Synthesis of 6,6′-dibromoindigo (Tyrian Purple)

To a large beaker add 50 g of 4-bromo-2-nitrobenzaldehyde, 1000 mL of water and 1100 mL of acetone, the pH of the solution must be maintained at 10 with 2M sodium hydroxide solution. The suspension must be stirred overnight and then filtered, washed with acetone and water and then dried.


index (1)

Smaller scale setup

index (2)

Sample of the pure product

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