July, 1922
THE JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
No apparent change occurred by heating these olefins with acetic acid up to 120" to 130" C. for a period of 8 to 10 hrs. These olefins were heated with abietic acid up to 290" C. for 6 to 8 hrs. Although the acid number of the mixture was reduced from 80 to 5, no formation of esters took place, the resulting product consisting practically entirely of unsaturated hydrocarbons, as the abietic acid had split off carbon dioxide a t the high reaction temperature. CONCLUSIONS
1-By eliminating the presence of certain metallic compounds, it is possible to introduce chlorine into the mixtures of hydrocarbons represented by the so-called "neutral oils" and thereby evenly to distribute the halogen in the hydro-
62 1
carbon molecule. The amount of chlorine which can be thus fixed by the hydrocarbons a t certain temperatures is sufficient to form tri- and tetrachlorides. 2-The elimination of chlorine from the chlorinated hydrocarbons can be effected without the application of any catalytic or HC1-absorbing agent by heating the chlorinated compounds as high as 250" C. Under these conditions a partial saturation of the primarily formed double linkages takes place through formation of cyclic hydrocarbons. 3-It is believed that the products obtained from the above process will ultimately find wide commercial application. 4-The writers have also chlorinated and dechlorinated such semidrying oils as soy-bean and cottonseed oils, the resulting products having greatly improved drying properties.
Studies in Chrome Tanning"' The Formation of
Equilibria between Tetrachrome Collagen and Chrome Liquors. Octachrome Collagen By Arthur W. Thomas3 and Margaret W. Kelly COLUMBIA UNIVERSITY, NEW Y ~ R I C N., Y
Measurement of the fixation of chrome by hide substance after 8.5-mo. contact with chrome liquors of oarious concentrations showed that maximum fixation occurred in a chrome liquor of a concentration of 1.5 g . Cr203 per I00 cc. of solution. The chrome collagen compound formed in this liquor proved to be an octachrome collagen, showing that the combining weight of collagen is as low as
94.
The changes taking place when tetrachrome collagen is in contact with chrome liquors over a similar time intercal have been measured, showing that the formation of tetrachrome collagen is not' strictly reoersible. The findings support the view that the "adsorption" of chromium from chrome liquors by collagen is a chemical reaction.
HE effect of concentration of chrome liquor upon the adsorption of its constituents by hide substance during the 48-hr. contact has previously been reported by the author^.^ The formation of a tetrachrome collagen was definitely established when 5 g. of hide substance (weight on dry basis) were rotated in contact with a chrome liquor containing 15.5 g. Cr203per 1. for 48 hrs. The purpose of the present experiments was to investigate the assumption that the formation of tetrachrome collagen is a reversible reaction. Since chromed hide powder does not lose any measurable amount of chromium upon several hours' washing, it was decided to allow tetrachrome collagen to remain in contact with solutions of varying chrome concentration for several months, before analysis. While me were almost convinced that a tetrachrome collagen was the best we could hope for in the amount of chromium combined with hide substance, it was considered prudent to set up a concentration adsorption series to run the
T
Presented before the Section of Leather Chemistry a t the 62nd Meeting of the American Chemical Society, New York, N. Y.,September 6 t o 10, 1921. 2 Published as Contribution No. 386 from the Chemical Laboratories of Columbia University. 8 Assistant Professor. 4 THISJOURNAL, 13 (1921), 31. 1
same length of time. Accordingly two sets of experiments were carried out as described below.
