Mechanistic study of 1,1-dimethylhydrazine transformation over Pt/SiO2 catalyst
Andrei V Smirnov1,2, Pavel A Kots1, Maksim A Panteleyev1
1Department of Chemistry, Lomonosov Moscow State University Leninskiye Gory 1, bld. 3 11991 Moscow Russia.
Abstract:
Catalytic oxidation of 1,1-dimethylhydrazine (UDMH) with molecular oxygen over Pt/SiO2 was studied by in situ FTIR spectroscopy coupled with online MS monitoring of the gas phase. An unusual two-step oxidation process was detected in experiments with the pulse UDMH feeding: initial UDMH oxidation over a fresh platinum surface quickly terminates due to the blockage of active sites; a time-separated second oxidation step corresponds to combustion of the surface residue. This residue consists of C[triple bond, length as m-dash]N nitrile groups formed via decomposition of the products of non-oxidative UDMH conversion, such as dimethylamine. The two-step oxidation picture is observed over a broad range of reaction temperatures and oxygen to UDMH ratios.
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