Process for the electrolysis of alkali metal chloride solutions

US4790915A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• August Winsel
• Rudolf Staab · Kelkheim, DE
• Nikolaj Medic · Kelkheim, DE

Key dates

• Filing date: Jan 12, 1987
• Grant date: Dec 13, 1988
• Expiry date: Jan 12, 2007

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25B1/46
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process is described for electrolyzing aqueous alkali metal chloride solutions in a membrane cell which contains an anode chamber with the anode and a cathode chamber with the cathode, the two chambers being separated from one another by a cation exchanger membrane. The cathode is porous and foil-like. The cathode and cation exchanger membrane form the actual cathode chamber filled with catholyte and the cathode and cell wall form a gas space. Water is fed into the cathode chamber and alkali metal hydroxide solution is withdrawn from it, hydrogen is withdrawn from the cathode chamber and gas space, and aqueous alkali metal chloride solution is fed into the anode chamber and gaseous chlorine, together with depleted alkali metal chloride solution, is withdrawn from it. A direct voltage which is at least the same as the decomposition voltage is applied to the cathode and anode. A higher pressure is established in the cathode chamber than in the gas space.