Surface and Calorimetric Behavior of N,N-Dimethylacetamide with n-Alkanols or 2-Alkanols

Abstract

The surface tension at the liquid–air interface of eight binary mixtures formed by N,N-dimethylacetamide and n-alkanols (from methanol to 1-pentanol) or 2-alkanols (from 2-propanol to 2-pentanol) was studied at three different temperatures (283.15, 298.15, and 313.15 K) and a pressure of 0.1 MPa. Surface tension deviations were also calculated. Moreover, the excess molar enthalpies for all of these mixtures were measured at T = 298.15 K and a pressure of 0.1 MPa. Both deviation and excess functions were correlated with the mole fraction by means of the Redlich–Kister equation. The surface tension deviations are found to be positive for the system containing methanol, sigmoidal for ethanol and negative for the rest of the alkanols. With regard to excess molar enthalpies, negative values are found for the system containing methanol, sigmoidal values for ethanol, and positive values for the rest of the alkanols.