Process of preparing solutions of alkali peroxide and percarbonate

US5766443A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Eilhard Hillrichs · Büdingen, DE
• Ulrich Sander · Rebstein, CH

Key dates

• Filing date: Jan 2, 1996
• Grant date: Jun 16, 1998
• Expiry date: Jan 2, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25B1/28
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

The process for preparing an aqueous alkaline solution containing a peroxide and/or percarbonate includes providing an electrochemical cell comprising a porous oxygen diffusion cathode including a carbon woven or nonwoven fabric, a gas diffusion anode containing a carbon woven or nonwoven fabric and fed gaseous hydrogen or an anode including a metal grid coated with a noble metal catalyst and coated on a side facing the cathode with a proton-permeable membrane acting as a solid polymer electrolyte, an electrolyte-containing chamber between the cathode and the anode containing an electrolyte and a direct current source connected across the anode and cathode; feeding an aqueous feed solution containing at least one alkali hydroxide and/or alkali carbonate in a concentration of from 30 to 180 g/l into the electrolyte-containing chamber to provide the electrolyte; supplying an oxygen-containing gas containing molecular oxygen to the carbon woven or nonwoven fabric of the cathode; operating the direct current source to provide an external cell voltage of from 0.5 to 2.0 volts across the anode and the cathode; and withdrawing, from the electrolyte in the chamber, the aqueous alkaline sol…