A. A. Ashlon St. Helens Technical College St. Helens, Lancashire, England
Simple Method for the Preparation of 2,4-Dinitroa~dhe
The standard practical organic textbooks either do not give a procedure for the preparation of 2.4-dinitroaniline from 2,4-dinitrochlorobenzene or state a method which involves gaseous ammonia.' The use of ammonia gas is inconvenient for the preparation by a large class of students because of the limited number of fume hoods and ammonia sources. The author found that 2,4-dinitroaniline could be conveniently prepared by refluxing 2,4-dinitrochlorobenzene in an alcoholic solution with the readily available concentrated ammonia solution.
Procedure. Dissolve 2 g of 2,4-dinitrochlorobenzene in 25 ml of alcohol denatured with methanolz in a 250 ml conical flask and then add 10 ml of ammonia solution (sp gr, 0.880). Connect the flask to a water condenser, the top of which is covered by an inverted 50-ml beaker, and reflux the mixture on a water bath at 80" for two hours. Then add an additional 10 ml of the ammonia solution and continue to reflux for another hour. After removing the flask and cooling the contents, collect the bright yellow crystals with suction and wash them with 5 ml of the cold denatured alcohol. Recrystallize the 2,4-dinitroaniline from a mixture of the denatured alcohol and water. Filter the crystals with suction and dry them below 90'. In this way 1.5 g of product melting a t 178-180' are obtained. l V ~A. ~I., ('A ~ Textbook ~ , of Prsctieal Organic Chemistry," 3rded., Longmans, Green and Co., London, 1956, pp. 638-9. a If readily availeble, ethanol will do.
Volume 40, Number 10, October 1963
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