Triphase hydrogenation reactions utilizing palladium-immobilized capillary column reactors and a demonstration of suitability for large scale synthesis

We have developed a practical and highly productive system for hydrogenation reactions utilizing capillary column reactors, which occupy less space than ordinary batch systems, are low cost and easy to handle, and show feasibility toward largescale chemical synthesis. Palladium-containing micelles were immobilized onto the inner surface of the capillaries. Nine palladium-immobilized capillaries were assembled and connected to a T-shaped connector, and hydrogen and a substrate solution were fed to capillaries via the connector. Hydrogenation of 1-phenyl-1-cyclohexene (1) proceeded smoothly to give phenylcyclohexane in quantitative yield. ne capillaries themselves occupy only ca. 0.4 mL and a high space-time yield has been achieved (124.3 mg/17 min/0.4 mL). In addition, leaching of palladium was not detected by ICP analysis after reactions.