The liquid−liquid equilibrium (LLE) curves for (phenylmethanol
+ CH3(CH2)nCH3) mixtures (n = 5, 6, 8, 10, 12) have been obtained
by the critical opalescence method using a laser scattering technique. All of the
systems show an upper critical solution temperature (UCST). In addition, the
LLE curves have a rather horizontal top, and their symmetry depends on the
alkane size. The UCST increases almost linearly with n. For systems including a
given alkane and phenol or phenylmethanol, the UCST is much higher than that
of the corresponding mixtures with hexan-1-ol or heptan-1-ol. This reveals that
dipolar interactions are stronger in solutions with aromatic alcohols. Preliminary
DISQUAC interaction parameters for OH/aliphatic contacts in the investigated
systems were obtained. It is remarkable that the coordinates of the critical points
of (phenol or phenylmethanol + alkane) mixtures can be described using the
same quasichemical interaction parameters for the OH/aliphatic and OH/
aromatic contacts.
