Impact of residence time distributions in reacting magnesium packed beds on Grignard reagent formation - pump-induced flow behaviour in non-reacting magnesium beds (part 1)

Grignard reagent formation in continuously operated magnesium packed-bed reactors can be influenced by fine tuning the residence time distribution within the magnesium packing. By decreasing the magnesium turning size and increasing the packing density, narrower residence time distributions and therefore improved Bodenstein numbers can be obtained. The utilized pump system and its induced flow behaviour also have an impact on the residence time distributions in packed-bed reactors. By using oscillatory flow rates instead of pulsation-free pumps, Bodenstein numbers within a magnesium filled reactor cartridge can be increased by 25% for fine magnesium turnings and by 70% for coarse magnesium turnings, resulting in minimized backmixing and approaching plug flow behaviour.