Abstract: An improved method and apparatus for the electrolysis of ionizable chemical compounds is disclosed including specifically a process for the production of chlorine and caustic soda containing low concentrations of sodium chloride by the electrolysis of brine which comprises electrolyzing brine solutions in a two compartment cell equipped with a cathode and an anode separated by permselective barrier formed by sandwiching together two or more membranes consisting essentially of a hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether having the formulaFSO.sub.2 CF.sub.2 CF.sub.2 OCF(CF.sub.3)CF.sub.2 OCF.dbd.CF.sub.2said copolymer having an equivalent weight of from about 900 to about 1600. By the use of a multilayer membrane sandwich as the barrier the caustic current efficiency of the process is increased over that obtained when a single layer membrane is used as the barrier separating the cathode and anode.

Abstract: An improved method and apparatus for the electrolysis of ionizable chemical compounds is disclosed including specifically a process for the production of chlorine and caustic soda containing low concentrations of sodium chloride by the electrolysis of brine which comprises electrolyzing brine solutions in a two compartment cell equipped with a cathode and an anode separated by permselective barrier formed by sandwiching together two or more membranes consisting essentially of a hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether having the formulaFSO.sub.2 CF.sub.2 CF.sub.2 OCF(CF.sub.3)CF.sub.2 OCF=CF.sub.2said copolymer having an equivalent weight of from about 900 to about 1600. By the use of a multilayer membrane sandwich as the barrier the caustic current efficiency of the process is increased over that obtained when a single layer membrane is used as the barrier separating the cathode and anode.