Synthesis, characterization, thermal and explosive properties of potassium salts of trinitrophloroglucinol

Three different substituted potassium salts of trinitrophloroglucinol (H₃TNPG) were prepared and characterized. The salts are all hydrates, and thermogravimetric analysis (TG) and elemental analysis confirmed that these salts contain crystal H₂O and that the amount crystal H₂O in potassium salts of H₃TNPG is 1.0 hydrate for mono-substituted potassium salts of H₃TNPG [K(H₂TNPG)] and di-substituted potassium salt of H₃TNPG [K₂(HTNPG)], and 2.0 hydrate for tri-substituted potassium salt of H₃TNPG [K₃(TNPG)]. Their thermal decomposition mechanisms and kinetic parameters from 50 to 500 °C were studied under a linear heating rate by differential scanning calorimetry (DSC). Their thermal decomposition mechanisms undergo dehydration stage and intensive exothermic decomposition stage. FT-IR and TG studies verify that their final residua of decomposition are potassium cyanide or potassium carbonate. According to the onset temperature of the first exothermic decomposition process of dehydrated salts, the order of the thermal stability from low to high is from K(H₂TNPG) and K₂(HTNPG) to K₃(TNPG), which is conform to the results of apparent activation energy calculated by Kissinger's and Ozawa-Doyle's method. Sensitivity test results showed that potassium salts of H₃TNPG demonstrated higher sensitivity properties and had greater explosive probabilities.