TETRACHROME COLLAGEN EQUILIBRIA
A sample of 112.5 g. of 1920 hide powder (equal to 100 g. dry substance) was treated with 4 1. of a commercial chrome liquor (concentration = 166.5 g. Cr'03 per 1.) for 72 hrs., when test showed that tetrachrome collagen had been prepared. The mixture was filtered through a cloth bag, washed with tap water, and then with distilled water until the washings showed the very faint test for sulfate which is characteristic of completely washed chromed hide powder. It was partly dried a t 30" C., completed a t looo, and then spread out in contact with air a t room temperature to come to equilibrium with atmospheric humidity. Analysis showed: moisture, 10.41 per cent; Cr203, 10.01; sos, 8.25; and protein (S X 5.614), 67.31. One gram of hide substance contained 122.5 mg. SO3 and 148.7 mg. Cr20s (slightly above the tetrachrome value). Portions of 7.286 g. (equal to 5 g. dry hide substance) each were placed in a series of twelve bottles, covered with 200-cc. portions of freshly prepared liquors, carefully sealed to prevent evaporation, set aside from October 21, 1920, to July 8, 1921, and shaken once a week. Duplicate portions of the solutions were set aside for the same interval. Analyses of the liquors are given in Table I. TABLE I I.IQVOR 1 2 3 4 5 6
7 8 9 10 11 12
G CmOs per Liter O(Iiz0) 0.43 3.01 7.80 15.36 29.99 51.15
79.03 112.2 134.6 151.8 208.
ORIGINALLIQUOR Log C H + ~ CH f October 21, 1920 July 8, 1921
....
-3.45 -3.36 -3.35 -3.22 -3.19 -2.99 -2.86 -2.73 -2.60 -2.47 -2.29
....
-3.43 -3.24 -3.18
-3.19 -3.11 -3.00 -2.86 -2.79 -2.69 -2.63
-2.32
FILTRATE Log CH July 8, 1921 -2.68
-3.22 -3.22 -3.17 -3.17 -3.12
....
....
-2.77 -2.66 -2.59 -2.41
The results tabulated are shown graphically in Fig. 1 and will be discussed later.
THE JOURNAL O F 1NDUSTRIAL A N D ENGINEERIhTG CHEMISTRY
622 TABLE11-COMPOSITION
OF
CHROMEDHIDE POWDER AFTER
TREATMENT
(All figures on moisture-free basis) Mg . Crz03 Protein Cr203 so3 per G. Per cent Per cent Per cent Protein 7 R f i 78.10 10.16 . 130 76 92 10.73 8.02 140 13.25 70.32 188 9.44 14.88 65.35 10.39 228 14.86 65.04 11.01 229 68.36 10.44 14.18 207 69.58 12.27 176 (10.26) 69.72 12.73 10.44 183 72.25 12.31 10.56 170 12.19 70.75 172 10.72 11.99 72.58 165 10.89 11.90 166 71.67 10.58
SAMPLE 1 2 3 4 5 6 7 8 9 10 11 12
TABLE111-CHANGE
IN
SAMPLE
8.5-Mo. M g . SO3 per G. Protein 98 104 134 169 169 153 'ME)
4-22
1-17 t 1 7
+29 27 +25
+
MONTH ADSORPTION Portions of hide powder equal to 5 g. dry substance svere treated with 200-CC.portions of the identical liquors and under the same conditions as the tetrachrome collagen just described. They were set up on October 21,1920, and filtered off July 7 , 1921. It was desired to duplicate as well as possible the conditions employed by the writers4 in a 48-hr. adsorption experiment in which 1918 hide powder was used. Since very little of the 1918 powder was available, and in anticipation of a possible variation due to the use of a later hide powder, the series was made completely with 1920 hide powder, but the first five concentrations were duplicated with 1918 powder. Since the liquors were identical with those described in the first part of this paper, the only additional analytical data are the CH+of the filtrates from the 8.5-mo. adsorption (Table IV). LIQUOR 2 a1
t
I
I
2
3 3
I
1
I
TABLE IV Log CR+
Crz03. This chromed hide substance is octachrome collagen, as calculated from the fact that it contains 26.6 g. Crz03 per 100 g. hide protein, checked by two batches of hide powder. In 1917 Wilson6 gave 750 as the molecular weight, or as a multiple of the equivalent weight, of collagen, which was based on work by Procter6 and by himself in Procter's laboratory. Using this value he calculated 3.38 g. Crz03 as the smallest amount to react in equivalent proportions with hide protein. Miss Baldwin? obtained a chromed collagen containing 13.4 g. Crz03 per 100 g. hide protein, which mas approximately four times Wilson's minimum value. She stated that this was the greatest amount of Cr203 ever reported as capable of comloining with collagen. From her values it followed that 187 could be regarded as the combining weight of collagen or hide protein. Our result for octachrome collagen, obtained in the same concentration of liquor that gave tetrachrome collagen in 48 hrs., is a new record and shows the combining weight of collagen to be about 94. Another interesting feature is the point of inflection occurring between the liquors containing 112 g. and 134 g. per 1. of Crp03, corresponding to tetrachrome collagen.
