title: Universal model for accurate calculation of tracer diffusion coefficients in gas, liquid and supercritical systems.
abstract: 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.
authors.affiliation: Department of Chemistry, Associate Laboratory CICECO, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. patricia.lito@ua.pt
authors.forename: Patrícia F
authors.initials: PF
authors.lastname: Lito
authors.forename: Ana L
authors.initials: AL
authors.lastname: Magalhães
authors.forename: José R B
authors.initials: JR
authors.lastname: Gomes
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Silva
mesh_terms: D002845:Chromatography / Q000379:methods*; D004058:Diffusion; D005740:Gases / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D005740:Gases; D009930:Organic Chemicals; D012997:Solvents