The Beckmann rearrangement is an organic reaction that converts a ketoxime to an amide under acidic conditions. The reaction is named after its discoverer, Ernst Otto Beckmann, who first reported it in 1886. The mechanism of the Beckmann rearrangement involves the following steps:1. Protonation of the ketoxime: The reaction starts with the protonation of the oxygen atom of the ketoxime under acidic conditions. This step generates a resonance-stabilized oxonium ion.2. Migration of the R group: The R group alkyl or aryl adjacent to the nitrogen atom migrates to the nitrogen, resulting in the formation of a nitrilium ion. This migration step is the key step in the rearrangement, and it involves the breaking of the C=N bond and the formation of a new C-N bond.3. Hydrolysis of the nitrilium ion: The nitrilium ion is then hydrolyzed under acidic conditions to form the corresponding amide.4. Deprotonation of the amide: Finally, the amide is deprotonated to give the neutral amide product.To illustrate the Beckmann rearrangement, let's consider the conversion of cyclohexanone oxime to -caprolactam, which is an important industrial process for the production of Nylon-6.1. Cyclohexanone oxime is protonated under acidic conditions to form a resonance-stabilized oxonium ion.2. The migration of the alkyl group cyclohexyl from the carbon to the nitrogen atom occurs, forming a nitrilium ion.3. The nitrilium ion is hydrolyzed to form -caprolactam, which is still protonated.4. Deprotonation of -caprolactam gives the final neutral -caprolactam product.In summary, the Beckmann rearrangement is a useful reaction for converting ketoximes to amides, and it proceeds through a series of protonation, migration, hydrolysis, and deprotonation steps. The reaction has significant industrial applications, such as the production of Nylon-6 from cyclohexanone oxime.