Diffusion in high viscosity liquids

Hiss, Timothy G.; Cussler, E. L.

doi:10.1002/aic.690190404

Cited by 141 publications

(71 citation statements)

References 24 publications

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“…This characteristic parameter would be directly related to the strength of interaction of diffusing species with its environment; the higher the value of α the lesser the interaction. Indeed, it has been found that α tends to 1 when the solute/solvent size ratio is greater than 5, and to 0 in extremely highly viscosity media [73]. Furthermore, α has been found to equal to 1 for water in hydrophobic media [71].…”

Section: H Nmr Dosymentioning

confidence: 99%

Tetrapropylammonium Occlusion in Nanoaggregates of Precursor of Silicalite-1 Zeolite Studied by 1H and 13C NMR

et al. 2016

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Abstract:The dynamic behavior of tetrapropylammonium (TPA) cations in the clear precursor sols for silicalite synthesis has been investigated by 1 H diffusion ordered spectroscopy (DOSY), T 1 , T 2 , and T 1ρ 1 H relaxation, as well as 1 HÑ 13 C cross polarization (CP) nuclear magnetic resonance. The DOSY NMR experiments showed the presence of strong solute-solvent interactions in concentrated sols, which are decreasing upon dilution. Similarities in dependence of diffusion coefficients with fractional power of the viscosity constant observed for nanoparticles, TPA cations and water led to the conclusion that they aggregate as anisotropic silicate-TPA particles. Relaxation studies as well as 1 HÑ 13 C CP experiments provide information on dynamic properties of ethanol, water and TPA cations, which are function of silicate aggregates. The general tendency showed that the presence of silicate as oligomers and particles decreases the relaxation times, in particular T 2 and T 1ρH , as a consequence of involvement of these latter in ion-pairing interactions with water-solvated TPA molecules slowing down their mobility. Furthermore, from the 1 HÑ 13 C CP dynamics curve profiles a change in the CP transfer regime was observed from fast (T CH << T 1ρH ) for solutions without silicates to moderate (T CH~T1ρH ) when silicates are interacting with the TPA cations that may reflect the occlusion of TPA into flexible silicate hydrate aggregates.

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Section: H Nmr Dosymentioning

confidence: 99%

Tetrapropylammonium Occlusion in Nanoaggregates of Precursor of Silicalite-1 Zeolite Studied by 1H and 13C NMR

et al. 2016

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“…As in the case of strongly viscous liquids, the anomalies arise upon diffusion of small admixtures [45,46]. The diffusion of various admixtures in 2-methylpentane-2,4-diol has been studied in [47].…”

Section: Determination Of Diffusion Rate Constant Using Reaction Of Dmentioning

confidence: 99%

Photoreduction of IrCl62? complex in alcohol solutions and its reaction with hydroxyalkyl radicals

Glebov

Plyusnin

Grivin

et al. 1998

Int. J. Chem. Kinet.

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The photochemistry of complex in simple alcohols have been studied using 2ϪIrCl 6 laser-flash photolysis. Single electron transfer from the solvent molecule to the light-excited complex has been shown to be the primary photochemical process. Quantum yields of the photoreduction of complex and the rate constants of its reaction with hydroxyalkyl 2ϪIrCl 6 radicals were determined at Deviations of the rate constants from Debye-Smo-200-330 K. luchowski equation for diffusion-controlled reactions are discussed.

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“…The enhanced diffusion has been explained by the so-called microviscosity effect, i.e., the viscosity around a small solute is different from the bulk viscosity of solvent. 67 Although Hiss and Cussler 58 have been able to rationalize the exponent of 2/3 on the basis of Eyring's absolute rate theory and Bagchi and Bhattacharyya 7,19 have indicated in their MCT studies that decoupling of the solute motion from the structural relaxation of the solvent could lead to fractional viscosity dependence, nonetheless, a quantitative theory of the FSE relation is still not yet available. Recently, however, there has been a great deal of interest [68][69][70][71][72][73][74][75][76] in the use of the FSE relation for the study of diffusion.…”

Section: B Solvent Dependencementioning

confidence: 99%

“…Except for macromolecules, however, numerous experimental studies 3,[57][58][59][60][61][62][63][64][65][66] have shown that tracer diffusivity is inversely proportional to a fractional power of the viscosity of the solvent instead. This fractional power dependence of viscosity on diffusion is often referred to in the literature as the fractional Stokes-Einstein (FSE) relation, (D 12 /T) ∝ η −t , where t is known to be normally less than unity and generally around 2/3.…”

Section: B Solvent Dependencementioning

confidence: 99%

“…This fractional power dependence of viscosity on diffusion is often referred to in the literature as the fractional Stokes-Einstein (FSE) relation, (D 12 /T) ∝ η −t , where t is known to be normally less than unity and generally around 2/3. 19,58 The FSE relation hence implies that the SE relation usually underestimates the diffusivities of solutes that are not very large as compared to solvent molecules. The enhanced diffusion has been explained by the so-called microviscosity effect, i.e., the viscosity around a small solute is different from the bulk viscosity of solvent.…”

Section: B Solvent Dependencementioning

confidence: 99%

See 1 more Smart Citation

Diffusion of aromatic compounds in nonaqueous solvents: A study of solute, solvent, and temperature dependences

Chan

Tang

2013

The Journal of Chemical Physics

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Tracer diffusivities (limiting mutual diffusion coefficients) of nonassociated aromatic compounds in n-hexane and cyclohexane have been measured at 298.2 K by Taylor's dispersion method. These new data, together with other diffusivities of nonassociated pseudoplanar solutes reported in the literature, are used to determine the separate effects of solute and solvent on tracer diffusion. The data show that for a given pseudoplanar solute diffusing in different solvents at 298.2 K, the tracer diffusivity is dependent not only on the fractional viscosity of the solvent but also on a function of the solvent's molar density, molecular mass, and free volume fraction. For different pseudoplanar aromatic solutes diffusing in a particular solvent at a constant temperature, there is a linear relationship between the reciprocal of the tracer diffusivity and the molecular volume of the solutes. The results are discussed in respect to relevant theories and experimental studies in the literature. An idealized relation, developed on the basis of the Einstein equation by incorporating the newly found solute and solvent dependences, is capable of describing a total of 176 diffusivities of nonassociated pseudoplanar solutes in various solvents at different temperatures to within an average error of ±2.8%. © 2013 AIP Publishing LLC. [http://dx

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Diffusion in high viscosity liquids

Cited by 141 publications

References 24 publications

Tetrapropylammonium Occlusion in Nanoaggregates of Precursor of Silicalite-1 Zeolite Studied by 1H and 13C NMR

Tetrapropylammonium Occlusion in Nanoaggregates of Precursor of Silicalite-1 Zeolite Studied by 1H and 13C NMR

Photoreduction of IrCl62? complex in alcohol solutions and its reaction with hydroxyalkyl radicals

Diffusion of aromatic compounds in nonaqueous solvents: A study of solute, solvent, and temperature dependences

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