Abstract: The preparation and reactions of Grignard reagents constitute fundamental experiments in organic chemistry laboratory courses. However, the conventional experiment involving the preparation of n-butyl Grignard reagent from 1-bromobutane and magnesium turnings, followed by its addition to acetone to yield 2-methylhexan-2-ol, fails to demonstrate the compositional and structural complexity of Grignard reagents and their impact on reactivity. In this study, we present a modified experimental design using existing materials, where student groups prepare n-butyl Grignard reagents in different ethereal solvents. These reagents, along with di(n-butyl)magnesium, are then reacted with styrene oxide to produce distinct products. Students analyze the resulting products through ¹H-nuclear magnetic resonance (¹H-NMR) spectroscopy and comparison with reference standards to determine product structures and distributions. By examining these experimental results and studying the Schlenk equilibrium through self-directed learning, students gain insights into the compositional complexity of Grignard reagents and the significant influence of Lewis acidic MgX₂ on their reactivity due to the Schlenk equilibrium. This research-oriented modification not only reinforces fundamental skills in air- and moisture-free synthesis but also enhances students’ abilities in molecular structure analysis and experimental methodology, thereby stimulating their scientific curiosity and fostering innovative thinking.

Key words: Grignard reagent, Improved experiment, Schlenk equilibrium, Property investigation, Styrene oxide