At a set residence time, flow rates can be lowered to minimise reactor volume and thus the starting material lost at the end of a synthesis to the internal volume of a reactor (defined here as the sum total of the volumes of any component through which any reagent or product mixture flow) and is particularly relevant at low injection volumes (defined here as the volume of the aryl halide stock solution that is pumped into the reactor prior to the system being stopped). However, reductions in flow rate need to be considered in context; successful flash flow chemistry relies on rapid, complete mixing. The extent of mixing depends on (but is not limited to) the flow rates of the incoming reaction streams and the efficiency of a given mixing element placed at or after the junction between reagent streams. So as to mitigate the lowered mixing quality associated with a lower flow rate then, a judicious choice of mixing elements is crucial in work towards a flash flow reactor which is effective at low flow rates.