INDUSTRIAL AND ENGINEERING CHEMISTRY
a34
Possible applications are (1) filtration of concentrated sodium hydroxide or sodium carbonate solutions in the paper, rayon, and textile industries; (2) filtration of bleach liquors; (3) removal of suspended material from strong acids, as in the refining of titanium dioxide; (4)any plant operation where it is necessary to filter caustic and corrosive solutions and where a long-life continuous system requiring a minimum of attention is desired.
Vol. 38, No. 8
ACKNOWLEDGMENT
The authors express their appreciation for the helpful suggacltiom and criticisms given them by the late H. G. Turner and by ** witt Hutchison. LITERATURE CITED (1) Turner, H.G., Isu. Exa. CHEM.,35, 145 (1943). (2) Turner, H, G , , J , Am. water Assoc., 36,431 (1944) (3) Turner, H.G., and Scott, G. S , Combustion, 5 , 23 (1934).
Acetic Acid-Ethyl EtherWater Svstem J
MUTUAL SOLUBILITY AND TIE LINE DATA COLEMAN J. MAJOR1
AND
OSCAR .J. SWENSOX, Cornell University, Ithaca,
>Iutual solubility and tie line data are presented for the system acetic acid-ethyl ether-water. Data at 25' C. were determined using reagent and commercial grade ether. 4dditional data were obtained for commercial ether at 20 C. The tie line data have been successfully correlated by each of four different methods. Data on the water side of the mutual solubility curve were obtained by a new method based on the difference in foaming tendency between a homogeneour and a heterogeneous solution of the three components.
I
9 T H E course of a laboratory investigation on liquid-liquid
extraction, mutual solubility and tie line data xere required on the system acetic acid-ethyl ether-water. Although a number of investigators have studied this system (1, 3, 6-15, 16, 18, 19, ?O), the published data are not sufficiently extensive t o permit mnstruction of a complete ternary diagram. The present study &vasundertaken for the purpose of obtaining the necessary data with both reagent and commercial grades ethyl ether. The equilibrium data for the system are presented in Tables I and I1 arid the ternary diagrams are given in Figures 1 and 2. The mutual solubility curve of Figure 1 for commercial ether lies below that of the reagent grade because the commercial ether used in this investigation contained, as an impurity, approximately 3.5 weight 70 ethyl alcohol. Figure 2 shows that very litI!(! difference exists between the data for 25" C. and for 20" C. 1
N. \.
The tie line data of Table I1 indicate that, a t low concentretiona of acetic acid, the acid concentration in the ether phase is Ion-er than that in the water phase; a t high concentrations of acetic acid the reverse is true. This is illustrated graphically by Figures 1 and 2, where the tie lines actually undergo a rcvrssl io dope as the acid concentration is increasrd. GRADE OF MATERIALS
ACETIC ACID. Baker and hdamson reagent, glaviiil acetic acid was used. Direct titration with standard alkali and phenolphthalein indicator showed the acidity to be 99.8% hy weight. Density data on the acid a t various temperatures are prwented in Table 111. At 23' C. the demity of the arid wn.5 1.0439 grams per ml. n-hereas the accepted literature value is 1.0440 for tJhe pure acid. ETHYLETHER.The reagent grade was obtaitir~lfrorii onepound bottles labeled "Ether Anhydroris LIwck". Th cations indicated that principal inipuritit:s ~verc 0.1 alcohol and 0.05yc n-ater. The comnitwial grade wa: from 5-gallon metal containers l a h c l ~ d"Ether [*.S.l'. LIvrck". It was an alcohol derivative containing itpproxinia t vIy :3.5 weight % ethyl alcohol. Density data on the two grades are prevcntcd in 'l'abltr 111. The density of the reagent grade at 23' C. ivas 0.7071 gram per nil. as compared n*ith the accepted literature valuc: of 0.7078 for the pure ether. 'ATER. Ordinary distilled water from the laboratory supply
Present address, Sharples Chemicals, Inc.. Kyandotte. Mich
A C E T I C ACID ACETIC ACID
-Reagent ---
2 0 0 c. 25' C.
