Sulfuric Acid → Sulfuric acid--aniline (1/1)

Participants

Reaction Steps

A 5 liter flask surrounded by an ice bath is charged with 300 grams of ice and 50 grams of water. The mixture is stirred and 130 grams of sulfuric acid 96% is added, followed by 100 grams of aniline, and a white dispersion of aniline sulfate is formed. The mixture is then cooled by ice addition to −5° C. and diazotized below 3° C. by the addition of 190 grams of a 40% aqueous sodium nitrite solution. The mixture is stirred until all white specks of aniline sulfate have dissolved into a clear solution. After an approximate five minute stir, unreacted nitrite ion is eliminated by the addition of small amounts of sulfamic acid. To the diazo, 140 grams of 2 methoxy 5 methylaniline is added, while the temperature is allowed to rise to 5–10° C. After 15 minutes of stirring, a sufficient volume of a 30% solution of sodium acetate is added to raise the pH of the reaction to 3.5. The reaction is stirred for 4 hours at 10–12° C. allowing for the essentially complete azo coupling. Next, 600 grams of xylene is now added followed by 110 grams of concentrated sulfuric acid. After a few minutes of stirring, the aminoazo compound is diazotized at 20–25° C. by the addition of 200 grams of a 40% sodium nitrite solution. A positive test for nitrite is maintained for 10 minutes then eliminated with sulfamic acid.

Provenance & Evidence