Investigation on Heterogeneous Catalytic Elimination of Lactones over Supported Magnesium Iodide

The elimination of lactones is a crucial method for preparing corresponding cycloalkane derivatives, but the commonly used catalyst NaI is unstable and non-recyclable. In this work, reusable MgI₂@SiO₂ was prepared for heterogeneous catalytic lactone elimination. Cyclopropyl methyl ketone was synthesized from 2-acetyl-γ-butyrolactone using MgI₂@SiO₂ as a catalyst at 180 °C and 1 atm. The yield and selectivity were both over 99%. The activity of MgI₂@SiO₂ was estimated to be 11 times that of NaI. The high activity of MgI₂@SiO₂ is attributed to the Lewis hard acidity of Mg²⁺ and the soft basicity of I⁻. The high selectivity of Cyclopropyl methyl ketone comes from the faster reaction rate, and its good stability is due to the strong interactions between Mg²⁺ and I⁻ with the carrier. This work provides a feasible scheme for the efficient and low-cost elimination synthesis of corresponding cycloalkanes from lactones.