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

Abstract

Abstract4,6‐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 L9 (34) 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 °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.