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.
