QUANTITATIVE INVESTIGATIONS OF AMINO ACIDS AND PEPTIDES The solubilities of the amino ...

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QUANTITATIVE INVESTIGATIONS OF AMINO ACIDS
AND PEPTIDES
IV. THE SOLUBILITIES OF THE AMINO ACIDS IN WATER-
ETHYL ALCOHOL MIXTURES*
BY MAX 8. DUNN AND FRANK J. ROSS
(From the Chemical Laboratory, University of California at Los Angeles,
Los Angeles)
(Received for publication, October 21, 1937)
The solubilities of the amino acids in water were reported in a
previous paper (2). The present studies on the solubilities of
eight amino acids in five concentrations of ethanol at four tempera-
tures were undertaken because only a limited number of values
are given in the literature and because dependable solubility
data are of both theoretical and practical import’ance.
EXPERIMENTAL
Amino Acids’-The amino acids used in these investigations
were prepared in this laboratory. The purity of the samples was
insured by repeated crystallization from water or aqueous alcohol
and by analysis. Water was used as the solvent for the final
crystallization of dl-leucine and dl-norleucine, 40 per cent ethanol
for dl-valine, and 70 to 80 per cent ethanol for the other amino
acids.
All but three of the amino acid samplesw ere analyzed by titra-
tion with standard base by the formaldehyde-glass electrode
* Financial assistance in this work has been received from the research
funds of the University of California.
A preliminary report of this work was given before the American Society
of Biological Chemists at Memphis, April 21-24, 1937. An abstract of this
paper has appeared (1).
1 The authors are indebted to B. 0. Blackburne, A. Cherkin, F. J. Clark,
E. R. Evans, S. W. Fox, B. W. Smart, N. L. Smith, and C. E. Redemann
for assistance in preparing amino acids and to A. Loshakoff and J. G. Weiner
who made the glass electrode analyses of the amino acids.
309
This is an Open Access article under the CC BY license.
Amino Acids and Peptides. IV
method of Dunn and Loshakoff (3). The milliequivalents of base
required to titrate eleven samples of the other five amino acids
averaged 99.93 =t 0.39 per cent of the theoretical amount. These
analyses were performed during the preliminary studies on the
glass electrode method prior to the development of the technique
which has been shown to be of high precision and accuracy. Since
it has been found repeatedly in later experiments that amino
acids purified as described in the present paper are almost in-
variably analytically pure (100.0 =t 0.1 per cent), it seems probable
that the amino acids used for the solubility studies were of higher
purity than is indicated by the data quoted. Additional analyses
by the improved technique were not made, since adequate samples
of the original amino acids were no longer available.
The solubility of only one optically active amino acid, d-glutamic
acid, was determined, because in many instances present knowl-
edge of the specific rotations of the amino acids is inadequate to
serve as a reliable criterion of purity. The difficulties encountered
by Cohn and coworkers (4) with Z-leucine illustrate this point.
The values of [cz]E5f or the two samples of d-glutamic acid used
in the present work were +31.4” and +32.0” when the molal
ratio of HCI to amino acid was 1.55: 1. Because these figures do
not agree as closely as desired with those reported previously
(2, 5), experiments are to be undertaken to explain the differences.
Solvents-Distilled water which had been in contact only with
block tin was used without further purification. It was shown,
however, by gravimetric analysis on four 50 ml. samples that the
distilled water contained an average of only 0.0002 per cent by
weight of non-volatile impurities.
Commercial ethyl alcohol was purified by fractional distillation
through a Hempel column. The first and last tenths of each
distillate were discarded to eliminate traces of diethyl ether,
higher alcohols, and other low or high boiling impurities. Al-
though the purified alcohol was not tested for ether, presumably
the latter was removed, because, as shown by McKelvy (6), its
presence in alcohol would be readily detected by the strong odor.
Higher alcohols were shown to be absent, since 5 ml. of the purified
alcohol, treated with 5 ml. of concentrated sulfuric acid, gave no
color after standing for 8 days.
