For these experiments all parameters that are typically used for the continuous synthesis of benzylmagnesium bromide are applied for the semi-continuous batch experiments. 23 g magnesium turnings (coarse turnings) or 27 g magnesium turnings (fine turnings) are filled into the flask. To this 20 mL (if coarse turnings) or 15 mL (if fine turnings) of the (bromomethyl)benzene/THF solution (0.7 mol/L) are added. This corresponds to the volume of liquid available in the reactor cartridge. After a 10-minute incubation period, the remaining solution (80 mL or 85 mL, respectively) of halide 1/THF solution is added.