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alyst (experiments 151, 155, 156, and 158 in Table I). The 7.8second viscosity bleached linters which were used were obtained from the Hercules Powder Co. The results indicated that the cotton linters were considerably more reactive toward hydrogenolysis than wood, but the yield of distillables was less. This was probsbly due to the high conversion t o water. ACKNOWLEDGMENT
The author would like to express his appreciation to the Plywood Research Foundation of Tacoma, Wash., for permission to publish the results of this investigation. He is indebted to J. G. Meiler, under whose direction it was carried out, and to R. G. Paquette, 8. A. Ryan, M. B. Perry, and Eliott Backup, who were active in this work at various periods. LITERATURE CITED (1) Bower, J. R., Jr., Cooke, L. M., and Ilibbcrt, H., J. Am. Chem. Soc., 65, 1192 (1943). (2) Ibid., p. 1195.
Vol. 43, No. 6
(3) Brewer, C. P., Cooke, L. M., and Hibbert, H., Zbid., 70, 57-9 (1948). (4) Godard, H. P., hlccarthy, J. L., and Hibbert, H., Ibid., 62, 988 (1940). (5) Ibid., 63, 3061 (1941). (6) Hachihama, Y., Jodai, S., Ogawa, S., and Tomihisa, K., J . SOC. Chem. Ind. J a p a n , 4 7 , 9 1 6 (1944). (7) Hachihama, Y., Jodai, S., Sawai, K., and Nakayama, M., Ibid., 4 7 , 2 1 8 (1944). (8) Hachihama, Y . ,Jodai, S., and Takeda, M., Ibid., 47, 215 (1944). (9) Harris, E. E., Paper Trade J., 111, No. 24, 27 (1940). (10) I. G. Farbenindustrie A.-G., Brit. Patent 531. 543 (Jan. 10, 1941). (11) International Hydrogenating Patents Co., Ltd., French Patent 827,600 (April 28, 1938). (12) Kronig, W.(to I. G. Farbenindustrie A-G.), Ger. Patent 725,602 (Aug. 13, 1942'). (13) Pepper, J. M., and Hibbert, H., J . Am. Chem. Soc., 7 0 , 6 7 (1948). (14) Sherrard, E. C., and Harris, E. E., U. S. Patent 2,328,749 (Sept. 7, 1943). (15) Zeidler, R., Tek. Fdren. i FinEand Fdrh., 62, 153-8 (1942); Bull. I n s t . Paper Chem., 13,265 (1943). R E C E I V ~January D 31, 1950.
Graphical Correlation of Physical Properties of a Ternary System VAPOR PRESSURE AND SPECIFIC GRAVITY FOR AMMONIAAMMONIUM NITRATE-WATER BURTON H. SANDERS AND DAVID A. YOUNG Spencer Chemical Co., Pittsburg, Kun. I n order to correlate data on vapor pressure and specific gravity of the system ammonia-ammonium nitrate water, a new type of graph was developed, comprising a ternary diagram in combination with a two-coordinate cross plot. The ternary diagram has the usual coordinates of' composition for the ternary system. One of the sides of the ternary diagram at the same time constitutes one of the coordinatesof the cross plot. The second coordinate of the latter represents temperature.
This makes it possible to introduce the effect of temperature, or other environmental condition, into a graph relating composition of a ternary system and some physical property without resorting to three-dimensional representation. The method is applicable when a two-coordinate graph relating a physical property and the environmental variable (temperature, pressure, etc.) gives lines representing varying compositions which are essentially parallel.
M
the logarithm of the vapor pressure against the reciprocal of the absolute temperature yields straight lines, representing different compositions, which are essentially parallel within the range covered (Figure 1). This makes possible a correlation between vapor pressure and temperature for any Composition of the system, based on the following relationships: 1. Because the lines on Figure 1 are straight for any composition, equal increments of 1/T are accompanied by equal increments in the logarithm of the vapor pressure. 2. If the lines of Figure 1 were exactly parallel, their intercepts with the temperature coordinate would form angles which are all equal. I n that case, for each composition 1, 2, 3, etc. between any two vapor pressures p l and pz-e.g., 2000 and 3000 mm.-the corresponding changes of the reciprocal of absolute temperature, A(l/Tl), A(l/T2), A( 1 / T 3 ) ,etc., are equal. 3. For any three-component system, there furthermore will be a number of solutions which a t a given temperature have the same vapor pressure. If a graph of the logarithm of the vapor pressure versus the reciprocal of the absolute temperature for these solutions gives lines of the same slope, these lines must coincide; hence, these solutions will have equal vapor pressures a t all temperatures. Therefore, while only one com osition has been indicated for each of the lines of Figure 1, iPthese lines were parallel each would correspond t o other compositions also. It will be shown that these compositions can be ascertained graphically.