Qualitative tests on the purified alcohol with Schiff’s sulfite-
M. S. Dunn and F. J. Ross
fuchsin reagent indicated that aldehyde was present. The con-
tent of aldehyde (expressed as acetaldehyde) was found to be
only 0.004 per cent by weight when the alcohol was analyzed by a
sulfite-fuchsin calorimetric procedure (7) with solutions con-
taining from 0.0001 to 0.0006 gm. by weight of pure acetaldehyde
in aldehyde-free ethyl alcohol as comparison standards. The
aldehyde-free alcohol was prepared by digesting anhydrous
alcohol with metallic aluminum and potassium hydroxide by the
method of Stout and Schuette (8) to remove acetaldehyde, since
this, the most common impurity, is not entirely removed by
fractional distillation according to the observations of McKelvy
(6). Since the latter investigator found that the aldehyde con-
tent of an aldehyde-free alcohol increased to the original con-
centration (0.0027 per cent) on exposure to diffused daylight for
a few hours or to the dark for a few weeks, the preparation of
aldehyde-free alcohol for use in the solubility measurements was
considered to be impractical. It was assumed, moreover, that
traces of acetaldehyde could have no measurable influence on the
amino acid solubility values.
Because it was evident that the quantities of non-volatile
material in the alcoholic solvents must be negligible and definitely
known if the solubility values, especially those in concentrated
alcohol, were to have quantitative significance, twenty analyses
were made on the various solvents during the course of the
experiments. In each determination a 50 ml. sample of the solvent
was evaporated to constant weight at 60”. It was found that
0.0006 gm. was the maximum and 0.000019 gm. the average
weight of non-volatile residue per 50 ml. of solvent.
In view of the intention at the beginning of these studies to
measure amino acid solubilities in anhydrous ethyl alcohol, the
latter was prepared by treating commercial ethyl alcohol with
calcium oxide. The purity of the alcohol was determined by
measuring its miscibility temperature with a standard paraffin
oil-kerosene mixture by the Crismer method as modified by
Andrews (9).
A few determinations were made of the solubilities of amino
acids in anhydrous ethyl alcohol, but this work was discontinued
because the acetaldehyde, which formed when the alcohol stood
for some time in the dark, gave colored reaction products with the
312 Amino Acids and Peptides. IV
amino acids during the evaporation of the solutions for gravimetric
analysis. The use of anhydrous alcohol was abandoned, also,
because the solubilities of the amino acids in this solvent were too
low to be determined with high accuracy by the authors’ method.
Method of Analysis-The densities of the alcoholic solvents
were determined to an accuracy of &O.OOOl by means of a West-
phal balance which had been calibrated against purified distilled
water.
The quantities of amino acids dissolved in the alcoholic solvents
were determined by a gravimetric method essentially the same as
that described in a previous paper (2). Florence flasks of 50,
200, and 250 ml. capacity to which 5 inch lengths of 12 mm.
Pyrex tubing had been sealed at the necks were used as con-
tainers. These special flasks were cleaned with cleaning solution,
rinsed ten times with tap water, ten times with distilled water,
and twice with the alcoholic solution in the order given.
The purified amino acid and the solvent were placed in duplicate
flasks of appropriate size which were sealed immediately by fusing
the necks with an oxygen flame. One of the mixtures was brought
to a temperature about 10” above, and the other about 10” below,
that of the thermostat. For the determinations at 0’ one mixture
was cooled to about -5”‘. Each mixture was maintained at the
specified temperature for about 15 minutes and was shaken at
intervals during this time to insure the formation of a nearly
saturated solution. As noted previously by Zittle and Schmidt
(10) a somewhat longer time is required to prepare saturated
solutions of dl-leucine, dl-norleucine, and dl-valine than the other
amino acids investigated, because of the difficulty with which
they are wetted by an aqueous solvent. Since the flasks were
sealed prior to the described treatment, the times required for
the mixtures to attain the desired temperatures were determined
by preliminary standardization experiments with open flasks.
