SOLUBILITY O F
ACETYL-p-TOLUIDINE
23
THE SOLUBILITY OF ACETYL-p-TOLUIDINE IN VARIOUS SOLVENTS1 D. L. POLLOCK, A. R. COLLETT,
AND
C. L. LAZZELL
Department of ChemistrzJ, West Virginia University, Morgantown, West Virginia Received September 10, 19.46 INTRODUCTION
The solubility of acetyl-o-toluidine in a number of different solvents a t a series of temperatures ranging from room temperature to the melting point of the solute has already been determined (3). It was the object of this work to add a similar series of solubility data for the paraisomer. Similar solubility data for all three isomers of the dihydroxybenzenes (6), nitroanilines (l),aminobenzoic acids (4), and nitrobenzoic acids (2) have also been determined. Pleuger (5) determined the solubility of acetyl-p-toluidine in pure ethyl alcohol, carbon disulfide, and carbon tetrachloride and in mixtures of ethyl alcohol and carbon tetrachloride, carbon disulfide and ethyl alcohol, and ethyl alcohol and water. It is hoped that the data obtained in making a wider range of solubility determinations will, when used in connection with other systematic data, be of some value in determining solubility relations in systems of this type. The solubility of acebyl-p-toluidine in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutyl alcohol, tert-butyl alcohol, benzene, carbon tetrachloride, chloroform, and diethyl ether was determined. Determinations were made a t a series of temperatures ranging from room temperature to the melting point of the solute. The synthetic method described by Walker, Collett, and Lazzell (6) was used. MATERIALS
The acetyl-p-toluidine used in this work was obtained from the Eastman Kodak Company. It was purified by crystallization first from carbon tetrachloride followed by several recrystallizations from water. The melting point of the material used was 148.5"C. (corrected). The solvents used were products having a high degree of purity and in each case were dried in the usual manner. The dried solvent was distilled through a Widmer column. Only the middle fraction of each distillate was used, and the boiling points of these fractions were checked with an Anschiitz thermometer. In table 1 are listed the boiling points and {he refractive indices of the solvents used: The thermometers used were checked with a Bureau of Standards thermometer, and stem corrections were made whenever necessary. The boiling ranges were all reduced to 760 mm. pressure. EXPERIMENTAL DATA
The experimental data obtained are included in tables 2 and 3. The data given in table 2 were determined experimentally, with the exception of the From a part of the thesis presented by Dorothy Love Pollock to the Graduate School of West Virginia University in partial fulfillment of the requirements for the degree of Master of Science, June, 1939.
24
D. L. POLLOCK, A . R . COLLETT AND C. L. LAZZELL
values given for the ideal solution curve, which were calculated by using Hildebrand's equation for ideal solutions. Using these data large-scale graphs were drawn, and from them the values found in table 3 were interpolated. In the tables N X 100 represents the mole per cent of the solute and t the Centigrade temperature at which complete solution took place. All of the determinations were checked by two trials and in many cases duplicate bulbs were made. The thermometers and weights used in obtaining these data were checked with a Bureau of Standards thermometer and Bureau of Standards weights. All the temperatures have been corrected for stem emergence. TABLE 1 Physical properties of solvents BOILINO POINT
SOLVENT
Methanol.. . . . . . . . . . . . . . Ethanol. ................ l-Propanol. . . . . . . . . . . . . . . 2-Propanol. . . . . . . . . . . . . . . . l-Butanol . . . . . . . . . . . . . . . . Isobutyl alcohol.......... tert-Butyl alcohol. . . . . . . . Benzene. . . . . . . . . . . . . . . . . Carbon tetrachloride.. . . . Chloroform. . . . . . . . . . . . . . Diethyl ether.. . . . . . . . . . .
BOILING EANGE
(I?ternational Cntical Tables)
OC.
"C.
