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Spectroscopy of Hydrothermal Reactions. 24. Kinetics of Alkyl Azide Decomposition Channels and N3 - Behavior in Water above 200 °C at 275 Bar
Ist Teil von
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 2003-05, Vol.107 (19), p.3764-3768
Ort / Verlag
American Chemical Society
Erscheinungsjahr
2003
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
The hydrothermolysis of the water-soluble alkyl azide dimethyl-2-azidoethylamine (2-DAMEZ) was studied at 200−250 °C and 275 bar in real time by flow reactor FTIR spectroscopy. The kinetics of 2-DAMEZ decomposition by N3 - formation represents a minor channel (8% at 250 °C). The main channel is loss of N2 whose presence was determined by mass spectrometry. The Arrhenius parameters for decomposition by the two routes are E a = 14.1 kcal/mol and ln(A, s-1) = 10.7 for the N2 channel and E a = 17.4 kcal/mol and ln(A, s-1) = 11.8 for the N3 - channel. Because of further reactions the organic products could not be identified, but (CH3)3N appears to be a major product. The N3 - ion was found to be stable in water at least to 340 °C. However, protonation of N3 - to form HN3 was pH dependent. ΔH values for the reaction were calculated from a van't Hoff plot. It was found that changes in the bulk dielectric constant affect the equilibrium more than do changes in K w in the 300−340 °C range. Ion pairing of NaN3 and LiN3 was also spectrally observed.