The reactor used for residence time distribution measurements is the same reactor used in part 1. It is a laboratory-scale reactor designed by Fraunhofer IMM and manufactured via 3D laser melting for the formation of organometallic halide reagents. Figure displays the reactor in more detail. It consists of a reactor cartridge and a magnesium replenishing unit that can be attached to the main reactor body for replenishing magnesium turnings during Grignard reagent synthesis. The reactor is charged with magnesium (Mg) turnings (23 g for coarse magnesium turnings, 27 g for fine turnings) while the jogging motor at the bottom of the reactor is running (9 V). An inert atmosphere in the reactor is realized with argon. Four thermocouples are placed along the magnesium bed for temperature monitoring. Before starting the synthesis, the reactor is purged for 30 minutes by an argon flow, while the magnesium bed is compacted due to vibrations generated by the jogging motor and the reactor cartridge is already tempered. Subsequently, the reactor is filled with a solution of educt halide in tetrahydrofuran (THF) at an elevated flow rate. This leads to a temperature increase resulting from the initiation of the exothermic reaction. As soon as the reactor is completely filled with educt solution, the pump is turned off and the reactor content is allowed to rest for 10 minutes for initial formation of Grignard reagent and further activation of the magnesium turnings. Afterwards, the pump is turned on again, recording of measured temperatures is started and the flow rate is reduced compared to the initial filling step of the reactor to keep temperatures below the solvent's boiling point. To accelerate the start of the reaction, an elevated temperature of 50°C is set. After waiting for about three residence times, samples from the outlet solution are taken and titrated by thermometric titration to determine the Grignard reagent concentration. Samples are quenched with methanol as well and analysed with GC measurements to determine byproduct concentration and residual halide educt concentration. Depending on the concentration of the halide used, portions of magnesium turnings are replenished in regular time periods (about 30 min) to keep the magnesium mass as constant and equal as possible for the individual residence time measurements. In case of residence time measurements, the magnesium is replenished in between two runs to avoid disturbance of the measurement and the flow behaviour. Specific reaction conditions for investigated Grignard reagents are summarized in table .