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INDUSTRIAL AND ENGINEERING CHEMISTRY
presence of trehalose and isogentiobiose. Part of the sample on which maltose ww obtained was sent t o another laboratory without identification &s to its origin. These workers reported maltose by paper chromatography, employing a series of dilutions and they estimated the concentration of the maltose t o be between 10 and 15%. In studies on the structure of starch, agreement has not been reached as t o whether some of the products which have been identified in starch hydrolyzates are fragments from the original starch molecule, or artifacts (reversion products). The present data show that some of the sugars found in starch hydrolyzates are produced from pure dextrose by a treatment identical with that used for the hydrolysis of starch. Thus, their presence in starch hydrolyzates is no indication that they existed in the original starch structure. CONCLUSIONS
The extended acid-heat treatment of cornstarch slurries, 42 and 60 D.E. cornstarch sirup, “70” and “80” corn sirups, or C.P. dextrose, whether the treatment is ‘hydrolysis or condensation polymerization, yields an equilibrated mixture of sugars, dependent upon the solids concentration of the sirup a t equilibrium. The composition of the sirups, based on the analytical data presented] is similar if not identical. The reaction results in a true equilibrium which can be shifted repeatedly from substantially pure dextrose to a complex mixture of monomeric and polymerized dextrose by altering the concentration of the substrate undergoing the acid-heat treatment. The rate a t which equilibrium is reached for a given solids concentration is dependent upon the temperature and pH of the sirup dndergoing the treatment. The higher the concentration of the sugar solids, the greater is the polymerization of the dextrose. The new sirups are noncrystallizing. The acid-heat treatment causes color and bitterness, the amount dependent upon the severity and extent of the treatment. ACKNOWLEDGMENT
The authors wish to acknowledge the assistance and criticism of Geo. T. Peckham, Jr., Clinton Foods Inc., and Karl Paul Link, University of Wisconsin, in the preparation of this paper. LITERATURE CITED (1) h s o c . Official Agr. Chemists, “Official and Tentative Methods of Analysis,” 7th ed., p. 348, 22.34, 1950. (2) Ibid., p. 506, 29.32. (3) Ibid., p. 528, 29.148. (4) Berlin, H., J . Am. Chem. Soc., 48, 2627 (1926).
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Cantor, S. M., “Summaries of Doctoral Dissertations,” Vol. IV, p. 113, Northwestern University, 1936. Cantor, S. M., U. S. Patent 2,203,325 (June 4, 1940). . . Cleland, J. E., and Fetaer, W. R., IND. ENQ. CHEM.,ANAL. ED., 13, 858 (1941). (8) Coleman, G. H., Buchanan, M. A., and Paul, P. T., J . Am. Chem. Soc.. 57, 1119 (1935). (9) Earle, F. R., and Milner, R. T, Cereal. Chem., 21, 567-75 (1944). (10) Eberti C., Newkirk, W. B., and Moskowita, M., U. S. Patent 1,704,037 (1929). (11) Etheredge, M. P., J . Assoc. O$ic. Agr. Chemists, 27, 404-12 (1944). (12) Farber, E., U. S. Patent 2,027,904 (Jan. 14, 1936). (13) Fetaer, W. R., Zbid., 2,210,659 (Aug. 6, 1940). (14) Fetzer, W. R., U. S. Patent Application Serial 735,247 (March 17, 1947). (15) Fischer, E., Ber., 