Nitric oxide vapor reactions

Nitrobenzene, blown in vapor form against the incandescent wire, decomposes violently, sometimes explosively, producing a charred mass and large quantities of nitric oxide. The reaction is moderated by diluting the vapors with aqueous vapor, but the obtainable products are so complex that their determination has not yet been accomplished (Lob 2). 

The catalytic activity of ln/H-ZSM-5 for the selective reduction of nitric oxide (NO) with methane was improved by the addition of Pt and Ir which catalyzed NO oxidation, even in the presence of water vapor. It was also found that the precious metal, particularly Ir loaded in/H-ZSM-5 gave a low reaction order with respect to NO, and then showed a high catalytic activity for the reduction of NO at low concentrations, if compared with ln/H-ZSM-5. The latter effect of the precious metal is attributed to the enhancement of the chemisorption of NO and also to the increase in the amount of NO2 adsorbed on in sites. 

As mentioned, the addition of a small amount of water to the bomb ensures that the vapor phase remains saturated throughout the experiment, so that liquid water is produced in the combustion reaction. It also ensures that the mixture of nitric oxides formed by the oxidation of the N2 will be converted to NOjT(aq), which is simple to determine. 

In the late 1960s, direct observations of substantial amounts (3ppb) of nitric acid vapor in the stratosphere were reported. Crutzen [118] reasoned that if HN03 vapor is present in the stratosphere, it could be broken down to a degree to the active oxides of nitrogen NO (NO and N02) and that these oxides could form a catalytic cycle (or the destruction of the ozone). Johnston and Whitten [119] first realized that if this were so, then supersonic aircraft flying in the stratosphere could wreak harm to the ozone balance in the stratosphere. Much of what appears in this section is drawn from an excellent review by Johnston and Whitten [119]. The most pertinent of the possible NO reactions in the atmosphere are... 

Sakamaki, F., S. Hatakeyama, and H. Akimoto, Formation of Nitrous Acid and Nitric Oxide in the Heterogeneous Dark Reaction of Nitrogen Dioxide and Water Vapor in a Smog Chamber, Int. J. Chem. Kinet., 15, 1013-1029 (1983). 

Several patents exist on the use of mixtures of nitrogen dioxide (N02) and nitric oxide (NO) as the reactant for the preparation of Y-nitroso compounds of secondary amines, both in the liquid and in the vapor state, usually in a flow reactor [31,32]. These reactions are not limited to dialkyl amines, as the earlier... 

Ozone is produced in substantial concentrations by industrial activity and, indirectly, from automobile exhausts. The most important sequence of reactions producing tropospheric ozone begins with hydrocarbon vapors, nitric oxide, and sunlight ... 

From the thermodynamic data of Appendix C, show that the product of the reaction of ammonia gas with oxygen would be nitrogen, rather than nitric oxide, under standard conditions and in the absence of kinetic control by, for example, specific catalysis of NO formation by platinum. (Assume the other product to be water vapor.)... 

In the presence of water vapor, another reaction involving nitric oxide and nitrogen dioxide occurs. The overall reaction can be written... 

Bone and co-workers [4] studied the formation of nitric oxide in the combustion of carbon monoxide and arrived at some very strange results, e.g., yields of nitric oxide exceeding equilibrium values, a sharply negative influence of water vapor and hydrogen, etc. Bone concluded that the reaction of nitrogen with oxygen is caused by activation of the nitrogen by radiation from the carbon monoxide flame. 

The formation of 1,2-dimethylcyclobutene (Formula 385) in the vapor phase irradiation of 2,3-dimethyl-l,3-butadiene (Formula 384) is not quenched by oxygen or nitric oxide (169). Addition of inert vapor (diethyl ether) increased the quantum efficiency in this reaction (169). The inert vapor presumably removes excess vibrational energy from the product cyclobutene thus stabilizing the product (169). Rate studies on the cis- and Jrans-isomers of 1,3-pentadiene in solution indicate that the iraras-isomer is the only source of 3-methylcyclobutene (169). The photoisomerization to 3-methylcyclobutene is faster than photoisomerization of trans- to m-l,3-pentadiene (169). 

Nitric oxide, NO, can be reduced by hydrogen gas to yield nitrogen gas and water vapor. The decomposition is believed to occur according to the reaction mechanism shown above. 

The practical motivation for understanding the microscopic details of char reaction stem from questions such as How does the variability in reactivity from particle to particle and with extent of reaction affect overall carbon conversion What is the interdependence of mineral matter evolution and char reactivity, which arises from the catalytic effect of mineral matter on carbon gasification and the effects of carbon surface recession, pitting, and fragmentation on ash distribution How are sulfur capture by alkaline earth additives, nitric oxide formation from organically bound nitrogen, vaporization of mineral constituents, and carbon monoxide oxidation influenced by the localized surface and gas chemistry within pores ... 

Ammonia gas enters the reactor of a nitric add plant mixed with 25 percent more dry air than is required for the complete conversion of the ammonia to nitric oxide and water vapor. If the gases enter the reactor at 185(°F) [85°C], if conversion is 85 percent, if no side reactions occur, and if the reactor operates adiabatically, what is the temperature of the gases leaving the reactor Assume ideal gases. 

In a subsequent study by Holmes and Sundaram the photolysis of hydrogen iodide in the presence of nitric oxide was run at 6 °C and —20 °C. The products at these two temperatures include important amounts of N2, which is insignificant at 25 °C, as well as I2, H2, and H2O. The major difference between the 25 °C results and those at lower temperatures is attributed to the much lower vapor pressure of I2 at 6 and —20 °C. Since runs were made at NO/HI > 4 and the experiments at 25 °C indicate all the H atoms are scavenged by NO at these concentration levels. Holmes and Sundaram assume that all the H2 arises from the reaction of HNO with HI in the products. 

Vapor Sttate. Here the situation is much simpler. Ionic species are no longer present, and in the absence of nitric oxide the choice lies merely between nitrogen dioxide and dinitrogen tetroxide. The proportions vary very much with temperature at 21.15° C., the tetroxide is 15.9% dissociated, whereas dissociation to NO2 is complete at 140°. It does not necessarily follow, however, that reaction at low temperatures involves dinitrogen tetroxide, as reaction with olefins clearly shows. 

Photoeffects with Ti02 in carbon monoxide, hydrogen, and water vapor have been sought 118, 128), but none have been found. Marked photo-reactions do occur, however, with nitric oxide and with the dye chlorazol sky blue 128, 129). 

Nitrogen dioxide is consumed in the reaction, probably as a result of the reaction of nitric oxide and the organic vapor, indicating that nitrogen dioxide is more than the radiation absorber. 

FIGURE 4-39 The acid deposition process. Acid precursors, notably oxides of nitrogen and sulfur, are emitted to the atmosphere, primarily by fuel-burning equipment. Acid precursors are oxidized in the atmosphere to nitric and sulfuric acids by a variety of homogeneous and heterogeneous reactions. The acids are deposited by precipitation-related processes such as washout and rainout, by sorption of nitric acid vapor, and by dry deposition of acidic particulate material such as ammonium sulfate aerosol. (Stern et ah, 1984.)... 

Reaction of material A was similar to that of powdered uranium dioxide, although a higher temperature, 400°C, was required to initiate the reaction. Reaction of material A was completed at 450°C. The temperature of the melt was reduced to 275°C following the completion of the oxidation reaction, and nitric acid vapor was added as in previous experiments. 

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