ANALYTTCAL EDITION
134
if in a tightly stoppered bottle, whereas the untreated blood rapidly deteriorates. To calculate the extent to which the sensitivity of the test is increased by this means, it is merely necessary to determine the ratio between the amount of gas taken from the cylinder and the amount taken as samples for the pyrotannic blood determination. If three samples are allowed, which, as has been shown, is a safe margin for obtaining all of the carbon monoxide, the ratio is 12,600 to 900 (3 X 300), or 1 to 14. As a matter of fact, however, all of the carbon monoxide is obtained in the first two samples taken, so that the ratio is really 1 to 20. Concentration by fractionation readily increases the sensitivity of the modified oxy-hemoglobin test 20 times. Obviously, by increasing the amount of the sample the sensitivity can be correspondingly increased. ACKNOWLEDGMENT We gratefully acknowledge the helpful suggestions and great assistance of Messrs. Wardell and Glekler of the research laboratory of the Ohio Chemical and Manufacturing Company in making this study. LITERATURE CITED (1) Booth, H. S., J . Chem. Education, 7, 1249 (1930). (2) Brooks, B. T., “The Non-Benzenoid Hydrocarbons,” p. 160, Chemical Catalog, 1922. (3) Bnmck, O., Z. angm. Chem., 25, 2479 (1912). (4) Burrell, G. A,, Bur. Mines, Tech. Paper 11 (1912). (5) Burrell, G. A., and Robertson, I. W., J. IND. ENQ.CHEX., 7, 210 (1915). (6) Burrell, G. A,, and Siebert, F. M., Ibid., 6, 241 (1914). (7) Czako, E., J. Gusbet., 57, 169 (1914). (8) De la Condamine, M., Compt. rend., 179, 691 (1924). (9) Douglass, C. G., Haldane, J. S., and Haldane, J. B. S., J. Physiol., 44, 275 (1912).
Vol. 4,No. 1
(10) Fay, I. W., and Seeker, A. F., J.A m . Chem. Soc., 25,646 (1903). (11) Graham, J. I., J . SOC.Chem. Ind., 38, 10-4T (1919). (12) Grehant, N., Compt. rend. SOC. b i d , 66, 69 (1909). (13) Harbeck, E., and Lunge, G., Z. anorg. Chem., 16, 50 (1898). (14) Harger, J., J . Chem. Met. Mining SOC.S. Africa, 15, 59 (1914). (15) Harger, J., Trans. Inst. Mining Eng., 1914, 533. (16) Henderson, Y., J . A m . Med. Assocn., 67, 580 (1916). (17) Hoffmann, X. A., and Sand, J., Be?., 33, 1340 (1900). (18) Hoover, C. R., J. IND.ENG.CHEW,13, 770 (1921). (19) International Critical Tables, Vol. 111,p. 3, McGraw-Hill, 1926. (20) Ibid., Vol. I , p. 179 (1926). (21) Ibid., Vol. 111, p. 265 (1928). (22) Just, G., 2. phys. Chem., 37, 342 (1901). (23) Katz, S. H., and Bloomfield, J. J., J. IND.ENG.CHEM.,14, 304 (1922). (24) Levy, L. A., J. SOC.Chem. Znd., 30, 1437 (1911). (25) Manchot, W., Liebig’s Ann. Chem., 370, 241 (1909). (26) Manchot, W., and Brand, W., Ibid., 370, 286 (1909). (27) McDaniel, A. S., J. Phvs. Chem., 15, 587 (1911). (28) McLoud, M. C., Coal Age, 23, 1007 (1923). (29) Mond, L., Langer C., and Quincke, F., J. Chem. SOC.,57, 749 (1890). (30) Mpser, L., and Schmid, O., Z. anal. Chem., 53, 217 (1914). (31) Nicloux, M., Compt. rend. SOC. biol., 89, 1331 (1923). (32) Nicloux, M., Bull. SOC. chim., 33, 818 (1923). (33) Pollard, F. H., J. Phys. Chem., 27, 356 (1923). (34) Sayers, R. R., Yant, 1%’. P., and Jones, G. W., Bur. iMines, Rept. Investigations 2486 (1923). (35) Sherman, W. O., Swindler, C. M., and McEllroy, W. S., J. Am. Med. Assocn., 86, 1765 (1926). (36) Sinnott, F. S., and Cramer, J., Analyst, 39, 163 (1914). (37) Sollmann, T., “A Manual of Pharmacology,” p. 766, Saundera, 1927. (38) Taylor, H. S., J. IND.ENG.CHEM.,13, 75 (1921). (39) Taylor, H. S., and Burns, R. M., J. A m . Chem. Soc., 43, 1273 (1921). (40) Treadwell, W. D., and Tauber, F. A., Helv. Chim. Acta., 2, 601 (1919). (41) White, A. H., “Gas and Fuel Analysis,” p. 36, MoGraw-Hill, 1920.
