Catalytic oxidation of benzoin by green chemistry

Based on the concept of green chemistry,three complexes of N,N′-Bis(salicylidene) ethylenediamine metal [M(Salen)](M=Co,Cu,Zn) were synthesized.Using these complexes as catalysts,benzil was synthesized by the oxidation of benzoin in air atmosphere.The results showed that the catalytic efficency of Co(Salen) was the best.Benzil could be obtained in highest yield(78%) at 80 ℃(the reaction time is about 45 min) by this method.All of the catalysts could be recycled and reused for three times.This method has many advantages such as: low cost,short reaction time and reduced emission of waste water.Furthermore,a new way of the oxidation of benzoin by green chemistry was opened up.