Crystallization process of 2-chloro-4, 6-diaminoresorcinol

In order to get 2-chloro-4, 6-dinitroresocinol (CDNR) with high purity, which influences the synthesis of 4, 6-diaminoresorcinol dihydrochloride, the solubility of CDNR in various solvents was measured by laser method and ethanol was chosen as the solvent. The recrystallization process of CDNR was investigated and crystallizing parameters such as cooling rate, temperature and time were discussed. Experimental results show that the time and temperature of crystallization greatly affect the yield and a higher yield can be received at -8°C for 5 h. Slow cooling rate is helpful to the crystallization of CDNR, and the mechanical stirring or ultrasonic treatment can increase the yield and the purity of CDNR.