Abstract:

The free radical reaction is a key point and a challenge in the environmental chemistry course. To achieve a good teaching effect, this study uses quantum chemical calculation combined with three-dimensional visualization graphics to demonstrate the single-electron process in free radical reaction by "spin density" index. We optimize and adjust the content and the form of teaching according to the specific status of students and teachers. Firstly, the electronic structure of hydroxyl radical was analyzed by molecular orbital theory, and the concepts of spin density, single electron and semi-filled orbital were clarified. Secondly, the classical free radical reaction was tracked by visualizing the spin density. Finally, a relationship between spin density and electrostatic potential was established to deepen the understanding of environmental free radical processes. Integrating organic chemistry with modern chemical theory endows the environmental free radical reaction with deeper connotation, provides more "handles" for research or operation, improves students' interest in learning, harmonizes the relationship between teachers and students, and achieves the expected teaching objectives.

Key words: Electron spin density, Free radical reaction, Hydroxyl radical, Electrostatic potential, Environmental pollutants, Migration and transformation