Six candidate mixer designs were studied based both on evidence in the literature of their performance at low flow rates, and potential for scaling down. These are listed in Table and were incorporated into the test system described in Figure . Noting that residence times on the order of tens of seconds are typically used to pre-cool reaction streams in aryllithium chemistry, we used a precooling loop residence time of 20 s for each input solution for this arm of the work. Where practically possible, residence times for the lithiation and trapping stages were kept constant at 1 s and 2 s respectively. For each mixer, the relative ratios of products derived from the lithiation of bromoanisole 1 (i.e. alcohol 3 formation and dehalogenation to 4) were assessed as a way to determine conversion of bromoanisole a) Blockage or pump stall occurred at all flow rates. b) Lithiation residence time was 2 s, due to the set length of the mixing channel. c) Assignment based on λ max = 270 nm observed in UV spectrum matching that of the literature and comparison with an authentic sample. d) Determined through integral ratios of aryl -OCH 3 signals. Anisole 4 was not detected in any of the reaction mixture samples processed for 1 H NMR analysis. We believe that the discrepancy between the HPLC and NMR data is in part due differences in sample preparation: direct sampling of reaction mixtures into a diluent was used for HPLC analysis, in contrast to NMR analysis where samples were concentrated under reduced pressure leading to leading to the potential loss of anisole 4 by evaporation.