Chemistry of sulfate chloride perhydrates. Part 2.—Reperhydration by H2O2

Abstract

The perhydrate, 4Na₂SO₄ NaCl2H₂O₂ , has been heated in order to fully desorb the H₂O₂ . The resulting powder [an intimate mixture of Na₂SO₄(III) and NaCl] was exposed to the vapour above a solution of H₂O₂ . Two mechanisms are observed for the regeneration of the perhydrate: at high concentrations of H₂O₂ (>0.60 g cm^–3), direct reaction between the powder and the gaseous H₂O₂ occurs; at concentrations <0.60 g cm^–3 , the powder becomes wet and the Na₂SO₄ phase (III) transforms into phase (V). Regeneration into the perhydrate then proceeds by crystallisation of the perhydrate from the slurry of Na₂SO₄(V) and NaCl. The two mechanisms occur together at intermediate concentrations of H₂O₂.