Comparison of the Crystals Obtained by Precipitation of CL‐20 with Different Chemical Purity

The precipitation of CL‐20 with different chemical purity is presented herein. Studies have shown that the first crystallization of the crude CL‐20 does not allow achieving the expected polymorphic purity and slightly increases chemical purity. Further precipitation processes result in gradual increase of the chemical purity about 1–2 % and in the improvement of the properties of crystals, i.e. density, polymorphic purity, and sensitivity to friction. This paper attempts a preliminary purification of the crude CL‐20 with columns filled with activated charcoal. A material of high purity, obtained by this process, was used in the process of precipitation. As a result of the crystallization a sample of CL‐20 was obtained with high chemical purity of 99.5 % and significantly reduced sensitivity to friction (128 N) and to impact (4 J). Additionally, samples of CL‐20, recovered from the filtrate after crystallization with a chemical purity of about 88 %, were purified on columns filled with activated charcoal. In this process a significant amount of impurities was removed and the purity was increased to 96 %.