Intermolecular Interactions in Liquid N-methylformamide-dioxane Mixtures Found by Measuring Their ¹H-NMR Spectra, Densities, Viscosities and Relative Dielectric Permittivities

Abstract

The ¹H-NMR spectra of liquid binary mixtures, N-methylformamide (NMF)-dioxane (Dx), were recorded at 298 K within nearly the whole range of the mixed solvent compositions. From these data the values of the spectral parameter, Δδ(NMF-Dx) were found. The densities and viscosities of the mixed solvents were measured at 298.15 K, as well as the dielectric permittivities at 293.15 K, 298.15 K, 303.15 K and 308.15 K. From all these new parent data, the values of molar volumes (V₁₂), kinematic viscosities(α₁₂/d₁₂) and their deviations from “ideality” were calculated. Additionally, the values of the temperature coefficients of dielectric permittivity, α₁₂ = (1/∊) · [d∊/d(1/T)], were found. The scrutiny of all these structural parameters as functions of the mixture composition points to the formation of a “complex” (sub-unit) of the 2NMF · Dx type in the bulk of the mixed solvents.

Key Words:

• ¹H-NMR spectra
• intermolecular interactions in the liquid mixtures