Each flask was clamped in the thermostat in an upright position
with the labeled portion of the neck emerging from the water and
shaken by hand at hourly intervals for 8 hours during the day in
such a manner that none of the mixture came into the neck of the
flask at any time. This precaution was taken to avoid possible
decomposition of the amino acid when the flask was opened by
breaking the tip of the neck with an electrically heated wire.
M. S. Dunn and F. J. Ross 313
Calibrated 5, 10, 25, and 50 ml. pipettes were used to remove
aliquots. At 45” and 65” the pipettes were previously heated to
the desired temperatures by suspending them in long tubes im-
mersed in the thermostat. The samples were pipetted as quickly
as possible through medicinal cotton or both cotton and silk
filters. The latter were required to remove completely the sus-
pensions of fine crystals which were present in 75 per cent ethanol
solutions of d-glutamic and dl-aspartic acids at 0”. Solubility
determinations of these amino acids in 95 per cent ethanol at 0”
could not be made, because the solutions could not be freed from
suspended material by filtration.
Five aliquots were taken from the duplicate flasks. One of
the aliquots was weighed and the density of the sample determined
from its weight and volume. The probable error in some of the
density values was about 0.2 per cent, but in others was as high
as 0.5 per cent because of the unavoidable slight cooling or heating
of the pipettes during the removal of samples from the thermostat.
Two aliquots from each of the duplicate flasks were placed in
crystallizing dishes of approximately 30 gm. weight and 80 ml.
capacity and evaporated to constant weight at 60” in an oven
heated by 50 volts A.C. A low voltage current was used to prevent
possible ignition of the alcohol vapors. All weighings, except
those for the determination of density, were made with a new
chainomatic balance.
A water thermostat was employed at 25”, 45”, and 65” and an
ice-water mixture at 0”. At 25” and 45” the water level was main-
tained by an automatic device and at 65” the rate of evaporation
was minimized by a layer of paraffin which is liquid at this temper-
ature. A Beckmann thermometer and a Central Scientific
Company 50” thermometer, graduated in O.l”, were calibrated
against a Bureau of Standards thermometer and used in measuring
the thermostat temperatures. The temperatures of the ther-
mostats, normally regulated to about 0.05”, are given in Table I.
The times found to be adequate for the attainment of equilib-
rium ranged from 26 hours for dl-norleucine in 50 per cent ethanol
at 45” to 246 hours for dl-alanine in 25 per cent ethanol at 45”.
The equilibrium times for all of the amino acids in the several
alcohol solutions ranged from 108 to 154 (average, 125) hours
at O”, 129 to 157 (average, 147) hours at 25”, 107 to 128 (average,
g + k ; K +d 8 g ” q
constant D’ wlution) 84.89 63.95 46.53 31.73 83.29 59.26 40.86 26.97 84.31 57.62 37.15 23.91 89.48 57.89 34.31 21.27
