Vapor-Liquid Equilibrium Diagrams of Alcohol-Ketone Azeotropes as a Function of Pressure E. C. BRITTON, H. S. NUTTING, and L. H. HORSLEY
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The Dow Chemical Co., Midland,
Mich.
Pressure
has a marked effect on the azeotropic composition and vapor-liquid equilibrium diagrams of alcohol-ketone systems (1). This is due to the fact that the slopes of the vapor pressure curves of alcohols are appreciably greater than for ketones; it results in an unusually larger change in the relative boiling points of the components of an alcohol-ketone system with change in pressure. As a result of the study of these systems, it has been found that the methanol-acetone azeotrope exhibits the unusual phenomenon of becoming nonazeotropic at both low and high pressures—that is, below 200-mm. pressure the system is nonazeotropic with methanol as the more volatile product, while above 15,000 mm. the system is nonazeotropic with acetone the more volatile component. Some of the equilibrium data for this system and two other alcohol-ketone azeotropes are shown in Figures 1 and 2 on the following pages. The similarity of the diagrams for the different systems at suitable pressures is of interest. For example, the diagram for methanol-acetone at 10,000 mm. corresponds approximately to the diagram for methanol-methyl ethyl ketone at 1000 mm. and for ethanol-methyl propyl ketone at 100 mm. Literature Cited (1) B r i t t o n , E. C., N u t t i n g , H. S., a n d Horsley, L. H. (to D o w Chemical C o . ) , U. S. Patent 2,324,255 (July 13, 1943).
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AZEOTROPIC DATA Advances in Chemistry; American Chemical Society: Washington, DC, 1973.
ADVANCES IN CHEMISTRY SERIES
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METHANOLMETHYL ETHYL KETONE
METHANOLACETONE
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200
200
200
ETHANOLMETHYL PROPYL KETONE
180
K V
— 1 I.09C mm
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V
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100 mm* 200 mn 40 20 10 0
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80
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0
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40
60
WEIGHT PER CENT Figure 1.
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ALCOHOL
Vapor-Liquid Equilibrium Diagrams of Alcohol-Ketone Systems at Various Pressures
AZEOTROPIC DATA Advances in Chemistry; American Chemical Society: Washington, DC, 1973.
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EQUILIBRIUM DIAGRAMS OF ALCOHOL-KETONE SYSTEMS
AVERAGE WEIGHT % A L C O H O L IN LIQUID AND VAPOR IN EQUILIBRIUM Figure 2.
Difference in Composition of Vapor and Liquid in Equilibrium As a function of corresponding average composition of vapor and liquid for alcohol-ketone systems
AZEOTROPIC DATA Advances in Chemistry; American Chemical Society: Washington, DC, 1973.
