Dilute solutions of formamide in carbon tetrachloride were studied by infrared spectroscopy in order to detect, characterize, and measure the bands of the formamide dimers. The structural and spectroscopic properties of these dimers, open or cyclic, were calculated using DFT procedures, with the B3LYP functional and 6-31G(d,p) or 6-31++G(d,p) basis sets, allowing proper assignments for the mentioned bands. Although a planar structure was predicted by the calculations for the monomer and cyclic dimer of formamide, in agreement with other authors, a nonplanar structure was found for the donor formamide molecule in the open dimer. Measurements made with solutions of different concentrations and at different temperatures allowed an estimation of the equilibrium constants between formamide and its dimers and of the corresponding dimerization enthalpies. Acceptable agreement was found between these experimental enthalpies and theoretical values after taking into account the solvation effects.

Density, viscosity, and refractive index measurements of pure formamide and of formic, acetic, and propionic acids in the temperature range (298.15 to 313.15) K were made. Additionally, measurements of the same properties and in the same temperature range were made on the following mixtures: formamide + (formic acid, or + acetic acid, or + propionic acid). The results were fitted to empirical equations, whose calculated values are in agreement with the experimental ones.

Measurements of density, viscosity, and refractive index in the T = (283.15 to 353.15) K temperature range at atmospheric pressure and vapor pressure over the P = (1.0 to 96.7, or 96.0, or 95.2, or 50) kPa pressure range for α-pinene, d-limonene, (±)-linalool, and citral, respectively, were made. The temperature dependence of these properties was fitted to empirical relations. The molar enthalpy of vaporization for these chemicals was calculated plotting the logarithm of the vapor pressure against the reciprocal temperature and using the Clausius−Clapeyron equation. The enantiomer ratios of α-pinene, d-limonene, and (±)-linalool were also obtained.