To synthesize 2,5-dibromopyridine, follow these steps:
Add 2-amino-5-bromopyridine (13.0 kg) into a water-cooled solution at 10 °C.
Slowly add 47% aqueous hydrogen bromide (37 L) to the mixture.
Introduce liquid bromine (11 L) into the mixture.
Maintain the reaction temperature below 10 °C.
Prepare a solution of NaNO2 (16.1 kg) and H2O (19 L) and add it dropwise to the mixture while keeping the temperature between 0-5 °C.
Stir the reaction mixture for 30 minutes.
Treat the mixture with a solution of NaOH (28.0 kg) in water (30 L) at a controlled rate below 20-25 °C.
Extract the reaction mixture with diethyl ether (3 × 40 L).
Dry the organic layer with anhydrous Na2SO4.
Remove the desiccant by filtration.
Evaporate the resulting filtrate under reduced pressure to dryness.
Suspend the residue in heptane (10 L).
Collect the target product molecule, 2,5-dibromopyridine, by filtration.
Synthesis method of 2,5-dibromopyridine