Theoretical kinetic investigation of thermal decomposition of nitropropane

Experimental and Modeling Investigation on the Pyrolysis of n-Decane Initiated by Nitropropane. Part I: 1-Nitropropane

Initiators can accelerate the pyrolysis of hydrocarbon fuels, thereby reducing the required reaction temperature in the hypersonic vehicle heat exchanger/reactor. Nitro-alkanes are considered as efficient initiators due to their lower energy barrier of the C-N bond cleavage reaction. To research the mechanism of the initiation effect of nitro-alkanes on the decomposition of hydrocarbon fuel, synchrotron radiation vacuum ultraviolet photoionization-mass spectrometry (SVUV-PIMS) was employed to experimentally study the pyrolysis of n-C₁₀H₂₂, 1-C₃H₇NO₂, and their binary mixtures in a flow tube under pressures of 30 and 760 Torr. The species identified and measured in the experiments included alkanes, alkenes, dialkenes, alkynes, nitrogen oxides, benzene, and free radicals, which revealed the mechanism of n-decane and 1-C₃H₇NO₂ pyrolysis, as well as the interactions of the two fuels. Experiments show that the presence of 1-C₃H₇NO₂ reduces the initial decomposition temperature of n-C₁₀H₂₂, and the increased pressures could achieve a stronger promoting effect on the conversion of n-C₁₀H₂₂. A detailed kinetic model containing 1769 reactions and 278 species was established and validated based on the mole fraction distributions of n-C₁₀H₂₂, major pyrolysis species, and important intermediates measured in pure fuel and initiated pyrolysis. The kinetic model can accurately predict the experimental data, and the mechanism of 1-C₃H₇NO₂-initiated pyrolysis of n-C₁₀H₂₂ is analyzed with the model. The effect of 1-C₃H₇NO₂ on the consumption of n-C₁₀H₂₂ and selectivity of cracked products is highlighted.

Catalytic Aerobic N-Nitrosation by Secondary Nitroalkanes in Water: A Tandem Diazotization of Aryl Amines and Azo Coupling

Secondary nitroalkanes underwent oxygen-mediated nitro-nitrite isomerization, serving as versatile N-nitrosating agents under aerobic conditions. To capitalize on the newly discovered aerobic nitro-nitrite isomerization phenomenon, a phase-transfer catalysis system employing KSeCN and TBAI was developed, in which the tandem diazotization and azo coupling with nitroalkanes as well as N-nitrosation of amines were accomplished. The current tandem diazotization and azo coupling strategy provides a facile synthesis of areneazo-2-(2-nitro)propane derivatives, a safe synthetic alternative to aryl diazonium salts.