Thermodynamics of Mixtures Containing a Very Strongly Polar Compound. 10. Liquid–Liquid Equilibria for N,N-Dimethylacetamide + Selected Alkanes

Abstract

Liquid−liquid equilibrium (LLE) temperatures versus composition for N,Ndimethylacetamide (DMA) + decane, + dodecane, + tetradecane, + 2,2,4-trimethylpentane, + methylcyclohexane, or + cyclooctane mixtures have been measured by means of the critical opalescence method using a laser scattering technique. All the systems show an upper critical solution temperature (UCST). In the case of n-alkane mixtures, UCST increases almost linearly with the chain length of the n-alkane. Moreover, these solutions show higher UCST values than those with isomeric cyclic alkanes. Branching leads to a strong decrease of UCST. The symmetry of the LLE curves depends on the size and shape of the alkane. DISQUAC correctly represents the coordinates of the critical points using interaction parameters available in the literature.