Process for preparing spherulitic nitroguanidine

摘要

In the production of spherulitic nitroguanidine having a high bulk and tap density nitroguanidine is dissolved in dipolar, aprotic solvents, e.g. DMF, DMSO, NMP, etc., by heating to above the saturation temperature ts and the supersaturated solution is cooled with a controlled temperature gradient ( DEG C/min), crystallization being assisted by the addition of particulate, spherulitic material. In order to obtain spherical nitroguanidine with high yield in a continuous process and with mother liquor reuse, during the heating to above the saturation temperature ts, spherical control particles with a diameter of 5 to 500 mu m are regularly added to the solution in a quantity of 0.05 to 5.00 mass %. The particle size is chosen in such a way that, as a function of the solution behaviour of the nitroguanidine used and its concentration, on dropping below the saturation temperature spherical control particles are still present in the indicated quantity in the supersaturated solution.