Abstract:

In order to bring the concept of green chemistry into basic laboratory teaching and to enhance the exercise on redox reactions, we designed an experiment about the mutual conversion between benzoin and benzaldehyde. In this experiment, benzaldehyde is catalyzed by Vitamin B₁ to be converted to benzoin, then benzoin is reduced with sodium borohydride into 1, 2-diphenyl glycol. Afterwards, the product will be oxidated into benzaldehyde under the catalyzing of new green catalyst NaMnO_x. ¹H NMR was used to authenticate the product in each step of the experiment, and the yield of the oxidation reaction is greater than 90% with HLPC measurement. By completing this cyclic conversion reaction, we conveys the idea of green chemistry to the students, and the students get practice on operating the redox reaction. At the same time, students' cognition and evaluation of chemical reaction can be more complete.

Key words: Green chemistry, Benzoin, Benzaldehyde, Redox reaction, Mutual conversion