Experimental and kinetic modeling study of iso-propylamine oxidation with SVUV-time of flight mass spectrometry

Atmospheric oxidation experiments of iso-propylamine (IPA) were conducted in a jet-stirred reactor over the temperature range from 550 to 870 K at fuel-equivalence ratios of 0.5 and 2.0. A combination of synchrotron vacuum ultraviolet (SVUV) photoionization and time-of-flight mass spectrometry (TOFMS) was utilized to identify and quantify oxidation products and intermediates. Compared to the previous n-propylamine (NPA) low-temperature oxidation [Proc. Combust. Inst., 39 (2023) 295–303.], some intermediates and products were newly observed among the 34 detected species, including nitrosyl hydride, methylamine, acetonitrile, nitrous oxide, ethyl isocyanide, propanenitrile, 2-propanimine, n-methylformamide and 2-methylallylamine. A kinetic model consisting of 815 species and 4402 reactions was developed based on the iso-propanol model [Prog. Energy Combust. Sci. 67 (2018) 31–68.] and an ethylamine model [Prog. Energy Combust. Sci. 44 (2014) 40–102.]. The onset temperature of IPA and O₂ consumption is 750 K under both lean and rich conditions. Rate-of-production (ROP) and sensitivity analyses were performed at 800 K to illustrate the reacting paths from parent fuel to major intermediates and products, and identify the most sensitive reactions. H₂O₂(+M) = 2OH(+M) is the most sensitive reaction with a promoting effect on IPA consumption while 2HO₂ = H₂O₂+O₂ is the most inhibiting one. Important N-containing pollutants like NH₃, NOx, HCN, CH₃NH₂ and so on were analyzed with respect to their reaction routes. (CH₃)₂CNH is abundant due to the H-abstraction reactions between tC₃H₆NH₂ radical with O₂. This work was made for gaining a more comprehensive insight into the oxidation of IPA and make a foundation for further exploring amine chemistry.