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ISOBARIC VAPOR-LIQUID EQUILIBRIA FOR THE BINARY SYSTEM OF 4 -METHYL-2 -PENTANONE WITH 1 -BUTANOL AT 20 AND 101. 3 KPA. Nelson Martíneza, Estela LLadosaa, Ma. Cruz Burgueta, Juan B. Montóna and Marlin Yazimonb a. Departamento de Ingeniería Química, ETSE, Universitat de València, 46100 Burjassot, Valencia, España de genie chimique et genie des procedes, iut A Lyon 1 Lyon France b. Departament Introduction Usually, a mixture of different alcohols with ketones forming azeotropes is very common product. Therefore, the purification of the ketones and recovery of the alcohols for recycling is usually impracticable by distillation. The separation can be improved making a simple change in pressure, provided that the azeotropic composition is sensitive to pressure “pressure swing distillation” In this work it has been studied the binary systems formed for 4 -methyl-2 -pentanone (MIBK) + 1 -butanol at isobaric conditions. at 20 and 101. 3 k. Pa, with the purpose of studying the influence of the pressure in the composition of the azeotropic mixture. Experimental section • A dynamic-recirculating still equipped with a Cottrell circulation pump was used in the equilibrium determinations (Figure 1). The system was kept at the boiling point for at least 30 min to ensure that the steady state was reached. Then, samples of liquid and condensate vapor were taken for analysis. § Compositions of the liquid and condensed vapor phase samples were determined by gas chromatography. § The accuracy of experimental measurements was 0. 01 K in temperature, 0. 1 k. Pa in pressure, and 0. 001 in mole fraction. Figure 1 Experimental equipment 1. 2. 3. 4. 5. 6. Immersion heater Cottrell pump Column Mixing chamber Magnetic stirrer Solenoid coil and valve hood 7. Pt-100 sensor Experimental results The Experimental data for the binary system are presented in the figure 2 at 20 k. Pa and 101. 3 k. Pa and compared with the results found in the literature We can to observed the strong dependency of azeotropic compositions on pressure The VLE data presented were found to be thermodynamically consistent using the Fredenslund test at both pressures. Figure 2. T-x-y diagrams of the system MIBK-1 Butanol at 101. 3 k. Pa and 20 k. Pa Experimental data (. ), Tamir et al [1] (o), Cabezas [2] (∆) and Wilson model (––) Thermodynamic Modeling • The activity coefficients of the solutions were correlated by Wilson, NRTL and UNIQUAC models. The results of this correlation are shown in Table 1, with the systems formed for methyl isobutyl ketone+ 1 -butanol The results show that all models fitted the experimental data of these systems at both pressures very well. § The figure 3 show the excess Gibbs energy for the liquid phase at 20 k. Pa y 101. 3 k. Pa, from which it is concluded that positive deviations from ideality are present in the liquid phase. Moreover, values for the excess Gibbs energy, decrease as the pressure increases for a given mol fraction. Table 1. Correlation of Binary Systems for Different G E Models Figure 3. Excess Gibbs energy function. P= 101. 3 k. Pa (. ); P=20 k. Pa(∆) ; Wilson (__) Conclusions Consistent VLE data have been determined for the systems 4 -methyl-2 -pentanone (1) + 1 -butanol (2), at 20 and 101. 3 k. Pa. The Wilson, NRTL and UNIQUAC models were capable of correlating the data for the binary system. The equilibrium diagram for 4 -methyl-2 -pentanone (1) + 1 -butanol (2), show that the azeotropic composition is very sensitive to pressure. Therefore, in view of the results, pressure-swing distillation could be a useful technique in order to overcome the binary azeotrope. [1] A. Tamir, J. Wisniak, J. Chem. Eng. Data 23 (1978) 293 -298 [2] J. L Cabezas, S. Beltran, J. Coca. Private Comunication (1978. From DDBST Software and Separation Technology Gmb. H Acknowledgements. Financial support from the Ministerio de Ciencia y Tecnología of Spain, through project CTQ 2007 -61400/PPQ, FEDER European Program and the Conselleria de Cultura, Educació i Esport (Generalitat Valenciana) of Valencia (Spain