Ethyl Alcohol-Ethyl Acetate and Acetic Acid-Ethyl Acetate Systems
V a p or-liquid Equilibrium Data
D
ESPITE the importance of ethyl acetate as a solvent,
very few data in the literature are applicable to the design of apparatus for the preparation of this material from the reactants used in its formation. The complete equilibrium diagram for the distillation equilibria of the system ethyl alcohol-acetic acid-ethyl acetate-water, would be complicated, but a great deal of information concerning the best means of preparation can be obtained from the data on the various binary systems involved. Of the six possible binary systems, vapor-liquid equilibrium data are available for two (ethyl alcohol-water, acetic acid-water). The other sets of data are still to be determined. This paper presents two of these missing sets.
C. C. FURNAS A N D W.B. LEIGHTON] Yale University, New Haven, Conn.
a boiling point of 77.15' C. and a specific gravity, di5, of 0.8935.
Analysis of still residue and condensed vapor in the Othmer apparatus was made by density determinations a t 25" C. with 10-cc. pycnometers. The specific gravity data as determined for mixtures of known composition are shown in Figure 1. The data on the equilibrium compositions of liquid and vapor are given in Table I and Figure 2. The determinations were all made a t atmospheric pressure, approximately 760 mm. of mercury.
Ethyl Alcohol-Ethyl Acetate The vapor-liquid equilibrium data determinations were made with the Othmer apparatus ( 3 ) . The absolute ethyl alcohol used had a boiling point of 78.32' C. a t 760 mm. of mercury. The ethyl acetate was of commercial grade, approximately 97 per cent pure. It was purified by repeated fractionation. The fraction used for the determinations had
TABLE I. VAPOR-LIQUID EQUILIBRIA FOR THE SYSTEMETHYL ALCOHOL-ETHYL ACETATE --CompositionCzHsOH CzHsOH In llquld in vauor
1 Present address, Carbide and Carbon Chemicals Corporation, Cherleston, W. Va.
2.5 8.0 10.0 13.0 24.0 36.0 56.3 65.3 71.0 73.5
ETHYL ALCOHOL, PERCENT BY W T .
w
B< >
K
I
2
W +
5
E< V
I !
*9 U '
1 > I
0
.#
I-
w -J
8 MOLE % $H,OH-
0
LIQUID
FIGURE2. VAPOR-LIQUIDEQUILIBRIUM CURVE FOR ETHYL ALCOHOLETHYLACETATE SYSTEM
76.7 75.5 75.0 74.4 72.6 71.8 72.0 72.4 72.8 73 1
--Composition-CzHbOH CzHsOH In liouid in vanor 77.6 78.5 83.3 87.3 87.8 90.8 93.2 54.2 58.4
66.5 67.5 73.5 77.3 78.3 82.3 86.8 88.0 96.5
Temp. pf Condensing Vaoor 73.5 73.6 74.2 74.9 75.0 75.6 76.1 76.4 77.7
Ethyl Acetate-Acetic Aoid
W
I
Vapor
There was no attempt to make an exact determination of the composition of the constant-boiling mixture or azeotrope, since it was not a point of particular significance in the present study. In Figure 2 the eauilibrium curve crosses the 45" -diagonal a t 46.2 per cent ethyl alcohol. By interpolation, then, this is the azeotropic mixture. This datum agrees very well with that of other investigators for the composition of the azeotrope (1, 2, 4, 5 ) . Their data range from 46.0 to 46.4 mole per cent ethyl alcohol for the composition of the constant-boiling mixture, with a range of boiling points from 71' to 72" C.
