Microfluidic Channels Modified With Collodial Palladium As An Efficient Catalyst For High Throughput Suzuki Coupling Reactions

It is highly desirable to develop a phosphine-free recyclable heterogenous catalytic system without the use of expensive and air-sensitive basic phosphines for palladium-catalysed coupling reactions. Nano-palladium catalysts for example, in various stabilised forms have been extensively explored as potential alternatives to achieve a higher catalytic activity. In line with the great interest directed towards the development of microfabricated chemical systems for a variety of chemical and biological applications, we demonstrate here a microreactor based on microfluidic channels on glass chips for the continous flow organic synthesis using immobilised nano-palladium. The palladium colliods were immobilised on the inner-walls of the microchannels via an intermediate organosilane monolayer. The covalent attachment of colloidal palladium provides minimum leaching of the catalyst. The Suzuki coupling of an aryl halide and an organoboron has been used a model system to investigate the performance characteristic...