Dielectric 75.70 61.25 45.85 31.70 66.70 53.45 39.60 26.90 60.25 48.00 35.10 23.80 54.75 43.20 31.15 21.10
Solute in aliquot (average of hot and cold sides), corrected M (vdes per 1.) 4.05 x 10-l 1.19 x 10-l 0.299 x 10-l 0.15 x 10-2 7.31 x 10-l 2.56 X 10-l 5.55 x 10-z 2.97 x 10-a 10.6 X 10-l 4.24 X 10-l 0.903 x 10-l 0.484 X lo-* 15.3 x 10-l 6.47 X 10-l 13.9 x 10-Z 7.45 x 10-a
I- I-
alculations N (m~ole.u.ection 0.878 X 10-S 0.315 x 10-Z 0.104 x 10-z 0.772 x lo+ 1.61 X 1O-2 0.681 x 10-S 0.195 x 10-2 0.152 X 1OF 0.239 x 10-Z 0.114 x 10-l 0.321 X lo-+ 0.252 X 1O-3 0.353 x 10-l 0.179 x 10-l 0.502 X lo+ 0.393 x 10-s
C m I. -/-
I Data ond Solute ,er 100 gsolvent, :orrectedt -- !Jm. 3.84 1.16 0.305 0.0167 7.09 2.52 0.573 0.0329 10.6 4.25 0.949 0.0545 15.9 6.68 1.48 0.0851
TABLE mental Density of i I aliquot of saturated solution (hot or cold side) __- 0.979 0.934 0.880 0.817 0.984 0.929 0.868 0.807 0.989 0.928 0.856 0.794 0.994 0.922 0.847 0.780
eri,
mary of Exp Temperature of thermostat* “C. 0.00 * 0.00 0.00 f 0.00 0.00 f 0.00 0.00 f 0.00 24.97 It 0.05 24.97 + 0.05 24.97 f 0.05 25.09 zk 0.05 45.16 f 0.06 44.96 f 0.03 44.98 f 0.03 45.19 f 0.03 64.96 zk 0.06 64.94 h 0.10 64.94 f 0.10 65.15 f 0.10
Sum ! - Volume ! at 20” per cent 24.93 50.10 74.50 95.14 24.93 50.10 74.20 95.14 25.28 50.10 74.20 95.14 24.93 50.10 74.20 95.09
Ethanol Weight VET cent 20.32 42.52 66.94 92.54 20.32 42.52 66.94 92.61 20.62 42.52 66.94 92.61 20.32 42.52 66.94 92.54
S
e
n
ni
a
Al
dl-
2 9 7 2 6 3 0 5 5 7 1 0 0 4 7 7 8 5 2 9 0 1 5 9 8 7 2 8
8284569631821308284569284184
5.1.5.7.3.9.6.1.8.5.3.7.4.1.1.5.1.5.7.3.9.6.4.1.8.5.3.1.
7646532643254327646532264322
0. 5 5 9 0 8 0 5 5 8 0 5 0 5 5 4 3 3 9 0 5 0 5 0 5 5 0 7
7289459590872107289459279084
5.1.5.6.3.9.6.0.7.5.3.4.3.1.1.5.1.5.6.3.9.6.4.0.7.5.3.1.
7646532643254327646532264322
lo+ 1O-3 10-3 10-Z 1OP 1OP 10-4 1OP IO-2 10-Z 1O-4 10-l 1OP 10-Z 10-3 1O-3 W3 1O-3 10-3 10-3 1O-3 1O-3 10-S 10-a 10-3 10-S 10-3 10-3
X X x x X X x X x x X X X x X X X X x x X X x x x x x x
12 87 74 91 689 07 2 86 75 90 6 08 96 831 76 62 35 98 1 21 18 24 13 4 4 13 68 30
5.1.0.1.0.2.1.4.1.3.2.1.3.0.0.5.2.0.9.8.2.0.0.2.3.5.0.0.
1 51 2
10-4 1O-4 1OP 10-a 1OP 1O-4 IO+ 10-3 10-3 10-4 IO-4 1OP 10-z 1O-3 10-4 10-4 1O-4 1O-4 1O-4 1O-4 1O-6 10-b 10-G 10-3 1O-4 1O-4 10-s 1OP -
x x X x X x X x X x x X x X x x X X X X X x x x X X X X
1.09 0.489 0.253 0.410 1.81 0.724 0.62 1.05 0.467 1.39 0.13 2.36 1.07 0.302 0.400 1.19 0.613 0.338 4.08 2.17 7.68 1.2 7.8 1.13 6.25 1.83 3.56 1.8
703 267 111 66 992 317 020 80 55 608 042 3 88 32 129 855 371 163 92 31 370 044 025 11 78 885 127 056
0002000620055100002100083000
0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
2 5 6 3 6 2 7 8 4 6 6 2 2 0 0 1 4 2 4 5 7 7 3 0 2 4 4 0
7386270515950487386260861597
9989988998799879989988799877
0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
-
3 3 3 6 6 5 2 4 4 2 3 3 3 3 3 4 9 3 9 1 5 5 5 3 3 3 7 3
0000001000000000000100000000
0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.x 0.
