A simple and efficient nitrating agent to achieve N-n-butyl-N-(2-nitroxyethyl) nitramine (Bu-NENA) and theoretical study of its compatibility with polyglycidyl nitrate (PGN) and glycidyl azide polymer (GAP)

Abstract

This paper presents a new simple experimental and highly efficient approach to synthesize N-n-butyl-N-(2-nitroxyethyl)nitramine (Bu-NENA) in the attendance of nitric acid and boric acid as a enable nitrating system. The advantages of this method are the excellent yield of product, easy work-up, short reaction time, and atom economy. The study of the compatibility of energetic binder glycidyl azide polymer (GAP) and polyglycidyl nitrate (PGN) with Bu-NENA for solid propellants by using the vacuum stability test (VST) and differential scanning calorimeter (DSC) as another part of this research work was investigated. The quantity of the volume of evolved gas of these blends and glass transition temperature (T_g) were also calculated. According to the results, the addition of plasticizers to PGN and GAP led to a decrease in T_g, which tells about the compatibility of plasticizers with both. Furthermore, VST showed that Bu-NENA is more compatible with PGN than GAP. In addition, theoretical studies on the interaction between Bu-NENA and binders, as well as molecular electrostatic potential surface (MESP), natural bond orbital (NBO), and the atoms in molecules (AIM) analyses at B3P86/def2-TZVP and PBE/def2-TZVP levels, were investigated. The nature of interactions was investigated using energy decomposition analysis (EDA) analysis at the BP86/TZ2P level. The results of theoretical studies agree with experimental observations about the compatibility of the plasticizer and show that the dispersion forces play a crucial role in compatibility.