Peanut Oil-Oleic Acid-Acetic Acid
and Peanut Oil-Oleic AcidFurfural Ternary Systems J
J
GOPALA VENIUTARAMAN AND G. S. LADDHA University of Madras, Madras, India
I
and if the mixture remained turbid for 20 minutes, the flask was reweighed. The weight of the solvent in the saturated mixture was determined by difference. From the weights of the components in the saturated mixture, the weight fraction of each was calculated. A sample of the saturated phase was removed and its density determined. A second series of mixtures was made up of the solvent (acetic acid or furfural) and oleic acid. The diluent (peanut oil) was added dropwise with vigorous mixing until a "stable', turbidity was produced. This procedure made i t possible to determine the composition of the solvent-rich phase portion of the solubility curve.
Tu' CONNECTION with a study of the extraction of fatty
acids from fatty acid-vegetable oil solutions, it was desired t o investigate suitable solvents for the extraction of oleic acid from oleic acid-peanut (groundnut) oil solutions. Hixson and Bockelmann ( 3 ) have investigated the ternary systems, liquid propane-oleic acid-triolein and liquid propane-oleic acid-refined cottonseed oil. Equilibrium diagrams for the oleic acid-olive oil-methanol and oleic acid-olive oil-ethyl alcohol systems have been reported ( 7 ) . Rigamonti and coworkers (6) have reported solubility data for the oleic acid-triolein-alcohols system using anhydrous methanol, 95% methanol, 90% methanol, and 95% ethyl alcohol a s solvents. I n the present paper complete equilibrium and phase distribution data are presented for the peanut oil-oleic acid-acetic acid and peanut oil-oleic acidfurfur31 systems, both a t 40" C. PURITY ,OF MATERIALS
OLEIC
Figure 1.
Oleic Acid. Laboratory grade oleic acid supplied by May and Baker was used. The density measured a t 30" C. was 0.8894, and the iodine value was 96. Acetic Acid. Acetic acid used had a boiling point range of 117-118" C. and a n acidity of 99.95%. The density a t 30" C. was 1.043. Furfural. Furfural supplied by Allied Chemical and Dye Corp., New York, 3.Y., was purified by vacuum fractionation. It had a boiling range of 64-65' C. a t a pressure of 25 mm. of mercury and a density of 1.1529 at 30" C. Free acidity calculated as acetic acid was 0.00270.
v 20
Figure 2.
w v 40
v
v v
\/
60
80
v\\
FURFURAL
Solubility curves and tie lines for peanut oiloleic acid-furfural system at 40' C.
The tie lines were located by preparing mixtures of the three components which would give two phases a t equilibrium according to the procedure described b y Othmer and coworkers (6). A clean separating funnel was weighed and known amounts of oleic acid, peanut oil, and acetic acid or furfural were weighed separately into the separating funnel. T h e mixture was agitated and then placed in the constant temperature bath a t 40' C. for a minimum period of 3 hours, until t h e mixture had separated into two clear layer%. The individual phases were then separated and weighed. Density of each phase was also determined.
ACID
Solubility curves and tie lines for peanut oiloleic acid-acetic acid system at 40' C.
v
/ OIL
Peanut Oil. Double-refined peanut oil supplied by Mysore Vegetable Oil Products, Madras, was used. I t s free acidity was 0.05%. It had a saponification value of 191, an iodine value of 94.6, and a density a t 30" C. of 0.9100.
The curve of saturated phase composition plotted against density was used t o establish the equilibrium phase compositions from the experimental densities of the saturated layers. The compositions of each pair of points determined in this manner were plotted and connected with straight lines. The point representing t h e composition of the original mixture was also plotted on the same graph. When this point did not fall on or very
Table I.
EXPERIMENTAL PROCEDURE
Oleic acid
All measurements were made a t 40" C. The solubility data were determined by titrating known mixtures of oleic acid and peanut oil, or oleic acid and solvent, with the third component until turbidity appeared. A known quantity of the diluent (peanut oil) was placed in a clean weighed flask. The flask was weighed again and a known quantity of the solute (oleic acid) was added. The flask containing the mixture was weighed again and placed in a bath controlled a t a constant temperature of 40' C. After 20 to 30 minutes the flask was removed and the solvent (acetic acid or furfural) was added from a buret. After each addition the mixture was agitated vigorously. The solvent addition was continued until a cloudiness appeared which did not disappear with mixing. T h e flask containing the mixture was again placed in the bath,
Equilibrium Data for Peanut Oil-Oleic AcidAcetic Acid System at 40" C. Oil
Solubility D a t a , Weight % Acetic Oleic acid acid
Acetic acid
Tie-Line D a t a , Weight %
-
Oil Phase Composition 6.0
9.25
12.0
1272
Oil
62.0
55.0 48.5
32.0
35.75 39.5
Acetic Acid Phase Composition 0.25 2.0 ' 97.75 6.0 10.25
5.0 10.5
89,O
79,25
June 1955
INDUSTRIAL AND ENGINEERING CHEMISTRY
near the line, some error in procedure or analysis was indicated. T h e compositions of the initial mixtures are indicated by circles within the two-phase region in Figures 1 and 2.
