Structure and hydrogen bonding in binary mixtures of N,N-dimethylformamide with some dipolar aprotic and protic solvents by dielectric characterization

Abstract

512-519The low frequency limit static dielectric constant, optical frequency dielectric constant, excess dielectric constant, and the Kirkwood correlation factor of the binary mixtures of N,N-dimethylformamide with water, ethyl alcohol, ethylene glycol, glycerol, dimethyl sulphoxide, acetone and 1,4-dioxane over the entire composition range are investigated at 30oC. The values of these functions emphasize strong N,N-dimethylformamide-water hydrogen bond interaction due to breaking of water tetrahedral structure, whereas the N,N-dimethylformamide-alcohols complexations show a strong hydroxyl group number dependence with enhancement in the structural ordering of alcohols. The dielectric functions of N,N-dimethylformamide-water and N,N-dimethylformamide-1,4-dioxane mixtures reveal the similarity in the complexes, although the N,N-dimethylformamide-water interactions are stronger. The excess functions confirm the weak hydrogen bond interactions of N,N-dimethylformamide with dimethyl sulphoxide and acetone. The pronounced deviation in the excess functions of the studied mixtures confirms the formation of a stable adduct of stoichiometric ratio 1:1 in these systems