Sustainable Styrene Synthesis via the Aerobic C–H/C–H Coupling of Benzene and Ethylene Using a Polymer-Supported 2-Hydroxypyridine-Pd Catalyst

This study reports a polymer-supported palladium catalyst featuring 2-hydroxypyridine ligands, enabling the direct synthesis of styrene from benzene and ethylene via C–H/C–H activation. Molecular oxygen is used as a sustainable oxidant, aiming to circumvent the harsh reaction conditions and step inefficiency of the 2-step industrial production of styrene. The reported approach enables facile catalyst recovery and reusability, resolving the limitations of related homogeneous C–H activation catalysts. The support material features an easily synthesizable 2-hydroxypyridine ligand incorporated into a highly cross-linked polyacrylate backbone. Advanced characterization techniques, including XAS and electron microscopy supplemented with EDX, were employed to elucidate the active single-atom palladium catalyst, ligand, and polymer support. The catalyst demonstrated a high catalytic performance, reaching over 290 TOs toward styrene at a high styrene selectivity (>91%) and was shown to be reusable at least 5 times with no detected leaching.