Self-diffusion and interdiffusion in complex-forming binary systems

Carman, P. C.

doi:10.1021/j100867a027

Cited by 43 publications

(26 citation statements)

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“…However, the effect of dimerisation of urea on the mutual diffusion coefficient has not been taken into account. Aspects of the general problem of the effect of solute association o n mutual diffusion coefficients have been discussed by several authors (25)(26)(27)(28). In particular, Schonert (28) has extended Stokes' analysis (24) of tracer diffusion in urea solutions to mutual diffusion, and concluded, in effect, that the experimental diffusion coefficients can be accounted for using a relative viscosity exponent (a in eq.…”

Section: Urea Solutionsmentioning

confidence: 99%

Tracer diffusion in aqueous sucrose and urea solutions

Easteal¹

1990

Can. J. Chem.

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ALLAN J. EASTEAL. Can. J. Chem. 68, 161 1 (1990). Tracer diffusion coefficients for water (as HTO), methanol ( I 4 C H 3 0~) , and acetonitrile (CT,CN) in aqueous sucrose (10-25% w/w) and urea (0.25-4 mol L -I ) solutions at 298 K have been determined using the diaphragm cell technique. For sucrose solutions tracer diffusion coefficients vary with the 213 power of the relative viscosity and the viscosity dependence is the same for the above tracers as for sucrose and oxygen. In urea solutions tracer diffusion coefficients appear to have a solute-specific viscosity dependence, but the solute specificity is largely removed when the effects of proton exchange and urea dimerisation are considered.

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Section: Urea Solutionsmentioning

confidence: 99%

Tracer diffusion in aqueous sucrose and urea solutions

Easteal¹

1990

Can. J. Chem.

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“…In the next two sections, a prior theoretical derivation [9,14,15] of the intrinsic mutual diffusion coefficient for self-association is presented. In general, a self-associating solute diffuses as its polymers i.e., monomers (A 1 ), dimers (A 2 ), trimers (A 3 ) etc.…”

Section: A Simplified Model For Self-associationmentioning

confidence: 99%

“…In general, a self-associating solute diffuses as polymers i.e., monomers, dimers, trimers etc. Using a simplified model for association, expressions for the intrinsic (or unweighted) mutual diffusion coefficients of associating solutes have been derived as a function of concentration [9,14,15]. However, for measurements, due to characteristics inherent in the type of analysis, weighted average diffusion coefficients are obtained …”

Section: Introductionmentioning

confidence: 99%

Theoretical Comparisons of the Concentration-Dependent Diffusion Coefficients from Dynamic Light Scattering and Taylor Dispersion Analysis

Latunde-Dada¹

2016

J Anal Bioanal Tech

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Dynamic Light Scattering and Taylor Dispersion Analysis are two methods employed for the measurement of the diffusion coefficients and interaction parameters of solutes. For self-associating solutes, the interaction parameter provides a measure for the degree of association and hence the stability of the solutes. Due to the characteristics, peculiar to each method, the measured values are weighted averages and are therefore different from the intrinsic or unweighted values. In this paper, using a simple model for self-association, theoretical expressions for the DLS, TDA and intrinsic diffusion coefficients are derived for self-associating solutes. The corresponding interaction parameters are also derived and compared. As expected, at low concentrations, it was found that the DLS gives higher diffusion coefficients than TDA and vice versa at high concentrations. More interestingly, points of inflection were found in the DLS and TDA diffusion coefficient-concentration curves which imply the presence of minima in measured interaction parameters with the TDA minimum occurring at a lower concentration than for DLS. These are absent in the intrinsic curves. Furthermore, it was found that whilst the intrinsic interaction parameter tends to a non-zero value in the limit of low concentrations, the measured interaction parameters vanish. These trends are important for the interpretation of the results obtained from both measurement methods especially when compared to the intrinsic values. With the interaction parameter being increasingly used as a measure of stability, consideration of these expected trends could prove valuable for explaining experimental data measured at low concentrations. Furthermore, they could prove important when comparisons are made between results from the two measurements which are increasingly being used as orthogonal methods for protein analysis.

