COMMUNICATION TO THE EDITOR
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REFERENCES (1) HOLMEB, H. N., A N D MCKELVEY, J. B.: J. Phys. Chem. SI, 1522 (1928). (2) H U ~ G I N M. B , L.: J. Org. Chem. 1, 407 (1936). (3) MAGNUB, A., A N D KIEFFER, R.: z. anorg. Chem. 179,215 (19%). (4) MCGAVACK, J., A N D PATRICK, W. A. : J. Am. Chem. SOC.42,946 (1920). W. A., A N D JONES,D . C.: J. Phys. Chem. !29, 1 (1925). (5) PATRICK, (6) THOMAB, A.: Lecture given before the Syracuse Chapter of Sigma Xi, in 1939.
COMMUNICATION TO T H E EDITOR PHOTOCHEMICAL REDUCTION OF FERRIC IRON BY OXALIC ACID
The paper on “The Photochemical Oxidation of Oxalic Acid Sensitized by Ferric Ion,” published by R. Livingston (J. Phys Chem. 44, 601 (1940)),contains a statement which I should like to support by additional evidence. The results on the photochemical reduction of ferric ion by oxalic acid, as published in 1928 by E. Mencke and myself (Z. Elektrochem. 34,598 (1928))must be discarded. In December, 1936,I repeated this investigation with Dr. H. Hoch in Vienna. We found the permanganate titration not reliable enough and adopted the titration with titanium trichloride, used by Allmand and Young (J. Chem. SOC.1931,3079). Our experiments showed (1)that the velocity of the reaction was approximately proportional to the first power of the light intensity, which result was in agreement with the findings of Allmand and Young but contrary to those of Kornfeld and Mencke, who stated a dependence on the square root of the light intensity, and (3) that the reaction proceeded until the end, regardless of the presence of ferrous ions. This result also agreed with the findings of Allmand and Young and disagreed with those of Kornfeld and Mencke. For external reasons the investigation was not completed, and publication of the results was postponed. Since I have not been able to resume the investigation I should like to clarify the issue now, in connection with Dr. Livingston’s paper. GERTRUDKORNFELD. Research Laboratories, Eastman Kodak Company, Rochester, New York.
