Optimization of the Process Parameters for the Synthesis of High Purity 4,6‐dinitrobenzofuroxan (4,6‐DNBF)

4,6-Dinitrobenzofuroxan (4,6-DNBF) is explosive and can also be used as an important intermediate in the synthesis of other explosives. It can be prepared by nitrating benzofuroxan (BF) with mixed nitric/sulfuric acid. However, little is known about its optimal synthesis parameters in the preparation process. In this study, Taguchi's experimental design method was used to improve the yield of 4,6-DNBF. A L-9 (3(4)) orthogonal array with four control factors and three levels of each control factor was used to design nine experimental conditions. The experimental data were transformed into a signal-to-noise (S/N) ratio to analyze and evaluate the experimental conditions of the optimal parameter combination for the maximum yield of 4,6-DNBF. The verification results indicated that the optimal synthesis parameters were as follows: nitration temperature was 40 degrees C, mass ratio of BF to H2SO4, was 1 : 15, volume ratio of HNO3 to H2SO4 was 1 : 2.0 and reaction time was 4 hours, and then the maximum crude yield and the maximum yield after purification could reach 73.2 % and 49.0 %, respectively. Furthermore, the synthesized 4,6-DNBF was identified by scanning electron microscopy (SEM), nuclear magnetic resonance spectrometer (NMR), Fourier transform infrared spectrometer (FTIR), elemental analyzer (EA), ultraviolet-visible spectrometer (UV-Vis) and thermogravimetry-differential scanning calorimetry (TG-DSC), and its sensitivity was determined using BAM fallhammer, BAM friction tester, and electrostatic spark sensitivity tester.