Interox Chemicals Limited

Graham V Hutson

Kenneth T Rowbottom

Terence M Conboy

John N Wilkinson

Alkyl phosphates, undiluted or dissolved in hydrophobic solvents can be destroyed in situ by reaction with hydrogen peroxide in the presence of certain transition metal catalyst systems. The invention catalyst system comprises a chromium compound, which dissolves in the aqueous phase, typically an alkali metal chromate, which is employed in conjunction with introduction of an alkali, preferably sodium hydroxide, or in the presence of an alkali buffer to keep the pH of the aqueous phase within a window spanning mildly acidic to mildly alkaline pH during the course of progressive introduction of the hydrogen peroxide, which often lasts from 3 to 10 hours, thereby enabling the oxidation of the alkyl phosphate to continue. The reaction is preferably carried out at a temperature of at least 60.degree. C., and particularly at about 65.degree. to 75.degree. C., or at about the boiling point of the aqueous phase. The window becomes somewhat wider as the reaction temperature increases, the term mildly acidic indicating a pH of at least about pH 6 at around 70.degree. C. to at least pH 5 at around 100.degree. C. Preferably, the solution is maintained at a pH of from 6.5 to 7.5.

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Seascale, United Kingdom

Graham V Hutson