FIGURE1. SPECIFICGRAVITYOF ETHYLAG COHOL-ETHYL ACETATE MIXTURES I
7.0 12.6 16.4 20.0 29.5 39.8 50.7 56.0 60.0 62.7
Temp. of Condensing
o
io 20 30 40 s o 60 70 ea so iw MOL€% ETHYL ACETATE LIQUID
-
FIGURE3. VAPOR-LIQUID EQUILIBRIUM CURVE FOR ETHYLACETATE -ACETIC ACIDSYSTEM 709
Experimental data have been reported for the isothermal liquid-vapor equilibria a t 42.00" and 59.96' C. (6) for the system ethyl acetateacetic acid, but none are available for constant pressure. Determination of the constant-pressure equilibria were made with the Othmer ap-
INDUSTRIAL AND ENGINEERING CHEMISTRY
7 10
TABLE 11. VAPOR-LIQUID EQUILIBRIA FOR THE SYSTEM ETHYL ACETATE-ACETICACID -CompositionEthyl Ethyl acetate in acetate in vapor liquid Mole % Mole % 2.6 4.3 2.7 4.7 3.4 7.2 3.5 10.0 11.7 4.0 4.4 10.2 6.7 17.8 7.0 18.8 7.5 24.0 8.6 23.0 10.7
32.4
Atm. Pressure Mm. H g 750.4
748.2
764.4
---CompositionEthyl Ethyl acetate in acetate in liquid vapor Mole % Mole % 12.5 37.5 14.8 40.0 15.2 44.2 16.4 43.8 22.5 21.9 555.8 5.5 30.2 64.8 31.0 64.8
Atm. Pressure M m . HQ 769,
39.5 53.0 52.2
76.6 88.0 86.8
746.8 758.8
67.5 75.0 89.3 91.8
96.0 97.8 99.6 99.2
760.8 760.8
r
paratus. The ethyl acetate was a purified sample with a specific gravity, dq6, of 0.8935, boiling a t 77.15' C. The ace-
VOL. 29, NO. 6
tic acid sample was purified by fractionation of a commercial acid. The purified product had a boiling point of 118.2" C. and a specific gravity, di6, 1.0489. Titration with sodium hydroxide and phenolphthalein indicator showed the sample to contain 100.9 per cent acetic acid. The compositions of the samples used in the equilibrium study were determined by density measurements with pycnometers. The data used for the density of mixtures of given compositions were those of the International Critical Tables. The equilibrium data as determined are givenin Table I1 and Figure 3.
Literature Cited (1) Alinari, Ann. chim. appiicata, 20, 1.59 (1930). (2) Hannotte, Bull. SOC. china. Belg., 35, 86 (1926). (3) Othmer, IND.ENG.CHEM.,20, 743 (1928). (4)Ramsey and Young, J . Chem. SOC.,49, 790 (1886). ( 5 ) Ryland, Am. C h m . J . , 22,384 (1899). (6) Schmidt, J . Russ. Phgs. Chem. SOC.,62, 1847 (1930). ~ n c E i v s DJanuary 21, 1937.
PARTING LABORATORY No. 78 in the Berolzheimer series of Alchemical and Historical Reproductions enables us for the second time t o bring a picture of a reproduction of an actual and famous laboratory, rather than a painting of one (see No. 1 in the Series, in our issue of August, 1931,page 966). The reproduced laboratory is in the Deutsches Museum in Munich and represents the Parting Laboratory (assay room) as operated in the mining and metallurgical industry in the time of Agricola (ahout 1550). This picture is of particular interest because it served as the model for the well known Priestley Room in The Chemists' Club, New York. This room, planned, designed, and resented to the Club by the late Dr. borris Loeb, is closely patterned after the typical alchemists' laboratory and is well worth seeing. It was fully described in The Percolator for August, 1932. See also INDUSTRIAL AND ENGINBERINQ CHEMISTRY, April, 1911, Volume 3, plate facing page 209.
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A detailed list of ,Reproduotions Nos. 1 to 60 appeared in our issue of January, 1936, page 129 and the list of Nos. 81 to 72 appeared in January, 1937, page 74, where also will be fdund Reproduction No. 73 Reproduction No. 74 appears on p y e 166, Februarv issue. No. 76 on Daze 345, M'arch issue, No. 76 on page 469, April issue, and N O 77 oh page.554, May iSsu5.