Table 11.
1273
Equilibrium Data for Peanut Oil-Oleic AcidFurfural System at 40' C.
Solubility D a t a , Weight % Oleic Oil Furfural acid Oil Furfural 0.0 69.7 30.3 0.0 3.9 2.5 65.0 32.5 2.9 4.6 5.3 4.6 61.8 33.6 5.5 6.7 57.9 35.4 6.3 8.0 8.5 55.2 36.3 10.0 7.4 37.1 10.0 62.9 12.0 8.5 11.6 50.6 37.8 13.6 9.8 40.0 15.2 12.5 47.5 12.3 41.2 13.7 45.1 14.6 16.5 42.8 17.3 14.5 42.7 18.2 16.5 39.2 44.3 18.1 19.7 47.0 18.4 17.7 35.3 21.8 51.5 18.7 29.8 55.5 19.0 25.5 Tie-Line D a t a , Weight 70 Oil Phase Composition Furfural Phase Composition Oleic acid
RESULTS
T h e equilibrium data for the peanut oil-oleic acid-acetic acid system are presented in Table I and shown graphically in Figure 1. T h e equilibrium data for the peanut oil-oleic acid-furfural system are presented in Table I1 and shown graphically in Figure 2.
4.6 9.5 14.5 18.25
61.75 53.5 43.75 32.75
4.0 8.0 11.0 15.0
33.65 37.0 41,75 49.0
5.0 6.3 8.25 12.0
91.0 85.7 80.75 73.0
0.50 /
--. d
5?
0.10
* I
Y r
0
4 P 12 16 WEIGHT % OLEIC ACID IN SOLVENT PHASE
Figure 3.
PO
Distribution of oleic acid between oil and solvent phases
0 Acetic acid 0
Furfural
0.09
*
c
I n Figure 3 t h e weight per cent of oleic acid in the solvent phase is plotted against the weight per cent of oleic acid in the oil phase for both systems. Oleic acid has a n affinity for the oil phase in both systems. T h e curves in Figure 3 have been extrapolated (dotted) t o indicate their general trend in approaching - t h e plait point which must fall on the 45' diagonal line-i.e., the compositions of the two phases in equilibrium must be identical at t h a t point. Various methods have been recommended for smoothing and interpolation of tie-line data, including those of Campbell ( 2 ) , Bancroft ( I ) , and Othmer and Tobias ( 4 ) . These methods give approximately linear relationships for the two systems studied. Figure 4 gives the correlation as suggested b y Othmer and Tobias. The plait point for the peanut oil-oleic acid-acetic acid system at 40" C. corresponds to %yooil, 14% oleic acid, and 47y0acetic acid, whereas for the peanut oil-oleic acid-furfural system a t 40" C. it is estimated t o be '24.5y0oil, 19% oleic acid, and 56.5y0 furfural. ACKNOWLEDGMENT
The authors wish t o express their gratitude t o Surajmal Hanumandas Oil Mills, Khamgaon, M. P., India, for the award of a research fellowship for this investigation. NOMENCLATURE = weight fraction of oil in oil phase b? = weight fraction of solvent in solvent phase
a1
0.3 (1
Figure 4.
-
1 .o
3.0
dl)/dl
Correlation of tie line data Q
0
Acetic acid Furfural
LITERATURE CITED (1) Bancroft, W. D., Physiol. Rev.,3, 21, 114, 193 (1895). (2) Campbell, J. A . , IND. ENG.CHEM.,36, 1158 (1944).
(3) Hixson, A. W., and Bockelmann, J. B., Tran,s. Am. Inst. Chem. Engrs., 38, 891 (1942). (4) Othmer, D. F., and Tobias, P. E., IKD.ENG.CHEM.,34, 693 (1942). (5) Othmer, D. F., White, R. E., and Truegar, E., Ibid., 33, 1'240 (1941). (6) Rigamonti, R., Vaccarino, C., a n d Duzzi, A., Chimica e industria (Milan),33, 619 (1951). (7) Rim, A . , and Martinez Moreno, J. M., Chem. Products, 11, 63 (1948). RECEIVED for review March 5, 1954. ACCEPTEDDecember 1 1 , 1954. Thesis approved by the University of Madras for the M.50. degree.
