Nitro-guanidine prodn. from guanidine carbonate - by dehydration with conc. sulphuric acid and reaction with conc. nitric acid, dilution and cooling

摘要

In the prepn. of nitroguanidine, (I), 100 pts. guanidine carbonate are charged to 280-330 pts. 82-88% H2SO4 at 35-70 degrees C, 770-820 pts. of 98-99% HNO3 are added to the formed guanidine sulphate/guanidine bisulphate mixt. dissolved in H2SO4, at 60 degrees C. The soln. is kept 1-2 hrs. at 40-60 degrees C, to cause an after-reaction. The H2SO4, contg. dissolved (I), is diluted to 25-33% by adding 5-10% H2SO4 obtd. from a previous batch. After cooling to 0 degrees C, the pptd. (I) is sepd. from the diluted H2SO4, washed free from acid and diluted. Guanidine carbonate contains 66% guanidine of 48% in guanidine nitrate. Some conversion to (I) requires 15-18% less guanidine carbonate. H2SO4 can be recycled, whereby fresh conc. H2SO4 consumption is reduced to 10-20% w.r.t. (I). Yields of (I) are 96-97% w.r.t. guanidine carbonate. Use of 82-88% H2SO4 excludes hazards of explosive decompsn.