‘
RECEIVED September 22, 1931.
Germanic Sulfide Quantitative Conversion of Sulfide t o Dioxide by Hydrolysis JOHN HUGHES MULLER AND ABNEREISNER, University of Pennsylvania, Philadelphia, Pa.
G
ERMANIC sulfide is usually converted to dioxide by repeated t r e a t m e n with nitric acid followed by evaporation and ignition to expel sulfuric acidfrom the r e s i d u a l oxide. It is known that this reaction is quite violent and that to cut down if the acid is the violence of the o x i d a t i o n , much free sulfur separates which is difficult to remove by subsequent treatment with excess of the oxidant. Small amounts of
GERMANIC SULFIDE can be conveniently transposed to dioxide by simple hydrolysis, the decomposition efected by injecting a current Of into the water suspension Of the su@de* Hydrolytic decomposition of the sulfide in larae masses is of special advantage because all processe8 involving oxidation of the su&de ape attended with violent reaction and accompanying errors* Germanium can be quantitatively determined by hydrolyzing the sulJide directly to oxide, when it is weighed, Elimination of the sulfur as hydrogen sulfide avoids sources of error common to methods involving oxidation of the su@de.
“Ifide Ordinarily with in the quantitative determination of gemanium may be converted t o oxide in this way, but even here results are likely to be low unless extraordinary care is taken to prevent mechanical loss. The first decided improvement in the determination of oxide from the sulfide was described by Johnson and Dennis ( I ) . These investigators dissolve the precipitated sulfide in ammonium hydroxide, oxidize with hydrogen peroxide, evaporate, and ignite to oxide.
The present paper describes a new method of c o n v e r t i n g large or small a m o u n t s of germanic sulfide to germanic oxide by simple hydrolysis in which all of the sulfur is removed as hydrogen sulfide. The authors claim t h a t t h e h y d r o l y t i c d e c o m p o s i t i o n of the sulfide may be advantageously used both for an accurate determination of germanium and for the rapid conversion of large masses of the bulky sulfide to oxide in the preparation of pure germanium compounds~
EXPERIMENTAL PROCEDURE A quantity of germanic sulfide was precipitated from a 6 N hydrochloric acid solution of the dioxide. (Arsenic-free
material was used throughout.) The precipitation was carried out with hydrogen sulfide under pressure in a closed system to exclude air. The bulky white sulfide was rapidly filtered on Biichner funnels and mashed with dilute hydro-
Jnnuary 15, 1932
INDUSTRIAL AND ENGINEERING CHEMISTRY
chloric acid saturated with hydrogen sulfide, then with alcohol saturated with the same gas, and finally with dry ether. The sulfide was quickly placed in vacuo to remove ether, remaining small amounts of moisture, and free hydrogen sulfide. The product was kept in a well-stoppered weighing bottle from which samples were taken for most of the following experiments. EXPERINENT 1. A portion of this sulfide weighing 20.670 grams was placed in a liter flask with about 900 cc. of freshly distilled water. The flask was immersed in an oil bath and a slow current of carbon dioxide was passed through the suspended sulfide. The escaping gas was conducted through a series of wash bottles containing, in all, more than enough copper sulfate solution to absorb all of the hydrogen sulfide split off by hydrolysis, assuming the reaction to reach completion. Appreciable reaction began in the cold as evidenced by the separation of .copper sulfide in the first several wash bottles. The temperature was slowly raised to the boiling point and a steadily increasing rate of decomposition was observed with the rise. At the