| abstract |
A stable antimicrobial aqueous hypochlorous acid solution that retains its activity for at least three months and can be provided with high levels of hypochlorous acid (more than 500ppm), the aqueous hypochlorous acid composition having low chloride concentrations (maximum chloride levels of 1:3 chloride to hydrochlorous acid) and a pH between 3.5 and 7.0, preferably between 5.5 and 6.5, to stabilise the composition without the need for additional stabilisers. Also claimed is a process for the preparation of an aqueous solution of hypochlorous acid comprising the steps of adding chlorine to calcium hydroxide to provide a solution of calcium hypochlorite, calcium chloride and water, removing the calcium chloride in solution to provide solid calcium hypochlorite, dissolving the calcium hypochlorite in water to provide an alkaline solution of calcium and hupochlorite ions, precipitating calcium as calcium hydroxide to enable subsequent removal, adjusting the pH of the resultant solution of hypochlorite ions to around 5-6 to precipitate any remaining calcium to enable its subsequent removal and adjusting the pH of the solution of hypochlorous acid to a pH of between 3.5 and 7. |