US1477099A - Anode for forming percompounds - Google Patents

Description

Dees;l l 1923.

G. BAUM` ANDE FOR FORMING PERCOMPOUNDS Filed Aug. 22 1922 Flai Z'fpurn,

Patented Dec. 11, 1923.

FBBIK WEISSEN STEIN orifice.

or' cnnmscnn G. M. B. H., OF GABINTHIA, AUSTRIA.

NODE ron FonmNG PEaconroUNns.

Application :tiledv August 22, 1922. Serial No. 588,665.

To all 'wiwm z't 'may concern.' i

Be it known that I, GUs'rAv BAUM, a citizen of the Republic of Austria, and residing at Weissenstein ob der Drau, Carinthia, Austria, have invented certain new and useful Improvements in Anodes for Forming Percompounds; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the Aart to which it appertains to make and use the same.

This invention relates to anodes for forming percompounds, said anodes consisting of tantalum o which the surface is only partly provided with -a platinum coating.

or 'making percompounds heretofore, anodes of pure platinum have been used. Whereas it is sometimes possible to replace platinum cathodes by other metals, for instance, tungsten or tantalum, it had been quite impossible, to use anything but pure platinum as anodes, since the above named metals, as well as any other metal, are either dissolved in the electrolyte or coated with a layer of oxide whereby the circuit is interrupted.

I have, however, shown that it is possible to avoid the above mentioned drawback and to obtain suitable anodes for forming percompounds by manufacturing anodes ofl a tantalum base and providin this base with a relatively small surface o? platinum coating which serves for transmitting` the current from the tantalum to the electrolyte.

It is surprising that anodes of the said construction can also be used for forming percompounds, since-it isea well known fact that the percompounds are especially sensitive to metal ycontaining catalyzers. The exposure of the surface of tantalum, however, either in the metallic or in oxidized condition has not the slightest injurious effeet on the process of formation and on the condition of the percompounds formed.

The use of platinum coating on a tantalum base to such an extent that the whole surface of the tantalum is not coated with platinum is in practice Yconsiderably simpler and cheaper than coating the whole tantalum base with the more expensive platinum. The. coating can, either by electrolysis, or by weldin rolling and the like.

t e. accompanying drawings an.` anode hammering,

for example, be eifected -b an anode o tantalum according front view by way of example. l

a designates a base of tantalum, which may be, for instance, 10mm. in breadth, 500 mm. in length, and 0.2 mm. in thic ness. This piece of tantalum is partly ond is used.

Examples.

to the" invention is illustrated in 1. (a.) A cylindrical cell of 600 ccm.

serves as electrolyzing vessel, a porous cylinder of 200 ccm. as diaphragm. The cathode is formed by a lead `coil which at the same time serves as a cooling device. 150 ccm. of a saturated solution of ammonium sulfate is used as anolyte (anodic liquid) sulfuric acid of 45 B. as catholte; the temperature remains below 18"A The anode is formed of pure platinum the surface of which is about 2 cm2; the current density during the electrolysis amounts to 1 amp/cm2. The output is 96.4%.

(b.) The same apparatus is used and the same conditions are maintained, when the platinum anode is substituted by an anode of tantalum, partly coated withplatinum. The output 1s 95%, that is to say the result is practically equal to that obtalned witha platinum anode.

2. (a.) The cylindrical cell, diaphragm 'and lead vcoil are the same as in the above described example. As electrolytev I use sulfuric acid of 45 B., the contents of the anodic cell being 150 ccm. The temperature variesbetween 18 and 20. C. The

vanodebeing of pure platinum and'havi-ng .an area of .5l cm2 being 1 amp/cm2 60.13%.

(b'.)\ If the latinumA anode is substituted partly coated With p atinum and it 4the e' conditions are maintained the output amounts to 60.55%. t

and the current density the output amounts to nos From the above it may be seen that "the anode according to my invention is of high commercial value as it is a perfect substitute for pure platinum.

I claim: l

1. An anode, for forming pereompounds, consisting of a tantaluln base portion having its` surface partially coated with platinum.

2. An anode for forming pereompounds,

consisting of a tantalum base portion having its surface partially covered with a coat: ing of platinum Welded thereto.

In testimony thatfI claim the foregoing as my invention, I have signed my name.

GUSTAV BAUM.

Witnesses:

ING. CHEM. J. RUMPLER, ING. En. Pnos'z.

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