Published: February 22, 2011 r2011 American Chemical Society 521 dx.doi.org/10.1021/je101035p | J. Chem. Eng. Data 2011, 56, 521–526 ARTICLE pubs.acs.org/jced Liquid-Liquid Equilibria of the (Water þ Ethanol þ Linalyl Acetate) Ternary System at Different Temperatures Aslı G€ ok, † Fatma Cebeci, † Hasan Uslu, ‡ and S - . : Ismail Kırbas - lar* ,† † Chemical Engineering Department, Engineering Faculty, : Istanbul University, 34320 Avcilar, : Istanbul, Turkey ‡ Chemical Engineering Department, Engineering & Architecture Faculty, Beykent University, 34500, : Istanbul, Turkey ABSTRACT: Liquid-liquid equilibrium (LLE) data of the solubility curves and tie-line compositions were examined of the (water þ ethanol þ linalyl acetate) system at T = (298.2, 308.2, and 318.2) K and P = 101.325 kPa. The relative mutual solubility of ethanol is higher in the water phase than in the linalyl acetate phase. The consistency of the experimental tie lines was determined through the Bachman correlation equation. The experimental LLE data were satisfactorily correlated with the nonrandom two-liquid model (NRTL), and the binary interaction parameters so obtained are reported. The best results were obtained with the NRTL method, using nonrandomness parameter (R = 0.3) for the correlation. Distribution coefficients (D) and separation factors (S) were evaluated over the immiscibility region. The influence of temperature on the LLE characteristics was found to be significant at the temperatures studied. ’ INTRODUCTION Citrus oils contain not only volatile components such as monoterpenes and sesquiterpenes and oxygenated compounds (alcohols, esters, aldehydes, ketones, etc.) but also nonvolatile compounds (methoxylated flavones, carotenoids, etc.). Citrus oils separate industrially by cold-press or steam-distillation methods. The oxygenated compounds of the citrus oils are more valuable than hydrocarbons. The oxygenated compounds can be separate from terpenes economically by the liquid-liquid ex- traction method. The volatile components of the citrus oil are completely soluble in ethanol but not completely soluble in water. The citrus oil, which contained ethanol, are mainly demanded by commercial companies for the following three reasons: (a) The ethanol-contained citrus oil is fairly soluble in aqueous solutions. Therefore, this mixture can be used to formulate drinks and fra- grances. (b) Oxidation reactions are decreased in the existence of the alcohol. (c) Ethanol increases the aromatic strength of the mixture. 1 Bergamot peel oil has a large importance in perfumery and food applications. The main component of the bergamot oil is linalyl acetate (3,7-dimethyl-1,6-octadien-3-yl-acetate; Figure 1). Linalyl acetate is an oxygenated component which involves over 35 % of the bergamot peel oil constituents. Linalyl acetate is used as an intermediate substance and is found in cleaning products, cosmetics, soft drinks, and chewing gum. 2,3 The liquid-liquid equilibrium (LLE) studies supply necessary information for the design and optimization of separation processes. Nevertheless, the solvent extraction technique is limited by the lack of LLE data for systems containing citrus oil components, water, and ethanol at some temperatures. 4 A number of investigations have been carried out in recent years on the LLE measurements by the some researchers. 5-11 The aim of this study is examined on the phase behavior of LLE for the (water þ ethanolþ linalyl acetate) system. For this system, three different temperatures, T = (298.2, 308.2, and 318.2) K, were chosen to study to observe the change of the equilibrium characteristics. ’ EXPERIMENTAL SECTION Materials. All chemicals used were chromatography-grade products supplied by Merck Co. with nominal purities of w < 0.99 for ethanol and w < 0.95 for linalyl acetate. NANO pure water was used throughout all of the experiments. These purities were verified by gas chromatography, and the chemicals were used without further purification. Apparatus and Procedure. Refractive indices and densit- ies were measured with an Anton Paar refractometer (RXA 170 model) and Anton Paar densimeter (DMA 4500 model), re- spectively. The estimated uncertainties in the refractive indices and density measurements were ( 5 3 10 -5 and ( 1 3 10 -2 kg 3 m -3 , Figure 1. Linalyl acetate structure. Table 1. Experimental and Literature 12 Properties of the Pure Components at T = 293.2 K and P = 101.325 kPa a F/(kg 3 m -3 ) n D T b /K compound expt. lit. expt. lit. expt. lit. linalyl acetate 895.06 895.1 1.45445 b 1.4544 b 493.2 493.2 ethanol 789.26 789.3 1.36115 1.3611 351.4 351.4 water 998.24 998.23 1.33304 1.3330 373.3 373.3 a Density (F); refractive indices (n D ); boiling point (T b /K). b 294 K. Received: October 13, 2010 Accepted: February 1, 2011