Nitrogen dioxide vapour

Figure 9.10 Nitrogen dioxide vapour pressure vs temperature...

N-(l-Naphthyl)ethylenediamine solution. Spray the plate with dilute sulphuric acid, expose it to nitrogen dioxide vapour for 15 minutes and then spray with the reagent. 

Nitrogen Dioxide Vapour produced by the action of mtnc acid on copper turnmgs For location m thm-layer chromatography the TLC plate is exposed to the nitrous fumes which are evolved... 

Q O The combustion of ammonia in oxygen to form nitrogen dioxide and water vapour involves covalent molecules in the gas phase. The oxidation number method for balancing the equation was shown in an example in this section. Devise a half-reaction method for balancing the equation. Describe the assumptions you made in order to balance the equation. Also, describe why these assumptions did not affect the final result. 

TATP has such a high vapour pressure that it can probably be directly detected, whereas RDX has such a low vapour pressure that dogs alert on the bouquet of solvents used in its manufacture. Nitrate esters readily decompose to eliminate nitrogen dioxide (NO2). This can be a clue for canines and certainly is for chemiluminescence. 

Nitroalkanes can be formed from the direct nitration of aliphatic and alicyclic hydrocarbons with either nitric acid ° or nitrogen dioxide in the vapour phase at elevated temperature. These reactions have achieved industrial importance but are of no value for the synthesis of nitroalkanes on a laboratory scale, although experiments have been conducted on a small scale in sealed tubes. 

Both nitric acid and nitrogen dioxide, in the liquid and vapour phase, have been used for the nitration of the alkyl side chains of various alkyl-substituted aromatics without affecting the aromatic nucleus.Thus, treatment of ethylbenzene with nitric acid of 12.5 % concentration in a sealed tube at 105-108 °C is reported to generate a 44 % yield of phenylnitroethane. The nitration of toluene with nitrogen dioxide at a temperature between 20-95 °C yields a mixture of phenylnitromethane and phenyldinitromethane with the proportion of the latter increasing with reaction temperature. ... 

The disadvantages of this mixture are its high vapour pressure resulting from the low boiling point of nitrogen dioxide, and its erosiveness. 

Shoryghin and Khait [57] brought cellulose into contact with vapours of nitrogen dioxide at room temperature and obtained a product largely oxidized and degraded, that contained up to 3.2% N. 

Height, kildmetres. Total pres sure, mm. Argon. Nitrogen. Water vapour. Oxygen. Carbon dioxide. Hydrogen. Helium. 

Using waste gases and cooling water, the compressed gases are cooled in a high-pressure heat-exchange system, where most of the nitric oxide is oxidised to nitrogen dioxide and most of the water vapour condenses... 

Detailed experiments on nitration of n-hexane with nitrogen dioxide in the vapour phase were recently carried out by Slebodzinski, T. Urbanski et al. [64], They nitrated n-hexane using the molar ratio... 

McKee Mid Wilhelm [92] found that the highest yield of nitration of benzene with nitrogen dioxide in the vapour phase was obtained at 310°C. In the presence of activated silica the yield was higher than that obtained without a catalyst Mid could Mnount to 83.6%. Nitrophenol was also formed in a yield rising with temperature, so that at 330°C it was the principal reaction product. The authors supposed that the catalytic action of activated silica was probably a specific one Mid did not consist only in binding the water formed during the nitration process. 

Nitration in the vapour phase, hi methods of this kind (e.g. the Wilhelm method [13]) a continuous stream of vapours of the aromatic hydrocarbon and nitric acid or nitrogen dioxide is introduced into the reactor. Sulphuric acid is not used in this reaction. 

Nitromethane, CH3N02, is a volatile liquid. It may be obtained by direct vapour phase nitration of paraffinic hydrocarbons either with nitric acid vapours (Hass et al. [1-8]) or with nitrogen dioxide (T. Urbanski and Slebodzinski [9]). It may also be prepared by the action of sodium- or potassium nitrite on chloroacetic acid... 

It is interesting to note that, whereas admixture with carbon dioxide, nitrogen, and oxygen does not considerably affect the rate of decomposition, the presence of water-vapour, chlorine, or nitrogen dioxide causes a marked acceleration.7... 

Carbon dioxide Oxygen Nitrogen Water-vapour... 

Zeolites have been used before in the vapour phase nitration of aromatic compounds using nitrogen dioxide.20 However, the conditions were harsh and there was no regioselectivity. Initially, therefore, we attempted to reproduce the mild conditions of Suzuki for nitration of chlorobenzene. Liquid N2O4 (approx. 10 ml) was condensed into a trap at -78 °C and was then warmed to 0 °C. Fe(acac)3 (0.355 g) and chlorobenzene... 

Concentrated sulphuric acid reddish-brown vapours of nitrogen dioxide, accompanied by pungent acid vapours of nitric acid which fume in the air, are formed on heating the solid nitrate with the reagent. Dilute sulphuric acid has no action (difference from nitrite) ... 

As is known (Vol. I). alkanes can be nitrated in vapour phase by nitric acid or nitrogen dioxide. Nitration with nitric acid at temperatures of 400-435 C (method of Hass, Vol. I. p. 86) became a well established commercial method of making nitroalkanes. A considerable number of papers mainly by Hass and co-workers (Vol. 1) and Titov (Vol. I) gave both theoretical and practical foundations for this remarkable process and subsequently less theoretical work has appeared. Less attention was paid to the nitration of alkanes with nitrogen... 

For these reasons, only nitrous oxide and NOv (x = 1 or 2) can be identified in practice in the air, if we disregard HNO, formed by the interaction of nitrogen dioxide and water vapour (see later). 

One of the first products of thermal deterioration, i.e. in the absence of light, is the highly reactive, highly toxic oxidising agent nitrogen dioxide (N02), identified by its yellow vapour and distinctive odour. This is formed... 

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. 

Jenkin, M. E., Cox, R. A., and Williams. D. J. (1988) Laboratory studies of the kinetics of formation of nitrous acid from the thermal reaction of nitrogen dioxide and water vapour, Atmos. Environ., 22, 487-498. 

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