paratus for the extraction of copper(I1) by LIX reagents have been reported recently (3-5). The results indicate that the interface plays an important role in the extraction process. It would be of interest to use the method proposed above to verify this conclusion.
ACKNOWLEDGMENT The authors are grateful to R. N. Longwell of the Bluebird Mine, Miami, Ariz., for providing the LIX reagents used in this work. LITERATURE CITED I. P. Allmarln, Yu. A. Zolotov, and V. A. Bodnya, Pure Appl. Chem., 25,
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Flgure 1. Variatlon of the rate of extraction of Cu2+ from an aqueous solution Into kerosene solutions of LIX reagents. The solution consisted of 75 mL of M Cu(NO& and 25 mL of kerosene. Two mL of the
concentrated LIX reagent in kerosene was injected into the solutlon that was being continuously stirred at 500 rpm with a magnetic stirrer. Millivolt readings were recorded 5 s after injection of the LIX is clearly a superior extractant than either LIX63 or LIX65N, several explanations have been advanced for the synergistic effect of LIX64N, but convincing experimental evidence that supports any of these explanations is lacking. Kinetic data obtained by the single drop method and the AKUFVE ap-
667 (1971). J. Rydberg, Acta, Chem. Scand., 2 3 , 647 (1969). R. L. Atwood, D. N. Thatcher, and J. D. Miller, Metall. Trans., 6B, 465
,.-. -,. fIQ75)
R. J. Whewell, M. A. Hughes, and C. Hanson, J . Inorg. Nucl. Chem., 37, 2303 (1975). (5) D. S. Flett, D. N. Okuhara, and D. R. Splnk, J. Inorg. Nucl. Chem., 35, 2471 (1973).
Stephen J. Kirchner Quintus Fernando* Department of Chemistry University of Arizona Tucson, Arizona 85721 RECEIVED for review April 26, 1977. Accepted June 9,1977. This work was supported by the Ranchers Exploration and Development Corporation, Albuquerque, N.M.
Corrosion of Stainless Steel by Organic Solvent Mixtures Sir: In the course of conducting liquid chromatographic experiments we have noted occasional problems which arise when organic liquids are allowed to remain in contact with stainless steel materials (type 316). Some corrosion effects are anticipated since it is known that formic, acetic, and propanoic acids are corrosive at room temperature (1-3). Carboxylic acids with higher molecular weight serve as corrosion inhibitors, while all organic acids are corrosive at temperatures above 300 "C (4). Other organic compounds, anhydrides, aldehydes, and those containing sulfur are also known to be corrosive to metals (5). By contrast, most of the common organic solvents are regarded as noncorrosive. We wish to report our finding that certain of these solvents, although noncorrosive individually, may display a highly corrosive attack upon stainless steel when used in the form of mixtures. Our findings can be summarized in terms of the following test. A 1.0-g piece of 316 stainless steel tubing, or of NBS Standard Reference Material No. 1155, was added to a glass vial containing 20 mL of a solvent or a solvent mixtureequally proportioned by volume, After 10 days of unagitated storage at 20-23 "C the samples showed the following changes. (I) No apparent change: with pure C C 4 (this solvent is occasionally quite troublesome in HPLC, however), tetrahydrofuran, acetone, or diethylether. (11) Slight yellow coloring of the liquid with CC14 + acetone, C C 4 + THF, C C 4 + diethylether, and CC14+ isopropyl ether + acetone. (111) Forms viscous, brown colored liquid: CCll diethylether + acetone, CC14 tetrahydrofuran acetone. The results were not dependent on storage in room light or in darkness. Mixtures I1 or I11 produced changes that could easily be detected spectrophotometrically, by 210% transmission loss after 2 or 3 h.
