Optimal conditions for maximising the formation of product were found to be 1.2 ml min -1 liquid flow rate of a 20 mM solution of 1•PMDETA, with 2.4 ml min -1 gas flow-rate of HCF3 at 2.5 bar forming 2 in 74 % yield, corresponding to a production rate of 1.1 mmol h -1 . With a space-time yield of 0.27 mol l -1 h -1 this corresponds to a 10-fold increase from the previously reported batch conditions. A multi-response model was then fit using productivity, solvent usage, and calculated gas destruction to accurately predict within experimental error the optimal process conditions. The optimal process conditions were found to be a 2.0 ml min -1 liquid flow-rate of a 110 mM solution of 1•PMDETA, 2.5 ml min -1 gas flow-rate of HCF3 at 3.1 bar forming 2 at a predicted 53 % yield (Figure ). These conditions were tested on a 3 g scale to give a confirmed 51% in situ yield corresponding to a production rate of 6.7 mmol h -1 , and space-time yield of 1.5 mol l -1 h -1 . Comparison of these optimal process conditions to those in batch reveals a dramatic reduction in solvent use (74 ml mmol -1 in batch; 18 ml mmol -1 in flow) and equivalents of HCF3 required (7 equiv. in batch; 1.4 equiv. in flow), with a 56-fold improvement in spacetime yield (0.026 mol l -1 h -1 in batch; 1.5 mol l -1 h -1 in flow).