ROTATING ANODE I N
ELECTROLYTIC SEPARATIONS.
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tion of the alkaloid and after filtration the colorless filtrate was titrated with standard acid. Calculated: Ti, 6 . 2 4 ; F, 14.80; H,O, 9.30. Found: Ti, 6 56; F, 15.24; H,O, 9.54. Anzlzne 7'itciniurn Flziorz'dc, (C,Hj.2'H?)?.I-I,TiI.',.H,0.--Pink colored
needles, readily soluble in water and in alcohol. The salt became perfectly anhydrous after standing for a period of three months, exposed to the air. Calculated: Ti, 13.05; F, 30.96. Found: Ti, 12.99; F, 30.88.
Piperine and santonine apparently do not form double fluorides with titanium. Numerous attempts were made, both by the boiling point and freezing point method, to arrive a t the molecular magnitudes of these several double salts but the results were quite discordant. In conclusion, it riiay be mentioned t h a t the titanic acid used in this study was derived from rutile from Magnet Cove, Arkansas, and t h a t this particular sample of mineral contained quite a considerable quantity of vanadiuni. U N I V E R S I T Y OF P I X N S Y L V A N I A ,
[CONTRIBUTION
FROM
THE J O H N HARRISON LABORATORY O F CHEMISTRY.]
THE USE OF THE ROTATING ANODE I N ELECTROLYTIC SEPARATIONS., BY MARY E. HOLMES. Received September 3, 198.
This investigation was undertaken with the view of learning what advantages could be had with the rotating anode, when using low currents. Heretofore, currents of from three to five amperes have been employed when using the rotating anode. The most exhaustive contribution to the subject of nietal separations, employing the rotating anode, was made by Ashbrook in 1 9 0 4 . ~ All his work was done with high currents, five amperes being generally used. Other separations were later recorded by Miss Langness (Thesis, 19o6), in which low currents and rotation were successful. The results would seem to indicate the possibility of obtaining other separations with low currents in comparatively short periods of time. Criticism of the rapid methods of electrolytic work has often been made to the effect that while the methods employed may be adequate for the determination of single metals, the introduction of more than one metal Compt. rend., 53, 161 (1861); Astrophysical Jour., 6, From the author's thesis for the Ph.D. degree. THISJOURNAL, 26, 1285.
22
(1897).
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MARS
E. ITOI,ivV2,S.
into the solution causes sticli :t variation in conditions that separations are iiot prncticaltle. ' 1 ' 1 ~ o i i l y aiisivcr t o siicli doubts is :I systematic stud!. o f tht. ivliole siil)jec.t of sc1)ar;itioiis. \.ar!.iiiX contlitioii or ciirrclit, rotatioii, time mid electrolytc iisctl, S(I t h a t ior c~tclimetal :ill possi1)iIities ma!. be tleterniirietl. This coniniunicatioii represents :i 1)eginniiig of such study niatle with the eleiiient cadmium. 'I'hc possibilities of its separation with low currents from the iiietals of Groups I I1 ant1 I\-, and froin magnesium ha\-e been ascertaiiietl, am1 ;I corriparisoii ninde o f tliese results with tliose previously obtained with high curreiits. I h e conditions of work were as follows: The current was kept in almost all cases below one anipere. Currents below 0.3 or 0.4. ampere \\ere not found useful. The rotating dish anode used first by Miss 1,angness ('I'hesis, 1906) was employed. 'The cathode was a piatinurn dish of 2oo cc. capacity, the usual form of dish emplo!.etl iii electro-atialysis. 'I'he time required for ii determinatioii \vas from forty-five niinutes to one hour, and the electrolytes iised \\'ere ( I j sulpliuric acid, :uicl ( 2 ) aninionium acetate and acetic :tcid.
,.
Experimental Part. A . . Y u l ~ / z u r i cAcid I
