The Vapor Phase Autoxidation of Unsymmetrical Dimethylhydrazine and 50- Percent Unsymmetrical Dimethylhydrazine - 50-Percent Hydrazine Mixtures

Abstract

Abstract : The autoxidations of unsymmetrical dimethylhydrazine (UDMH) and a mixture of 50-percent UDMH and 50-percent hydrazine (50-50 blend) have been studied at pressures of several Torr in 44-cm reaction vessels and several ppm in a long path cell. With initial UDMH pressures of several Torr, autoxidation proceeded too slowly to be differentiated from natural decay processes. When the initial UDMH pressure was lowered to a few ppm, the addition of oxygen caused approximately first order decay with a half life of about 84 hours. The main oxidation product under these conditions was formaldehyde dimethylhydrazone. The 50-50 blend did not behave as two independent systems; instead, there were substantial positive synergistic effects observed. At concentrations of a few Torr of each component, the addition of oxygen resulted in a 10- to 20-fold increase in decay rate over that shown by UDMH or hydrazine by itself. At ppm concentration levels, the situation was similar for UDMH where a four-fold oxidation rate increase was observed when compared with a similar experiment with no hydrazine present. However, hydrazine oxidation in the 50-50 blend was somewhat slower that it was in a similar experiment with only hydrazine present. (Author)