GB739722A - Electrolysis process and apparatus - Google Patents

Abstract

739,722. Electrolytically decomposing salts of organic acyciic acids. HOOKER ELECTROCHEMICAL CO. Nov. 20, 1952 [Aug. 26, 1952], No. 29371/52. Drawings to Specification. Class 41. In the electrolytic decomposition of salts of organic acyclic acids there is provided an anode in contact with electrolyte containing an organic acyclic acid resulting from the electrolysis, a cathode in contact with electrolyte containing the cation resulting from the electrolysis, the electrodes being separated by a permselective membrane wet with electrolyte and the electrode compartments having means for introducing an electrolyte and an outlet for separately recovering gaseous products of electrolysis. According to a preferred modification, a three compartment cell is used, the solution of the salt to be electrolysed being introduced into the middle compartment which is separated from the other compartments by diaphragms, at least one of which is permselective, being anionic if adjacent the anode compartment or cationic if adjacent the cathode compartment. The permselective diaphragms can be constructed of ion-exchange resins made into thin continuous sheets. Such sheets can be made by intimately and uniformly distributing a substantial proportion of an insoluble infusible ion-exchange resin into plastic material such as a synthetic hydrocarbon type plastic, or natural or synthetic rubber. Examples relate to the electrolysis of sodium acetate or sodium formate, but salts of other acyclic acids such as propionic, butyric, monochloracetic, trichloracetic, acrylic, methacrylic, acetoacetic, pyruvic, oxalic, succinic, and maleic acids are referred to. If it is desired to produce a pure cathodic product such as sodium hydroxide, a cationic permselective membrane is provided facing the cathode and the salt to be electrolysed is introduced into the compartment on the other side of the membrane. If it is desired to produce a pure anodic product (the acyclic acid) an anodic permselective membrane is provided facing the anode, and the salt is introduced into the compartment on the other side of the membrane. Preferably a cell is employed with an anodic permselective membrane facing the anode and a cathodic permselective cell facing the cathode to form three compartments, a solution of the salt flowing into the centre compartment and water flowing into the electrode compartments. A solution of the acid leaves the anode compartment and a solution of sodium hydroxide leaves the cathode compartment; or if carbon dioxide is bubbled through the cathode compartment, a solution of sodium carbonate. The anode may be graphite, nickel, magnetite or platinum. The cathode may be steel. The employment of three compartment cells containing one permselective diaphragm and one conventional diaphragm is also referred to.