Convenient and clean synthesis of imines from primary benzylamines

The current syntheses of imines from benzylamines are often performed in organic solvents or under harsh reaction conditions. Clean oxidation of primary benzylamines to imines has been successfully achieved using H2O2 in water at room temperature catalyzed by V2O5. Among the 10 imine products, 5 of them precipitated from the reaction and led pure products after simple filtration. No organic solvents are needed in the whole process. The yields are good to quantitative. This represents an efficient and green procedure of the synthesis of imines. A similar green oxidation of benzylamines to aromatic aldehydes is also reported. A benzylic anion-involved mechanism is proposed based on the experiments.