23, 3687-91 (1890). (16) Ibid., 28, 3024-8 (1895). (17) Frahm, H., Ann., 555, 187-213 (1944). (18) Frahm, H., Be?., 74B, 522-5 (1941). (19) Gautier, A., Bull. SOC. chim. France, (2) 22,145 (1874). (20) Graefe, Gerd, Sttlrke, 2, 27 (1950). (21) Grimaux, E., and LefBvre, T., Compt. rend.. 103, 146 (1886). (22) Hill, A. C., J. Chem. Soc., 1898, 634-58. (23) Zbid., 1903, 578-98. (24) Hurd, C. D., and Cantor, S. M., J . Am. Chem. Soc., 60, 2677 (1938). (25) Lampitt, L. H., Fuller, C. H. F., and Goldenberg, N. J., J . SOC. Chem. I n d . , 66, 117-21 (1947). (26) Leuck, G. J., U. S. Patent 2,375,564 (1945). (27) Ibid., 2,387,275 (1946). (28) Zbid., 2,400,423 (1946). (29) Zbid., 2,436,967 (1948). (30) Moelwyn-Hughes, E. A., Trans. Faraday Soc., 25,503 (1929). (31) Musculus, F., Bull. soc. chim. France, (2) 18, 66 (1872). (32) Myrbiick, Karl, Advances in Carbohydrate Chem., 3, 308 (1948). (33) Noyes, W. A., Crawford, G., Jumper, C. H., Flory, E. L., and Arnold, R. B., J. Am. Chem. SOC.,26,266-80 (1904). (34) Ost, H., 2. angew. Chem., 17, 1663 (1904). (35) Ost, H., and Broadkorb, Th., Chem.-Ztg., 36,1125-6 (1911). (36) Pacsu, Eugene, and Mora, P. T., J. Am. Chem. Soo., 72, 1045 (1950). (37) Roessing, A., Chem.-Ztg., 29,867-73 (1950). (38) Saeman, J. F., IND.ENQ.CREM.,37,43-52 (1945). (39) Scheibler, C., and Mittelmeier, H., Bey., 242, 301 (1891). (40) Sohmitt, C., and Cobenzl.,Ibid., 17, 1000-15 (1884). (41) Schmitt, C., and Rosenhek, J., Ibid., 17, 2456-67 (1884). (42) Schoch, T. J., J. Am. Chem. SOC.,64, 2954 (1942). (43) Silin, P.M., and Sapegina, E. A., Trudg voroflezh, K h i m . Teknol. Inst., 3-4,79 (1939). (44) Syniewski, W., Ann., 324, 212-68 (1902). (45) Taylor, T. C., and Lifschitz, D., J . Am. Chem. SOC. 54, 1054 (1932). (46) Wohl, A,, Bey., 23, 2084-110 (1890). RECEIVED for review September 11, 1952. ACCEPTEDJanuary 23, 1053. Presented before the Division of Sugar Chemistry, Memorial Program Celebrating the 100th Anniversary of the Birth of Emil Fischer and J. H. van’t Hoff, at the 122nd Meeting of the AMERICANCHEMICAL SOCIETY, Atlantic City, N. J.
Ternary System: Furfural-Me thvl Isobutyl ketone-Water at 25” C.‘ JOSEPH B. CONWAY AND JAMES B. PHILIP‘ Department of Chemical Engineering, Villanova College, Villanova, Pa.
I
N CONNECTION withthe solvent extraction of furfural from aqueous solutions Trimble and Dunlop (7) suggested the use of ethyl acetate as the extracting solvent. A research program is now under way t o obtain the necessary data to evaluate various solvents for this extraction. The System presented herein represents but a portion of this program. 1
Present addreas, Merck & Co., Ino., Rahway, N. J.
MATERIALS
Technical furfural (Quaker Oats Co.) was purified using a laboratory-type (Vigreux) fractionating column about 2 feet in height. Purification Was carried out at 15 mm. of mercury and the first and last portions (about 50 ml.) of the distillate were discarded. The furfural was purified as needed, 250 at a timel using a 1-liter distilling flask as a still pot. The purified product was clear and had a very faint straw-yellow color. Methyl isobutyl ketone (Carbide and Carbon Chemicals
INDUSTRIAL AND ENGINEERING CHEMISTRY
1084
Corp.), boiling range 111" t o 117' C. a t 760 mm. water, prepared fresh daily.
