Effect of water on the heck reactions catalyzed by recyclable palladium chloride in ionic liquids coupled with supercritical CO2 extraction

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.