boiling point the decomposition was quite rapid, and after about 3 hours no trace of hydrogen sulfide could be detected in the escaping gas. The flask was disconnected, and when the volume had been reduced by evaporation to about one-third of the original, its contents were filtered through an alundum cone to separate the undissolved micro-crystalline oxide from the saturated solution above it. It was observed that the original bulky mass of sulfide had become dense and finely crystalline as hydrolysis took place and, unlike the suspended sulfide, rapidly settled to the bottom of the flask as soon as the gas current was discontinued. Under the microscope the product of hydrolysis was distinctly crystalline, and in this respect was unlike the oxide formed by hydrolysis of the tetrachloride, as the crystalline nature of the latter can only be observed by xray spectral examination. The deposited oxide and the filtrate were separately analyzed for sulfur content to determine the extent of hydrolysis undergone by the original sulfide. This was accomplished by treating each with an excess of nitric acid followed by evaporation on a water bath and retreatment with fuming nitric acid to make sure of complete oxidation of any free sulfur or thio compound to sulfuric acid. After extraction with water, the sulfuric acid was determined in the usual way as barium sulfate. The barium sulfate from the filtrate weighed 0.0010 gram, whereas that from the undissolved oxide amounted to 0.0051 gram. The sum of these represents a total sulfur content of 0.0021 gram, which is only 0.02 per cent of the sulfur originally present in the sample of sulfide. It is thus evident that it is possible to convert the sulfide to oxide completely by a reaction that does not involve oxidation, and that all, or practically all, of the sulfur can be expelled as hydrogen sulfide if air is excluded from the system. EXPERIMENT 2. A mass of germanic sulfide weighing 75.0 grams was suspended in a 3-liter flask with about 1500 cc. of air-free water, and after expelling the air by carbon dioxide, a rapid current of steam was injected. Condensation of steam in the flask was prevented by immersing the container in an oil bath heated to 110" to 120" C. Large masses of the sulfide showed a tendency to foam during the first part of the reaction but thia was successfully prevented by leading a second steam current into the flask through a small tube terminating above the surface of the boiling liquid. The main current of steam was introduced through a tube of larger bore which passes under the liquid nearly to the bottom of the flask. Analysis of the product of hydrolysis carried out as in experiment 1 gave a total sulfur content of 0.00146 gram, or 0.004 per cent of the sulfur present in the original sulfide. Further experiments with still larger amounts of sulfide were made. In one case 300 grams of sulfide were converted to
135
oxide in about 2.5 hours by rapid steam injection. The residual mass of micro-crystalline dioxide so produced was then directly converted to tetrachloride in the same vessel by detaching the steam tube and replacing it with an inlet tube for hydrochloric acid gas and a condenser for the volatile tetrachloride which was caught in a chilled receiver. I n dealing with some 300 grams of sulfide, the equivalent of 230 grams of oxide, it was convenient to use a 5-liter round-bottom flask containing 2 to 2.5 liters of water t o effect the initial hydrolysis of the sulfide. The water remaining after hydrolytic decomposition could then be further reduced in volume or completely evaporated before introducing hydrochloric acid in sufficient excess to effectthe distillation of the chloride from the same flask.
TABLEI.
