A Three Step Synthesis of Benzoyl Peroxide

Benzoyl peroxide is used as a bleaching agent for flour and whey processing, a polymerization initiator in the synthesis of plastics, and the active component of acne medication. Because of its simplicity and wide application, benzoyl peroxide is a target molecule of interest. It can be affordably synthesized in three steps from bromobenzene using procedures that can be performed in four, four hour laboratory periods. This process includes a Grignard reaction to turn bromobenzene into benzoic acid, nucleophilic acyl substitution to transform the resulting carboxylic acid into an acid chloride, and the addition of H2O2 to the acid chloride to yield benzoyl peroxide. Most organic students are familiar with these traditional reaction mechanisms because they are covered in introductory organic chemistry courses. The starting materials for each reaction are commercially available and the products can be readily characterized using NMR, IR, and melting point.