UCH information has appeared in the literature regarding
methods for graphically correlating physicochemical data. Such correlations are extremely useful, because they enable the engineer and chemist t o evaluate and interpolate experimental data. There are many ways by which properties of compounds or mixtures of two components can be expressed graphically. I n the case of three-component systems, the well-known ternary diagram can be used to show the relation between composition and some physical property-for example, vapor pressure-at any one temperature. Conversely, i t can be used t o show the relation between temperature, or other environmental condition, and composition at any one vapor pressure, or other physical property. It is shown here that i t is possible to introduce the effect of an environmental condition into a graph relating composition and aome physical property without resorting t o three-dimensional representation. VAPOR PRESSURE CORRELATION
I n the course of investigations regarding physical properties of ammoniating solutions, information was required on vapor pressures of the ternary system ammonia-ammonium nitrate-water. It has been found experimentally that, for this system, a graph of
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INDUSTRIAL AND ENGINEERING CHEMISTRY
For the purpose of the correlation referred to, an average slope of the lines of Figure 1 is determined, and all the lines then are pivoted around the center of the coordinate 1/T to conform with this average slope; the lines then are exactly parallel (these new lines have not been shown). The center of the temperature coordinate is chosen to minimize the error introduced. Using the new values for the mixtures containing 0% water (compositions 1, 2, 4, 8, and 12 on Figure l), a cross plot is constructed (see the left-hand section of Figure 2) having as the coordinates the reciprocal of the absolute temperature (for convenience, a Fahrenheit temperature scale is added opposite this coordinate) and the composition of the now binary system ammonia-ammonium nitrate. This will yield a series of lines, each representing a certain vapor pressure. Construction of the cross plot is facilitated greatly by relationships 1 and 2. From relationship 1 it follows that for any composition it is sufficient to predetermine values for 1/T for only two vapor pressures; the relation between 1/T and vapor pressure is logarithmic, so that, for instance, predetermined values of 1/T for vapor pressures of IOOO and ZOO0 mm. enable location of any other vapor pressure value against the corresponding value for 1/T. From relationship 2 it follows that it suffices to determine vapor pressure values p l and p , for one mixture of ammonia and ammonium nitrate only, and to determine only one vapor pressure, pl or p z , for the other ammonia-ammonium nitrate mixtures: because of the relationship of vapor preserure intervals PI fi and the corresponding A( l/Z'), the vapor pressure lines on the cross plot are parallel. A ternary diagram for the system ammonia-ammonium nitrate-water now is attached to the cross plot in such a way that the composition coordinate of the cross plot at the same time constitutes the 0% water line of the ternary diagram (Figure 2). From relationship 3 it follows that a mixture, A , having no water, as well as mixtures AI, A,, etc., containing all three constituents of the system but having different compositions, have equal vapor pressures a t all temperatures. These compositions on the ternary diagram are connected by isobaric lines. For example,
-
r RECIPROCAL OF ABSOLUTE
TEMFERATWE-I/*K
Figure 1. Relation between Vapor Pressure and Absolute Temperature for Fixed Compositions of the System Ammonia-Ammonium Nitratewater Symbol
Line No.
Composition, Weight %
NHI
1 2
NH4NOa
HsO
Reference
45 48 50 35 45 35
3 4
5
6 7
35
30
8 9
30 30
10
40 25
11
12 13
27
on Figure 2, composition A (32% ammonia, 68% ammonium n i t r a t e ) a t 140"F. ( 1 / T 0.00300) has a vapor pressure of 6000 mm., and a t 112" F. ( 1 / T = 0.00315) a vapor pressure of 3740 mm. These properties are shared by mixtures Al (36% ammonia, 54% ammonium nitrate, 10% water), At (38.5% ammonia, 41.5% a m m o n i u m nitrate, 20% water), and all other mixtures connected by the isobaric line through A , AI, and Az. The directions of the 180baric lines are established from vapor pressure data of ternary mixtures which are available. For example, after the slopes of the lines on Figure 1 are adjusted, it is =i
WEIGHT V* WATER Figure 2.
x d
.
