VOL. 11, NO. 5
INDUSTRIAL AND ENGINEERING CHEMISTRY
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(15) McAlpine, R. X.,and Soule, B. A., “Qualitative Chemical Analysis”, p. 287, New York, D. Van Nostrand Cb., 1933. (16) Mitchell, C. A., “Recent Advances in Analytical Chemistry, Vol. 11, Inorganic Chemistry”, p. 334, Philadelphia, P. Blakiston’s Son & Co., 1931. (17) Noyes, A. A., and Bray, W. C., “Qualitative Analysis for the Rare Elements”, New York, Macmillan Co., 1927.’ (18) Scott, W. W.,”Standard Methods of Chemical Analysis”, 4th ed., p. 388, New York, D.Van Nostrand Co., 1929. (19) Short, M. N., U. S. Geol. Survey, Bull. 825, 165 (1931). (20) Wada, I., and Nakazona, T., Sei. Papers Inst. Phys. Chem. Research (Tokyo), 1, 139 (1923).
(7) Benedetti-Pichler, A. A., and Spikes, W. F., Mikrochemie, 19, 239 (1936). (8) Benedetti-Pichler, A. A., and Spikes, W. F., Ibid., Molisch Festschrift, 3 (1936). (9) Cole, H. I., Philippin,; J . Sci., 22, 631 (1923). (10) Fresenius, W. T., Introduction to Qualitative Chemical Analysis”, p. 37, New York, John Wiley & Sons, 1921. (11) Geilmann, W.,“Bilder our qualitativen Mikroanalyse anorganischer Stoffe”, p. 39, Leipzig, Leopold Voss, 1934. (12) Gilchrist, R., Bur. Standards, J . Research, 9, 547 (1932). (13) Rillebrand, W. F.,and Lundell, G. E. F., “Applied Inorganic Analysis”, p. 107, New York, John Wiley & Sons, 1929. (14) Iwanow, W.N., Chent. Zentr., 4, 135 (1923).
Pregl Sulfur Combustion of Metallic Compounds JOSEPH F. ALICINO, Fordham University, New Yorlr, N. Y.
HE only limitation to the excellent Pregl catalytic cornfor sulfur is its lack of applicability to bustion which contain a (I). As these Occur fiequently, an attempt was made to modify the method to include them. a few preliminary experiments showed that the residue from this type of substance contained a considerable amount of metallic sulfate, attempts were made to prevent its formation or to decompose it when formed. The substitution of a porcelain boat to avoid the catalytic effect of platinum did not prevent its formation, and the addition of various substances, such as potassium dichromate, chromium trioxide, sodium peroxide, and cupric nitrate, to the sample did not leave the residue sulfate-free. As it seemed probable that the formation of sulfate could not be avoided under the conditions of the determination, it was decided that the solution of the problem depended on treatment of the combustion products to obtain the theoretical yield of barium sulfate. While only a comparatively few compounds were readily available, their metals belonged to four of the five qualitative groups and possessed widely different chemical behavior.
T
This treatment ensures the quantitative transfer of sulfate ion with the minimum amount of solvent. In the case of the barium compound, the transfer of the residue to the crucible was accomplished by overturning the boat and spraying vigorously from the wash bottle t o remove the last traces of residue. Other barium compounds, if present, are dissolved by the acid, leaving only the insoIubIe sulfate. Insoluble residues of other metals must be extracted by boiling gently with 0.1 N hydrochloric acid and treating the extract with barium &loride in the usual manner, Chromium residues contain no sulfate (Table I), and subsequent treatment of the residue is unnecessary. TABLE11. YIELDOF BARIVM SVLFATE (Separate treatment of residue omitted) BaSO4 Sulfur Sample Found Calcd. Found Calcd. Me. Mg. Mg. % % Lithium cystinate 5.324 9.81 9.85 25.32 25.40 co per cystinate Barium cystinate 5.500 5.840 7.22 8,47 7.25 7.49 21,15 16.98 21.21 17.04 So$iumj3-na htho6.904 6.17 6.19 12.29 12.31 quinone suyfonrtte Compound
I
Discussion *
TABLE I. YIELDOF BARIUM SVLFATE
Compound
(Reaidue and contents of spiral treated separately) YBaSOdFrom Total Bas04 Sample From residue spiral Found Calcd. Me. Mu. % Mg. Me. Mg.
Lithium cystinate. C~HioO4N~,BLi, Bariumoystinate CsHioOiNzSiBa) Reinecke salt, C~HIONISIC~ Co per cystinate, &HIoO~N&CU Sodium8-naphthoquinonesulfonate, CioHsOsSNa
.
6.695 5.545 6.087 6.872 4.356 4.542 5.503 4.552 6.705 7.333
6.02 4.99 3.17 3.61
48.75 48.87 42.27 42.47
1:58 1.31 3.14 3.44
18:65 18.71 52.21 52.36
..
...
6.33 5.22 4.33 4.89 12.12 12.62 6.89 5.69 2.86 3.13
12.35 10.21 7.50 5.50 12.12 12.62 8.47 7.00 6.00 6.57
12.38 10.25 7.55 8.52 12.09 12.60 8.50 7.03 6.01 6.57
Sulfur .7
Found
Cdcd.
26.34 25.29 16.92 16.98 38.22 38.16 21.14 21.12 12.29 12.31
25.40
%
%
17.04 38.11 21.21 12.31
-
The residue and the contents of the spiral were treated separately, as shown in Table I, to show the yields of barium sulfate. Table I1 shows the results when the separate treatment of the residue is omitted. The acid-soluble residues are placed in the weighed and dissolved by means of the acid washings of the spiral contents. The total sulfate is collected and treated with barium in the fashion. When insoluble residues other than barium are formed, the hydrochloric acid extract can be added to the partly evaporated contents of the spiral previously placed in the weighed crucible. In this manner accurate results can be obtained.
Acknowledgment Experimental The substances were run according to pregys method (8, 31, (4). The contents of the spiral were treated in the usual manner and the weights of barium sulfate recorded. The residues left in the boat were weighed, but, owin t o the variable amounts of sulfur and metal present in the Sam&, did not conform to the weight demanded by the pure sulfate. This indicated that the oxide or carbonate was formed in addition to the sulfate, and the weights were therefore disregarded as of no significance. The acid-soluble residues, which included all but the barium derivative, were transferred t o another weighed crucible and dissolved in 7 to 10 ml. of 0.1 N hydrochloric acid, and the boat was rinsed with hydrochloric acid (1 t o 200) from a wash bottle. as modified by Saschek
The author is indebted to G. Toennies of the Lankenau Hospital, Philadelphia, for the lithium and barium salts used in this work.
Literature Cited (1) Niederl and Niederl, “Organic Quantitative Microanalysis”, pp. 141-53, New York, John Wiley & Sons, 1938. (2) Pregl, F., “Die quantitative organische Mikroanalyse”, 3rd ed., pp. 131-65, Berlin, JuIius Springer, 1930. (3) Roth, H., and Daw, E. B., “Quantitative Organic Microanalysis of Fritz Pregl”, pp. 116-28, Philadelphia, P. Blakiston’s Son BC Co., 1937. (4) Saschek, W., IND. ENQ.CHEM.,Anal. Ed., 9, 491 (1937).
