Diffusion Coefficients of Organic Compounds at Infinite Dilution in Ternary Mixtures: Experimental Determinations and Modeling†

2010 ◽  
Vol 55 (12) ◽  
pp. 5449-5452 ◽  
Author(s):  
Amor Safi ◽  
Christophe Nicolas ◽  
Evelyne Neau ◽  
Joan Escandell
Keyword(s):  
Organic Compounds ◽  
Diffusion Coefficients ◽  
Infinite Dilution ◽  
Ternary Mixtures

Activity Coefficients at Infinite Dilution of Organic Compounds in 1-(Meth)acryloyloxyalkyl-3-methylimidazolium Bromide Using Inverse Gas Chromatography

2008 ◽  
Vol 112 (12) ◽  
pp. 3773-3785 ◽  
Author(s):  
Fabrice Mutelet ◽  
Jean-Noël Jaubert ◽  
Marek Rogalski ◽  
Julie Harmand ◽  
Michèle Sindt ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Organic Compounds ◽  
Activity Coefficients ◽  
Infinite Dilution ◽  
Inverse Gas Chromatography

Diffusion coefficients and viscosities of organic aerosol components through equilibrium and non-equilibrium molecular dynamics simulations

2021 ◽  
Author(s):  
Katerina S. Karadima ◽  
Vlasis G. Mavrantzas ◽  
Spyros N. Pandis
Keyword(s):  
Molecular Dynamics ◽  
Functional Groups ◽  
Organic Compounds ◽  
Diffusion Coefficients ◽  
Amorphous Solid ◽  
Good Effect ◽  
Hydroxyl Groups ◽  
Chemical Structures ◽  
Organic Particles ◽  
Non Equilibrium

<p>Organic aerosols have been typically considered to be liquid, with equilibration between gas and aerosol phase assumed to be reached within seconds. However, Virtanen et al. (Nature, 2010) suggested that particles in amorphous solid state may also occur in the atmosphere implying that mass transfer between the atmospheric particulate and gas phases may be much slower than initially thought. Experimentally, the direct measurement of the diffusion coefficients of different compounds inside atmospheric organic particles is challenging. Thus, an indirect approach is usually employed, involving viscosity measurements and then estimation of diffusion coefficients via the Stokes-Einstein equation, according to which the diffusion coefficient is inversely proportional to the medium viscosity. However, the corresponding diffusion estimates are highly uncertain, especially for highly viscous aerosols which is the most important case. Molecular simulation methods, such as molecular dynamics (MD), can be an alternative method to determine directly the diffusion rates and the viscosity of the constituents of atmospheric organic particles. MD also provides detailed information of the exact dynamics and motion of the molecules, thus offering a deeper understanding on the underlying mechanisms and interactions.</p><p>In the present work, we use equilibrium and non-equilibrium MD simulations to estimate the viscosity and diffusion coefficients of bulk systems of representative organic compounds with different chemical structures and physicochemical characteristics. Hydrophilic and hydrophobic compounds representative of primary and secondary oxidized organic products and of primary organic compounds emitted by various sources are considered. The viscosity and self-diffusion coefficients calculated by our simulations are in good agreement with available experimentally measured values. Our results confirm that the presence of carboxyl and hydroxyl groups in the molecule increases the viscosity. The number of carboxyl and hydroxyl groups, in particular, seems to have a good effect on diffusivity (the diffusivity decreases as the number of these functional groups increase), and to a lesser extent on the viscosity. We also discuss the role of the hydrogen bonds formed between these functional groups.</p>

scholarly journals Diffusion Coefficients of Methane in Methylbenzene and Heptane at Temperatures between 323 K and 398 K at Pressures up to 65 MPa

2020 ◽  
Vol 41 (8) ◽  
Author(s):  
Malyanah Binti Mohd Taib ◽  
J. P. Martin Trusler
Keyword(s):  
Diffusion Coefficients ◽  
Infinite Dilution ◽  
Hydrodynamic Radius ◽  
Taylor Dispersion ◽  
Relative Uncertainty ◽  
Dispersion Method ◽  
Solvent Density ◽  
Einstein Model ◽  
Taylor Dispersion Method ◽  
Simple Empirical Model

Abstract We reported experimental measurements of the diffusion coefficient of methane at effectively infinite dilution in methylbenzene and in heptane at temperatures ranging from (323 to 398) K and at pressures up to 65 MPa. The Taylor dispersion method was used and the overall combined standard relative uncertainty was 2.3%. The experimental diffusion coefficients were correlated with a simple empirical model as well as the Stokes–Einstein model with the effective hydrodynamic radius of methane depending linearly upon the solvent density. The new data address key gaps in the literature and may facilitate the development of an improved predictive model for the diffusion coefficients of dilute gaseous solutes in hydrocarbon liquids.

scholarly journals Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes in the Ionic Liquids N-Ethyl- and N-Octyl-N-methylmorpholinium Bis(trifluoromethanesulfonyl)imide. A Useful Tool for Solvent Selection

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 634 ◽  
Author(s):  
Łukasz Marcinkowski ◽  
Joachim Eichenlaub ◽  
Elham Ghasemi ◽  
Żaneta Polkowska ◽  
Adam Kloskowski
Keyword(s):  
Ionic Liquids ◽  
Organic Compounds ◽  
Activity Coefficients ◽  
Infinite Dilution ◽  
Retention Data ◽  
Separation Processes ◽  
Study Results ◽  
Conscious Choice ◽  
Potential Applications ◽  
Partial Molar Enthalpies

In recent years, many papers describing ionic liquids (IL) as promising solvents in separation techniques have been published. The conscious choice of appropriate ionic liquid as absorption media in effective extraction of selected types of analytes requires deeper understanding of the analyte−IL interactions. Therefore, intensive research is conducted to determine the values of activity coefficient at infinite dilution, which allows us to characterize the nature of these interactions. Based on the inverse gas chromatography retention data, activity coefficients at infinite dilution γ 13 ∞ of 48 different organic compounds in the ionic liquids N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide [C2C1Mor][TFSI] and N-octyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide [C8C1Mor][TFSI] were determined. The measurements covered a broad range of volatile organic compounds, including n-alkanes, n-alkenes, n-alkynes, alcohols, aldehydes, ketones, aromatic compounds and common polar solvents, representing different types of interactions. Activity coefficients at infinite dilution were measured in the temperature range from 313.15 to 363.15 K. The excess partial molar enthalpies and entropies at infinite dilution were determined. Selectivity at infinite dilution was also calculated for exemplary separation processes in the hexane/benzene system. The obtained results were analyzed and compared with literature data for ionic liquids containing the same anion [TFSI]¯ and different cations. The study results indicate that some potential applications of the investigated ionic liquids in separation problems exist.

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