Physicochemical Parameters of Insensitive Munition Constituent Methylnitroguanidine (MeNQ) of Importance to Environmental Fate and Transport

Abstract

1‐methyl‐3‐nitroguandine (MeNQ) is being pursued as an insensitive munition to replace legacy munitions such as TNT and RDX. This study was intended to determine the basic physicochemical properties of MeNQ as well as potential environmental fate pathways. The solubility of MeNQ was determined to be 12.92±0.52 g/L and aqueous photolysis was found to efficiently degrade the munition, where its quantum yield and half‐life were found to be 0.009 and 0.59 days, respectively. Hydrolysis was an insignificant degradation pathway resulting in 8.1 % degradation at pH 4, 2.6 % at pH 7, and 6.2 % at pH 9 after five days at an elevated temperature. Volatilization at environmentally relevant conditions was found to be insignificant as the molecule thermally degrades, leading to an inability to calculate Henry's Constant for volatilization from water. Spectroscopic (UV‐vis, FTIR, NMR) and analytical (HPLC) studies were undertaken and are shown alongside the parent molecule, NQ, for comparison to characterize the emerging munition.