US Patent 7049467 Process for the manufacture of isobutyric anhydride

This process for the manufacture of isobutyric anhydride by reacting acetic anhydride with isobutyric acid, distilling the acetic acid generated as it is formed, is characterized in that the reactor is initially loaded with at least a portion of one of the reagents and a portion of the other such that the reagents are in an excess molar ratio relative to the stoichiometry of one of the reagents, and the reaction is carried out while adding the remainder of the reagents as the reaction progresses and according to the place left free in the reactor by the distillation of the acetic acid produced by the reaction, until the desired overall molar ratio of the reagents is reached.