Tartrazine → 8-(5-Amino-o-toluenesulfonamido)-1,3,6-naphthalenetrisulfonic acid

Participants

Reaction Steps

A mixture of 20.0 g of 8-(5-nitro-o-toluenesulfonamido)-1,3,6-naphthalenetrisulfonic acid, trisodium salt, 90.0 ml of water and 2.0 g of 10% palladium on carbon catalyst is hydrogenated as described in Example 1. The reaction mixture is filtered through diatomaceous earth and the filtrate is evaporated. The residue is dissolved in a minimum amount of water, then is added dropwise to 800 ml of stirred absolute ethanol. The mixture is stirred for 2 hours and allowed to stand for 48 hours. A light yellow solid is collected, washed with ethanol and ether, then is dried to yield 15.0 g of 8-(5-amino-o-toluenesulfonamido)-1,3,6-naphthalenetrisulfonic acid, trisodium salt.

Provenance & Evidence