Liquid-liquid equilibrium (LLE) temperatures have been determined for acetophenone + CH3(CH2)(u)CH3 (u = 8,10,12,14) mixtures by means of the opalescence method using a laser scattering technique. All the solutions show an upper critical solution temperature (UCST), which increases almost linearly with u. Acetophenone + benzene, or +alkane, or +1-alkanol mixtures have been treated by means of the DISQUAC model. The corresponding dispersive and quasi-chemical interaction parameters for the contacts CO/aromatic; CO/aliphatic; CO/c-CH2 and CO/hydroxyl are reported. The model correctly describes LLE diagrams and excess molar enthalpies, H-m(E), of the investigated solutions, over a wide range of temperature using the same set of interaction parameters. Mixtures with alkanes are mainly characterized by dipolar interactions. From the analysis of molar excess functions: H-m(E), volumes, V-m(E) and internal energies at constant volume, U-Vm(E), and on LLE for such systems, it is shown that interactions between acetophenone molecules are stronger than those between 2-hexanone or 2-octanone molecules and that they are similar to acetone-acetone interactions. Thus, the phenyl ring in acetophenone leads to strengthened interactions between alkanone molecules. Dipolar interactions are also important in mixtures containing 1-alkanols, and become more relevant in solutions with longer 1-alkanols. The enthalpy of the alcohol-acetophenone interactions, Delta HOH-CO, were determined. This magnitude increases with the alkanol size and remains practically constant from 1-butanol. (C) 2015 Elsevier B.V. All rights reserved.