Fluid Phase Equilibria 198 (2002) 229–237
High pressure vapor–liquid equilibrium data for the systems carbon dioxide/2-methyl-1-propanol and carbon dioxide/3-methyl-1-butanol at 288.2, 303.2 and 313.2 K Marta Vázquez da Silva, Domingos Barbosa∗ Departamento de Engenharia Qu´ımica, Faculdade de Engenharia da Universidade do Porto, Pólo FEUP do Centro de Biotecnologia e Qu´ımica Fina, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal Received 11 June 2001; accepted 28 November 2001
Abstract In this work, we report vapor–liquid equilibrium data for the systems carbon dioxide (CO2 )/iso-butanol and CO2 /iso-pentanol at 288.2, 303.2 and 313.2 K, and for pressures up to the critical point. The interaction parameters for the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOS) that best fit the experimental results are also given. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Equation of state; Data; Phase equilibrium; Carbon dioxide; iso-Butanol; iso-Pentanol
1. Introduction Supercritical extraction with carbon dioxide (CO2 ) has been suggested as one of the most promising techniques for the dealcoholization of beverages such as wine, beer and cider [1,2]. The correct evaluation of the feasibility of this process requires information on the solubility of the constituents of these beverages in CO2 , particularly of their aromatic compounds. However, at the moment, this assessment cannot be done due to the lack of solubility data for most of these components. In our previous work [3,4], we reported phase equilibrium data for ethyl acetate, iso-amyl acetate and n-butanal in CO2 , which are some of the esters and aldehydes that can be found in most of the alcoholic beverages. Pursuing our research programme, we now report experimental values for the solubility of iso-butanol (2-methyl-1-propanol) and iso-pentanol (3-methyl-1-butanol) in CO2 . The experimental data was obtained in a static type equilibrium apparatus, which allows measurements for temperatures between 273.15 and 353.15 K, and pressures up to 30 MPa. The data was then fitted by the Soave–Redlich–Kwong (SRK) [5] and Peng–Robinson (PR) [6] equations of state (EOS). Abbreviations: CALC, calculated value; EOS, equation of state; EXP,2 experimental value; PR, Peng–Robinson equation of state; RQD, relative quadratic deviation ( nres k=1 ((xEXP,k −xCALC,k )/xEXP,k ) /nres); SRK, Soave–Redlich–Kwong equation of state ∗ Corresponding author. Fax: +351-22-508-1449. E-mail address:
[email protected] (D. Barbosa). 0378-3812/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 8 - 3 8 1 2 ( 0 1 ) 0 0 7 6 6 - X
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M.V. da Silva, D. Barbosa / Fluid Phase Equilibria 198 (2002) 229–237
2. Experimental 2.1. Apparatus Since the aim of this work is to obtain equilibrium data for the dealcoholization process, which, due to the thermal degradation problems, must operate at low temperatures (i.e.
