Osmotic and Activity Coefficients for the Symmetrical Tetraalkyl Ammonium Halides in Aqueous Solution at 25°<sup>1</sup>

Lindenbaum, Siegfried; Boyd, G. E.

doi:10.1021/j100786a038

Cited by 259 publications

(144 citation statements)

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“…10). Comparison of the activity coefficients with those measured isopiestically 21 show good agreement. This shows that the response of the electrode in aqueous solutions is linear to the Bu 4 N 1 ions most likely due to the specific interaction of the Bu 4 N 1 ions to the electrode.…”

Section: Discussionsupporting

confidence: 57%

“…Nevertheless, it cannot be excluded that using formamide as solvent the polymer electrode could react differently with respect to the two mentioned sources for uncertainties. Actually, we are not able to prove this influence, and thus the measurements of the cell potential can be used only to estimate 21 The data points marked with crosses in (a) (0.2 to 7 Â 10 À3 molal) are lying on a straight line within the error bars. Thus, it may be assumed that the activity coefficient for these concentrations is constant and a straight line can be fitted to these data points.…”

Section: Discussionmentioning

confidence: 92%

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Activity of surface active substances determined from their surface excess

Andersson

Krebs

Morgner

2005

Phys. Chem. Chem. Phys.

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Commonly, the surface excess is determined from surface tension measurements via the Gibbs equation. This equation relates the activity (chemical potential), the surface excess, and the surface tension. When knowing two out of the three quantities, the third one can be calculated. Unfortunately, in the case of surface active components the concentration is in most cases too low to determine the activity from a measurable change in the bulk properties and thus assumptions are made about the activity coefficients. However, if the surface excess is measured directly and the surface tension is known, the activity can be determined making use of the Gibbs equation. The surface excess is the quantity of a surfactant solution which changes most strongly with the concentration. Thus it is obvious that this procedure should be used to determine activity coefficients of surfactants. One of the few techniques for determining the surface excess directly is neutral impact collision ion scattering spectroscopy (NICISS). With NICISS concentration depth profiles can be measured in the surface near region with a depth resolution of a few angstro¨ms. The surface excess and the activities are investigated here for the system tetrabutylphosphonium bromide (Bu 4 PBr) dissolved in the polar solvent formamide.

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 92%

Activity of surface active substances determined from their surface excess

Andersson

Krebs

Morgner

2005

Phys. Chem. Chem. Phys.

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“…Further, tetraalkylammonium salts constitute a class of electrolyte, which show peculiar properties in aqueous solutions. The aqueous solutions of these salts have been found to give high viscosities [13], apparent molar volume [14], high apparent molal heat capacities [15,16] and peculiar activity coefficients [17].…”

Section: Introductionmentioning

confidence: 99%

Volumetric and Viscometric Behaviour of some Amino Acids and their Group Contributions in Aqueous Tetramethylammonium Bromide at Different Temperatures

Ali¹,

Shahjahan²

2008

Zeitschrift Für Physikalische Chemie

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“…In spite of the uncertainty about their exact values, it is possible to see the effects of changes in structure on K, on AH, and hence on AS, the entropy of formation of ion-pairs (Table 4b). Lindenbaum & Boyd (1964) and enthalpies of dilution listed in Table 2.…”

Section: B)mentioning

confidence: 99%

“…From the osmotic coefficients the excess free energies (GEX) were calculated as described by Lindenbaum & Boyd (1964), the excess function being the difference between the value for the solution and that for an ideal solution of the same composition. The enthalpy of dilution of an ideal solution is zero, so the experimental values are estimates of minus the excess enthalpy (HEX; if this is negative the solution will absorb heat when diluted and the enthalpy of dilution will be positive) and can be used with the excess free energies to calculate the excess entropies of the solutions (SEX; Lindenbaum, 1966).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Properties and Biological Activity: Thermodynamic Properties of Compounds Related to Acetylcholine Assessed From Depression of Freezing‐point and Enthalpies of Dilution

Barlow

1974

British J Pharmacology

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1 Measurements have been made of the osmotic coefficients and enthalpies of dilution of acetylcholine and of compounds related to it in which the carbonyl and ether groups have been replaced by methylene and the trimethylammonium group by triethylammonium. All were iodides. Measurements were also made with tetraethylammonium iodide and agree with published values. 2 Where necessary the affinities of the compounds for acetylcholine receptors in the guinea-pig ileum and frog rectus, or their activities relative to acetylcholine, have been measured. 3 The osmotic coefficients were used to calculate activity coefficients and excess free energies, which have been used with the excess enthalpies to calculate the excess entropies of the solutions. These indicate that the ester and carbonyl groups have a marked ordering effect on the ions in water compared with methylene groups; the ether group has an intermediate effect.4 When the results are interpreted in terms of ion-pair formation they can be used to calculate the ion-association constants and enthalpies and entropies of formation of ion-pairs, and lead to similar conclusions: that the order associated with ion-pair formation is greater with the esters and ketones. There appears to be extensive ion-association in the concentrations (0.5 to 1 M) usually used in n.m.r. studies. 5 There is no obvious correlation between the effects of groups on water and their activity or affinity at muscarine-sensitive acetylcholine receptors but it is possible that ability to activate nicotine-sensitive receptors may be associated with an increase in order, though it would be necessary to study entropy changes in systems actually involving receptors in order to prove this. It is also necessary to suppose that ability to activate these receptors is limited to compounds with small onium groups.

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Osmotic and Activity Coefficients for the Symmetrical Tetraalkyl Ammonium Halides in Aqueous Solution at 25°¹

Cited by 259 publications

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Activity of surface active substances determined from their surface excess

Activity of surface active substances determined from their surface excess

Volumetric and Viscometric Behaviour of some Amino Acids and their Group Contributions in Aqueous Tetramethylammonium Bromide at Different Temperatures

Physicochemical Properties and Biological Activity: Thermodynamic Properties of Compounds Related to Acetylcholine Assessed From Depression of Freezing‐point and Enthalpies of Dilution

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Osmotic and Activity Coefficients for the Symmetrical Tetraalkyl Ammonium Halides in Aqueous Solution at 25°1

Cited by 259 publications

References 0 publications

Activity of surface active substances determined from their surface excess

Activity of surface active substances determined from their surface excess

Volumetric and Viscometric Behaviour of some Amino Acids and their Group Contributions in Aqueous Tetramethylammonium Bromide at Different Temperatures

Physicochemical Properties and Biological Activity: Thermodynamic Properties of Compounds Related to Acetylcholine Assessed From Depression of Freezing‐point and Enthalpies of Dilution

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Osmotic and Activity Coefficients for the Symmetrical Tetraalkyl Ammonium Halides in Aqueous Solution at 25°¹