Patent GB-592240-A (GB)
Title: Improvements relating to the production of dinitroethyleneurea
IPC: C06B25/34
Filed: 1945-01-05
Abstract: Nitric acid is formed in the nitration of ethyleneurea to dinitroethylene urea by means of nitrogen pentoxide in an inert non-aqueous solvent (see Group IV) and may be removed substantially as fast as it is formed by means of a reagent which will react with the nitric acid but not with the nitrogen pentoxide, being itself insoluble in the solvent and giving insoluble reaction products. Specified reagents are phosphorus pentoxide which reacts with nitric acid yielding 1 nitrogen pentoxide and meta-phosphoric acid and the fluorides of sodium, potassium, ammonium, zinc and magnesium which form nitric acid adsorption complexes.  Specifications 588,012 and 592,219 are referred to.ALSO:Dinitroethylene urea is prepared by reacting ethylene urea with nitrogen pentoxide dissolved in an inert non-aqueous solvent. Preferably, the solvent is one in which ethylene urea and nitrogen pentoxide are soluble and the product insoluble. The ethylene urea may be added to a solution of nitrogen pentoxide in a solvent which dissolves the ethylene urea but not the nitrated product which is thus precipitated.  This process may be operated in a continuous manner by continuously adding ethylene urea, if desired in solution, to the nitrating solution in a reaction zone following which the mixture is transferred to a filtering zone and the nitrated product separated; the nitrating solution may be intermittently or continuously refortified with nitrogen pentoxide and returned to the nitration zone.  Alternatively, the ethylene urea and nitrogen pentoxide may be continuously introduced in the correct proportions into a similar solvent in a mixer and the nitrated product separated at the bottom as a precipitate.  A suitable solvent for these methods in which the nitrated product is insoluble is chloroform.  If desired, the nitric acid liberated in the reaction may be removed substantially as fast as it is formed by conducting the process in the presence of a reagent which reacts with the nitric acid but which does not react with nitrogen pentoxide, being itself insoluble in the solvent and giving insoluble reaction products, for example phosphorus pentoxide and the fluorides of sodium, potassium, ammonium, zinc and magnesium.  Phosphorus pentoxide reacts with the nitric acid to form nitrogen pentoxide and metaphosphoric acid while the fluorides form an adsorption complex.  The nitrating solution may be contacted with phosphorus pentoxide batchwise or in continuous operation and preferably, the nitrated solution is circulated first through a mixing zone with the ethylene urea which is added in the solid state or in solution and in which zone the dinitroethylene urea is separated by filtration or settling after which the nitrating solution is circulated through a regenerating zone of phosphorus pentoxide.  The fluorides may be used in line manner.  Nitration is generally effected with solutions containing 5 to 50 grams of nitrogen pentoxide per 100 ,c.cs. of solution and at temperatures from -20 DEG  to 30 DEG  C.  The dinitroethylene urea may be hydrolysed to ethylene dinitramine.  In examples, the batchwise nitration of ethylene urea with nitrogen pentoxide dissolved in chloroform is described.  Specifications 588,012 and 592,219 are referred to.