Isobaric vapor–liquid equilibria for the binary systems isobutyl alcohol + isobutyl acetate and tert-butyl alcohol + tert-butyl acetate at 20 and 101.3 kPa
Introduction
Isobutyl acetate (IBAc) and tert-butyl acetate (TBAc) are solvents widely used in chemical industry. They are used alone or in solvent blends in applications including coatings, inks, adhesives, industrial cleaners and degreasers. Both acetates are produced by esterification of acetic acid with the corresponding alcohol. Final purification of acetates in traditional technologies is a relative complex procedure due to the existence of a minimum boiling point azeotrope in the isobutyl alcohol (IBA) + IBAc mixture and a low relative volatility region in the tert-butyl alcohol (TBA) + TBAc system at atmospheric pressure.
The separation can be improved by adding an agent that alters the relative volatility of the components (extractive distillation) or making a simple change in pressure, provided that the azeotropic composition is sensitive to pressure (pressure swing distillation).
Unfortunately, azeotropic data frequently are not available at different pressures. The present work was undertaken to measure the phase equilibrium properties (VLE data) of the two systems mentioned at 20 and 101.3 kPa. Further, we can use these properties to simulate the pure components recovery without adding a separating agent and to find a feasible sequence in which the columns operate at different pressures. Some VLE data are available in literature for these related mixtures [1], [2], but only at atmospheric pressure.
The VLE data were found to be thermodynamically consistent at all pressures and were correlated with their composition by Wilson, UNIQUAC and NRTL equations.
Section snippets
Chemicals
IBA (99.5 mass%, HPLC grade), IBAc (>99 mass%, analytical grade), TBA (>99.5 mass%, HPLC grade) and TBAc (>99 mass%, analytical grade) were purchased from Aldrich Ltd. The reagents were used without further purification after chromatography failed to show any significant impurities. The water content was small in all chemicals (<0.05 mass%). Before measurements, the liquids were dried over molecular sieves (Union Carbide, type 4 Å, 1/16 in. pellets). The densities and refractive indexes of pure
Results and discussion
The pure component vapor pressure for isobutyl alcohol was taken from Ref. [6]. For isobutyl acetate, tert-butyl alcohol and tert-butyl acetate, pure component vapor pressures were determined experimentally as a function of the temperature, using the same equipment as that for obtaining the VLE data. The pertinent results appear in Table 2. The measured vapor pressures were correlated using the Antoine equation:whose parameters Ai, Bi and Ci are reported in Table 3
Acknowledgment
Financial support from the Ministerio de Ciencia y Tecnología of Spain, through project No. PPQ 2000-1335 and the Conselleria de Cultura, Educació i Esport (Generalitat Valenciana) of Valencia (Spain) is gratefully acknowledged.
References (14)
- et al.
Fluid Phase Equilib.
(1999) - et al.
Chem. Eng. Sci.
(1976) Collect. Czech. Chem. Commun.
(1977)- et al.
An. Quim.
(1985) - TRC Thermodynamic Tables. Non-Hydrocarbons, Thermodynamic Research Centre, The Texas A&M University System, College...
- et al.
Physical and Thermodynamic Properties of Pure Chemicals. Data Compilation
(1989) Phase Equilibria in Chemical Engineering
(1985)
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