Ambient Pressure Ir@Hal-Catalyzed Hydrogenation of Aryl Aldehydes, Ketones, and Phenol.

A reliable method for encapsulation of iridium nanoparticles (6-8 nm particles) in halloysite Ir@Hal has been developed. The Ir@Hal nanocomposite was found to be a highly efficient catalyst for the hydrogenation and transfer hydrogenation of the carbonyl group of aryl aldehydes, aryl ketones, and aliphatic ketones to afford alcohols in high yields. In addition, phenol could be hydrogenated to furnish cyclohexanol (93-95% yield) at ambient pressure at 50 °C. Further, the catalyst was easily recovered and recycled without significant loss of catalytic activity over multiple trials.