LIQUOR Log CH+ 5 a -2.85 -3.18 9 .... 10 5 b -3.27 (2) 6 a -2.66 -3.61 11 -3.11 3a 6b -2.45 -3.66 -3.18 36 12 -2.97 7 -3.47 4a -2.90 8 -3.37 4b 1 a refers t o 1920 and b t o 1918 hide powder. 2 Samples had decomposed and hence were discarded. 2 bl
Log CH+
2 50
b
CUNCfNTRAT/ONOF LIQUOR IN GRAMS Cr, O3 PER LITER FIG.1
+46 +79 4-80 1-59 4-28 +34 i-24
The striking feature brought out by these curves is the point of maximum obtained in the liquor containing 15.36 g.
146 162 150 148
COMPOSITIONOF TRTRACHROME COLLAGEN AFTER 8.5-Mo. CONTACT M g . CrzOa per G. Mg ,SOs per G. Protein Lost or Protein Lost or Gained Gained
1 2 3 4 5 6 7 8 9 10 11 12
Vol. 14, No. 7
LIQUOR
(2)
C,
0 0
03 USING /9/8 BIDE POWDER
*-e
48 HOUR AD50RPVON Of Cr203
0---0
48
,,
n
" so,
TABLE v-COMPOSITION
AFTER 8.5-MO. ADSORPTION (All figures on dry basis) Mg , CrzO3 M g . SO3 Protein Crz03 SO3 per G. per G. SAMPLE Per cent Per cent Per cent Protein Protein1 3a 79.81 9.56 7.06 120 83 112 83 3b 81.05 9.07 7.22 209 134 9.69 4a 6s.69 14.36 198 135 4b 70.20 13.87 9.91 164 5 a 63.68 16.94 10.80 266 163 10.99 5b 64.91 17.29 266 146 10.41 6a 68.95 13.85 201 209 10.70 6b 69.38 14.53 148 135 7 72.10 12.00 166 10.08 132 161 8 72.81 11.02 9.99 127 9.81 9 74,08 10.58 143 124 9.64 I36 10 74.59 10.11 111 9.00 118 11 77,40 9.13 5.36 45 55 12 88.89 4.03 1 Corrected for S present in hide powder. The 1918 hide powder ( b series) contained 0.62 per cent sulfur (dry basis calculated a s sod, and t h e 1920 (a series), 0.53 per cent.
These results are graphically represented in Fig. 2. For comparison with the 8.5-mo. curves, the 48-hr. picture of the concentration relationships, previously published, has been included in Fig. 2.
CONCWTRATIObJ O f LIQUOR IN GRAMS Cr, 0, PER LITER PIG.2
Fig. 1, showing the changes taking place when tetrachrome collagen is in contact with different concentrations of liquors proves that in water, and in the most dilute liquor, a hydrolysis of the chrome collagen and collagen sulfate compounds 5 6 7
J . A m . Leather Chem. Assoc., 12 (1917), 108. J. Chem. S O L , 108 (1914), 313. J . A m . Leethev Chem. d s s o c . , 14 (19191, 433.
