heintz, A.; Verevkin, S. P. (2005) J. Chem. Eng. Data 50, 1515-1519.
A.C.=22 ± 1.5
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system: 1-methyl-3-octylimidazolium tetrafluoroborate+Octane @ 323 K
1) Liquid phase
Activity Coefficients at Infinite Dilution in 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids
Foco, G. M.; Bottini, S. B.; Quezada, N.; de la Fuente, J. C.; Peters, C. J. (2006) J. Chem. Eng. Data 51, 1088-1091.
A.C.=16.3 ± 1.7
2) Liquid-Gas phases
Solubilities of the Gaseous and Liquid Solutes and Their Thermodynamics of Solubilization in the Novel Room-Temperature Ionic Liquids at Infinite Dilution by Gas Chromatography
Zhang, J.; Zhang, Q.; Qiao, B.; Deng, Y. (2007) J. Chem. Eng. Data 52, 2277-2283.
A.C.=8.4 ± 0.6
How can it be explained? Should I consider only G-L phases data or L phase?
Thanks in advance
These data refer in all cases to the solute in the LIQUID state. The differences between values from different sources are (unfortunately) of the usual order of magnitude for limiting activity coefficients. (By the way, the A.C. at 323 K are not for octane, but for heptane).
It seems that the specifications "liquid" and "liquid-gas" are just intended to furnish details about the experimental setup used in each case.
As far as I know
These data belong to different sources. May be some of them are not reliable. Also, many model have the same condition. For example you can see my last paper in molecular liquids.I think if you want reliable investigation,you must do experiments by yourself.
Thank you Dr Khosharay. I would like to express my heartfelt gratitude for writing me this. I read some of your invaluable works and allow me to admire accurate models and your skills especially in thermodynamics. i am going to find an accurate model for prediction/evaluation of activity coefficients at infinite dilution of organic solutes in ionic liquids whereas there are doubts about the reliability of the data, as you said, it might go back to the difference of methodology of difference sources or other consideration should take into account. It seems I should gather only reliable data for each binary at certain temperature to avoid confusing the final model.
By the way, thank you very much.
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