Ether
Commercial Ether
" WATER
Y
"
"
"
"
WATER ETHER
Figure 1. Mutual Solubility Curves and Tie Lines for Acetic Acid-Ethyl Ether-Water System at 25" C.
ETHER
Figure 2. Mutual Solubility Curve and Tie Lines for Acetic Acid-Commercial Ether-Water System at 20" and 25" C.
835
INDUSTRIAL AND ENGINEERING CHEMISTRY
August, 1946
Commercial Ether, 25' C. Acetic Corn. acid ether Water
Reagent Ether, 2 j 0 C. Acetic Kac&iit acid Ptlier R-ater
.-
0 9.5 17.4 22.7 26.1 29 I 31, :3 31.2 28 n 22.8 13 7 0
0 9.3 16.9 20.3 25.8 28.4 30.3 30.5 28.3 22.7 13.7 6.3 0
1.3 4.5 8.4 11.6 I5,9 20.3 30.7 -'3.9 XI.3 66.3 78.6 93.6
97.7 85.2 73.7 67.8 56.7 49.3 36.5 26.6 16.8 11.3 7.6 7.1 6.7
c.
25.0
rt 1 1 0 ~ .
C o i i ~ i i i i ~ i ~ r ~ ~ : 2~0I . 0
et1ii.r
98.1 85.3 74.0 68.0 56.5 36.2 27.3 11.7 6.6
0.20
a1
-
Cl
0.10 1
11. TIELISE DATA W t , $: in Water Layer _ _ . Ether Water
~
Acid
29.6 25.4 19.8 14.3 8.9 4.2
49.0 60.0 70.5 78.9 86.6 93.0
21.4 14.6 9.7 6.8 4.5 2.8
28.7 23.6 18.1 12.5 7.3 3.8
47.7 61.3 71.5 80.3 87.7 92.6
23.6 15.1 10.4 7.2 5.0 3.t;
27.Y 23.1 18.4 13.8 8.8 5.1
Ib.4
28.9 18.1 3.9
46.0 71.2 93.3
26.1 10.7 2.8
27.8 18.1 4.7
I6 6 9.9 6.4
I L
,
9.8
8.1
11.9 sl.5 8.0 7.2 6.9
MUTUAL SOLUBILITY DATA
Thc. ucluilibrium data are expressed in m i g h t pur cent. All compoiit*nts were measured by volume from standard burets. The dt'iisity data of Table I11 Rere used in computing the wcighrs of mn tctrial udded. bltwurcd volumes of acetic acid and ether nwre added from burets to a glass-stoppered Erlenmeyer flask of 125-cc. capacity. Water was added dropwise t o this solution until the mixture became t,urtiid and remaiiied so for about 3 seconds. Tho flask was t,lien stoppered and placed in a constant temperature bath maintained within *0.1" C. of the desired temperature. After reaching a constant, temperature, the flask was removed and
-
1.00 -
-
a, I-
01
0.20
-
1.9 5.4 9.3 11.8 17.9 33.8 42.5 65.7 93.4
--
Wt. % in Ether Layer Acid Ether Water
23,0
Coll~lllcrTlal
0
9,s
16.7 20.2 25.6 30.0 30.2 22.6 0
-
~
TABLE
,relllp,,
0.50 0.40 0.30
Commercial Ether, 20' C. Acetic Com. acid ether Water
2.3 5.5 9.4 11.9 17.5 22.3 33.2 42.9 54.9 66._0 78., 86.6 93.3
.
0.50
0.70 --
I. L\~UTUAL SOLUBILITY IS KEIGHT PERCENT
TAn1.c
-
::q/ll 0.03
0.05
I
I
I
0.50
bz
69.6 75.8
Figure 4.
Log Plot of cI/a against c r , ' I i .
