Universal model for accurate calculation of tracer diffusion coefficients in gas, liquid and supercritical systems

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• 作者：Patrí ; cia F. Lito ^{patricia.lito@ua.pt} ; Ana L. Magalhã ; es ^{anamagalhaes@ua.pt} ; José ; R.B. Gomes ^{jrgomes@ua.pt} ; Carlos M. Silva ; ^{carlos.manuel@ua.pt}
• 关键词：Diffusion coefficient ; Modeling ; Non-polar systems ; Polar systems ; Transport properties ; Universal model
• 刊名：Journal of Chromatography A
• 出版年：2013
• 出版时间：17 May, 2013
• 年：2013
• 卷：1290
• 期：Complete
• 页码：1-26
• 全文大小：1737 K

文摘

In this work it is presented a new model for accurate calculation of binary diffusivities (D₁₂) of solutes infinitely diluted in gas, liquid and supercritical solvents. It is based on a Lennard-Jones (LJ) model, and contains two parameters: the molecular diameter of the solvent and a diffusion activation energy. The model is universal since it is applicable to polar, weakly polar, and non-polar solutes and/or solvents, over wide ranges of temperature and density. Its validation was accomplished with the largest database ever compiled, namely 487 systems with 8293 points totally, covering polar (180 systems/2335 points) and non-polar or weakly polar (307 systems/5958 points) mixtures, for which the average errors were 2.65 % and 2.97 % , respectively. With regard to the physical states of the systems, the average deviations achieved were 1.56 % for gaseous (73 systems/1036 points), 2.90 % for supercritical (173 systems/4398 points), and 2.92 % for liquid (241 systems/2859 points). Furthermore, the model exhibited excellent prediction ability. Ten expressions from the literature were adopted for comparison, but provided worse results or were not applicable to polar systems. A spreadsheet for D₁₂ calculation is provided online for users in Supplementary Data.