To a clean, dry 125-mL Erlenmeyer flask and magnetic stir bar, add 3 grams of 2,4-dintrophenylhydrazine, 20 mL of water and 70 mL of 95% ethanol. Place the flask in an ice bath in a beaker. Stir and allow the mixture to cool. When the temperature reaches 10 °C, with continued rapid stirring, begin the slow addition of 15 mL concentrated sulfuric acid, trying to avoid boiling. If the temperature goes above 20 °C, stop addition until the temperature goes back to 10 °C. When the sulfuric acid has been added, turn off the stirrer, remove the ice-bath and place the flask on a stirrer-hotplate. Stir and warm the flask until the 2,4-dintrophenylhydrazine stops dissolving or the temperature reaches 60 °C, whichever comes first, then continue stirring without heating. When the solution has cooled, filter through a fritted funnel, if necessary.

Hazards

2,4-Dinitrophenylhydrazine [119-26-6] is a flammable solid, which must be kept moist and is harmful if swallowed, inhaled, or absorbed through the skin. Concentrated sulfuric acid [7664-93-9] is poisonous and corrosive. Its mist can cause severe burns to all body tissue. It may be fatal if swallowed or by skin contact. It is harmful if inhaled and may cause cancer. Ethanol [64-17-5] is flammable and should be kept from ignition sources. Eye and face protection, protective clothing, and gloves must be worn.

Literature Cited

1. Linstromberg, W. W.; Baumgarten, H. E. Organic Experiments, 6th ed.; Houghton Mifflin: Boston, 2002; p 175. Shriner, R. L.; Hermann, C. K. F.; Morrill, T. C.; Curtin, D. Y.; Fuson, R. C. The Systematic Identification of Organic Compounds, 8th ed.; Wiley; Hoboken, NJ, 2004; pp 278–279.