Ionic mobility and ionic association of singly charged ions in glycerol

Abstract

Experimental molar conductivity data for KCl, NaCl and LiCl in glycerol at 298.15 K were analysed by least-square fitting in the concentration range 0.5-100 mol m À3 in order to compute the values of the molar conductivity at infinite dilution à 0 and the Onsager constant S. Using previously measured transference numbers and assuming the Kohlrausch infinite dilution law, the limiting ionic mobilities were deduced. The results obtained show that the transport mechanisms in this solvent and other similar hydrogen-bonded solvents such as water and ethylene glycol are the same. The data were also interpreted in terms of ion-ion and ion-solvent interactions using the Fuoss paired ion model in the concentration range 0.5-100 mol m À3 . The fitting of Fuoss' equation of 1978 to these data led us to an estimate of the ionic association by computing the conductimetric pairing constants. The latter were further analysed by Gilkerson's equation to yield the difference between the solvation energy of the free ions and the ion pairs. The computed values allow an estimation of whether the electrolyte is a structure maker or a structure breaker.

Hydrogen-substituted β-tricalcium phosphate synthesized in organic media

“…Notably, neither the temperature nor the precursor Ca/P ratio nor the total concentration had an effect on the final Ca/P ratio in the crystals, indicating that the Ca deficiency is not the result of limited Ca ion supply or diffusion during crystallization. This conclusion is in line with the fact that the Ca/P ratio was identical in platelets produced in glycerol, a solvent exhibiting a 30-fold lower ionic mobility compared with ethylene glycol due to its higher viscosity (Kameche et al, 2005). Also, since the final stoichiometry was independent of the reaction time (varying from 1 min to 24 h), the Ca deficiency cannot be a result of Ca diffusing out of the crystals after their formation.…”

A Flexible Ionic Polymer for “Soft Machines” – Where is the Low Temperature Limit?

“…One of reasons for high conductivity of proposed hydrogels is optimal content of solvent embedded within the polymer matrix that ensures good mechanical strength without sacrificing the ionic mobility. With this, electrolytes proposed in this study surpass the conductivity threshold reported for polymer electrolytes used in leakage-free (flexible, stretchable) energy sources (up to 10 À 4 S cm À 1 [28] ). Notably, the effect of glycerol content on ionic conductance at room temperature is significant (Figure 4a).…”

Solution Properties of Inorganic Contamination in Mixed Solvents: Theory, Progress, and Limitations

“…Table 6 lists the mixed-solvents electrolyte solutions for which association and stability data were available. The majority of the data are for symmetrical univalent electrolytes, particularly alkali halides, in pure nonaqueous (Hoshina et al, 2004;Kameche et al, 2005;Wurm et al, 2005) and mixed aqueous-organic solvents. In comparison, little information was available for symmetric polyvalent (Molinou and Tsierkezos, 2001;Molinou, 2000, 2006) and unsymmetric electrolytes (K 2 SO 4 , Na 2 SO 4 , Cd(NO 3 ) 2 , CdCl 2 , CaCl 2 , Ca(NO 3 ) 2 , CoCl 2 , and Zn(NO 3 ) 2 ) in nonaqueous (e.g., Gibson et al, 2006;Pura, 2007) or mixed solvents (Fujii et al, 2006;Qiao et al, 2008).…”