SOLUBILITY DIAGRAMS
229
(3) BRIGGS AND HUBARD: J . Phys. Chem. 46,806 (1941). (4) CHEESMAN, DUNCAN, AND HARRIS:J. Chem. SOC.1940,837. (5) FOOTE,BRADLEY, AND FLEISCHER: J . Phys. Chem. 87, 21 (1933). (6) KLEMM:Magnetochemie. Akademische Verlagsgesellschaft, m.b.H., Leipzig (1936). (7) PAULING: The Nature of lhc Chemical Bond, 2nd edition, p . 111. Cornell University Preas, Ithaca, New York (1940). (8)RAE: J. Chem. SOC.lW1, 1578. (9) RAE: J. Phys. Chem. S6, 1800 (1931). (10) WHEAT: Thesis, Cornell University, 1939.
T H E SOLUBILITY DIAGRAMS FOR T H E SYSTEMS ETHYLI D E N E DIACETATE-ACETIC ACID-WATER AND VINYL ACETATE-ACETONE-WATER JULIAN C. SiMITH
Plant Research Laboratories, Shawinigan Chemicals Lid.,Shawinigan Falls, Quebec, Canada Received July $8, f04f
Both vinyl acetate and ethylidene diacetate are produced commercially in large quantities by the reaction of acetylene with acetic acid, but the published data on both of these compounds are very incomplete. The solubility diagram for the system vinyl acetate-acetic acid-water has already appeared (2), and the diagrams in figures 1 and 2 are submitted in order to supplement the available information. The limiting solubility curve (see table 1) for the system ethylidene diacetate-acetic acid-water was determined by placing known mixtures of ethylidene diacetate and water in a set of small Erlenmeyer flasks and immersing them in a constant-temperature bath at 25°C. They were then titrated with pure glacial acetic acid until turbidity just disappeared. The tie lines were determined by making up a series of mixtures containing about equal quantities of ethylidene diacetate and water and varying amounts of acetic acid. After thorough shaking a t 25"C., each mixture was transferred to a separatory funnel and allowed to settle. About 1 cc. was then pipetted from the top layer and placed in a tared flask. A somewhat larger sample was withdrawn from the bottom layer. After weighing, each sample was analyzed for acetic acid by titration with standard 0.2 N sodium hydroxide. I n each case the tie line determined by the two analyses passed through the point representing the over-all composition; this served to check the accuracy of the work. The limiting solubility curve for the system vinyl acetate-acetone-water
230
JULIAN C. SMITH
TABLE 1 Data for the system ethylidene diacetate-acetic acid-water
I
LJMITINQ 0OLURILITY CURVE
TIE LINEB
Ethylidene discetgta
Water
Acetic wid
Acetio acid in ethylidene d h t a t i layer
Acetic’acid in water lsyer
per cent
per cent
per cent
per cenf
per cent
95.0 75.0 61.6 50.8 43.2 35.4 27.8 20.8 13.7 7.9 5.0
5.0 10.7 18.2 26.3 33.0 40.1 47.9 55.8 65.7 78.7 95.0
3.4 5.7 9.5 12.5 14.5 17.7 21.0
4.0 7.6 11.5 15.3 18.1 20.9 23.1
14.3 20.2 22.9 23.8 24.2 21.3 23.4 20.6 13.4 H Ac
E.0
-
.-
WEIGHT PER CENT WATER FIG.1. Solubility diagram for the system ethylidene diaeetate-acetic acid-water a t 25°C.
was determined by titrating known mixtures of vinyl acetate and water with acetone until turbidity disappeared. From the data (table 2) the limiting solubility curve was drawn.
232
JULIAN C. SMITE
The tie lines for this system were determhed by the method described by Evans (l),which avoids any direct analyses. Known amounts of vinyl acetate, acetone, and water were placed in a separatory funnel and thoroughly shaken a t 25°C. After settling, the lower layer was carefully drawn off into a tared flask, and weighed. The weight of each layer was then known. Three arbitrary tie lines were then drawn through the point representing the over-all composition of each mixture. From the corresponding percentages of vinyl acetate in each layer, as given by these tie lines, and from the known weights of each layer, the total weight of vinyl acetate present was calculated from the equation:
O.Ol(W,
+ mozu)= M
in which m = weight of each layer, z = percentage of vinyl acetate, M = total weight of vinyl acetate,
w (subscript) = water layer, and v (subscript) = vinyl acetate layer.
Agraph was then drawn for each tie line, in which the total weight of vinyl acetate was plotted against the percentage of vinyl acetate in the light layer. Since the actual weight of vinyl acetate present was known, the true percentage of vinyl acetate in the light layer was easily determined by interpolation. As a check, the total amount of acetone present was calculated from the results and was found to agree very well with the amount actually taken. REFERENCES (1) EVANS,THEODORE W.: Ind. Eng. Chem., Anal. Ed. 6, 408 (1934). (2) SMITH,JULIANC.:J. Phys. Chem. 46, 1301 (1941).
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SOLUBILITY DIAGRAMS
TABLE 2 Data for the system vinyl acetate-acetone-water L M T I N Q BOLUBILITY CURVE
Vinyl acetate
Water
pm cent
per cenl
99.9 83.0 63.5 50.1 38.2 31.7 27.1 22.8 18.6 14.7 10.6 6.1 4.1 2.5
0.1 2.0 4.0 6.5 10.8 15.2 19.6 25.1 31.2 37.5 45.8 59.5 73.1 97.5
1
~
! ~
Acetone
Acetone in vinyl acetate laver
Acetone in water layer
per cent
per cent
per cenl
15.0 32.5 43.4 51.0 53.1 53.3 52.1 50.2 47.8 43.6 34.4 22.8
8.0 14.0 18.4 22.9 27.2 30.8 34.2 37.2 42.8 47.1 50.6 52.9 53.3
2.2 6.2 9.7 12.1 15.0 17.3 19.3 21.8 24.3 30.0 35.2 39.2 44.1
! Acetone
V.
H2C WEIGHT PER CENT WATER
FIG.2. Solubility diagram for the system vinyl acetate-acetone-water a t 25°C.