Distilled
Vol. 45, No. 5 METHYL
KETONE
PROCEDURE
The ternary solubility data were determined according to the method described by Othmer, White, and Trueger ( 5 ) . 9known volume (about 50 ml.) of methyl isobutyl ketone was measured into a 250-ml. Erlenmeyer flask and maintained in a constant temperature bath a t 25" C. It v-as then titrated u i t h water until the solution became cloudy. If the solution remained cloudy even after it was allowed to remain in the constant temperature bath for 15 minutes, this was taken as the end point. During this time the flask IT as agitated periodically without being removed from the bath. This titration established the solubility of water in ketone.
A known quantity of furfural was then added to this mixture, which resulted in a solution whose composition was well within t h e one-phase region. This mixture was titrated with water again until it became cloudy. The same end point was used as described previously. This procedure was repeated until the ketone side of the solubility curve had been determined. As a check the procedure was repeated using a mixture of furfural and water and using methyl isobutyl ketone t o produce a homogeneous solution after titration to turbidity by the addition of water. The points obtained by both methods fell on the same curve, The water side of the solubility diagram was determined in a similar manner. I n the above procedure, each time a point on t h e solubility curve was obtained the solution was heated t o 28" C. and its specific gravity was measured with a Chain-omatic Westphal balance. The specific gravities for each side of the equilibrium curve were plotted against weight per cent furfural and used in locating the tie lines. Tie-line data weie determined by making up mixtures of the three components whose compositions fell within the t1vr-o-phase region of the diagram. These mixtures were agitated and allowed t o stand in a constant temperature bath a t 25" C. for 24 hours. The two phases were separated and then heated to 28' C. Their specific gravities v-ere measured with the Westphal
TABLEI. EQUILIBRIUM DATA FOR FURFUR.4L-hhTHYI. ISOBUTYL KETONE-WATER SYSTEM AT 25 a C. ( D a t a in weight per cent: specific gravities a t 28O C.) Furfural, Ketone, Water. Rperifir % Gravity % c/o 0.0 98.1 1 9 0.7997 0.0 1.7 98.3 0 9960 0.0 1 8 98 2 3.5 94 1 2 3 5.2 0 8 94 0 5.3 0 8 93 9 5,7 0 8 93 6 0 2 7.8 92 0 8.5 91 5 0 0 91 4 0 0 8.6 20.8 76 6 2 7 27.4 70 3 2 2 27.9 70 2 2 0 67 5 29.7 2 8 66 1 31.4 2 4 63 4 33.7 2 9 63 8 33.9 2 4 59 1 38.0 2 9 55 3 41.6 3 1 55 6 41.7 2 8 52 7 44.0 3 2 50.9 3 3 45.9 0 9423 48.6 3 3 48.3 0 9437 43.0 53.4 0 9666 3 6 42.1 3 5 54 4 0 9693 37.4 3 6 59.0 0 9907 3 6 33.7 62.6 1 0025 65.7 3 8 1 0184 30.5 66.0 29.9 1 0094 4 1 77.1 4 2 18.8 1 0644 78.0 17.9 4 2 1 0635 78.4 17.2 4.3 1 0678 9.2 1 1028 86.0 4.8 95.0 8.0 1 1445 0.0 Tie-Line D a t a
% furfural in ketone layer 29 8 37.5 54.4 68 6 79.0
Yofurfural in water layer 4 2 4 5 4 9 5 3 5.9
Figure 1. Equilibrium Diagram a t 25 C. for FurfuralMethyl Isobutyl Ketone-Water System
9 Figure 2.
Othmer and Tobias Plot of Tie-Line Data
W T % FURFURAL ( M I K L A Y E R )
Figure 3.
