Electrochemical Syntheses of Sodium Percarbonate in Aqueous Solution

Abstract

The present research is focused on electrochemical production of sodium percarbonate as both the 2Na 2 CO 3 . 3H 2 O 2 form and the Na 2 C 2 O 6 formulation. The routes to these two electrochemical syntheses from carbonate solution proceed through oxygen reduction at the cathode and electrochemical oxidation of water at the anode, respectively. We have studied each of these reactions separately, potentiostatically for the cathodic reaction and galvanostatically for the anodic side.In both cases, the effects of experimental conditions, such the addition of a stabilizer or the use of a cation-permeable membrane, have been investigated; products were analyzed for % active oxygen content in dry samples according standard methods.

Promotive Effect of Bicarbonate Ion on Two‐Electron Water Oxidation to Form H2O2 Catalyzed by Aluminum Porphyrins

“…One is the formation of sodium carbonate peroxyhydrate (2 Na 2 CO 3 ⋅3 H 2 O 2 ) upon a simple mixing of the two components, in which H 2 O 2 is trapped in a lattice‐type structure of carbonate ions in water without definite covalent bond formation between H 2 O 2 and CO 3 2− . The other is the formation of hydroperoxycarbonate (HOOCO 2 − ) through the formation of a covalent bond (O−C) between H 2 O 2 and CO 3 2− , which is generally caused by electrochemical oxidation of the carbonate ion . The retardative effect of Na 2 CO 3 on the complex formation (intermediate IV from I ) is caused by the competing formation of the former sodium carbonate peroxyhydrate in this case because no oxidation of the carbonate ion is involved in the process.…”

One Electron‐Initiated Two‐Electron Oxidation of Water by Aluminum Porphyrins with Earth's Most Abundant Metal

“…These observations cannot rationalize the hypothesis of direct four‐electron water oxidation by AlTMPyP. Because sodium carbonate is well known to stabilize hydrogen peroxide in aqueous solution by forming a peroxocarbonate and electrochemical synthesis of peroxocarboante on BDD electrode has also been reported, the hydrogen peroxide produced by the catalytic reaction of AlTMPyP should competitively form peroxycarbonate with sodium carbonate, thus accumulating peroxide in the form of peroxycarbonate. As described above, AlTMPyP itself forms a peroxide complex very efficiently, with the equilibrium constant K 1 =2.0×10 5 m −1 .…”