Nitrous from decomposition

Copper metal surface area was determined by nitrous oxide decomposition. A sample of catalyst (0.2 g) was reduced by heating to 563 K under a flow of 10 % H2/N2 (50 cm min"1) at a heating rate of 3 deg.min 1. The catalyst was then held at this temperature for 1 h before the gas flow was switched to helium. After 0.5 h the catalyst was cooled in to 333 K and a flow of 5 %N20/He (50 cm3mirr ) passed over the sample for 0.25 h to surface oxidise the copper. At the end of this period the flow was switched to 10 % H2/N2 (50 entitlin 1) and the sample heated at a heating rate of 3 deg.min"1. The hydrogen up-take was quantified, from this a... 

Since nitrous oxide was cut off from the feed stream, the sum of evolved nitrous oxide and nitrogen is equal to the adsorbed amount of nitrous oxide on the catalyst in stationary state of the reaction. This amount is extremely small compared to that on CuO and this fact also implys that the adsorption of nitrous oxide could be the slowest step in the overall reaction of nitrous oxide decomposition on MgO. 

Compensation parameters calculated from data reported by Winter for the decomposition of nitrous oxide (263) and nitric oxide (264) on various oxides are given in Table V, B and C, respectively. The variation of data in the latter reaction is relatively small (aL = 0.795, Table V, C) and the values of B and e can be reliably determined. Interpretation of the results for nitrous oxide decomposition is, however, less straightforward since the compensation trend for reactions on the rare earth sesquioxides (B = 19.831 and e = 0.0571) was significantly different from that for all other oxides studied (B = 23.226 and e = 0.0321) and the combined data give the intermediate values of Table V, B. Thus, we are unable to discriminate between the possibilities that either there are two distinct lines or the number of points available is insufficient to characterize fully the compensation effect at the observed level of standard deviation. 

Atomic oxygen formation from H202 at conjugated dehydrogenation of hydrocarbons on the reactor walls is of low probability, but to justify the possibility of oxygen participation in dehydrogenation, nitrous oxide decomposition [3] ... 

The process developed by Radici includes a multi-bed reactor (Figure 7.5) [10]. The gaseous flow containing N2O is subdivided into three flows that are fed separately to the three catalytic layers. The flow from the final catalytic bed exhibits a residual nitrous oxide content below 500 ppm and is subdivided into two flows, one being vented to the atmosphere and one being mixed with the feed to the first catalytic bed and re-circulated into the nitrous oxide decomposition process. 

Figure 22 5 shows what happens when a typical primary alkylamine reacts with nitrous acid Because nitrogen free products result from the formation and decomposition of diazonium ions these reactions are often referred to as deamination reactions Alkyl... 

When the salt is heated to temperatures from 200 to 230°C, exothermic decomposition occurs (4,21). The reaction is rapid, but it can be controlled, and it is the basis for the commercial preparation of nitrous oxide [10024-97-2]. 

Sodium azide does not react with carbonyl sulfide to form 5-hydroxy-1,2,3,4-thiatriazole, nor with carboxymethyl xanthates, RO-CS SCH2COOH, to form 5-alkoxy-l,2,3,4-thiatriazoles. The latter, however, could be prepared from xanthogenhydrazides (RO-CS NHNH2) and nitrous acid. They are very unstable and may decompose explosively at room temperature only the ethoxy compound (6) has been examined in detail. This is a solid which decomposes rapidly at room temperature and even at 0°C is transformed after some months into a mixture of sulfur and triethyl isocyanurate. In ethereal solution at 20° C the decomposition takes place according to Eq. (16)... 

The reaction conditions necessary to obtain a good yield of the title compound (a difficult isomer), and to avoid hazards during the nitration of resorcinol, are critical and strict adherence to those specified is essential. The necessary 80% white fuming nitric acid must be completely free from oxides of nitrogen and nitrous acid, and procedures for this are detailed. Then the temperature dining addition of the diacetate must be kept between -10 and 0°C by regulating the rate of addition. The alternative use of 80% sulfuric acid as solvent for the 80% nitric acid (5 equiv.) is preferred as more reliable, but both methods have led to violent exothermic decomposition, accompanied by fume-off, after an induction period. In any event, the explosive 2,4,6-trinitroresorcinol ( styphnic acid ) is produced as a by-product. 

Despite several decades of studies devoted to the characterization of Fe-ZSM-5 zeolite materials, the nature of the active sites in N20 direct decomposition (Fe species nuclearity, coordination, etc.) is still a matter of debate [1], The difficulty in understanding the Fe-ZSM-5 reactivity justifies a quantum chemical approach. Apart from mononuclear models which have been extensively investigated [2-5], there are very few results on binuclear iron sites in Fe-ZSM-5 [6-8], These DFT studies are essentially devoted to the investigation of oxygen-bridged binuclear iron structures [Fe-0-Fe]2+, while [FeII(p-0)(p-0H)FeII]+ di-iron core species have been proposed to be the active species from spectroscopic results [9]. We thus performed DFT based calculations to study the reactivity of these species exchanged in ZSM-5 zeolite and considered the whole nitrous oxide catalytic decomposition cycle [10],... 

The reaction of Curtius, which is especially to be preferred in the case of the higher members on account of the favourable solubilities of the intermediate products, involves as its first stage the preparation of the hydrazide from an ester (or acid chloride). The hydrazide is then converted, usually very readily, by the action of nitrous acid into the azide. In many cases it is more convenient to prepare the azide by treating an acid chloride with sodium azide previously activated with hydrazine hydrate.1 Azides easily undergo thermal decomposition, the two azo nitrogen atoms being eliminated as elementary nitrogen. In this way, however, the same radicle is formed as was invoked above to explain the Hofmann reaction ... 

New examples of the formation of pyrazolo[3,4-r/ [l,2,3]triazoles from 4-aminopyrazoloureas, described above in Section 10.05.9.1.2(vii)), have been described. The recent publication of Maggio and co-workers provides an insight into the mechanism of the reaction. It has been shown that nitrosation of 230 with nitrous acid at 0°C followed by adjustment of the pH to 8 and room temperature extraction furnishes, from amongst a mixture of products, the 5,5-bicycle 231 whilst extraction and work-up at 0°C yielded the 5,7-bicycle 232 as the single reaction product. The latter is the precursor to the pyrazolotriazole which results simply from room temperature solution decomposition involving loss of (m)ethyl isocyanate. The formation of the triazole 231 from the tetrazepinone 232 is rationalized as shown in Scheme 48 <2006ARK120>. 

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