Distribution of Furfural between W-ater and Ketone Phases
balance and used in conjunction with the calibration curves to locate the terminal compositions of each tie line. The equilibrium curve for the furfural-methyl isobutyl ketonewater system is shown in Figure 1. The data are presented in Table I. CORRELATION O F TIE-LINE DATA
The tie-line data were plotted according to the method of Othmer and Tobias ( 4 ) . Thevalue (1 - a)/a was plotted against
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INDUSTRIAL AND ENGINEERING CHEMISTRY
the value (1- b ) / b on log-log paper where a is the weight fraction of water in the water phase and b is the weight fraction of ketone in the ketone phase. This'plot yields a straight line as shown in Figure 2. The distribution of furfural between the water and ketone phases is shown in Figure 3. The tie-line data were also correlated in the manner proposed by Bachman (1). According to this method a plot of the ratio x / y versus x on rectangular coordinates should yield a straight line. (a: is the weight fraction of nonconsolute A in the A-rich layer and ?J is the weight fraction of nonconsolute B in the B-rich layer.) Such a plot for this system is shown in Figure 4. It is noted that these data do not yield a straight line with furfural as the other nonconsolute or with methyl isobutyl ketone as the other nonconsolute. T o investigate this method of correlation a little further, a Bachman plot was prepared using data from the following systems: Furfural-ethyl acetate-water Butanol-ethyl acetate-water Butanol-benzene-water Aniline-toluene-watei
(7) (2) (8) (6)
In every case the data did not give a straight line, but rather plotted as a smooth curve similar t o those in Figure 4. It seems therefore t h a t the Bachman method is limited to those systems which contain only one pair of nonconsolute liquids. This is in agreement with the work reported by Brown (5).
W T % WATER IN WATER RICH LAYER
Figure 4.
Bachman Plot of Tie-Line Data
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The tie-line correlation proposed by Brown (5)and representing a modification of the Bachman ( I ) method seems t o apply very well t o systems containing two pairs of partially miscible liquids. The present data correlated in this manner fall along a straight line and are shown in Figure 5. It is noteworthy that the slope of this line is the same as the slopes of the lines for the systems reported by Brown (5). Furthermore, the points representing the present data are colinear with the line for the cyclohexanecetane-aniline system reported by this author. It was found t h a t if a plot was made of the logarithm of the weight per cent water in the water phase against the weight per cent solvent in the solvent phase, a straight line would be obtained in systems containing two partially miscible Dairs. Such a plot is shown in Figure 6 for five such systems. I n this case the solvents are: methyl i s o b u t y l ketone, ethyl acetate, benzene, and toluene. These lines have a positive slope, except in the case of the butanol-ethyl acetate-water system. This phenomenon is easily explained in terms of the ternary diagram for this system. The solubility curve on the water side exhibits a decreasing water content (expressed as weight per cent W T X SOLVENT IN SOLVENT RICH PHASE water) as the Figure 6. Conway-Philip Method weight per cent solof Tie-Line Correlation vent (ethyl acetate) 1. Furfural-methyl isobutyl ketonewater system increases. This be2. Furfural-ethyl acetate-water system h a v i o r r e s u l t s in 3. Butanol-benzene-water system 4. Butanol-ethyl acetate-water 8ystem the negative slope 5. Toluene-aniline-water system shown in Figure 6. Although this method of tie-line correlation seems t o apply very well to ternary systems containing two partially miscible pairs, it does not apply t o the points corresponding t o the mutual solubility data. ACKNOWLEDGMENT
The authors would like to acknowledge the cooperation of the Quaker Oats Co. in furnishing the furfural used in this work. LITERATURE CITED (1) Bachman, I., IND. ENG.CHEM.,ANAL. ED.,12,38 (1940). (2) Beech, D.G., and Glasstone, S., J . Chem. SOC.,141, 67 (1938). (3) Brown, T. F., IND.ENG.CHEM.,40, 103 (1948). (4) Othmer, D.F.,and Tobias, P. E., Ibid., 34, 690 (1942). (5) Othmer, D. F., White, R. E., and Trueger, E., Ibid., 33, 1240 (1941) , (6) Smith, J. C.,and Drexel, R. E., Ibid., 37, 601 (1945). (7) Trimble, F.,and Dunlop, A. P., IND.ENG.CHEM.,ANAL.ED., 12, 721 (1940). (8) Washburn, E. R., and Strandskov, C. V., J . Phys. Chem., 48, 241 (1944).
Figure 5. Tie-Line Data Plotted According to Brown Modification of Bachman Plot
RECEIVED for review June 11, 1952.
ACCEPTEDDecember 3, 1952.
