DNEU

melting point ? °C	boiling point ? °C	DNEU	molecular mass ? g/mol	density ? g/mL
table key	sensitivity ?	chemical formula X₂Y₃Z₄	explosive velocity ? m/s	estimated cost $?.00 /g

DNEU, an acronym for N,N’-dinitroethyleneurea, is a fairly stable insensitive high explosive. Other names include 2,5-dinitro-2,5-diazacyclo-1-pentanone; and 1,3-dinitro-2-imidazolidone. DNEU has been used as a booster charge, as a base charge in blasting caps, and an ingredient of detonators. It has excellent resistance to mechanical shock, a property that makes it valuable in detonators. It was first prepared in 1888, but its commercial development was not researched until WWII. While this is a powerful high explosive in its own right, DNEU is frequently used as an intermediate in the production of the explosive EDNA. Its use in preparing EDNA resulted in more economical modes of synthesis.

CHEMICALS APPARATUS

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Synthesis 1: Prepare an acid mixture consisting of 68.5 g of sulfuric acid, 22g of nitric acid, and a total of 9.5 g of water. This does not mean add 9.5 g of water to 70% nitric acid, this means the water present in 95-99% acid should be taken into account for the 9.5 g total. Cool the acid mixture in an ice bath to below 10 C. Slowly add, with stirring, 10 g of ethyleneurea while keeping the temperature under 10 C. After the addition is complete cool the mixture to under 2 C, and hold it there for 2 hours. Pour the reaction mixture into a large volume of cold water to drown out the acid. Pour this solution over a filter to collect the product and wash it thoroughly with ice cold water to remove all traces of acid. Synthesis 2: Prepare a solution of 4.99 g of ethyleneurea in 85 mL of chloroform. Prepare a second solution by dissolving 47.2 g of nitrogen pentoxide in enough chloroform to make 250 mL. Chill the pentoxide solution to -4 C by immersing in a salt-ice bath. Slowly add the ethyleneurea solution to the pentoxide solution with stirring. Some product should begin to precipitate immediately. There will be a rise in temperature, but it should not be allowed to exceed 17 C. Allow the reaction to proceed for 30 minutes after the addition is complete while keeping the temperature below 17 C. Pour the mixture over a filter to collect the product, and wash thoroughly with ice cold water to remove all traces of acid. After the final product has been collected the remaining waste filtrate can be recycled and used again. Do not combine the water wash with the solvent filtrate. The main byproduct is nitric acid as water formed during the reaction combines with nitrogen pentoxide. The filtrate also contains some unreacted ethyleneurea. The nitric acid can be partially reconverted to nitrogen pentoxide by stirring the filtrate with a portion of phosphorus pentoxide. This will produce phosphoric acid as a byproduct, which is insoluble in chloroform and can be removed in a separatory funnel. A subsequent reaction can then be performed using the filtrate with only fresh nitrogen pentoxide and ethyleneurea being used, not more chloroform. Alternatively the nitric acid can be removed from the filtrate by distillation.

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