Method of producing high bulk density spheroidal nitroguanidine

Abstract

A process for producing high bulk density spheroidal nitroguanidine by forming a solution of from 2 to 9 weight percent of nitroguanidine, 0.5 to 2.0 weight percent of methylcellulose, and 0.5 to 2.0 weight percent of partially hydrolyzed poly(vinyl alcohol) in water at a temperature of from 50 DEG C. to 100 DEG C., and then cooling the solution at a rate of from I to 20 DEG C./minute until the solution temperature is less than 40 DEG C.

What is claimed is: 
     
       1. A process for recrystallizing nitroguanidine comprising: (1) forming an aqueous nitroguanidine solution at a temperature of from about 50° C. to about 100° C. which comprises (a) from 2 to 9 weight percent of nitroguanidine;   (b) from 0.5 to 2.0 weight percent of methyl cellulose,   (c) from 0.5 to 2.0 weight percent of a polyvinyl alcohol; and with   (d) water being the remainder of the solution;     (2) cooling the aqueous nitroguanidine solution under continuous and vigorous agitation at a cooling rate of from 1° C./minutes to 20° C./minute until the temperature of the solution is below 40° C.; and   (3) isolating the product spheroidal nitroguanidine crystals.   
     
     
       2. The process of claim 1 wherein nitroquandine comprises from 6 to 8 weight percent of the nitroguanidine solution in step (1). 
     
     
       3. The process of claim 1 wherein methyl cellulose comprises from 0.6 to 1.0 weight percent of the nitroguanidine solution in step (1). 
     
     
       4. The process of claim 1 wherein the polyvinyl alcohol comprises from 0.6 to 1.0 weight percent of the nitroguandine solution in step (1). 
     
     
       5. The process of claim 1 wherein the temperature in step (1) is from 50° C. to 100° C. 
     
     
       6. The process of claim 1 wherein the cooling rate in step (2) is from 1° C. to 20° C./min. 
     
     
       7. The process of claim 1 wherein the aqueous nitroguanidine solution is agitated in step (2) by stirring.