OBINNA OKAFOR^1,2, RUTH GOODRIDGE¹, VICTOR SANS^{1, 2}*
*Corresponding author
1. Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom.
2. GSK Carbon Neutral Laboratory, University of Nottingham, Nottingham, United Kingdom

Abstract

The employment of Additive Manufacturing (AM) to produce compact continuous-flow reactors with mixing channels embedded with static mixers that allow advanced mixing capabilities has the potential to redefine many industrial synthetic processes. The freedom of design and the possibility of fabricating complex devices in a simple and inexpensive fashion, unique features of AM, enable the fabrication of highly efficient mesoscale reactors, which will open new avenues in process intensification in continuous-flow reactor engineering. AM techniques available for the production of advanced mesoscale flow reactors are discussed, also outlining benefits of its used in areas such as nanoparticle synthesis and in catalytic applications.

INTRODUCTION
Additive Manufacturing (AM) is emerging as a novel and powerful set of technologies that can produce devices with complex geometries (1). Recently, the possibility of employing AM/3D printing to manufacture small chips for continuous-flow synthesis has been reported by Kitson et al (2). Since then, numerous applications have been reported, mostly focused on microfluidic applications (3-5). This is of great interest for developing applications in sensing and biology, but the small dimensions represents a limitation in terms of the productivity that can be achieved (6). Mesoscale flow reactors offer the potential to bridge the gap between microreactors, primarily diffusion based, and macro reactors where the mixing is largely dependent on turbulent flow generated at high Reynolds numbers.  Both microscale (less than 1mm ID) and mesoscale reactor (scale between micro and macro-reactors, in the order of millimetres) share the advantages of process control compared to batch processing. The superior control of temperature, pressure, mixing and residence time leads to minimised reagent waste, an increase in selectivity and higher space time yields tha ...