3 f 3 f 2 f 6 f 6 f 4 f 7 f 5 f 5 f 7 f 1 f 1 f 1 f 7 f 0 f 1 f 1 f 3 f 5 f 8 rt 7 f 4 f 4 f 1 * 7 + 3 f 0 f 3 z!
0000010222299000000000002929
0.0.0.5.5.5.5.5.5.5.5.4.4.5.5.0.0.0.5.5.5.5.5.5.5.4.5.4.
222244446666 2222244444
93 10 20 55 25 28 14 74 18 28 14 93 10 20 14 74 18 28 55 25 35 14 0 55 18 35 14 0
4.0.4.4.0.4.5.4.0.4.5.4.0.4.5.4.0.4.4.0.4.5.0.4.0.4.5.0.
2572579257925792572579025790
32 52 94 00 66 03 61 16 59 03 61 32 52 94 61 16 59 03 00 66 11 61 0 00 59 11 61 0
0.2.6.0.2.7.2.0.2.7.2.0.2.6.2.0.2.7.0.2.7.2.0.0.2.7.2.0.
2462469246924692462469024690
d8 d]/
aci aci
artic amic
Asp Glut
dl- d-
constant D' 3olution) 87.05 64.16 46.28 31.72 90.76 60.24 40.77 26.94 1 00.35 60.39 37.04 23.87 115.81 1 64.13 34.26 21.17 76.12 61.44 45.86 31.67 67.52
Dielectric D solvent 75.70 61.25 45.75 31.70 66.70 53.45 39.60 26.90 60.40 48.00 35.10 23.80 54.75 43.20 31.15 21.05 75.70 61.25 45.75 31.65 66.70
Solute in sliquot (average of hot and cold sides), corrected M (moles per 2.) 5.00 x 10-l 1.28 X 10-l 2.33 X 1OP 0.86 X 10-S 1.06 X loo 2.99 x 10-l 0.515 x 10-l 0.18 X 1O-2 1.76 X loo 5.46 X 10-l 0.855 X 10-l 0.311 x 10-z 2.69 X loo 9.22 x 10-1 1.37 x 10-l 0.508 x 1OP 1.86 x 10-z 0.839 X 1OP 0.464 X 1OP 0.72 X 1OP 3.61 X 1OP
-
10-Z 10-2 10-a 10-d 10-l 10-Z 10-z 10-d 10-l 10-l 1O-2 10-4 10-l 10-l IO-2 IO-3 10-s IO-3 10-3 10-4 1O-3
X X X x X x X x x x X X X X x X x X X X X
1.06 0.332 0.810 0.45 0.232 0.793 1.81 0.945 0.395 0.147 0.306 1.61 0.628 0.253 0.496 0.268 0.392 0.218 0.161 0.365 0.772
ued Solute 1er 100 gm solvent, mrectedt 07% 3.95 1.03 0.200 0.0080 8.72 2.47 0.448 0.0172 15.0 4.62 0.756 0.0294 I’ 24.5 8.03 1.23 0.0488 0.251 0.118 0.0693 0.0116 0.493
n
BLE I-Conti 1 Density of aliquot of saturated solution (hot or cold side) . 0.988 0.942 0.884 0.820 0.994 0.931 0.869 0.806 1.01 0.928 0.856 0.795 1.03 0.930 0.847 0.784 0.971 0.935 0.881 0.819 0.964
A
T
9 9 9 4 5 5 5 5 3 3 3 3 5 5 3 4 0 0 0 0 5
000000000000000000000
Temperature of thermostat* “C. 0.02 f 0.0.02 f 0.0.02 f 0.0.01 f 0.24.97 f 0.24.97 f 0.24.97 f 0.25.09 f 0.44.98 f 0.44.98 f 0.44.97 f 0.45.19 f 0.65.11 f 0.65.10 f 0.65.07 f 0.65.00 f 0.0.00 f 0.0.00 f 0.0.00 f 0.0.00 f 0.24.97 f 0.
