Hydrochloric Acid → Disodium

Participants

Reaction Conditions

Reaction Steps

A solution of 12.0 g of 2-amino-5-nitrobenzenesulfonic acid sodium salt and 3.5 g of sodium nitrate in 80 ml of water is added to a mixture of 125 ml of crushed ice, 12.5 ml of concentrated hydrochloric acid and 25 ml of acetic acid in an ice-salt bath. The mixture is stirred for approximately 15 minutes then 15.2 g of sodium trihydrate in 25 ml of water is added. This is followed almost immediately by a solution of 14.5 g of 6-amino-4-nitro-2-naphthalenesulfonic acid, sodium salt in 100 ml of water. The mixture is allowed to cool to 0° C and is filtered and washed with a 33% aqueous solution of sodium acetate trihydrate, then with ethanol and ether to give 6-amino-4-nitro-5-(4-nitro-2-sulfophenylazo)-2-naphthalenesulfonic acid, disodium salt, a dark brown powder, as the product.

Provenance & Evidence