Dielectric constant and molecular association in binary mixtures of N,N-dimethylethanolamine with alcohols and amides

The hydrogen-bond molecular interactions and molar ratio of stable adduct in binary mixtures of N,N-dimethylethanolamine with alcohols (ethyl alcohol, ethylene glycol, glycerol) and amides (formamide, N,N-dimethylformamide, N,N-dimethylacetamide) have been investigated over the entire concentration range at 30 °C by dielectric measurements. The effect of molecular size, number of hydroxyl groups of alcohols molecules and the extent of substitution in amide molecules on the hydrogen-bond molecular interactions in amine–alcohols and amine–amides binary mixtures were determined using the concentration dependent values of the excess dielectric constant. Results confirm that N,N-dimethylethanolamine form expressive hydrogen-bond interactions with alcohols and behave weakly with N,N-dimethylformamide and N,N-dimethylacetamide, but these interactions are very strong with formamide.