GB389244A - Electrodes for carrying out electro-chemical processes and processes of electrolysis employing the same - Google Patents

Abstract

389,244. Electrolysis. BERL, E., 40, Wilhelmstrasse, Darmstadt, Germany. Jan. 30, 1932, No. 2806. [Class 41.] Electrolytic processes are promoted by the use of anodes and/or cathodes consisting wholly or in part of activated carbon. The invention is particularly applicable to the production of hydrogen peroxide by cathodic reduction of oxygen, the electrolytic manufacture of perborates and persulphates, and the electrolytic oxidation and reduction of organic and other substances which are only slightly soluble in the electrolyte. The electrode may be in the form of a pipe activated on the outside, to the inside of which a reacting gas is supplied. The interior of the pipe may be filled with porous material such as carbon. Alternatively the upper end of the electrode may project into a gas chamber. The processes may be carried out at atmospheric pressure or at higher or lower pressures. The activation of the electrodes may be effected by impregnating them with the potassium salts of the soluble acid tars produced in the purification of petroleum or coal tar fractions with sulphuric acid, and heating. The electrodes may be provided with insertions of higher conductivity such as graphite or metal gauze or the active carbon may be packed in a grid of such material The electrodes may be impregnated with catalysts which promote the desired reaction or which inhibit detrimental decomposition reactions. Examples of the latter class are #-nitroso naphthol for use in alkaline solutions, and salicylic acid for use in acid solutions. The electrodes may be coated with an extremely thin layer of a water-repellent substance such as paraffin. In an example, oxygen is led through a tubular activated cathode into a cell without a diaphragm containing a solution of sodium borate ; the anode being of platinum and having a surface one-third that of the cathode. At a voltage of 10 and temperature of 5‹ C. solid perborate separates on both electrodes. The process can also be operated with a diaphragm with sodium borate as the anolyte and sodium carbonate or bicarbonate as the catholyte or vice versa.