nt
ce 93 10 50 09 93 10 20 14 93 10 20 14 93 10 20 14 93 10 50 14 93
per 24.50.74.95.24.50.74.95.24.50.74.95.24. 50.74.95.24.50.74.95.24.
Ethanol Weight cent wr 20.32 42.52 67.27 92.54 20.32 42.52 66.94 92.61 20.32 42.52 66.94 92.61 20.32 42.52 66.94 92.61 20.32 42.52 67.27 92.61 20.32
e
Glycine dl-Leucin
53.95 39.86 26.94 61.80 48.99 35.47 23.87 57.09 44.98 31.99 21.21 76.16 61.49 45.90 31.68 67.74 54.17 40.00 26.96 62.23 49.43 35.86 23.90 57.97 45.90 32.51 21.23
53.45. 39.60 26.90 60.40 48.00 35.00 23.80 54.75 43.20 31.15 21.10 75.70 61.25 45.75 31.65 66.70 53.45 39.60 26.90 60.40 48.00 35.10 23.80 54.75 43.20 31.15 21.05
10-Z lo+ 10-a 1O-2 10-2 10-Z 1OP 10-l 10-l 10-l 10-Z lo-” 10-Z 1OP 10-3 1OP 1OP 1OP 1OP lo-* 10-Z 1OP 1O-2 10-I 10-l 10-l 10-2
x X x X x x X x X X x X x X X X X x X X X X X X x X x
2.22 1.16 1.59 6.15 4.35 2.09 0.285 1.03 0.783 0.372 0.500 2.03 1.05 0.669 1.18 4.56 3.16 1.76 0.255 8.07 6.31 3.36 0.458 1.42 1.19 0.601 0.795
10-s 10-3 10-d 10-a 10-a 10-a lo+ 1OP 10-Z 10-Z 10-3 10-a 1OF 10-a 1OF 10-s 10-Z 10-Z 10-S 10-Z 10-s 10-Z 10-S 10-Z 10-Z 10-z 10-S
X x x x x x X X X x X x X X X x X X x x X x X x X X X
0.588 0.404 0.808 1.33 1.17 0.750 1.48 0.225 0.214 0.135 0.265 0.429 0.272 0.231 0.603 0.977 0.838 0.613 0.131 1.75 1.69 1.19 0.238 0.315 0.324 0.218 0.421
0.318 0.175 0.0258 0.853 0.633 0.323 0.0471 1.45 1.16 0.584 0.0844 0.275 0.147 0.0995 0.0192 0.625 0.453 0.266 0.0417 1.12 0.918 0.518 0.0759 2.02 1.76 0.944 0.134
0.924 0.868 0.806 0.958 0.912 0.856 0.795 0.948 0.900 0.844 0.780 0.972 0.938 0.883 0.819 0.965 0.924 0.868 0.806 0.957 0.913 0.855 0.793 0.948 0.902 0.842 0.780
5 5 5 1 1 5 5 3 5 3 3 0 0 0 0 5 5 5 5 3 3 3 3 3 3 3 3
000110000000000330000000000
0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
f f f f f f f f f f f f It f f f f f f f f f f f & f f
24.97 24.97 25.09 45.24 45.24 45.18 45.18 65.16 65.20 65.15 65.07 0.00 0.00 0.00 0.00 25.69 25.69 24.97 25.09 44.97 44.96 44.96 45.18 65.17 65.17 65.17 65.01
50.10 74.20 95.14 24.93 50.10 74.50 95.14 24.93 50.10 74.20 95.09 24.93 50.10 74.50 95.14 24.93 50.10 74.20 95.14 24.93 50.10 74.20 95.14 24.93 50.10 74.20 95.14