55.7 65.0 72.1 78.2 84.0 88.0
viater \va> again added until tht: mist uri, 1lcXc.anli. turbid and remained so for a relatively long t i n i i , This procedure yielded data for the etlier side ot t l i i , 55.6 solubility curve. The end poinis in all rahi'b \vcbrt. 72.0 quite sharp. 88.9 The normal Drocedure for obtaining ( l a t a C ) I I the x a t e r side of the bo1utiili.v cuive coii\ikt> in adding ether dropmise t o a mixture of aretic acid and water and noting the turbidity end point. It wa.found, however, that the exact point a t wlicah turliiility p('rsisted was difficult t o determine even when it com~~aiison solution was used. Sasaki (17 ) showed that homogencou. w l i i t iori. of acetic acid, ethyl ethcr, and water tend to forni toani w I i t L n shaken in a flask; heterogeneous solutions of these c.i~rrii~onont~. however, represented by points btxlow the water side oC t l i c s iiiiitii:il solubility curve, show little or no tendency to form f o : i n i . .411vantage was taken of this phenomenon in the prestwt iiivc'.qtigation in establishing the water side of the aollibility curvr. A11 aqueous solution of acetic acid has a slight toridency to foani when shaken in a flask. As ether is addcd, t h c foaining ttsntl(wcy increases markedly until the ether phase begins to uc,paixtc, oiit. At this point, when ether is present in very slight ~ x c e s s t,l i ( x iiiisture has little tendency to form foam. The proctLdure which \vas finally used in obtxiniiig t1:it:i f o r the water side of the mutual solubility curve was as follo\v-.: .I preliminary run was first niaclc to establish an approxiiiialt, ?.rid point. This was done b y measuring definite quantities 0 1 :ic-ctic. acid and water into a flask anti adding ether until thv niixtui,i. IJVcame turbid. Since the exact point at which turbidity pcwi~ri~il was hot n-ell defined, the above procedure yie1di:tl o i i l y 311 :ipproxL mate end point. Four separate solutions \vt'rcL t1ic.n prcxp:irivl, each of which contained the same amounts of ivatc'r an(] : i m ~ ti v acid as did the trial run, but eontaincd variou:, amounts of 1ii.r. The solutions were stepped in huch a manner that t h e fir51 O I I I ~ was known t o have been in the homogencous region while t I i r laht was definitely in the hetcrogeneous region. A4fter thv 1)r01)1'1 (71
-
TABLB 111. DENSITY DATA
7
Temp.,
Reagent ether
Density, Gram8 per M1. Commercial ether
Acetic acid
19.0 20.0 21.0 22.0
0.7133 0.7122 0.7112 0.7102 0.7092 0.7081 0.7071 0.7060
0.7192 0.7180 0.7168 0.7157 0.7145 0.7133 0.7121 0.7110
1.0502 1.0492 1.0481 1.0470 1.0460 1.0449 1.0439 1.0428
c.
I
t
0.2
I
I
0.3 0.40.5
-
t
I
I
0.7
t
1.0
I - bt
bz Figure 3.
I
0.20
"I."
0.10-
0.05 0.1
I
0.10
Log Plot of (1 (1 b)z/bz
-
23.0
-
al)/ol
against
24.8 25.0 26.0
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
836
amounts of ether were added, the flasks were stoppered and placed in a constant temperature bath. The flasks n-ere then removed and shaken vigorously for about 10 seconds. Care was exercised in mabing certain that all solution? received t h e same amount of agitation The solutions were then c2 c o m p a r e d f o r foam stability. The point at Figures. Log Plot of c1against cd which a sharp change was noted in the nature of the foam represented the transition from the homogeneous to the heterogeneous region. The final end point was then determined by preparing several other solution- ovrr 4imt vr intervals of ether concentration
Vol. 38, No. 8
Campbell ( 2 ) demonstrated that tie line data for a large nurnber of systems are successfully correlated by plotting log C I against log cp. Figure 5 shows that this method of tie line correlation is likewise applicable to the present system. The writers found that a straight line results from a plot of log (1 - c l ) / c l against log (1 - c;)/cz, as Figure 6 shows. This method of tie line correlation is not applicable to all ternary systems but does apply t o a large number of them. For clarity the points representing the tie line data for commercial ether a t 20" C. were omitted from Figures 3, 4, 5 , and 6. These points fall in a substantially straight line, however, when plotted by each of the four methods described.