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“…Equations [15], [17], [18], [20], and [21] have been simplified by dropping subscripts "1 1" from L and D and subscript "1" from C, U , and p. In addition, the solute has been assumed to be ideal in the thermodynamic sense.…”

Section: Binary Mixturesmentioning

confidence: 99%

“…Binary diffusion of dimerizing solutes (2,(17)(18)(19)(20) and ternary diffusion of solutes A and B that form complex AB (21) have already been studied. The equations developed in the present paper extend the earlier treatments to nonelectrolyte mixtures that contain arbitrary numbers of components and association equilibria.…”

Section: Introductionmentioning

confidence: 99%

Diffusion in associating nonelectrolyte mixtures: stepwise aggregation and micelle formation

Leaist¹

1988

Can. J. Chem.

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Equations have been developed to predict diffusion coefficients and Onsager coefficients for associating nonelectrolyte solutes in binary or multicomponent solutions with any number of association equilibria. The equations are used to interpret previously reported data for binary diffusion with stepwise association of ethanol and N-methylacetamide in carbon tetrachloride solutions. Diffusion of Triton X-100, a non-ionic micelle-forming surfactant, is also analyzed. In contrast to the gradual decrease in the diffusivity caused by stepwise association, formation of micellar aggregates produces a sharp drop in the diffusivity at the critical micelle concentration. The relation between interdiffusion coefficients and intradiffusion coefficients for associating nonelectrolyte solutes is discussed. DEREK G. LEAIST. Can. J. Chem. 66, 1129 (1988). On a dtveloppt des tquations qui permettent de prtdire les coefficients de diffusion et les coefficients dlOnsager de solutts non-tlectrolytes qui s'associent dans des solutions binaires ou B plusieurs composants et qui comportent n'importe quel nombre d'kquilibres d'association. On a utilist les tquations pour interprtter des donnkes rapporttes anttrieurement pour de la diffusion binaire impliquant une association par ttapes de l'tthanol et du N-mtthylacttamide dans des solutions de tttrachlorure de carbone. On a aussi analyst la diffusion du Triton X-100, un agent de surface non-ionique qui forme des micelles. Par opposition avec la diminution graduelle de la possibilitt de diffusion provoqute par cette association par ttapes, la formation d'aggrkgats micellaires provoque une diminution importante de la possibilitk de diffusion B la concentration micellaire critique. On discute de la relation entre les coefficients d'interdiffusion et les coefficients d'intradiffusion pour les solutks non-tlectrolytes qui s'associent.[Traduit par la revue] Introduction Many nonelectrolyte solutes associate (1). Aqueous urea, for example, is extensively dimerized (2,3). In nonpolar solvents, carboxylic acids and phenols form dimers (4-7). Other solutes, such as nucleic acids (8), amides (9-1 l), and certain dyes (12), associate in a stepwise manner to form chain-like aggregates. Non-ionic surfactants illustrate an extreme case of association in which micellar clusters containing several hundred molecules can form (13-16).The work reported here was undertaken to study the diffusion behavior of associating nonelectrolytes. The effects of association on diffusion are interpreted by determining changes in the solute mobility and the free energy gradient, the driving force for diffusion.Binary diffusion of dimerizing solutes (2,(17)(18)(19)(20) and ternary diffusion of solutes A and B that form complex AB (21) have already been studied. The equations developed in the present paper extend the earlier treatments to nonelectrolyte mixtures that contain arbitrary numbers of components and association equilibria.Weinheimer et al. (15) have reported an approximate expression for estimating the diffusion...

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Self-diffusion and interdiffusion in complex-forming binary systems

Cited by 43 publications

References 11 publications

Tracer diffusion in aqueous sucrose and urea solutions

Tracer diffusion in aqueous sucrose and urea solutions

Theoretical Comparisons of the Concentration-Dependent Diffusion Coefficients from Dynamic Light Scattering and Taylor Dispersion Analysis

Diffusion in associating nonelectrolyte mixtures: stepwise aggregation and micelle formation

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