42.52 66.94 92.61 20.32 42.52 67.27 92.61 20.32 42.52 66.94 92.54 20.32 42.52 67.27 92.61 20.32 42.52 66.94 92.61 20.32 42.52 66.94 92.61 20.32 42.52 66.94 92.61
-
dl-leucine-con- tinued dl-Norleucine
constant D' solution) 76.81 61.55 45.81 31.65 69.85 54.36 39.51 26.90 66.73 49.92 35.44 23.81 66.64 46.80 31.52 21.06 79.60 62.64 46.31 31.69 28.25
Dielectric D :solvent) 75.70 61.25 45.75 31.65 66.70 53.45 39.35 26.90 60.40 48.00 35.10 23.80 54.75 43.20 30.95. 21.05 75.70 61.25 45.85 31.65 28.23
Solute in aliquot (average of hot and cold sides) corrected M (moles per 1.) 4.89 X lo-’ 1.30 x 10-2 2.55 X 1OP 6 x IO-5 1.39 x 10-l 4.02 X 1OP 6.93 X IO-+ 2.15 X IO+ 2.79 x IO-’ 8.46 X 1OP 1.50 x 10-Z 4.38 X 1O-4 5.24 X 10-l 1.59 x 10-l 2.53 X 1OP 1.1 x 10-a 1.72 X 10-l 0.612 X 10-l 2.02 x 10-Z 1.94 x 10-z 0.92 x 10-3
N (mole fraction solute) 1.03 x IO-3 3.35 x 10-d 0.882 X 1OP 3 x 10-e 2.99 x IO-3 1.06 X 10-S 2.43 X 1OP 1.1 x 10-c 6.09 X 1OP 2.27 X IOP 5.35 x 10-h 2.3 X lo+ 1.15 x 10-2 4.31 x 10-3 9.21 x 10-h 5.94 x 10-5 0.366 X 1OP 0.159 x 10-Z 0.695 X 10-a 0.974 x 10-4 0.534 x 10-d
m
uded Solute ,er 100 gsolvent, mrectedt Qm. 0.530 0.146 0.0304 0.0008 1.54 0.461 0.0840 0.0028 3.14 0.985 0.185 0.0058 5.99 1.88 0.318 0.0152 2.10 0.769 0.269 0.0277 0.0136
I-ConclTABLE - knsity of tliquot of iaturated solution (hot or :old side) 0.975 0.938 0.882 0.818 0.970 0.923 0.869 0.806 0.968 0.912 0.857 0.793 0.974 0.909 0.844 0.783 0.975 0.942 0.881 0.819 0.797
Temperature of thermostat* “C. 0.00 zt 0.00 0.00 f 0.00 0.00 f 0.00 0.00 f 0.00 25.14 f 0.05 25.14 rt 0.05 25.10 f 0.05 25.09 rt 0.05 45.15 Ik 0.12 45.04 i 0.03 45.04 It 0.03 45.18 It 0.03 65.26 f 0.03 65.25 f 0.03 65.24 f 0.03 65.01 f 0.03 0.02 z!z 0.03 0.02 f 0.03 0.02 f 0.03 0.01 f 0.01 0.03 f 0.03
V0lIlJXle at 20” per cent 24.93 50.10 74.50 95.14 24.93 50.10 74.50 95.14 24.93 50.10 74.20 95.14 24.93 50.10 74.50 95.14 24.93 50.10 74.20 95.14 100.0
Ethanol - Weight cent per 20.32 42.52 67.27 92.61 20.32 42.52 67.27 92.61 20.32 42.52 66.94 92.61 20.32 42.52 67.27 92.61 20.32 42.52 66.94 92.61 00.0
-
dl-Serine dl-Valine