July, 1922
THE JOURNAL OF I N 0 USTRIAL A N D ENGINEERING CHEMISTRY
took place, which is reflected also in an increase in the H-ion concentrations of the liquors. From that point there is a steady addition of SO4 and of Crz03,approaching theoctachrome collagen which was to be expected from the results obtained in the adsorption experiments; but while a considerable loss in chrome was to be expected in liquors containing over 29 g. Crz03 per l., in view of the steady fall in the 8.5-mo. adsorption curve, it is not so great as anticipated. I n other words, the reaction in the concentrated liquors is not strictly reversible. This would indicate that the fall in the adsorption concentration curves is due to the effect of the increased H-ion concentration of the liquors, making the collagen more electropositive and more highly hydrated and thus inhibiting its combination with chrome, which is not possible with tetrachrome collagen since the nature of the collagen has been decidedly changed by chemical combination with the chromium. These results lend extra support to our belief, previously stated,4 that the combination of chrome with collagen is strictly a chemical reaction, and not a physical adsorption process. ADDENDUM
As a precautionary measure, a duplicate of the tetrachrome equilibria and of the concentration series adsorption experiments were set up on April 29, 1921. After the values reported above in the 8.5-mo. series mere obtained, it was considered of interest in the latter part of August 1921 to filter off these duplicate sets which represented about a 13wk. contact, and compare the action with that of the experiments of longer duration of time. For brevity, details are omitted. The values are not included on the graphs in order to avoid confusion, but if they were plotted it would be seen that the tetrachrome equilibria figures in Table VI are practically identical with those obtained after 8.5-mo. contact. This
Pressure Bottle for Laboratory Use By Arthur D. Hirshfelder and M. C. Hart DEPARTMENT O F PHARMACOLOGY, b-NIVERBITY MIPI'NEAPOLIS, MINN.
I
OF
MINNEEOTA,
N the course of experiments upon the preparation of aromatic alcohols, it was sometimes necessary to resort to syntheses under pressure at temperatures of about 150" C. On account of the pressures generated it was important that the vessel should have a safety valve. The authors adopted a modification of a pressure bottle which has been used in the chemical laboratory of the Johns Hopkins University. The apparatus used there consists of a pint ginger ale bottle held in a tripod frame. The mouth of the bottle is closed by a sheet rubber gasket pressed down by a brass plate, which is held in place by three wing nuts, In the modification of this apparatus the brass plate A surmounting the bottle is pressed down, not by nuts, but by means of a valve spring from a Ford automobile, the tension of which is regulated by a second brass plate, B, screwed down by wing nuts. A brass rod from the brass plate passes loosely through a hole in the upper brass plate and the tension of the spring can be regulated by the distance to which the upper plate is screwed down. In the case of ginger ale bottles with an aperture of about 20 cm., a compression of 6 mm. of the Ford valve spring corresponds to about 1 atmosphere of pressure.
623
TABLEVI-CHANGE
IN COMPOSITION OF TETRACHROME COLLAGEN IN CONTACT WITH CSROMELIOUORS FOR 13 WKS. Concentration of Original Liquor M g . CrzOa per G. G.Cr203 per 100 Cc. Protein Lost or Gained No. 1 0 (HzO) - 7 0.049 2 + 7 0.190 3 +48 0.719 4 73
5 6
++8Q
1.469 2.785 4.617 7.118 10.64 13.58 14.95
7
8 9 10
11
+47 +33 +26 23 27 30
+ ++
TABLE VII-COMPOSITION OF CHROME COLLAGEN RESULTINGFROM 13WK. CONTACT OF HIDE POWDERWITH VARIOUSCHROMELIQUORS Mg. Crz03 per Mg. CrzOa per LIQUOR KO. G. Protein LIQUORNo.1 G. Protein 164 Decomposed 7 111 196 239 197
1
8 9 10
11
149 141 133 113
Concentrations given in Table VI.
shows that the 8.5-mo. values represent in this instance an equilibrium that had been attained several months prior to the conclusion of the experiment. On the other hand, although the results given in Table VI1 follow the same shape of curve as those for 8.5-mo. reaction and closely approach the values set therein, they show one striking exception; namely, that the octachrome point was not reached in a 13-wk. reaction a t room temperature, the maximum fixation of chrome being 239 mg. Cr203 per g. protein, as compared with 266 mg. Cr203of the octachroine collagen found after an 8.5-mo. contact of hide powder with a chrome liquor conper 100 cc. of solution. taining about 1.5 g. ACKNOWLEDGMENT We take pleasure in expressing our indebtedness to Messrs. A. F. Gallun & Sons Co., of Milwaukee, Wis., for their generous support of this investigation.
The brass rod is therefore graduated at intervals of 6 mm. (beginning a t the point where the spring is not compressed a t all), which correspond roughly to a scale of pressures in terms of atmospheres. The whole apparatus can be conveniently heated in an oil bath. Several ordinary ginger ale bottles, of the type with slightly convex bottoms, which have been tested by Prof. F. B. Rowley of the College of Engineering of the UniverGR42UATIONS sity of Minnesota, have ( 6 mP.Fcr A t m . ) uniformly resisted a breaking pressure of 400 lbs. per sq. in. FORD VALVE SPRING (more than 26 atmosRUBBZR GASKET pheres). (Inner Tire "hbIng) The pressure bottle has worked very satisfactorily a t temperatures of 150" to 160' C., and the valve pops GINGER ALE BOTTLE off very well when set for 5 or 6 atmospheres. It should also be satisfactory for somewhat higher temperatures a& presRUBBER QA8K!$T sures.
