Isomeric derivatives of triazoles as new toxic decomposition products of 1,1-dimethylhydrazine

Abstract

Unsymmetrical dimethylhydrazine (UDMH) is a rocket propellant for carrier rockets and missiles. UDMH is environmentally hostile compound, which easily forms a variety of toxic products of oxidative transformation. The liquidation of unused UDMH from retired launch sites is performed by the complete burning of UDMH-containing wastes. Due cyclicity of the burning equipment the UDMH-containing wastes are subject of prolonged storage in contact with atmospheric oxygen and thus contains a complicated mixture of UDMH degradation products. High performance liquid chromatography (HPLC), high resolution mass spectrometry (HRMS) and NMR were used for the isolation on characterization of new highly polar and potentially toxic UDMH transformation products in the mixture. Two series of unreported isomers with high ionization cross section in electrospray ionization were isolated by repeated preparative HPLC. The structures of the isomers were established by tandem HRMS and NMR. The cytotoxicity of the isolated compounds has been preliminarily studied and found to be similar to UDMH or higher.

Keywords: 1,1-Dimethylhydrazine degradation; HPLC-MS; MTT assay; Tandem mass spectrometry; Triazole isomers; UDMH.