QUANTITATIVE CONVERSION OF GERMANIC SULFIDE TO DIOXIDE BY HYDROLYSIS
SAMPLE
GeOz TAKEN GeOn FOUND Gram
Gram
ERROR Gam
0.2619 0.2519 0.0000 0.1269 0.1260 -0.0009 0.0132 0.0129 -0.0003 0.0053 0.0058 +0.0005 0.0266 0.0259 -0.0007 0.0053 0.0057 +O ,0004 0.0133 0.0137 +O. 0004 +O .0003 0.0160 0.0163 0.2519 0.2519 0.0000 0.2519 0.2521 +o .0002 0.2519 0.2620 +o ,0001 0.1259 0.1258 -0.0002 -0 * 0001 13O 0.0050 0.0048 a Sulfide preci itates hydroly~edin weighed clear quartz beakers EO that after removal o f filter crucible, solution oould be direotly evaporated to dryness, ignited and weighed in same vessel. This canoela errors arising from dissolved 'constituents of glass and avoids transference of partly evaporated solution to another vessel. 1 2 3 4 5 6 7 8 9 10 11" 120
HYDROLYSIS APPLIED TO QUANTITATIVE DETERMINATION Definite quantities of germanic oxide were obtained from several standardized solutions of pure germanic dioxide containing, respectively, 5.0380 and 0.5038 grams of oxide per liter. All flasks, pipets, and burets were carefully calibrated at 22' to 25" C. The exact concentrations of the germanic oxide solutions used were determined by evaporating 50-cc. samples to dryness in weighed quartz beakers, and igniting the residue to anhydrous oxide a t 900" C. Various amounts of dioxide, as shown in Table I, were taken by pipet or buret into 0.25-liter Erlenmeyer flasks and all samples brought to approximately 50-cc. volumes by addition of water. Each sample was treated with enough concentrated sulfuric acid to give about 6 N free acid (7 to 8 cc. for each 50 cc. volume). Germanic sulfide was precipitated by attaching the flask or series of flasks t o a hydrogen sulfide generator delivering the gas under pressure of about 2 feet (60.9 cm.) of water. Air was rapidly removed from the system by a brisk current of gas, and complete precipitation effected by allowing the hydrogen sulfide to remain in the closed system under pressure for at least 12 hours before filtering. The precipitated sulfide was removed by filtration through porous-bottom porcelain crucibles (15 cc. capacity), with coarse-grade filters purposely selected to make filtration as rapid as possible. The precipitate was washed with a little 1 N sulfuric acid saturated with hydrogen sulfide and sucked down as dry as possible on the crucible bottom. The crucible was then dropped into a beaker containing sufficient boiling water to immerse it completely, and active boiling was continued in the covered beaker until the hydrolyzed sulfide had completely entered solution. The small crucible was then removed and rinsed with a jet from the wash bottle. The solution was reduced by further evaporation to somewhat less than 40 cc. and then transferred to a weighed porcelain crucible in which evaporation to dryness was effected.
ANALYTICAL EDITION
136
Vol. 4, No. 1
covered during the initial hydrolysis or if the water is not kept actively boiling to exclude air while hydrogen sulfide is escaping. The residual dioxide was ignited a t 900" C., as usual.
The dry or nearly dry residue was in each case treated with a few drops of nitric acid, although in no case could any noticeable action be observed. The treatment with acid was made, however, in order to oxidize any traces of free sulfur which may have formed by accidental oxidation of escaping hydrogen sulfide, Noticeable amounts of sulfur form only if the beaker containing the suspended sulfide is allowed to remain un-
LITERATURE CITED (1) Johnson and Dennis, J. Am. Chem Sot., 48, 3 (1925). R~~~~~~~~~l~ 18, 1931.
A Vapor-Pressure Nomograph VIRDENW. WILSONAND C. Ross BLOOMQUIST, University of North Dakota, Grand Forks, N , D.
I
N THE course of another investigation, the writers found it necessary to calculate many vapor pressures from data
entails considerable work in order that" the scales may cover a sufficiently large range and still have the same relative accuracy. The chart is composed of six scales, four of which are divided. These are as follows: 1. The horizontal scale at the top of the chart is the temperature scale, divided into Centigrade degrees and numbered on the upper side according t o the absolute scale, on the lower in ordinary Centigrade degrees with zero at the melting point of ice; these scales are uniformly divided. 2. The horizontal scale at the bottom of the chart is graduated on both sides. The lower side, an evenly divided scale, represents the value of the constant A as given by the International Critical Tables. It must always be borne in mind that all values marked on this scale are multiplied by the factor 104. For example, the location of the point 38340 is determined between the divisions marked 3 and 4 in the same manner as it would be on a slide rule. The upper side of the scale is
given in the International Critical Tables. Since much of these data are given in the form log p,, = - (0.05223 A / T ) B, where A and B are constants for the material under investigation, T the absolute temperature, and p , , the vapor pressure in millimeters, certain mathematical and mechanical difficulties make calculation by ordinary methods difficult, particularly since a slide rule cannot be used directly. In order to simplify and speed up these calculations, the accompanying nomograph has been designed. The mechanical construction of this chart is not difficult, and results from the combination of two of the type forms described by Lipka ( 1 ) . Details of construction of this chart need not be discussed here, but it may be mentioned that the choice of the correct ranges for the various scales
+
T dcgrees Alsolule 1000
300
800
700
600
500
400
IO0
0
46
so
200
300
05223 A
400 gw