64.5 78.4 97.7 82.1 117.6 107.0 82.7 80.0 76.6-76.7 61.0-61.2 34.5
64.5 78.5 97.8 82.3 117.7 107.3 82.8 79.6 76.8 61.2 34.5
BEFBACTIVE INDEX
Found
Intermtiotlal Crifical Tables
1.3295 1.3614 1.3857 01.3791 1 ,3995 1.3960 1.3879 1.5014 1.4609 1.4462 1.3530
1.329 1.361 1.3860 1.378 1.3993 1.396 1.387 1.5014 1.4607 1.4467 1.3526
By the use of Hildebrand's equation relating ideal solutions to the heat of fusion and the melting point of the solute, the heat of fusion was .calculated:
Lf/4.58is the slope of a curve whichmay be obtained by plotting log N against 1/T, Since the curves so obtained are more nearly straight near the melting point of the solute, it would seem that the ideal solution would be most nearly approached by $he concentrated solutions. Therefore, the majority of siopes used in calculating Lf were chosen as close to the melting point as possible. The average of a large number of values for L f shows the heat of fusion for acetyl-ptoluidine to be 6400 cal. No calorimetric value for the heat of fusion could be found in the literature. DISCUSSION O F RESULTS
The seven alcohols used as solvents in this work all give the same type of solubility curves. At a given temperature the solubility of acetyl-p-toluidine in each alcohol will vary by no more than 4 or 5 mole per cent. Acetyl-p-
25
SOLUBILITY OF ACETYL-P-TOLUIDINE
toluidine is more soluble in methanol than in any of the other alcohols. Its solubility curve is very similar to the ideal curve, and from about 40 mole per cent to 100 mole per cent the two curves almost coincide. Of the alcohols studied tert-butyl alcohol is the poorest solvent. The others distribute themselves between these two in the following order: 1-propanol, ethanol, and 1butanol. These three are very close t o methanol but are not quite as good solvents. Isobutyl alcohol and 2-propanol are next in decreasing solubility TABLE 2 Experimental values for the solubility of acetyl-p-toluidine i n mole percentage ~
N X 100
I
f
Methanol "C.
4.904 10.01 10.35 22.75 27.67 40.60 44.24 59.05 88.95 100.0
39.1 59.1 60.3 83.7 91.7 105.3 109.31 123.3 142.7 148.5
2-Propanol 3.787 10.38 20.72 25.67 29.01 43.01 58.35 68.15 100.0
32.2 62.9 87.4 91.0 93.6 110.1 122.3 129.3 148.5
1
N
x
loo
55.2 77.6 87.1 100.1 109.5 117.7 128.1 136.6 148.5
1
Ethanol
I
"C
3.345 5.660 10.22 11.oo 14.74 22.50 49.58 66.10 100.0
N
O1-Propanol O '
9.539 20.42 31.27 . 43.35 53.72 54.52 61.32 88.59 100.0
56.9 81.3 95.6 108.0 117.2 118.9 123.8 139.1 148.5
Isobutyl alcohol 32.6 59.5 82.8 95.9 106.0 116.0 127.7 137.8 148.5
Benzene 1.916 4.764 10.00 22.66 38.43 61.09 78.01 100.0
I
"C.
27.5 43.9 62.0 63.7 73.1 86.1 116.6 129.3 148.5
4.490 10.32 23.96 31.28 39.82 52.15 66.56 81.72 100.0
X
.
1-Butanol
tert-Butyl alcohol 7.44 15.27 21 .oo 31.47 40.75 50.88 64.49 76.94 100.0
1
,
7.169 10.45 21.73 31.64 41.20 52.42 62.96 72.59 100.0
51.4 62.8 85.1 97.9 106.5 116.5 12b. 0 130.9 148.5
Carbon tetrachloride 70.1 79.7 88.5 98.8 111.3 128.5 137.8 148.5
1.254 3.744 5.395 12.02 20.06 30.45 49.55 60.82 65.69 77.99 83.29 100.0
81.0 91.2 93.4 99.7 103.5 108.5 120.8 127.7 130.5 137.6 140.4 148.5
TABLE 2-Continued
I
N X 100
N X 100
1
Water
t
100 119.0 118.6 122.4 123.3 130.4 131.3 134.5 143.9 148.5
I 10.41 18.44 30.78 37.44 41.78 55.19 70.75 77.76 100.0
1)
'
I
t
Diethyl ether
I1
'C.
"C.
55.2 70.9 89.5 96.9 104.4 117.4 131.9 136.7 148.5
4.36 7.40 11.15 20.80 30.02 33.14 42.60 47.93 48.88 50.76 51.45 54.52 54.81 56.52 57.01 57.13 58.51 62.55 71.22 100.0
Ideal
10 20 30 40 50 60 70 80 90 100
N X 100
1
Chloroform OC.