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The foregoing experiments were repeated using solvents of varied purity: reagent grade, those which had been commercially redistilled (in glass), and "spectroscopy" grade. The results were clearly dependent on the chemical nature of the materials and qualitatively, at least, independent of their source or purity. Since the presence of C C 4 seemed critical to the results gathered so far, we also tested the effect of using chloroform in its place. These results were quite similar, although the reaction rates were clearly slower. The weight loss was measured in experiments similar to I1 and 111. After a period of time the steel was removed and rinsed with solvent. This removed a thin f i i from the surface of the steel. Mixed CC14 THF caused weight loss that was linear with time up to 10% loss after 8 days. The loss from mixed CC14 + THF acetone was also linear, but at twice the rate, up to 4 days. Then the rate accelerated to 23% loss after 24 days. The rates in I11 were boosted considerably by heating under boiling reflux. When the film was allowed to remain intact through gentle handling, the same experiments showed a weight gain of the dried sample of metal plus film. Gas chromatographic analysis of the liquid phase showed that a number of volatile products had formed. In a separate experiment, mixtures of steel and solvent were stored in the dark at room temperature for 10 days. Gas chromatography showed that the reaction products contained a series of volatile compounds, as shown in Figure 1. An attempt to use GC/MS did not provide specific structure determinations, but it became clear that most of the volatile species contained more than one chlorine atom. The volatile products in the case of the two mixtures in 111, at least, seem to be quite dangerous. Severe eye irritation and headache were experienced after a single restricted exposure to test the odor. Gas evolution from any of the mixtures in
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ANALYTICAL CHEMISTRY, VOL. 49, NO. 11, SEPTEMBER 1977
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complexes (7, a), and the peroxide induced formation of CC13 radicals from CC14 (9, IO). Our experiments show that the present corrosion effects are primarily due to the presence of the halogenated hydrocarbon solvent while the other solvents may accelerate the attack and make the reactions more complicated. It is clear that certain organic mixtures are peculiarly unstable during prolonged contact with stainless steel. For this reason we suspect that certain combinations of sample and solvent would lead to chemical changes in the components in the sample.
LITERATURE CITED (1) C. N. Rowe, NASA Spec., Pub/., NASA, JP-318, 527-568,(1972)(Pub.
1973). (2) U. R. Evans, “The Corrosion and Oxidation of Metals. First Supplementary Volume”, Edward Arnold (Pubilshers), Ltd., London, 1968,p 247. (3) E. Heitz, Oberfhche Surf., I!,331 (1974). (4) G.T. Paul, and J. J. Moran, Stainless Steel, Corrosion Resistance of Metals and Alloys”, 2nd ed., ACS Monogr., 158, 375 (1965). (5) R. K. Swanby, “Corrosive, Corrosion Resistance of Metals and Alloys”,
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Figure 1. Gas chromatographic analysis of the following: (A) control mixture of acetone, tetrahydrofuran, and carbon tetrachloride; (B) same as A but after 10-days contact with stainless steel; and (C) after 10 days of contact with steel, tetrahydrofuran, and carbon tetrachloride. Conditions: 3% OV-101 on Chromosorb W, acid wash, DMCS treated, 50-275 ‘C program. At the asterisk (*), the FID amplifier gain was boosted 200-fold
I11 was sufficiently rapid that the vial was left unclosed to avoid pressure buildup. After three days of recirculating a mixture of CC4+ THF through an &-steel HPLC apparatus, the liquid stream turned dark brown and fouled the apparatus. These results indicate a number of chemical changes which seems to be consistent with the known auto-oxidation of ethers (6),the ability of certain metals to form etherate
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ANALYTICAL CHEMISTRY, VOL. 49, NO. 11, SEPTEMBER 1977
2nd ed., ACS Monogr., 158, 45 (1965). (6) D. Ehd, in “The Chemistry of the Ether Linkage”, S.Patai, Ed., Interscience Publisher, London, New York, etc., 1967,p 361. (7) W. Herwig, and H. H. Zeiss, J. Am. Chem. Soc., 79,6561 (1957). (8) K. J. Kiabunde, A m . Chem. Res., 8, 393 (1975). (9) R. Hiatt, in “Organic Peroxldes”, D. Swern, Ed., Why Interscience, New York, N.Y., 1970, p 802. (IO) M. S.Kharasch, E. J. Jersen, and W. H. Urry, J. Am. Chem. Soc., 69, 1100 (1947).
Alice Y.Ku David H. Freeman* Department of Chemistry University of Maryland College Park, Maryland 20742
RECEIVED for review April 18, 1977. Accepted June 14,1977. This work was supported by the National Science Foundation, Grant Number MPS 75-04802.