Effect of Temperature and Composition upon Vapor Pressure of the System Ammonia-Ammonium Nitratewater
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Vol. 43, No. 6
creasing percentages of ammonia. Composition 12 (25% ammonia, 75% water) gives a maximum discrepancy of 20% a t '70" F.; a t the same temperature, the deviation for composition 1 (45% ammonia, 55% ammonium nitrate) is -3%. At 130" F., both compositions give vapor pressure deviations of +1%. This is explainable partly by the fact that an average slope was determined from the 13 lines of Figure 1, although the corresponding compositions are not distributed evenly over tht: range covered by thc isobaric lines on the ternary diagram. Slight inaccuracies in the curvature of the constant. pressure line8 also will cause an error. Despite these factors, the over-all average discrepancy for the 13 compositions used is 201,; the average positive deviation is +5%, the average negative dcviation -2%.
+
+
SPECIFIC GRAVITY CORHELATlON
TEMPERATURE
- 'F
Figure 3. Relation brtv een Specific Gravity and 'l'e111peratlire for Fixcd Compositions of the Systern L m monia-Ammonium Nitrate-Water qi
lllhol
0
Line No 1
2
3 4
5 6
7
8 9
10 11
71 eight _Coinposition _ _ _ _--__ ~
% ~
\I13
SHaNOj
€120
16.6 0 21.7
66 8 40 68 0 30 GO 68
16 6 60 13 3 70
0
25 30 0 26.0 33 0
40
3 65 10 60
12 1
80 18 0 90 0
.j
Hefeiencc
In extending the studies of the system ammonia-ammoniuin nitrate-water to include specific gravities, it has been found experimentally that a plot of this property versus temperature yields stmight lines for different compositions which are essentially parallel for a wide composition range (Figure 3). Proceeding in a manner analogous to that for the vapor pressure correlation, an average slope is determined, and the lines are made exactly parallel by pivoting about the center of the temperature coordinate. The cross plot has the coordinates temperature and compositions for the binary system ammonium nitrate-water; the latter forms the 0% ammonia coordinate of the ternary diagram (Figure 4). Modifying the relationships of the vapor pressure correlat,ion, any specific gravity gradients dz - d1 for any two compositions are accompanied by equal temperature gradients; the fipecific gravity lines of the cross plot therefore are parallel and equidistant. Data presented by Shultz and Elmore ( 3 ) lor R temperature of 35" C. helped t o establish the shape of the constant specific gravity lines of the cross plot. 4 n accuracy check, made by comparing values read from Figures 3 and 4, indicated an average deviat'ion of +0.2%. The largest deviations, as a result of pivoting the lines of Figure 3,
found that cornpositmi 10 (30% ammonia, 607, ainmonium nitrate, 10% water) hat. a vapor pressure of 2800 mm. at a temperature giving 1/T = 0.00315. From Figure 2 , this is found to correspond to an ammonia-ammonium nitrate mixture having 27% ammonia (composition B ) . The rolution under consideration is indicated as B,; an isobaric line is drawn to connect B1 and B. Only a few isobaric lines h a x been shown, the vapor pressures of intermediate compositions being found p. by interpolation between 9 the depicted lines t o m r d the 0% water coordinate, and reading the desired data from the cross plot for the resulting 0% water mixturc. The accuracy of the correlation was investigated by comparing the data from Figure 1 with corresponding values from Figure 2 . For the compositions containing '% water, the Figure 4. Effect of Temperature and Composition upon Specific Gravity of the System curacy increases with inAmmonia-Ammonium Nitrate-Water
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INDUSTRIAL AND ENGINEERING CHEMISTRY
were exhibited by the solutions containing 0% water; they were found to vary with temperature from -0.33 to 0.50%. Time has not permitted an investigation of additional properties which may lend themselves to the above-described type of correlation. However, it is felt that the following generalization may be made: Whenever lines of varying cornpositions of ternary systems on a graph with two variables as the coordinates are entirely or practically parallel, the method is applicable. Furthermore, cross plots can be attached to all three sides of one ternary diagram; this will permit the correlation of three physical properties of one ternary system, using one graph.
