Study of ion-solvent interaction of some tetraalkylammonium and common ions in N-methylacetamide from apparent molal volume data

Abstract

The apparent molal volumes, s, of six tetraalkylammonium iodides, namely, Et4NI to Hep4NI, have been determined in N-methylacetamide (NMA), at different temperatures and concentrations from which the limiting apparent molal volumes, ,°s, have been obtained for these salts. The results indicate that the vs. -\/c curves are almost straight lines for all the salts in the concentration range studied here. The curves for Et4NI and Pr4NI salts have a positive slope, and those for Bu4NI, Pen4NI, Hex4NI, and Hep4NI have a negative slope.Also °of the R4N iodides increases with the rise in temperature; however, / decreases with the rise in temperature for the smaller R4N iodides, while it remains almost temperature independent for the larger R4N iodides. Common electrolytes behave more or less like the smaller R4N iodides although °/ even becomes negative in these cases. An attempt has been made to explain these results from the point of view of electrostatic solvation and electrostriction in the case of smaller R4N+ ions and from the penetration and the relative volume effects for the larger R4N+ ions.(1) Work supported by the Council of Scientific and Industrial Research (CSIR), India,(2) (a) To whom requests for reprints should be addressed at the De-

Apparent molar volumes and isentropic compressions of benzylalkylammonium ionic liquids in dimethylsulfoxide from 293.15 K to 328.15 K

“…On the other hand, the slope, S v shows that the ionion interactions. In generally, S v is positive, but it can be negative for some electrolytes; particularly for tetraalkylammonium salts [52][53][54], and also have been observed in this work, values of V m 1 , S v and B v for the ILs + DMSO systems were obtained at various temperatures by a linear regression analysis, and the results are listed in Table 4 along with their the standard deviations. It was found that the apparent molar volumes at infinite dilution, V m 1 for the ILs increase with the increase in the methyl group in the cation/ anion part of ILs at a particular temperature.…”

“…The k s (solvent intrinsic) is the isentropic compression due to the compression of solvent molecules (DMSO), while k s (solute intrinsic) is the isentropic compression due to the compression of the hydration shell of ions or penetration of solvent molecules into the ILs [52].…”

On the nature of tetraalkylammonium ions in common electrochemical solvents: General and specific solvation – Quantitative aspects

“…They found that four water molecules are tightly associated with the organic cation, in addition to several more distant and more loosely associated water molecules. Gopal and Siddiqi suggested from partial molar volume measurements that Me 4 N + , Et 4 N + and Pr 4 N + are specifically solvated in N-methylacetamide, but that larger ions are not [15]. Gill reported that the apparent ionic radius of Me 4 N + ion in a variety of solvents is larger than its crystallographic radius, which would be consistent with it bearing a solvent shell [16].…”

Volumetric behavior of a bolaamphiphile in different amides–water and ethylene glycol–water mixtures

“…In pure FA, the DHLL slope S v at 298.15 K is 1.104 calculated by Dunn [19] from experimentally determined ∂ ln ε/∂P data (ε, dielectric constant; P , pressure) according to the Redlich equation. However negative S * v has been found for a number of electrolytes in FA and in different other solvents [18,[20][21][22][23] as well as in aqueous solutions. Going from higher to lower compositions, there is a change in the sequence of φ V curves, after 25% in EG/W and after 75% in FA/W.…”