Diffusion Coefficients of Aromatic Compounds at Infinite Dilution in Binary Mixtures at 298.15 K

Abstract

Infinite dilution diffusion coefficients of aromatic compounds (benzene, toluene, chlorobenzene, ethylbenzene, p-chlorotoluene, naphthalene, pyrene, and perylene) in mixtures of hexane + heptane and of benzene in polar mixtures (hexane + ethanol and acetone + ethanol) were measured at 298.15 K by the Taylor dispersion technique. Experimental data were correlated by means of literature models depending in most cases on the diffusion coefficient of the solute at infinite dilution in the pure solvent. It is shown that the use of experimental values for should always be preferred to the Wilke−Chang predictions, especially in the case of nonideal mixed solvents. All models provide equivalent predictions except the Maxwell−Stefan and Dullien−Asfour equations, which lead to less stable results.

Understanding Adsorption of Violanthrone-79 as a Model Asphaltene Compound on Quartz Surface Using Molecular Dynamics Simulations

“…The attractive interaction between n -heptane and toluene was found to be stronger than that between the same species (see Section S2 in SI), which could be the reason why diffusion is faster in the pure solvents. The D values in heptol also decrease with decreasing proportion of n -heptane, which is consistent with earlier studies , in which the diffusion coefficients of binary mixtures decrease with decreasing alkane content.…”

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

“…As was outlined in the introduction, the purpose of this work was to study the extension to ternary solvents of the methods previously considered ,, for the correlation of infinite dilution diffusion coefficients D 1m ∞ in binary mixtures. First of all, we check the influence of the estimation of the diffusion coefficients D 1i ∞ of the solute (1) in the pure solvent (i), by considering only the correlations independent of the viscosities (eqs and ); second, we compare the results obtained with the other models (eqs to ) according to the method used for estimating the mixture viscosities η m .…”

“…The Taylor dispersion technique was used to determine diffusion coefficients in ternary solvents. The experimental apparatus and procedures for the measurement of diffusion coefficients of solutes in binary solvents have been described in previous papers. ,,, A model 655A liquid chromatographic pumping system (Merck-Hitachi) was used to provide constant laminar flow at 0.1 mL·min −1 . The diffusing tube (a stainless steel pipe) was 10 000 cm long with an inner diameter of d tube = 0.0476 cm and coil diameter of d coil = 22 cm.…”

“…The modeling of experimental data was performed using literature models commonly considered for binary systems, and special attention was paid to their extension to ternaries using mixture viscosity correlations. A previous work concerning the Maxwell−Stefan, Leffler−Cullinan, Eyring, and Dullien-Asfour models has shown that the use of the experimental values of diffusion coefficients, D 1i ∞ , of the solute (1) in the pure solvents (i) clearly improves the description of diffusion coefficients, D 1m ∞ , in mixed solvents, especially in the case of nonideal mixtures. It was also observed that the Leffler−Cullinan and Eyring models provide the best results, assuming experimental values of mixture viscosities, η m .…”

Effect of Reaction Medium Mixture on the Lipase Catalyzed Synthesis of Diacylglycerol

“…The diffusion coefficient of glycerol and oleic acid in different types of solvent systems were calculated using Wilke and Chang 30 correlation. Meanwhile for blended mixtures, the diffusion coefficient was calculated using eqs 4 and 5 as proposed by Safi et al 31 Because of the unavailability of ϕ values, 2.60, (ϕ of water) and 1.0, (ϕ of hydrocarbons), are used in the calculation of glycerol and oleic acid, respectively. 32 Hydrophobicity is reflected by log P, for which P is the partition coefficient for a given solvent between n-octanol and water.…”