Hydrochloric Acid → HCID 136355258, compound

Participants

Reaction Steps

1.6 g (5 mmol) of the compound from Step 9.3 was dissolved in 20 mL of water and 1.7 g of hydrochloric acid (32%) and to the solution was added dropwise with agitation, in an ice bath, 0.35 g (5 mmol) of sodium nitrite in 2 mL of water. The mixture was allowed to agitate in the ice bath for an additional 30 minutes after which a few drops of 10% sulfaminic acid solution was added and the mixture was poured into a solution of 0.72 g (5 mmol) of 2-naphthol in 8 mL of isopropanol. The pH was then increased to 9 by addition of saturated sodium carbonate solution which resulted in the formation of a brown solution. After 30 min, the mixture was neutralized by addition of 2-normal hydrochloric acid and, to isolate the dye, evaporated to dryness in a rotary evaporator. The residue was then taken up in 80 mL of methanol, the inorganic salts were filtered off and the solution was concentrated to a total volume of about 10 ml. The addition of about 30 mL of isopropanol caused the dye to precipitate.

Provenance & Evidence