+
A
EXPERIMENTAL PROCEDURE
*
VAPORPRESSURE DETERMINATION.The experimental data were obtained by placing a solution of desired composition in a previously evacuated metal bomb, which was connected either to a mercury manometer (subatmospheric range) or a calibrated pressure gage (aboveatmospheric range). The bomb waa immersed in a constant-temperature bath, and determinations were made at steady-state conditions. The accuracy was found to be *2.4%. SPECIFICGRAVITYDETERMINATION.The specific gravities were determined by weighing the constituents into a glass
l433
cylinder containing a hydrometer and thermometer. The cylinder was enclosed in a transparent plastic case, reinforced to withstand pressure. The entire assembly was immersed in a constanttemperature bath prior to taking the readings. The average accuracy was *0.02y0. The ammonia and ammonium nitrate used in the determinations had a minimum purity of 99.95%. ACKNOWLEDGMENT
Acknowledgment and thanks are due to the Spencer Chemical Co. for the privilege of publishing these correlations. Special thanks are extended to the Technical Department and Research Section of the company for having determined physical property data required for this work. LITERATURE CITED
(1) Perry, J. H., ed., “Chemical Engineers’ Handbook,” 2nd ed.,p. 413,New York, McGraw-Hill Book Co., 1941. (2) Ibid., p. 2544. (3) Shultz, J. F., and Elmore, G. V., IND.ENQ. CEEM.,38, 296-8 (1946). (4)
Spencer Chemical Go., unpublished data, 1960.
RECEIVED November 24, 1950.
Ternarv Svstem FurfuralEthylene Glycol-Water J
d
J
d
JOSEPH B. CONWAY AND JOHN J. NORTON’ Villanova College, Villanova, Pa.
..
T h e present work was undertaken to evaluate the applicability of furfural toward the extraction of ethylene glycol from aqueous solutions, in terms of the ternary equilibrium and tie-line data for this system. The ternary equilibrium diagram for the system, furfural-ethylene glycol-water at 25’ C. is presented together with several tie lines. The tie-line data are correlated in terms of previously proposed methods. A comparison of equilibrium data, using previously published data for the two alcohol systems, indicates that furfural is a better extractive solvent for ethylene glycol than either n-amyl or n-hexyl alcohol.
L
ADDHA and Smith (6) investigated the extraction of ethylene glycol from aqueous solutions and considered some normal alcohols aa solvents. Ternary equilibrium data together with several tie lines were presented in an effort to evaluate the solvents considered. Data on n-amyl and n-hexyl alcohol indicated that these were poor extractive solvents for removing glycol from aqueous solutions. The distribution greatly favored the water phase, and n-amyl alcohol seemed to be better than n-hexyl alcohol. An approximate method for predicting distribution and selectivity in ternary liquid systems has been proposed by Conway ( 2 ) . This method is based on the physical properties of the components and makes it possible to determine approximately if good selectivity in a solvent will be obtained. This method was employed in evaluating the extraction of ethylene glycol from aqueous solutions. The prediction that amyl alcohol may be a better solvent for this extraction than n-hexyl alcohol is substantiated by the data of Idaddha and Smith (6). Further1
Present address, Panelyte Division, St. Regia Paper Co., Trenton, N. J.
more, the method proposed by Conway ( 9 ) was used to predict that furfural might be a good solvent for the extraction of glycol from water, better than either n-amyl or n-hexyl alcohol. The present work was undertaken to verify this prediction and to compare furfural as an extractive solvent for ethylene glycol with n-amyl and n-hexyl alcohol. MATERIALS
Laboratory-distilled water was used. Technical furfural (Quaker Oats Co.) was purified by fractionation in a small fractionating column. Purification was carried out a t 15 mm. of mercury and the first and last portions of the distillate were discarded. The purified product was clear and had a very faint straw-yellow color. Ethylene glycol (Eimer and Amend, refined ethylene glycol) had a specific gravity of 1.11 at 25’ C. PROCEDURE
All measurements were made at 25’ C., using the method discussed by Othmer, White, and Trueger (7‘). The furfural side of the curve was obtained by taking a dilute solution of glycol in furfural and titrating to turbidity with water. A measured quantity of glycol was added until the mixture was made homogeneous and it was then titrated to turbidity again with water. This process was repeated until the furfural side of the equilibrium curve was obtained. The water side of the equilibrium curve was determined in a similar manner. In determining the equilibrium curve each time a point on the binodal curve was obtained, its specific gravity was determined with a Chaino-matic Westphal balance. The specific gravity values for each side of the equilibrium curve were plotted against weight per cent glycol and used in establishing the tie lines. Tie-line data were obtained by making up mixtures .whose compositions fell within the two-phase area of the equilibnum curve. These mixtures were agitated, stoppered, and allowed
