To generate a reference data set, initial reaction conditions for semi-continuous batch experiments are taken from a reference book and the indicated quantities are halved, resulting in a total liquid volume of 117.19 mL and a bromomethylbenzene concentration of 2.13 mol/L Tetrahydrofuran is used instead of diethyl ether, as this solvent is also used in further Grignard reagent syntheses, resulting in a different boiling point (66°C instead of 35°C). However, the flask is tempered at 35°C, which corresponds to the boiling point of the diethyl ether and thus allows comparability with the literature reaction conditions. Coarse magnesium turnings (6.075 g) are filled into the flask, poured over with 25 mL THF and 1.48 mL of (bromomethyl)benzene is added while stirring. After initiation of the reagent formation, the remaining halide 1 (28.21 mL), dissolved in 62.5 mL of THF is added. Cooling in an ice bad is applied when boiling is too vigorously.