Fluid Phase Equilibria 338 (2013) 30–36 Contents lists available at SciVerse ScienceDirect Fluid Phase Equilibria journa l h o me page: www.elsevier.com/locate/fluid Vapor–liquid equilibrium for the ternary carbon dioxide–ethanol–nonane and decane systems Miguel G. Arenas-Quevedo a , Luis A. Galicia-Luna a,∗ , Octavio Elizalde-Solis b , José A. Pérez-Pimienta c a Laboratorio de Termodinámica, SEPI-ESIQIE, Instituto Politécnico Nacional, UPALM, Ed. Z, Secc. 6, 1 ER piso, Lindavista, C.P. 07738 México, D.F., Mexico b Departamento de Ingeniería Química Petrolera, ESIQIE, Instituto Politécnico Nacional, UPALM, Edif. 8, 2 ◦ piso, Lindavista, C.P. 07738 México, D.F., Mexico c Departamento de Ingeniería Química, Área de Ciencias Básicas e Ingenierías, Universidad Autónoma de Nayarit, Edificio E2, Ciudad de la Cultura Amado Nervo, C.P. 63155 Tepic, Nayarit, Mexico a r t i c l e i n f o Article history: Received 18 May 2012 Received in revised form 8 October 2012 Accepted 16 October 2012 Available online 23 October 2012 Keywords: Vapor–liquid equilibrium Carbon dioxide Ethanol Nonane Decane a b s t r a c t In this work, experimental vapor–liquid equilibrium (T, p, x i , y i ) data for the ternary carbon dioxide–ethanol–nonane and carbon dioxide–ethanol–decane systems are reported in the temperature range of 313–373 K from low pressures to the nearest of the corresponding critical pressure. Measure- ments were performed in an apparatus based on the static-analytic method with an on-line ROLSI sampler-injector device. Vapor–liquid equilibrium (VLE) data for both ternary systems are predicted using the Peng–Robinson equation of state coupled to the Wong–Sandler, one parameter van der Waals and two parameters van der Waals mixing rules. Binary interaction parameters are obtained from the VLE data of binary mixtures reported in the literature. © 2012 Elsevier B.V. All rights reserved. 1. Introduction The study of phase equilibrium behavior of multicomponent systems is necessary in order to understand and establish the tem- perature (T) and pressure (p) conditions where phases coexist. Thermodynamic models are used to represent the phase behav- ior of multicomponent mixtures; however, in some cases these models are not enough accurate and give an approximation of the phase behavior. Therefore, experimental data is the basic informa- tion that can be obtained accurately [1,2]. Experimental methods for the determination of phase equilibrium data are classified with the aim of selecting the one suitable based on the involved phases [3,4]. The vapor liquid equilibrium behavior for carbon diox- ide + alkanol + alkane systems is scarcely available in the literature [5–9]. These studies are about critical end points, critical lines, mis- cibility windows and isothermal phase diagrams utilizing linear alkanols (pentanol to dodecanol) and alkanes (tetradecane to tetra- cosane). However, there is a lack of VLE data for short carbon chains of alkanes and alkanols. As a continuation of a previous work, we present the vapor–liquid equilibrium behavior for the ternary systems carbon ∗ Corresponding author. Tel.: +52 55 5729 6000x55133; fax: +52 55 5586 2728. E-mail address: lgalicial@ipn.mx (L.A. Galicia-Luna). dioxide + ethanol + nonane or decane at three temperatures in a wide range of pressure. The experimental VLE results are com- pared with the prediction using the Peng–Robinson equation of state with classical and Wong–Sandler mixing rules. Separation fac- tors between solutes are calculated from experimental vapor and liquid phase compositions. 2. Experimental 2.1. Materials Properties of chemicals [10] are listed in Table 1. Carbon dioxide of supercritical grade was supplied from Infra Air-Products. Ethanol was purchased from Merck Chemicals and alkanes were provided by Sigma–Aldrich. These were used as received with no previous purification stage. Water content was determined in a Karl–Fisher coulometer and are presented in Table 1 as well as certified purities. 2.2. Apparatus The experimental apparatus where measurements were car- ried out is based on the static–analytic technique. Details of the operating principle and its reliability for VLE measurements were described in previous papers [11,12]. The apparatus is mainly con- stituted by a 100 cm 3 high-pressure view-cell made of titanium alloy, a gas chromatograph (Hewlett-Packard, 5890 series II). Both 0378-3812/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fluid.2012.10.012