Liquid–liquid and vapor–liquid equilibrium data for biodiesel reaction–separation systems Diogo I. Segalen da Silva a , Marcos R. Mafra a , Fabiano Rosa da Silva b , Papa M. Ndiaye a , Luiz P. Ramos b , Lucio Cardozo Filho c , Marcos L. Corazza a,⇑ a Department of Chemical Engineering, Federal University of Paraná (UFPR), CEP 81531-990, Curitiba, PR, Brazil b Department of Chemistry, Federal University of Paraná (UFPR), CEP 81531-990, Curitiba, PR, Brazil c Department of Chemical Engineering, Maringá State University (UEM), CEP 87020-900, Maringá, PR, Brazil highlights " We measured phase equilibrium data for the system involving biodiesel, methanol, ethanol, glycerol and soybean oil. " VLE and LLE data were measured for binary and ternary systems. " The boiling point temperatures were obtained using Othmer-type ebulliometer. article info Article history: Received 2 April 2012 Received in revised form 18 February 2013 Accepted 25 February 2013 Available online 13 March 2013 Keywords: Biodiesel Soybean oil Vapor–liquid data Liquid–liquid data Methanol abstract This work reports experimental vapor–liquid and liquid–liquid equilibrium data for binary and ternary systems comprised of various mixtures of biodiesel (from soybean oil), methanol, ethanol, glycerol and soybean oil. The binodal curves for biodiesel + methanol + glycerol, biodiesel + ethanol + glycerol, biodie- sel + methanol + soybean oil and biodiesel + ethanol + soybean oil systems were obtained at two different temperatures by titration. An Othmer-type ebulliometer was used for vapor–liquid equilibrium measure- ments at pressures ranging from 14.0 kPa to 92.0 kPa. Binodals curves (LLE) indicated that the tempera- ture range used in this study has no effect on the immiscibility region for the biodiesel + methanol + soybean oil system. By contrast, for the biodiesel + ethanol + soybean oil system, the immiscibility region was larger at the lower temperature. For the vapor–liquid equilibrium data, the results showed that the addition of glycerol to the biodiesel + ethanol binary system does not signif- icantly affect the boiling temperature of the system while with the addition of methanol to the biodie- sel + soybean oil system the boiling temperatures of the ternary mixture are reduced. These results can be used to enhance the reaction conversion and the purification processes associated with biodiesel production. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Due to environmental problems and economic issues related to the use of fossil fuels, intensive research has been carried out in the past decade with the main objective of developing renewable and economically sustainable alternative energy sources. Derivatives of vegetable oils and animal fats, known as biodiesel, obtained through chemical transformation processes constitute an interest- ing alternative to fossil fuels, in so far as their use contributes to reducing emissions of the main gases related to global warming and the dependence of certain countries on diesel [1,2]. Biodiesel can be produced through the transesterification of vegetable oils and animal fats or the esterification of free fatty acids by means of acid, alkaline or enzymatic catalysis, in homoge- neous or heterogeneous media [3–5]. An analysis of the Brazilian Program for Production and Use of Biodiesel (PNPB) shows that soybean oil is the main raw material used for this purpose, accounting for 77.90% of the national production, compared with 3.50% for cottonseed oil, 16.15% for beef tallow and only 2.45% of other fatty materials [6]. Due to factors related to process simplification, biodiesel is commonly produced by homogenous catalysis using methanol and NaOH as catalyst. Purification is carried out in a sequence of unit operations which include removal of the free glycerol, excess alcohol and residual catalyst. The purification process includes sev- eral techniques, for instance, washing with distilled water and acid, 0016-2361/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2013.02.059 ⇑ Corresponding author. Tel.: +55 41 3361 3587. E-mail address: corazza@ufpr.br (M.L. Corazza). Fuel 108 (2013) 269–276 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel