Compact apparatus for rapid measurement of high-pressure phase equilibria of carbon dioxide expanded liquids
Introduction
Volatile organic compounds (VOC) emissions must be reduced to address environmental problems, such as photochemical smog and global warming. Among the many industries, the paint industry is the largest source of VOC emissions. VOCs are used as the carrier and the diluent of polymers and pigments in paints. Although aqueous coatings and powder coatings are used as one method to reduce VOCs, these techniques cannot be applied to all surfaces due to coating quality and conformability. Lewis et al. [1] proposed a spray coating system using supercritical carbon dioxide as a viscosity reduction solvent. This new painting method for VOC reduction gained much attention. Carbon dioxide is environmentally benign and highly soluble in VOCs. However, adding a supercritical fluid to polymer solutions can cause phase separation and formation of polymer-rich and solvent-rich phases [2]. To consider alternative solvents, information on the phase equilibria of paint mixtures including carbon dioxide are needed to develop low VOC coatings or new paint formulations. Further, since there are so many combinations of polymers and solvents possible for paint, a method to allow rapid measurement of the phase equilibria is needed. In this work, our objective was to construct an apparatus that allows rapid measurement of high-pressure phase equilibria and that could be used to measure carbon dioxide–solvent systems. We report on the measurements of carbon dioxide–solvent binary systems that have application to paints and coatings.
Until now, many apparatus have been proposed for phase equilibria measurements [3]. A method that does not require composition analysis is favorable since it eliminates time-consuming analysis steps. The synthetic method [4], [5] was chosen to be appropriate considering the objectives.
Solubilities of carbon dioxide in methanol were measured at temperature 313 and 330 K to confirm reliability of the developed apparatus. Moreover, solubilities of carbon dioxide in three kinds of ketones (acetone, methyl ethyl ketone, and methyl isobutyl ketone) are reported.
Section snippets
Experimental
Carbon dioxide (purity > 99.99%) supplied from Showa Tansan Co. Ltd. Methanol (purity > 99.8%), acetone (purity > 99.8%), methyl ethyl ketone (MEK) (purity > 99%), and methyl isobutyl ketone (MIBK) (purity > 99.5%) were purchased from Wako Pure Chemical Industries, Ltd. All compounds were used without further purification.
The synthetic method was used for the measurement of phase equilibria of carbon dioxide expanded liquids, in which bubble-point pressures were determined at various temperatures for
Results and discussion
The solubility of carbon dioxide in methanol was measured to confirm the reliability of the apparatus. Relationships between pressure and position of the piston for the carbon dioxide + methanol system are shown in Fig. 3. In the figure, solid and open symbols denote the single phase and the vapor–liquid coexisting phases, respectively. Intersection of lines of the vapor and liquid compressibilities can be seen in the figure. Bubble-point pressures were determined from these intersections.
Conclusion
A new apparatus based on synthetic method was developed. This apparatus can be used to rapidly obtain phase equilibria data. Solubilities of carbon dioxide in acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK) were measured at temperatures of 313, 333, and 353 K. The solubilities of carbon dioxide in these ketones at a given pressure were found to be practically identical over the given range of temperature. The quadrupole moment of the carbon dioxide and its interaction with
References (13)
Fluid Phase Equilib.
(1996)- et al.
Fluid Phase Equilib.
(1998) - et al.
J. Chem. Thermodyn.
(1980) - et al.
Fluid Phase Equilib.
(1988) - et al.
Met. Finish.
(2000) - et al.
Macromolecules
(1985)
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