0.65 Cl -
b,+c,
0.60 Commercial
T I E LINE DATA
0.55
The tie line data were obtained by preparing various mixtures
of the three components and analyzing the ether and x-ater layers for acetic acid. The mixtures were placed in 125-cc. glass-stoppered Erlenmeyer flasks and shaken vigorously. The flasks were kept for several hours in a constant temperature bath. Samples of the light and heavy layers w r e pipettcd from the flasks into another set of glass-stoppered flasks and weighed. Each layer was then diluted with water and titrated with standard alkali and phenolphthalein as indicator. CORRELATION. Satisfactory correlation of tie line data habeen obtained by each of four different methods. Othmer and Tobias (15) showed that a st,raight line is obtained when log (1 - a l ) / a , is plotted against log (1 - bz)/bZ, where a1 is the fraction of solvent (ether) in the solvent phase and bz is the fraction of diluent (water) in the diluent phase. Figure 3 verifier the applicability of the method to the acetic acid-ethyl ether-watcr system,
0.50 -
0.50
o
0.1'
0.2
0.3
0.4
c2 b2+C2
Figure T . Effective Concentration Curves for System Acetic AcidEthyl Ether-Water Othmer et al. (14) shoived that relative efficiencies of solvents may be ascertained by plotting (fraction solute)/(fraction solute fraction water) in the solvent phase against the same quantity in the water phase. I n such a plot the best solvent would have the highest solute concentration in the solvent phase for a given solute concentration in the water phase. Figure 7 shows that, weight for weight, reagent-grade ether is a more efficient solvent for acetic acid than t h e commercial grade.
+
NOiM W C LATUR E
0.20
a = weight fraction of solvent (ether) b = weight fraction of diluent (water) c = weight fraction of solute (acetic acid) 1 = subscript referring to solvent (ether) phase 2 = subscript referring to diluent (water) phase
-
I-CI -
LITERATURE CITED
0.05
0.10
0.20
I-c2 -
0.40
c2
Figure 6. Log Plot of (1 against (1 c2)/c2
-
- c1)/c;
(1) Berthelot and Jungfleisch, Ann. chim. phys., 26, 396 (1872). (2) Campbell, J. A., IND.ENG.CHEM.,36, 1158 (1944). (3) Garraud, thQse de pharmacie, Bordeaux, 1897. (4) Hand, D. B., J. P h y s . Chem., 34,1961 (1930). (5) Hantzsch and Sebaldt, 2. p h y s i k . Chem., 30, 258 (1899). (6) International Critical Tables, Vol. 111, p. 424 (1928). (7) Kolosovskii. N. .L, Bull. soc. chim., 9, 632 (1911). (8) Kolosovskii. N. d.,Bull. S O C . chim. Belg., 25, 183 (1911). (9) Landolt-BGrnstein, Physik.-chem. Tabellen. 5th ed., Vol. 1. p. 741 (1923). (10) Ihict.. 3rd supplement, p. 649 (1938). (11) Livingston, J., Morgan, It., and Benson, H. K., J . Am. Chem. SOC.,29, 1176 (1907). 112) T,iifman. N.. 2. anoro. alloem. Chem.. 107. 241 (1919). (13) Slalvesk. P.rBul2. S O ~ chim.. . 5 , 332 (1909). 114) Othmer. D. F., Bergen, W.S.,Schlechter, N.. and Bruins. P. F., ISD. ENG.CHEM., 37, 890 (1945). (18) Othmer, D. F., and Tobias, P. E., Ibid.. 34, 693 (1942) (16) Pinnow, J., 2. anal. Chem., 54,321 (1915). (17) Sasaki, Bull. Chem. SOC.J a p a n , 13, 669 (1938). (18) Schilow, X., and Lepin, L., 2 . p h u s i k . Chern., 101, 353 (1922). (19) Smith, H. W., J . P h y s . Chem., 25,605, 616 (1921). (20) Waentig, P., and Pescheck, G., 2. p h y s i k . Chem., 93, 529 (1919). \--,
Hand ( 4 ) showed that a straight line is obtained when log cl/al is plotted against log c z / b 2 , where c1 is the fraction of solute in the solvent phase, c2 is the fraction of solute in the diluent phase, a; is the fraction of solvent in the solvent phase, and bl is the fraction of tliliient in the diluent phase. The applicability of his method to the present system is substantiated by the straight-line correlations of Figure 4.
I
"
