Effect of Water on the Heck Reactions Catalyzed by Recyclable Palladium Chloride in Ionic Liquids Coupled with Supercritical CO₂ Extraction

Abstract

The Heck coupling of iodobenzene with olefins occurs with high efficiencies at low temperatures in imidazolium-based ionic liquids catalyzed by PdCl2/Et3N, and the catalyst can be recycled after extraction of the products by supercritical CO2. The coupling efficiency is dependent on water content of the ionic liquid. With a low water content (<50 ppm) in the ionic liquid, the Heck coupling reaction would proceed with >90% yield at room temperature using this catalytic system.