Viscosity B Coefficients for Some Homologous Series of Organic Electrolytes in Aqueons Solutions. The Effect of Ionic Groups

Abstract

The viscosity B coefficients for the three homologous series of sodium alkane carboxylates (acetate to butyrate), sodium n-alkyl sulfonates (methyl to hexyl), and n-alkylammonium chlorides (methyl to hexyl) in aqueous solutions at 25 °C have been determined. The B values increase linearly with the number of carbon atoms in the alkyl chains for each homologous series studied in this work, as well as for a homologous series of n-alkyl sulfate ions previously studied. In the case of the three kinds of organic anions with the same alkyl groups, the B values increase in the order: –COO−>>–SO3−>–OSO3−. The ion-solvent interaction effect, as estimated by the combination of the B values with the molal volume at an infinite dilution for ions, is positive for each carboxylate ion; however, it is negative for the lower alkyl sulfonate, alkyl sulfate and alkylammonium ions. From these facts, –COO− may be classified as an “electrostrictive structure-maker,” whereas, –SO3−, –OSO3−, and –NH3+ are “electrostrictive structure-breakers.” In this connection, the reported specific interactions of these ionic parts with simple counter-ions on the activity coefficients of organic electrolytes, the counter-ion binding of polyelectrolytes, and the effect of counter-ions on the critical micelle concentrations of long-chain electrolytes are briefly discussed on the basis of the change in water structure induced by both cations and anions in water.

Hydration and hydrogen bond network of water around hydrophobic surface investigated by terahertz spectroscopy

“…42 From a thermodynamical point of view, the -COO − group is a "structure-maker," while the -NH 3 + group acts as a "structure-breaker." [43][44][45][46][47] These observations, in combination with recent MD simulations where the -COO − group accommodates more HBs with the proximal water molecules than -NH 3 + , 48,49 imply hydrophilic hydration is dominated by the strong hydration capacity of the -COO − group, with a relatively small contribution from the -NH 3 + group. Based on the RDF of glycine aqueous solution, Campro 49 calculated the to- tal number of HBs between glycine and water, 5.7, which is larger than our result n hyd (gly) = 1.9; suggesting large fraction of the water molecules (i.e., 5.7 − 1.9 = 3.8 molecules) forms relatively weak HBs with the glycine solute, and thus, their reorientational dynamics are hard to distinguish from those of bulk water.…”

“…Hydrophobicity of the amino acid side chain (π) is calculated by the equation: π = log P(amino acid) − log P(glycine), where P is the partition coefficient of the amino acid and of glycine in octanol/water. 43 Although a linear positive correlation was observed, it should be noted that both hydrophobic hydration and hydrophilic hydration are counted as hydration water (except for glycine, where hydrated water is entirely originated from hydrophilic nature of polar groups in the amino acid backbone; while the other three amino acids have additional hydrophobic side chains, -CH 2 -). Our estimate of n hyd (gly) = 1.9 represents the hydrophilic hydration capacity of the amino acid backbone.…”

Transport Properties for Aqueous Sodium Sulfonate Surfactants

“…In the premicellar solutions of alkyl sulfonate the viscosity follows the relation (29) ϭ 0 ͑1 ϩ BC͒, [11] where 0 is the water viscosity and B is an interpolating coefficient. For a low number of carbon atoms in the hydrocarbon chain, n C ϭ 1-6, the following was found (in mol Ϫ1 dm 3 ) (29):…”

Complex Formation between Dodecylpyridinium Chloride and Multicharged Anionic Planar Substances

“…In the case of the dye with a dispersed charge arrangement (Figure B), on the other hand, the disordered water structure around the sulfonato group , weakens the hydrophobic interaction between the hydrophobic parts of the surfactant and dye.…”