N-hydroxy-N'-nitrourea and related compounds as high energy density materials

Abstract

Novel compounds are provided in the form of a salt having the structure of formula (I) or formula (II) wherein: R 1 is selected from the group consisting of H, C 1 -C 24 alkyl, C 2 -C 24 alkenyl, C 2 -C 24 alkynyl, C 5 -C 20 aryl, C 6 -C 24 alkaryl, and C 6 -C 24 aralkyl; R 2 is H, C 1 -C 24 alkyl or nitro; X is O or NR 3 in which R 3 is H, C 1 -C 24 alkyl or nitro; Z m+ is a monovalent cation, a divalent cation, or a trivalent cation; M + is an alkali metal cation; and m and n are 1, 2 or 3, with the proviso that the compound contains at least one nitro group. Exemplary such compounds are the ammonium salt of the N-hydroxyl-N′-nitrourea (NHNU) monoanion and the disodium salt of the NHNU dianion. Also provided, as novel compositions of matter, are N-hydroxyl-N′-nitrourea and N-hydroxyl-N-nitroguanidine in electronically neutral form. The compounds are useful in a variety of contexts, but are primarily useful as high energy oxidizing agents in explosive compositions, propellant formulations, gas-generating compositions, and the like. Compositions containing the compounds are also provided, including energetic compositions, as are methods for synthesizing the compounds.

1 . A compound in the form of a salt having the structure of formula (I) 
     
       
         
         
             
             
         
       
     
     wherein:
 R 1  is selected from the group consisting of H, C 1 -C 24  alkyl, C 2 -C 24  alkenyl, C 2 -C 24  alkynyl, C 5 -C 20  aryl, C 6 -C 24  alkaryl, and C 6 -C 24  aralkyl; 
 R 2  is H, C 1 -C 24  alkyl or nitro; 
 X is O or NR 3  in which R 3  is H, C 1 -C 24  alkyl or nitro; 
 Z m+  is a monovalent cation, a divalent cation, or a trivalent cation; and 
 m and n are 1, 2 or 3, 
 with the proviso that the compound contains at least one nitro group. 
 
   
   
       2 . The compound of  claim 1 , wherein R 1  is H, R 2  is nitro, X is O, such that the compound is a salt of N-hydroxyl-N′-nitrourea monoanion. 
   
   
       3 . The compound of  claim 2 , wherein m and n are 1, and Z is ammonium ion, such that the compound is N-hydroxyl-N′-nitrourea, ammonium salt. 
   
   
       4 . A compound in the form of a salt having the structure of formula (II) 
     
       
         
         
             
             
         
       
     
     wherein:
 R 1  is selected from the group consisting of H, C 1 -C 24  alkyl, C 2 -C 24  alkenyl, C 2 -C 24  alkynyl, C 5 -C 20  aryl, C 6 -C 24  alkaryl, and C 6 -C 24  aralkyl; 
 R 2  is H, C 1 -C 24  alkyl or nitro; 
 X is O or NR 3  in which R 3  is H, C 1 -C 24  alkyl or nitro; and 
 M is an alkali metal, 
 with the proviso that the compound contains at least one nitro group. 
 
   
   
       5 . The compound of  claim 4 , wherein R 1  is H, R 2  is nitro, X is O, and M is potassium, such that the compound is N-hydroxyl-N′-nitrourea, dipotassium salt. 
   
   
       6 . N-hydroxyl-N′-nitrourea. 
   
   
       7 . N-hydroxyl-N′-nitroguanidine. 
   
   
       8 . An energetic composition comprising the compound of  claim 2  and a polymeric binder. 
   
   
       9 . An energetic composition comprising the compound of  claim 3  and a polymeric binder. 
   
   
       10 . An energetic composition comprising the compound of  claim 5  and a polymeric binder. 
   
   
       11 . A propellant composition comprising the compound of  claim 2 , a polymeric binder, a metallic fuel, and an igniter compound. 
   
   
       12 . A propellant composition comprising the compound of  claim 3 , a polymeric binder, a metallic fuel, and an igniter compound. 
   
   
       13 . A propellant composition comprising the compound of  claim 5 , a polymeric binder, a metallic fuel, and an igniter compound. 
   
   
       14 . A gas-generating composition comprising the compound  claim 2 , a polymeric binder, a nitrogenous fuel, and an igniter compound. 
   
   
       15 . A gas-generating composition comprising the compound  claim 3 , a polymeric binder, a nitrogenous fuel, and an igniter compound. 
   
   
       16 . A gas-generating composition comprising the compound  claim 5 , a polymeric binder, a nitrogenous fuel, and an igniter compound. 
   
   
       17 . A method for synthesizing a salt of N-hydroxyl-N′-nitrourea, comprising treating a basic salt of a lower alkyl nitrocarbamate and a monovalent cation with a hydroxide-releasing base in the presence of aqueous hydroxylamine until a salt of the monovalent cation and di-anionic N-hydroxyl-N′-nitrourea precipitates. 
   
   
       18 . A method for synthesizing N-hydroxyl-N′-nitrourea, comprising carrying out the method of  claim 17  and thereafter processing the precipitate with a sulfuric acid solution to obtain N-hydroxyl-N′-nitrourea in electronically neutral form. 
   
   
       19 . A method for synthesizing the ammonium salt of N-hydroxyl-N′-nitrourea, comprising: carrying out the method of  claim 18 ; and re-dissolving the N-hydroxyl-N′-nitrourea in a solvent containing a stoichiometric amount of ammonia.