Volumetric and steric properties of hydroxamic acids in ethanol at different temperatures

Physical properties, such as density, ρ and refractive index, n of two hydroxamic acids (N-Phenylbenzo, C6H5NOH·C6H5CO and N-o-tolylbenzo, o-CH3·C6H4NOH·C6H5CO) have been measured in ethanol as a function of concentration at T = (298.15, 303.15, and 308.15) K. The apparent molar volume, VϕVϕ, apparent molar volume at infinite dilution, Vϕ0 and the slope, SV∗ are calculated from the experimental value of density, ρ   by applying the Masson’s equation. The apparent molar expansibility at infinite dilution, ϕE0, molar volume, V and the excess molar volume, VE are also computed. The refractive index, n, data have been used to calculate the steric parameters viz. molar refraction, RM, excess refractive index, nE  , excess molar refraction, RME and polarizability, α of these molecules. The results obtained have been qualitatively used to interpret the solute–solute and solute–solvent interactions between hydroxamic acids and ethanol.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Density, ρ and refractive index, n of PBHA and o-TBHA are measured in ethanol at different temperatures. ► From the experimental value of ρ and n  , VϕVϕ, Vϕ0, SV∗, ϕE0, V, RM, RS and α are calculated. ► Excess properties such as VE  , RME, nE are also computed. ► The behaviour of these parameters suggests that PBHA and o-TBHA act as structure maker in ethanol.