SOLUBILITY RELATIONS OF ISOMERIC ORGANIC COMPOUNDS VII. The Mutual Solubility of the Dinitrobenzenes with the Nitroanilines, and of the three Chlorobenzoic Acids* BY JOHN JOHNSTON ASD EDWIS P. JOSES'
I n two previous papers it was shown that, solutions of the three dinitrobenzenes,2 and of the three nitroanilines? are substantially ideal with respect to the mutual solubilit'y of the several isomers; the present paper extends the measurements to the other nine binary systems-namely of each nitroaniline with each dinitrobenzene--for it was of interest t,o ascertain if these pairs behave similarly, as in fact they do. The mutual solubility in the three binary systems of the chlorobenzoic acids mas also determined; with the results that these systems also prove to be substantially ideal in this respect. On the other hand, the pairs of like isomers of the chloronitrobenzenes and bromonitrobenzenes appear in each of the three cases to form an unbroken series of mixcrystals; p-nitrobenzoic acid and p-toluic acid show only partial crystal miscibility. The Dinitrobenzenes with the Nitromilines The method of purification and the criterion of purity was the same as previously d e s ~ r i b e d . ~ :The ~ experimental procedure was somewhat different in that the solid system, contained in a tube surrounded, as before, by a heating coil and a Dewar v e s ~ e lwas , ~ slowly heated, and the temperature at which the last crystal just disappeared was observed directly; during this process the mixture was continuously stirred by the rotation. forward and reverse, of a smaller tube enclosing the thermoelement. This procedure, when carefully carried out, yields a result entirely comparable with that derived from a series of cooling curves. properly interpreted, and is more rapid; it is advantageous particularly for systems in which the stable solid phase crystallizes sluggishly, as proved to be the case with 0- and vi-nitroaniline and m-dinitrobenzene from some of the mixtures. Each experimental datum in the tables is the average of at least two concordant observations of the last melting temperature t (centigrade) of the mixture containing the mol percentage C A of substance A . Discussion. I n order to secure a better comparative picture of the several solubilities the results were plotted in terms of log S vs. ~ o o o / Ton a large scale, and values read off at regular intervals of the reciprocal temperature. *Contribution from the Department of Chemistry, Tale Cniversity. the dissertation presented by Edwin P. Jones to the Graduate School of Tale University in June 1926,in candidacy for the degree of Doctor of Philosophy. 2 Andrews: J. Phys. Chem., 29, 1041 (1925). 'Kohman: J. Phys. Chem., 29, 1048 (192j). Compare also ibid., 29, 882, 914, 1 3 1 7 (1925);30, 7 0 (1926). 4 Arranged so that the mixture within could be illuminated and observed. 1 From
JOHN JOHNSTON AND EDWIN P. JONES
594
These are presented in Tables I11 and IV, along with values similarly inter, ~ the ideal polated from the respective data of Andrews* and of K ~ h m a nand value as derived from the calorimetric data of Andrews, Lynn and J ~ h n s t o n . ~ As the values finally published differ, owing to the adoption of a better value for the specific heat of the silver standard, from those used in the previous similar calculations, they are tabulated below, together with the coefficients derived from them in the ideal solubility equation6
TABLE I Experimental Data on the Solubility of the Solid Phase A in Mixture with the Second Component B. (I)
B = o-Nitroaniline t C* 100.0 116.8 102.9 76.5 56.0 87.5 36.0 68.8 Eutectic 54.0
76.0 55.9 35.6 18.2
172.8 156.7 138.9 114.6 79.0
Eutectic
62.0
100.0
=
100.0
87.9 76.6 70.0
101.8
Eutectic
A
p-Nitroaniline
c*
116.8 109.9
87.5 74.9 60.1
90.8 81,2
Eutectic
87.8 76.9 66.9
Eutectic
89.8 82.2 73.7 64.9 61 . o
110.5
104.4 99.8 93.3
TA + Kz log T +
89.5 74.8
89.8 83.6 72.5
Eutectic
70. I
100.0
172.8 165.2 154.0 142.0 139.0 131.3
100.0
(3) A = p-Dinitrobenzene 100.0 172.8 89.0 166.6 78.3 159.1 145.7 61.8 49.3 133.1 117.5 36.6 27.6 102.5 Eutectic 97. I
log XA = Ki (T+T)
t 116.8
m-Dinitrobenzene
100,0
'
Eutectic
o-Dinitrobenzene
100.0
(2)
75.5 54.6 46 ' 5
=
m-Nitroaniline C* t
89.8 72.5 53.0 43 4 37.8
100.0
A
86.5 69.4 55.1
K3
52.5 44.4 37.4
122.2
Eutectic
119.3
(TA- T)
T A denoting the absolute melting temperature of pure A and T the last melting temperature (absolute) of a mixture containing the mole fraction NAOf A (CA = 100 XA). ~
6
J. Am. Chem. SOC.,48, 1274 (1926) Cf. Andrews: ref. 2, p. 1043.
SOLUBILITIES OF ISOMERIC ORGANIC COMPOUNDS
595
TABLE I1 Experimental Data on the Solubility of the Solid Phase A in Mixture with the Second Component B. (I) A = +Nitroaniline B = o-Dinitrobenzene C* t
69.9 64.7 59.3 54. o
100.0
90.7 81.6
Eutectic
pDinitrobeneene
m-Dinitrobenzene C* t
69.9 63.1 55.9 47.3 41, I 37 . 8
100.0
90.3 80.8 69.0 61.7
Eutectic
A = m-Nitroaniline 100.0 112.0 91.4 107.7 89.4 106.7 76.3 98.7 74.9 97.5 64.7 89.7 57.7 83.8 49.0 75.6 37.5 63.2 Eutectic 6 I .o
CA
t
100.0
90. I
69.9 64.4
Eutectic
62 . o
(2)
100.0
83 ‘ 5 74.7 65.8 64.9 55.6 50.7
112.0 103.8 98.7 93.3 93.2 86.3 82.8
Eutectic
81.2
54.2
147.5 137.1 121.6 112.6
43 ’ 4
100.2
100.0
84.3 63.9
50.2
Substance
+dinitrobenzene mp-
” ”
o-nitroaniline m- ” p- ”
Eutectic
93.3
108.0 101.8
Eutectic
97. I
100.0
147.5 142.3 135.4
103.5 93 ’ 1 81.8 70. I
Heat of melting (cal.) a t t
4245 2224 5893 2773 4224 3015
112.0
91.2 80.7
(3) A = p-Nitroaniline 100.0 147.5 90.8 141 ’ 5 84.3 136.8 127.3 73.2 62.0 116.7
41.5 33.8
Eutectic
100.0
+ I5.81t - 0.0460 t2 + 26.49t - 0.0565 t2
+ 3.41t + 0.0077 t2 + - 0.0382 t2 + 19.2t - 0.0650 t2 + 23.ot - 0.0630 t2 20.2t
Ta K, 389.9 1.964 362.9 5.556 445.9 -2.714 343.0 3.564 385.1 3.330 420.6 4.139
91.6 82.6 70.6
Eutectic
Kz
-20.60 -28.86 +0.401
-20.67 -27.53 -28.89
125.2
119.3
I