0.109 39.51 45.93 53 * 75 55.27 69.13 b.82 74.84 93.84 100.0
I
50.4 74.9 89.7 103.0 112.9 121.4 129.4 134.9 141.9 148.5
90.5 97.4 103.8 110.1 114.6 116.5 119.9 125.0 125.33 126.5 125.7 127.8 128.0 131.9 132.2 132.3 132.7 134.5 137.7 148.5
TABLE 3 Solubility of acetyl-p-toluidine in various solvents, interpolated at a series of temperatures and expressed in terms of mole percenta!
-- - - - - -
TEKF-EXATUXE
.
IETHANOL
ETHANOL
-PRO'ANOL
2-PROPANOL
--
-
3.2 4.0 5.1 6.2 7.5 , 8.9 10.9 12.7 15.1 17.5 20.5 24.0 27.7 31.9 36.2 40.5 45.0 49.7 55.02 62.3 68.0 75.0 83.0
3.6 4.7 5.3 ' 4 . 3 5.8 15.0 6.6 ,5.9 7.0 7.7 8.2 9.0 9.5 10.6 12.5 11.4 14.7 13.5 17.4 15.9 20.5 18.7 23.7 21.7 27.3 25.0 31.2 28.7 35.5 33.0 40,3 37.6 45.4 43.1 50.9 49.0 56.6 55.4 62.5 62.4 69.0 70.0 76.2 77.0 83.0 83.0
1-BUPANOL
SOBUTYl \LCOEOL
CertBUTYL LCOEOl
BENZENE
ELORO. :ARBON FORM
TETRA ELOBIDE
1.3 2.4 4.2 6.2 8.3 10.4 12.9 15.4 18.3 21.3 24.6 28.3 31.7 35.2 39.1 43.3 48.1 52.6 57.7 62.8 69.0 75.0 83.0
0.2 0.2 0.3 0.3 0.4 0.4 0.4 0.5 0.6 0.8 1.2 2.0 3.7 6.7 13.0 23.0, 32.2 40.4 47.7 56.1 64.5 70.7 83.0
LTEER
WATER
-
7
"C
30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140
4.0 4.5 5.5 6.4 7.6 8.8 10.3 11.9 13.7 16.0 18.8 22.0 25.6 29.6 33.7 38.2 41.5 48.3 54.0 60.0 67.5 73.8 83.0
* Very insoluble at
4.0 4.7 5.5 6.5 7.6 8.9 10.6 12.5 14.8 17.4 20.3 23.4 27.0 31.0 35.5 40.6 46.0 51.4 57.3 63.2 70.0 77.6 84.0
4.5 5.0 5.5 6.2 7.1 8.3 9.7 11.3 13.4 15.8 18.7 21.8 25.5 29.4 34.2 38.5 45.0 51.0 57.0 63.5 70.0 77.5 84.0
0.8 1.1 1.4 1.8 2.6 3.8 6.0 8.3 10.7 14.0 16.6 19.9 23.6 27.4 31.7 36.2 41.4 47.0 53.1 59.5 66.7 74.0 83.0
0.4 0.4 0.4 0.4 0.5 0.6 0.7 1.0 2.6 3.1 5.0 7.7 11.7 17.6 24.4 30.2 36.3 42.3 48.7 57.0 64.5 72.8 83.0
0.7 0.7 0.9 1.1 1.2 1.3 1.4 1.6 1.9 2.5 3.7 5.6 8.4 12.2 18.3 * 27.5 33.0 49.0 48.5 58.7 55.6 67.4 63.2 76.0 83.0 85.0
-
low temperatures forms two liquid layers at 117.6"C. 26
-
27
SOLUBILITY O F ACETYL-p-TOLUIDINE
effect. The dipole moments of the alcohols seem to have nothing to do with the order in which they are arranged, since the values are as follows: methanol, 1.69; l-propanol, 1.64; ethanol, 1.64; l-butanol, 1.56; isobutyl alcohol, 1.70; 2-propanol, 1.70; tert-butyl alcohol, 1.65. Several of these curves cross each other, usually at about 50 mole per cent. Chloroform appears to be the best solvent investigated. It follows the ideal curve very closely except at low mole per cents, where it shows much greater divergence from it than do the alcohols. Carbon tetrachloride and benzene show very similar solubility curves for acetyl-p-toluidine, which is slightly more soluble in benzene than in carbon tetrachloride. The solubility curves for these two solvents differ widely from the 8 ,
FIG. 1. Typical solubility curves for acetyl-p-toluidine in various solvents: 1, ideal curve; 2, methanol; 3, tert-butyl alcohol; 4, benzene; 5 , diethyl ether.
