Interox Chemicals Limited

David Smith Horne

Robert Eric Talbot

Peter John Russell

Joseph E McCrudden

Alan E Comyns

Alan Smith

Alan Prodgers

The invention provides bleaching and detergent compositions containing a diacyl peroxide of general formula ROOR.sup.1 in which R represents a phthaloyl radical and R.sup.1 a radical such that ROOR.sup.1, ROOR and R.sup.1 OOR.sup.1 are all soluble in mildly alkaline aqueous solutions. The compositions, optionally containing a persalt such as sodium perborate, preferably in a mole ratio of one mole per mole of diacyl peroxide, are particularly suitable for washing or bleaching at a temperature of from 30.degree.- 60.degree. C. The invention also provides diacyl peroxide compositions desensitized to impact or abrasion by intimate contact with a diluent, e.g. magnesium sulphate, lauric acid or sodium tripolyphosphate and protected against destructive interaction with other components of the bleaching on detergent composition during storage. Preferred diacyl peroxides include diphthaloyl peroxide, especially for colored fabrics.

Bleaching composition

The present invention provides a process for making diphthaloyl peroxide by reacting phthalic anhydride with aqueous hydrogen peroxide at a pH controlled to between pH 8 and 10, preferably pH 8.8 to 9.2 and a low temperature preferably maintained at 0.degree. to 5.degree. C, and thereafter removing diphthaloyl peroxide from solution, suitably by acidification and filtration. Preferably excess solid phthalic anhydride is employed and is filtered out before the solution is acidified. Desirably the concentration of active oxygen species is maintained at below 0.3 moles/liter. Diphthaloyl peroxide is particularly suitable for bleaching/washing fabrics, optionally in conjunction with an inorganic persalt e.g. sodium perborate, at a temperature of from 30.degree. to 60.degree. C.

Preparation of a peroxide

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Warrington, United Kingdom

David Smith Horne