Vapor-Liquid Equilibrium of Binary Mixtures Containing Ethyl Acetate + 2-Methyl-1-propanol and Ethyl Acetate + 2-Methyl-1-butanol at 101.3 kPa Jose ´ M. Resa,* Jose ´ M. Goenaga, and Juan Lanz Departamento de Ingenierı ´a Quı ´mica, Universidad del Paı ´s Vasco, Apartado 450, 01006, Vitoria, Spain Miguel Iglesias Departament d’Enginyeria Quı ´mica, Escola Te `cnica Superior d’Enginyeria Quı ´mica, Universitat Rovira i Virgili, Avinguda Paı ¨sos Catalans 26, Campus Sescelades, 43007 Tarragona, Espan ˜a Isobaric vapor-liquid equilibria (VLE) data at 101.3 kPa were reported for the binary mixtures ethyl acetate + 2-methyl-1-propanol and ethyl acetate + 2-methyl-1-butanol. VLE experimental data were tested for thermodynamic consistency by means of a modified Dechema test and were demonstrated to be consistent. The activity coefficients were correlated with the Margules, van Laar, UNIQUAC, NRTL, and Wilson equations. The ASOG model also was used for prediction. Introduction This work is part of a research project whose objective is to measure thermodynamic properties and vapor-liquid equilib- rium (VLE) data for binary systems involved in wine distillation processes for subsequent simulation. 1-5 In this process, multi- component mixtures are present with the main components being water and ethanol, with several minor compounds such as alcohols, aldehydes, and acetates present. These minor com- pounds are called congeners. For modeling and process simula- tion in such mixtures, binary data are needed. By this, it is very important to have available vapor-liquid equilibrium data of mixtures formed by water + congeners, ethanol + congeners, and congeners + congeners. From measurements, parameters of the Wilson, NRTL, and UNIQUAC equations can be calculated, and the results can be applied to simulate the distillation of wine. Experimental Section Ethyl acetate mole fraction (x > 0.998) and 2-methyl-1- propanol (x > 0.995) were supplied by Fluka, and 2-methyl- 1-butanol (x > 0.99) was supplied by Aldrich. 2-Methyl-1- butanol was purified by distillation in a laboratory column of 100 plates; the purity of the material was checked by gas- liquid chromatography (GLC x > 0.997). All products were degassed using ultrasound and dried over molecular sieves (type pore diameter, 3‚10 -3 m from Fluka) before use. Densities, refractive indices, and boiling points of the pure substances are given in Table 1 and compared with literature values. 6 Instru- mentation and apparatus specifications are defined in refs 1 and 2. Standard curves of density versus mole fraction were used to calculate the compositions of the vapor and liquid phases. All samples were prepared by weighing with a Salter electronic balance (model ER-182A, uncertainly ( 0.0001 g). The uncertainty of comparison measurements was estimed to be ( 0.001 mole fraction. Table 2 shows the density composition values. Results and Discussion The activity coefficients γ i of the components were calculated from where x i and y i are the liquid and vapor mole fractions in equilibrium, φ i is the fugacity cofficient, P is the total pressure, and P i 0 is the vapor pressure of pure component i. * Corresponding author. E-mail: iqpredij@vc.ehu.es. Table 1. Physical Properties of Pure Compounds: Densities G, Refractive Indices nD, Speeds of Sound u at 298.15 K and Normal Boiling Points Tb F/(kg‚m -3 ) nD u/(m‚s -1 ) Tb/K obs lit. a obs lit. a obs lit. obs lit. a ethyl acetate 894.3 894.5 1.36978 1.36978 1139.6 1137.66 b 350.15 350.261 2-methyl- 1-propanol 797.8 797.8 1.39366 1.39389 1186.4 1185.63 b 380.93 381.036 2-methyl- 1-butanol 814.7 815.0 1.40866 1.40860 1251.8 1253.29 c 401.93 401.850 a Riddick et al. 6 b Resa et al. 2 c Resa et al. 17 Table 2. Densities G for Ethyl Acetate (1) + 2-Methyl-1-propanol (2) and Ethyl Acetate (1) + 2-Methyl-1-butanol (2) at 298.15 K ethyl acetate (1) + 2-methyl-1-propanol (2) ethyl acetate (1) + 2-methyl-1-butanol (2) x1 F/(kg‚m -3 ) x1 F/(kg‚m -3 ) 0.049 802.3 0.050 817.8 0.101 806.8 0.099 820.9 0.153 811.5 0.150 824.2 0.202 816.0 0.200 827.5 0.251 820.6 0.250 830.9 0.300 825.2 0.300 834.4 0.350 829.9 0.349 838.0 0.401 834.7 0.399 841.7 0.451 839.5 0.451 845.6 0.501 844.3 0.499 849.4 0.550 849.0 0.549 853.3 0.600 853.8 0.598 857.3 0.650 858.8 0.650 861.6 0.700 863.7 0.699 865.8 0.751 868.9 0.750 870.2 0.801 873.8 0.793 874.2 0.850 878.7 0.846 879.1 0.900 883.8 0.900 884.2 0.950 888.9 0.950 889.1 γ i ) y i Φ i P x i P i 0 (1) 595 J. Chem. Eng. Data 2006, 51, 595-598 10.1021/je050420+ CCC: $33.50 © 2006 American Chemical Society Published on Web 02/01/2006