Optimization of the synthesis parameters and analysis of characteristics of 1,1-diamino-2,2-dinitroethylene

Abstract

2,2-Dinitroethene-1,1-diamine (FOX-7) is a low-sensitive explosive suitable for various energy-material applications. It can be synthesized based on the nitration and hydrolysis of heterocyclic precursors derived from 2-methylimidazole-4,5-dione (MID) or 2-methylpyrimidine-4,6-diol (MPD). However, more information about its optimal synthesis parameters during production from MPD as a starting material is needed. In this study, Taguchi's experimental design method was used to improve the yield of FOX-7. Verification of the results shows that the optimal synthesis parameters are as follows: the molar ratio of HNO₃/MPD is 8, the reaction time is 180 minutes, and the reaction temperature is 15°C; the maximum yield of FOX-7 can reach 79.14%. Furthermore, the synthesized FOX-7 was identified and characterized by nuclear magnetic resonance (NMR) spectroscopy analysis, Fourier transforms infrared spectroscopy (FTIR), Raman spectroscopy analysis, and powder X-ray diffraction (PXRD).