Nitrous oxide, reactions with

Experiment shows that the primary reaction in the homogeneous decomposition of nitrous oxide proceeds with stoichiometry N20 => N2 + 0.5 02 and rate equation... 

The mechanism of reaction (9a) has been examined by isotope techniques using nitrous oxide labelled with 15N (Clusius et al. [66,67]). The course of the reaction... 

Decomposition accompanied by the development of nitrous oxide compatible with the scheme (4) only starts above 170° C. Marked decomposition together with the evolution of nitrogen, nitric oxide and water, corresponding with the reaction (3), begins at a temperature of about 220°C [11]. 

Ellagic acid concentration can be determined through an oxidation reaction with nitrous acid, and two methods have been described by Bate-Smith (1977) and by Wilson and Hagerman (1990), respectively. 

The hydrated electron can be conveniently converted into a hydroxyl radical by reaction with nitrous oxide [reaction (5)]. 

Nitrous oxide reacts with carbon monoxide in the presence of a ceria-promoted rhodium catalyst to form dinitrogen and carbon dioxide. One plausible sequence for the reaction is given below ... 

In this chapter, we present an example of a study following the second line of approach. The catalytic activity of a highly divided stoichiometric nickel oxide, one of the best catalysts in oxidation reactions (18), has been studied, for several years, first at the Faculty des Sciences of Lyon and, then, at the Institut de Recherches sur la Catalyse, Villeurbanne, France, in carbon monoxide oxidation and related reactions (oxygen isotopic exchange, nitrous oxide decomposition) with the help of different experimental techniques. It is fortunate that the same type of investigations on the same material were also conducted at the Institute of Physical-Chemistry in Prague, Czechoslovakia. This allowed many comparisons and checks of experimental results and interpretations. 

Not being aware of the earlier work, the present author first noticed the phenomenon in 1981. Geiger and Huber10 had photolyzed dimethylnitrosamine in the gas phase at 1 Torr and under 100 Torr N2 buffer. This compound fragments from the first excited singlet state into dimethylaminyl radicals and nitrous oxide NO with unity quantum yield, but neither photoproducts nor a decrease of the initial compound pressure were observed. Even after 20 h photolysis the back-reaction was complete to more than 99.9% (Scheme 6). This seemed quite puzzling because sterically unhindered aminyl radicals are transient and readily self-terminate by coupling and disproportionation. 

In the 1470-A. photolysis of cyclohexane-nitrous oxide solutions, nitrous oxide reacts with excited cyclohexane molecules to form nitrogen and oxygen atoms. The reaction of N20 with photoexcited 2,2,4-trimethylpentane molecules is much less efficient than with cyclohexane. In the radiolysis of these solutions, G(N2) is the same for different alkanes at low 5 mM) N20 concentrations. At higher concentrations, G(N2) from the radiolysis of cyclohexane is greater than G(N2) from the radiolysis of 2,2,4-trimethylpentane solutions. The N2 yields from 2,2,4-trimethylpentane are in excellent agreement with the theoretical yields of electrons expected to be scavenged by N20. The yield of N2 in the radiolysis of cyclohexane which is in excess of that formed from electrons is attributed to energy transfer from excited cyclohexane molecules to nitrous oxide. 

Obenauf et al. [271] have measured the quantum yield of fluorescence per molecule of target gas consumed in the reaction of barium vapour with nitrogen dioxide and nitrous oxide, obtaining values of 0.20—0.27 for the stronger fluorescence from the nitrous oxide reaction, and 0.015 0.003 for the nitrogen dioxide reaction. Using the values for total reaction cross-section reported by Jonah et al. [270], Obenauf et al. [271] estimate the cross-sections for the chemiluminescent reactions to be < 6—7 for the nitrous oxide reaction and about 2—3 for the nitrogen dioxide reaction. 

However, all exothermic reactions do not react with unit efficiency, as is clearly evident in the case of nitrous oxide reacting with atomic metal cations. In extensive experiments with nitrous oxide, rate constants and product branching ratios for the reaction of 67 atomic metal cations were measured. The reaction efficiencies are plotted as a function of metal cation OA in Figure 8.3. In reactions with nitrous oxide a significant number of metal cations react with only moderate to low efficiency, despite being strongly exothermic. As discussed by Bohme and co-workers and by Armentrout et al., this apparent lack of reactivity can be related to the electronic structure of reactants, products and possible interconnecting transition states. 

By boiling the residue with hydrochloric acid and sulphate of iron, whereby the nitro-cellulo.se givew a nitrous oxide reaction. 

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