Static Dielectric Constants and Kirkwood Correlation Factor of the Binary Mixtures of N-Methylformamide with Formamide, N,N-Dimethylformamide and N,N-Dimethylacetamide

Static dielectric constant values of the binary mixtures of N-methylformamide with formamide, N,N-dimethylformamide and N,N-dimethylacetamide have been measured in the whole composition range at 303 K. The Kirkwood correlation factor values of the amide–amide mixtures were determined from the measured values of the static dielectric constant and high-frequency limit dielectric constant. The evaluated values of the excess dielectric constant and deviation in the Kirkwood correlation factor infer that deviations of their mixture values occur from the mole-fraction mixture law. Results confirm that there are strong hydrogen-bond interactions between unlike molecules of amide–amide mixtures and that 1:1 complexes are formed.