In collaboration with our Chemical Engineering colleagues we have developed a prototype continuous flow multi-channel microreactor [1] that is also capable of internal surface functionalisation with, for example, a palladium metal to achieve transfer hydrogenation reactions [2]. Simple chemical deposition techniques were used to deposit palladium(0) on the channel wall surface of a polymeric multi-capillary extrudate made from ethylene-vinyl alcohol copolymer. The palladium coating of the microcapillaries was characterized by mass spectrometry and light and electron microscopy.

In other work we present further proof of concept reactions for the CDM using plastic microcapillary flow discs (MFDs) [3]. These flat reactor discs were constructed from a flexible, temperature resilient, solvent resistant fluoropolymer microcapillary film comprising 10 parallel capillary channels. The MFDs can be heated within the microreactor via conductive heat transfer from two heated surfaces, which were in contact with the flat outer surfaces of the disc. This allowed continuous flow processing of liquid phase reactions through the reactor at elevated temperatures and pressures at a precisely controlled residence time. The process characteristics of the reactor system were established experimentally by investigating the hydraulic response and the temperature profile or modeled analytically such that the residence time characteristics inside the device could be predicted. A series of organic chemical reactions, namely electrophilic fluorination and the formation of various mono- and bicyclic heteroaromatic compounds, were conducted in the system at temperatures between 110 and 120 °C.

Publications

1. A microcapillary flow disc (MFD) reactor for organic synthesis
C.H. Hornung, M.R. Mackley, I.R. Baxendale and S.V. Ley
Org. Proc. Res. Dev., 2007, 11, 399-405.

2. A palladium wall coated microcapillary reactor for use in continuous flow transfer hydrogenation
Adv. Synth. Catal. 2010, 352, 1736-1745
C.H. Hornung, B. Hallmark, M.R. Mackley,* I.R. Baxendale and S.V. Ley*

3. Multiple microcapillary reactor for organic synthesis
Ind. Eng. Chem. Res., 2010, 49, 4576-4582
C.H. Hornung, B. Hallmark, M. Baumann, I.R. Baxendale, S.V. Ley, P. Hester, P. Clayton, M.R. Mackley