Method for preparing small sized benzoyl peroxide crystals

Abstract

A method for the preparation of benzoyl peroxide in crystalline form, which crystals may range in size below 10 microns, comprises forming a first solution of the benzoyl peroxide in a precipitate promoting material, adding the first solution to a second solution comprising an aqueous solution of a dispersant, to precipitate the benzoyl peroxide in the desired crystalline form, and finally recovering the crystalline benzoyl peroxide from the first and second solutions. The precipitate promoting material may be selected from sulfur-containing aliphatic ethers, long-chain aliphatic and araliphatic ethers, ethylene oxide derivatives, and mixtures thereof. The dispersant may be selected from cellulosic derivatives, anionic surfactants, nonionic surfactants, colloidal inorganic materials, and mixtures thereof. The present method may be performed at room temperature and is therefore safe and energy conservative. The resulting benzoyl peroxide crystals are of desirably reduced size, and are particularly well suited for incorporation into commercial cosmetic and pharmaceutical preparations.

Dependencies are inferred from the claim text.