Peroxyester preparation method

摘要

The present invention relates to a process for the preparation of a peroxyester which can be used in particular in polymerizations, such as the polymerization of vinyl chloride, or in the thermosetting of polyester resins. This process comprises the reaction of a hydroxyhydroperoxide salt with an acid halide or an acid anhydride under the following conditions: the molar ratio R_b of the hydroxyhydroperoxide corresponding to the hydroxyhydroperoxide salt to the acid halide is between 0.5 and 1.5; or alternatively the molar ratio R_b' of the hydroxyhydroperoxide corresponding to the hydroxyhydroperoxide salt to the acid anhydride is between 1.0 and 3.0; the hydroxyhydroperoxide salt was prepared beforehand by reaction of the corresponding hydroxyhydroperoxide with a base according to a molar ratio R_a of the base to the hydroxyhydroperoxide of between 0.5 and 1.5; and this process is carried out in aqueous media. The invention also relates to an aqueous emulsion comprising the peroxyester obtained and to a polymerization process employing a radical initiator comprising this peroxyester.