ideal curve and from any of the curves given by the alcohols. The solute is very insoluble in benzene at low temperatures, but its solubility increases from about 1 mole per cent at 90°C. to 12 mole per cent at 100°C. From 100°C. to the melting point the solubility is shown by a straight. line. These two solvents were the only solvents used having an electric moment of zero. Acetyl-p-toluidine and water form two liquid layers with less than 8 mole per cent of the solute up to 45 mole per cent of the solute. The solubility curve from 45 mole per cent to the melting point of the solute is a straight line. The solubility curve for the solute in diethyl ether shows a distinctly different type of curve from any studied. The curve has a break at a composition of 55 mole per cent and a temperature of 128°C.; this indicates the possibility of compound formation, which, however, was not confirmed.
~
28
D. L. ISOM AND HERSCHEL HUNT
SUMMARY
The synthetic method was used to determine the solubility of acetyl-p-toluidine in methanol, ethanol, l-propanol, 2-propanol, l-butanol, isobutyl alcohol, tertbutyl alcohol, chloroform, benzene, carbon tetrachloride, diethyl ether, and water from about 35" t o 148.5"C. The heat of fusion of acetyl-p-toluidine as calculated from solubility measurements mas found to be 6400 cal. per mole. REFERENCES (1) GOLLETTAND JOHNSTON: J. Phys. Chem. 30, 70-82 (1926).
(2) (3) (4) (5) (6)
COLLETT AND LAZZELL: J. Phys. Chem. 34, 183847 (1930). HALL,COLLETT, AND LAZZELL: J. Phys. Chem. 37, 1087-94 (1933). LAZZELL AND JOHNSTON: J. Phys. Chem. 32, 1331-41 (1928). PLEUQER: Physik. Z. 20, 167-70 (1925). WALKER, COLLETT, AND LAZZELL: J. Phys. Chem. 36, 3259-71 (1931).
T H E SEPARATION OF DIASTEREOISOMERS BY ADSORPTION FROM T H E VAPOR PHASE1 D. L. ISOM
AND
HERSCHEL HUNT
Department of Chemistry, Purdue University, Lafayette, Indiana Received June 90, 10.46
The purpose of this investigation is to determine if diastereoisomers of the type dl-sec-butyl 1,2-acetoxypropanoateor dl-sec-butyl Z-lactate can be separated by a preferential adsorption of one of the esters on activated charcoal. If one of the esters is adsorbed to a greater extent than the other, then when a mixture of the two is passed over the carbon, the first and last fractions t o be expelled from the charcoal should have different percentages of the two esters. In order to prepare dl-sec-butyl Z-lactate, a sterile mixture of glucose, water, calcium carbonate, and malt was inoculated with Bacillus delbriickii and incubated at 45OC. The excess calcium carbonate was removed from the flask and the solution concentrated a t reduced pressure. Sulfuric acid was used as a catalyst during the esterification process. The acid solution, an excess of 2butanol, and 200 ml. of benzene were put in a flask equipped so that as the benzene, alcohol, and water mixture boiled out it was condensed and the benzenealcohol layer returned to the reaction mixture. The mixture was heated until the condensate ceased to separate into two phases. The mixture of esters was purified by distillation. It had the following constants: refractive index, 1.4178; d ?'= 0.966 g. per cc.; aioo= 7.12"; boiling point = 67-69°C. (17 mm.). dl-secButyl 1,2-acetoxypropanoate was made by treating dl-sec-butyl Z-lactate with 1 This article is based upon a thesis submitted by D. L. Isom to the Faculty of Purdue University in partial fulfillment of the requirements for the degree of Doctor of Philosophy, June, 1945.
