Abstract:

In this work, a 12-h comprehensive chemical experiment was designed. Based on the synthesis of Keggin-type polyoxometalate (POM) and the oxidation reaction of benzaldehyde in current textbooks, an amphiphilic two-dimensional material, g-C₃N₄, was introduced to construct a Keggin-type POM@Pickering emulsion microreactor, promoting the efficient oxidation of benzaldehyde and optimally designing the reaction site. Different from the original content, the selection of Keggin-type POM was improved from H₃PMo₁₂O₄₀ to K₃PW₁₂O₄₀. The unique antioxidant properties of K₃PW₁₂O₄₀ can promote the catalytic oxidation reaction. Importantly, the synthesis process of K₃PW₁₂O₄₀ is simple, raw materials are environmentally friendly and easy to obtain, and flammable solvents (such as diethyl ether) are not used. The amphiphilic g-C₃N₄ material with large specific surfaces, the hydrophilic group and conjugated skeleton in its structure, can simultaneously adsorb POM molecules, hydrogen peroxide, and benzaldehyde molecules, promoting the equimolar ratio conversion of hydrogen peroxide and benzaldehyde. The improved experiment is more consistent with the characteristics of "atomic economy" in green chemistry. Moreover, the combination of infrared spectroscopy and thin layer chromatography detection technologies can strengthen the integration of theoretical learning and practical operation. This work embodies the development of outcome based education (OBE) education for the cultivation of creative talents by introducing the frontier research into undergraduate experimental teaching, which is conducive to cultivate innovative consciousness of students and to improve their ability of comprehensive analysis and solving practical problems.

Key words: Potassium tungstophosphate, g-C₃N₄, Pickering emulsion, Green chemistry, Benzaldehyde oxidation