Static, Microwave, Infrared, and Visible Permittivity Related to Chemical Structure:N-Methylacetamide, N,N-Dimethylacetamide, and Their Mixtures in CCI, at 32 C

Static dielectric permittivities, eo, and visible refractive indices, nI, (at the sodium doublet X = 589.3 nm) are reported forN-methylacetamide (NMA), N,N-dimethylacetamide (DMA), their mixtures with CCl, over a broad concentration range,and NMA-DMA mixtures over a broad range of concentrations at 32 OC. UHF and microwave complex permittivities from0.3 to 90 GHz and far-infrared refractive indices at F = 130 and 3 = 380 cm-' for NMA and their mixtures with CC4 andat F = 130 cm-' for DMA-CC14 mixtures up to 1 M DMA at 32 OC are also reported. Dramatic differences between NMAand DMA in both the static permittivities and relaxation times (for both pure liquids and their mixtures in CCl.,) are attributedto chain formation through H bonding for the monosubstituted amides. DMA acts as a kind of "chain-terminator" whenadded to NMA. The difference in behavior between the two liquids disappears in the cases of infrared permittivities andvisible nD2 values.