Nitrous oxide formation mechanisms

NO Formation through Nitrous Oxide A third reaction path to NO proceeds through nitrous oxide. This mechanism is initiated by the reaction... 

The nitrogen atoms are then oxidized to NO by reaction with OH (R116), or they can be converted to N2 by reaction with NO (R114b). At lower temperatures the oxidation mechanism for HCN is more complicated, involving formation and consumption of a number of pollutant species including oxicyanides, amines (NH,), and nitrous oxide (N20). 

NO Formation through NNH The fourth mechanism for formation of NO from molecular nitrogen was discovered fairly recently [40,94], This mechanism has some similarities to the nitrous oxide mechanism. The initiating step is addition of a hydrogen... 

Both imidogen (NH) and nitrous oxide (N20) may subsequently be oxidized to NO. Even though NNH, because of its low stability, never reaches significant concentrations, the NNH mechanism may contribute significantly to NO formation under certain conditions. It seems to be most important in diffusion flames, where NNH may form on the fuel-rich side of the flame sheet and then react with O inside the flame sheet [383]. 

The ability of nitrous oxide to forma 1,3-dipole (Section 7.2) seems to be of critical importance for the reaction with alkenes. The oxygen transfer proceeds via the 1,3-dipolar cycloaddition mechanism, assuming intermediate formation of a 1,2,3-oxadiazoline complex, the decomposition of which leads to a carbonyl compound ... 

Probable mechanism of nitrous-oxide- and nitrogen-containing acid formation. Hydrogen peroxide ability to induce free-radical oxidation reactions. 

NO Formation from Dinitrogen Oxide (Nitrous Oxide) takes place during combustion of gaseous hydrocarbons of volatiles in the case of lean mixtures. In accordance with this mechanism at first the dinitrogen oxide N2O is formed by the termolecular reaction ... 

Nitrous oxide generation has been induced from both 2 and 8, but it is apparent from preliminary experiments that the mechanisms for the processes differ. In particular, oxygen atom transfer yields an oxo-bridged dicopper(II) species in the polypyridyl compounds but affords N02 in the case of the NO reaction with 4 and TpPh2Cu(CH3CN). Preliminary evidence suggests that N-N bond formation involves mononuclear intermediates in the latter reactions, but the subsequent steps remain unclear. 

Although reaction (xliii) appears to be the major reaction between H atoms and nitrous oxide, this does not exclude the occurrence of the alternative reaction (xliv). Indeed reaction (xliv) has been specifically suggested to explain (a) the formation of the nitric oxide responsible for the sensitizing effect of N2O on H2 + O2 explosions [268] (cf. Sect. 8.3), and (b) the formation of nitric oxide in H2+ N2O flames at 1500—2000 K [293] and shocked gases at 1900—2800 K [294]. More recent investigations of the thermal H2+N2O reaction have also shown that the mechanism is more complex than that suggested by Melville [287, 288]. 

Nitrous oxide has a potential for abuse (15), one of the major complications of which is myeloneuropathy. Altered vitamin B12 metabolism has been suggested as a mechanism (16), and in some cases the patients concerned have been found to have pre-existing subclinical B12 deficiency (17). Nitrous oxide interferes with vitamin B12 formation by causing irreversible oxidation of cobalt in... 

The main-chain scission yield was recently compared at room and liquid nitrogen temperatures [415] in the presence of a large number of additives known as radical, cation or electron scavengers. The results are given in Table 31. The protection index, in this case defined as 100(7V0 — N)/N where N0 and N are the number of scissions per chain in the absence and in the presence of additive, respectively, is nearly independent of the irradiation temperature marked protection is observed for all the additives studied with the exception of nitrous oxide. It must therefore be concluded that the mechanism of main-chain scission is identical at room and liquid nitrogen temperatures and that ions and radicals are involved in the radiolysis. A detailed study of the effect of ethyl mercaptan on main-chain scission and volatile formation was then undertaken [395]. About 75% protection of main-chain scission was obtained at 313 and at 77°K when the polymer contained 1.49 wt. % of ethyl mercaptan the protection index increases to 90% for concentrations of the order of 10 wt. %. The yield of volatile products was, however, unaltered by the presence of 1.5 wt. % ethyl mercaptan. 

Andrews and co-workers have used the matrix reaction between lithium atoms and some inorganic compounds to produce species of spectroscopic interest. Reaction of lithium with molecular oxygen [301] produces, in addition to the molecule Li02, the molecule LiO and a dimer Li2 02. Reaction with nitric oxide produced a nitroxide compound [302], but analysis of the infrared spectrum indicated that in this compound the lithium atom was bound to the oxygen atom (LiON), rather than to the nitrogen atom (LiNO), as would be expected by analogy with the known compounds HNO and RNO. The matrix deposition of lithium and nitrous oxide [303] leads to the formation of LiO and LijO. The other alkali metals have also been reacted in the same way with nitrous oxide [304]. Potassium, rubidium and caesium all led to the formation of the compounds MO and M2O. No sodium oxides were produced when sodium and nitrous oxide were co-deposited. This is to be compared with the mechanism advanced for the sodium-catalysed gas-phase reaction between N2O and CO, where sodium is assumed to react with N2O, (Section 4, ref. 

Reduction of the N-N bond affords the parent amine and nitrous oxide. Reduction of the N-O bond gives the unsymmetrical hydrazine, which can be further reduced to give the parent amine and ammonia. Because both reaction pathways ultimately result in the formation of the parent amine, it can be difficult to discern the reaction mechanism for reduction. Reduction of N-nitrosoamines to the parent amine is generally considered a detoxification pathway for nitrosoamines however, formation of the hydrazine has been suggested to be a possible pathway for bioactivation (Tatsumi et ah, 1983). 

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