'The purple-colored filtrate decomposed and deposited .L tion constants of the acids. Since there is s o t i i t ' dark solid which was insoubIe in the carbon tetrachloride controversy over this constant in the literature, The residue could be extracted with chloroform to yield inore purple 5olutioi1, vhirh tlso drcotnposed in a it.!\ we have redetermined this constant for hypobroIt was found possible to add sufficient chlorine to ,I \ample of nickel a-benzildioxime to diwolvc it coinpletel, but this solution was also unstable. Hydrolysis of ar -Benzildioximonickelic(In) Bromide. Approximately 1 g. of a-benzildioximonickelic(I11) bromide was stirred in 50 ml. of cold concentrated ammonium hydroxide. A maroon-colored compound formed which \\as somewhat soluble in the ammonia solution. The product was filtered, washed vr.ith distilled mater, and itlied in ct desiccator The product decomposes slowly to give nickel cu-benzildioxime. I t is slightly soluble in dioxane but insoluble 111 uater and in organic liquids such as benzene, carbon tetrachloride, diethyl ether, ethanol and acetone. Action of Bromine on Other Nickel-oximes.-Besides ru-benzildioxime and dimethylglyoxime, other nickeloxime derivatives were treated with bromine in carbon tetrachloride solution. These include ar-furildioxime, cyclohexanedionedioxime, glyoxalglyoxime, diacetylinonodxime monophenylhydrazide and ethylenediaminebis-diacetyldioxime. The last of these gave a stable bromide and the glyoxalglyodme gave an unstable deriv'i tive The other compouiid~ were decomposed Itv the I Irornine. RECFIVFI)3 T 4 3~3 , 1050
The 6-Phenylphenacyl Ester of Phenylacetic Acid 1)raL.e and Sweeney' reported 63" (dec.) as the melting point of the p-phenylphenacyl ester of phenylacetic acid. In the course of undergraduate instruction we recently had occasion to prepare this ester and found it to melt a t 88.2-88.8' (cor.). Five preparations2 showed the same melting point. Experimental p-Phenylphenacyl Phenylacetate .--This compound was prepared by the standard method.3 The light tan crude product was recrystallized three times from ethanol (once \I tth charconl) . The pure white analytical sample melted 88 3 88 8' icor.) to a completely colorlesi mc.lt. ..lncil. Cctlctl for C&,d) . c', 7'1 03. 11. 7 10 i ' o c i i ~ l . C, 79 -I{;H , iti0 '\i
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acid. Shilow and Gladchikova2 found by lectrometric titration that a t 20' = 2.Ori x I O and according to the same method, AHOCL a t 30" = 3.16 X lo-*. While the latter value is in good agreement with the results of other ~ n v e s t i g a t o r sand ~ , ~ is also close to the figure obtained by Skrabal and Berger6 from the kinetics of the hypochlorite decomposition (viz., 5.6 X IO-* a t 25'), the correctness of the above value of I ~ H O Bwas ~ questioned by SkrabaLG He calculated from data on the rate of decomposition of hypobromite depending upon the $H, the much lower value of 2 X a t 25'. The following method was used for the deterinination of the dissociation constant of the hypobromous acid : T o a hypochlorite solution, kept a t ct pH approximately equal to its p K , the equivalent amount of bromide was quickly added and the change of the pH was accurately measured by Iiiedns of a glass electrode. Since, upon the addition of the bromide, all the hypochlorite was con1-erted to hypobromite,' the observed ApH according to the Henderson-Hasselbach formula was in good approximation, equal to the A,PK of hypochlorous and hypobromous acid. In Table I, the results of a series of experiments &re given, In these experiments, the solutions used were prepared by a method previously tlescribed.' The bromide was added to the hypochlorite solution while the electrodes were iiniiiersed in that solution. The final PH was establtshed within a few seconds after the addition of t h e hronude7,9and remained constant for more t h m 1:) niinutes. 'The solutions were analyzed for hypochlorite before, and for hypobromite inimediately after, the addition of the bromide according to the method already describeds; no change i n the oxidation capacity was found, the hypochlorite being quantitatively converted t o iiious
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