The jogging motor placed at the bottom of the reactor cartridge is used to maintain a homogeneous and dense magnesium bed. It has been demonstrated in previous work that the use of the jogging motor has a positive influence on the reaction start and yields of Grignard reagent syntheses. The generated vibrations cause abrasion of the passivating oxide layer on the magnesium surface and thus a larger active magnesium surface is accessible for Grignard reagent synthesis. This jogging motor also plays an important role during the initial filling of the reactor cartridge in preparation of the synthesis. Figure depicts the Bodenstein numbers over a flow range of 1 mL/min to 4 mL/min when using a cartridge filled with coarse magnesium turnings and introducing the tracer toluene to a THF-filled reactor cartridge. If the jogging motor is used during filling of the reactor cartridge and during RTD measurements, Bodenstein numbers increase up to a value of 90. In contrast, if the jogging motor is only used during RTD measurements, Bo are lower by about 25 and this behaviour is independent of the chosen flow rate. This behaviour is mainly due to less magnesium turnings being filled in the reactor cartridge when not using the jogging motor during the initial filling. Even though figure shows the results for the coarse magnesium turnings, independent of the size of the turnings around 10 % less magnesium mass fits in the reactor cartridge when not using the jogging motor due to the missing compaction. If the jogging motor is used only for filling the reactor cartridge, Bodenstein numbers are equally low as for the case of RTD measurement only. Since missing compaction and less magnesium mass cannot be the reason for this observation, this indicates that the jogging motor also influences the flow behaviour during RTD measurements. At low volumetric flow rates both effects influence the RTD. This can be observed especially at a flow rate of 3 mL/min compared to 4 mL/min: Using the jogging motor only for filling, mean Bodenstein numbers decrease (46 to 41) while when using it only for RTD measurements mean Bodenstein numbers show a still increasing trend (52 to 56) and in combination of filling and measurement the trend remains almost constant (80 to 81). The decreasing trend in Bodenstein numbers for the case of "filling only" at 3 mL/min to 4 mL/min indicates an increasing influence of the lighter toluene shooting through at increasing volumetric flow rates. In contrast, the cases of using the jogging motor during RTD measurements indicate, that the jogging motor superimposes a transverse movement of the fluid counteracting the axial movement due to the difference in densities. From figure it can be deduced that it is favourable to use the jogging motor for filling with magnesium turnings to ensure compaction and also during the introduction of a fluid of lower density to a fluid of higher density, as it occurs in Grignard reagent synthesis, in which the lighter halide educt solution enters the reactor from the bottom with the higher density Grignard reagent already formed within the reactor cartridge. When using fine magnesium turnings, only few differences between the Bodenstein numbers for using the jogging motor only during filling of the magnesium cartridge or additionally during the residence time measurement are noticeable (figure ). Furthermore, the fluctuations of Bo increase with increasing volumetric flow rate. Both effects are due to the more compact and more homogeneous packing which is possible because of the smaller magnesium turnings.