Liquid–liquid equilibria for acetophenone + n-alkane mixtures and characterization of acetophenone systems using DISQUAC Juan Antonio González a, *, Cristina Alonso-Tristán b , Isaías García de la Fuente a , José Carlos Cobos a a G.E.T.E.F., Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain b Dpto. Ingeniería Electromecánica, Escuela Politécnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain A R T I C L E I N F O Article history: Received 8 October 2014 Received in revised form 29 January 2015 Accepted 30 January 2015 Available online 2 February 2015 Keywords: Acetophenone Hydrocarbons 1-Alkanols Liquid–liquid equilibria DISQUAC Interactions A B S T R A C T Liquid–liquid equilibrium (LLE) temperatures have been determined for acetophenone + CH 3 (CH 2 ) u CH 3 (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-CH 2 and CO/hydroxyl are reported. The model correctly describes LLE diagrams and excess molar enthalpies, H E m , 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 E m , volumes, V E m , and internal energies at constant volume, U E Vm , 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, DH OH–CO , were determined. This magnitude increases with the alkanol size and remains practically constant from 1-butanol. ã 2015 Elsevier B.V. All rights reserved. 1. Introduction Acetophenone is a precursor to resins which are components of coatings and inks. Moreover, it is widely used as an ingredient in fragrances. Acetophenone derivatives have medical applications as, e.g., new agents for potential application in Alzheimer’s disease [1]. On the other hand, the study of mixtures containing an aromatic compound with a polar functional group allows investigate a number of effects such as intramolecular interactions between the phenyl ring and a polar functional group (n–p interactions). In this framework, we have reported liquid–liquid equilibrium (LLE) phase diagrams for 2-phenoxyethanol [2], N-methylaniline [3], benzylamine [4] or benzaldehyde [5] +alkane mixtures and isobaric excess molar heat capacities for benzyl- amine + heptane, or +1-alkanol systems [6]. As continuation, we provide now LLE measurements for acetophenone + decane, +dodecane, +tetradecane, or +hexadecane mixtures, and we extend the DISQUAC group contribution model [7] to solutions containing this aromatic ketone and n-alkanes, cyclohexane, benzene or 1-alkanols. DISQUAC treatments for n-alkanone + alkane [8], +aromatic hydrocarbons [9,10], or +1-alkanol [11] systems are available in the literature. It should be also mentioned that some acetophenone + n-alkane mixtures have been investigated using DISQUAC under the assumption that the interaction parameters of the carbonyl/aliphatic contacts are the same as in the correspond- ing mixtures with 2-alkanones [12]. 2. Experimental 2.1. Materials Table 1 shows the main characteristics of pure compounds used in the present work including source, purity, water contents, determined by the Karl-Fischer method, and density (r). The * Corresponding author. Tel.: +34 983 423757; fax: +34 983 423136. E-mail address: jagl@termo.uva.es (J.A. González). http://dx.doi.org/10.1016/j.fluid.2015.01.026 0378-3812/ ã 2015 Elsevier B.V. All rights reserved. Fluid Phase Equilibria 391 (2015) 39–48 Contents lists available at ScienceDirect Fluid Phase Equilibria journal homepage: www.elsevier.com/locate/fluid