DENSITY AND VOLUMIC PROPERTIES OF N,N-DIMETHYLFORMAMIDE -METHOXYETHANOL+1,2-DIMETHOXYETHANE LIQUID TERNARY MIXTURES(2)

Densities (rho) at various temperatures ranging from -10 up to +80 deg rees C have been measured for thylformamide+2-methoxyethanol+1,2-dimet hoxyethane ternary solvent system, employing 66 mixtures covering the whole miscibility field. Polynomial equations describing the dependenc e on temperature, rho=rho(t/degrees C), and molar composition, rho=rho (X(1),X(2)), have been checked. Furthermore, the excess molar volumes (V-E), derived from rho values, can provide useful suggestions about t he formation of solvent-cosolvent complexes. Excess molar volumes have been interpreted on the basis of specific interactions between unlike molecules, taking into account geometric effects and steric hindrance s. The V-E quantities have been isothermally fitted by an empirical re lation of the type V-E=V-E(X(1),X(2),X(3)) formally derived from the w ell known Redlich-Kister equation. As a rule, for all the here tested relationships, the calculated values agree very well with the experime ntal ones, indicating that all the equations can be safely employed fd r predictive calculations in correspondence of the experimental data g aps.