Nitric oxide hydrocarbons

In summary the concentration of ozone in the polluted atmosphere is controlled by the intensity of sunlight and the ratio of nitrogen dioxide to nitric oxide. Hydrocarbons and other pollutants—such as aldehydes, ketones, chlorinated hydrocarbons, and carbon monoxide—react to form peroxy radicals. These, in turn, react with nitric oxide, causing the ratio [NOjjilNO] to increase. As a consequence of Equation 2-5, the ozone concentration also increases. 

Glasson, W. A. Effect of carbon monoxide on atmospheric photooxidation of nitric oxide—hydrocarbon mixtures. Environ. Sci. Technol. 9 343-347, 1975. 

Nitric oxide Aluminum, BaO, boron, carbon disulflde, chromium, many chlorinated hydrocarbons, fluorine, hydrocarbons, ozone, phosphine, phosphorus, hydrazine, acetic anhydride, ammonia, chloroform, Fe, K, Mg, Mn, Na, sulfur... 

In a vacuum, uncoated molybdenum metal has an unlimited life at high temperatures. This is also tme under the vacuum-like conditions of outer space. Pure hydrogen, argon, and hehum atmospheres are completely inert to molybdenum at all temperatures, whereas water vapor, sulfur dioxide, and nitrous and nitric oxides have an oxidizing action at elevated temperatures. Molybdenum is relatively inert to carbon dioxide, ammonia, and nitrogen atmospheres up to about 1100°C a superficial nitride film may be formed at higher temperatures in the latter two gases. Hydrocarbons and carbon monoxide may carburize molybdenum at temperatures above 1100°C. 

An important side reaction in all free-radical nitrations is reaction 10, in which unstable alkyl nitrites are formed (eq. 10). They decompose to form nitric oxide and alkoxy radicals (eq. 11) which form oxygenated compounds and low molecular weight alkyl radicals which can form low molecular weight nitroparaffins by reactions 7 or 9. The oxygenated hydrocarbons often react further to produce even lighter oxygenated products, carbon oxides, and water. 

Similar chemical steps occur in the ambient air and in laboratory smog chamber simulations. Initially, hydrocarbons and nitric oxide are oxidized... 

In contrast to carbon monoxide, small hydrocarbon molecules and soot that result from incomplete conversion of the hydrocarbon fuels, nitric oxide and nitrogen dioxide, are noxious emissions that result from the oxidizer—air. However, fuel components that contain nitrogen may also contribute, in a lesser way, to the formation of the oxides of nitrogen. 

Based solely on this relationship, it has been predicted that the ozone concentration should be about 2 pphm at solar noon in the United States. Indeed [7], in unpolluted environments, ozone concentrations are usually in the range of 2-5 pphm. However, in polluted urban areas, ozone concentrations can be as high as 50 pphm. Peroxy radicals formed from hydrocarbon emissions cause this enhanced ozone concentration. These radicals oxidize nitric oxide to nitrogen dioxide, thereby shifting the above steady-state relationship to higher ozone levels. 

Praliaud, H., Mikhailenko, S., Chajar, Z. et al. (1998) Surface and bulk properties of Cu—ZSM-5 and Cu/A1203 solids during redox treatments. Correlation with the selective reduction of nitric oxide by hydrocarbons, Appl. Catal. B, 16, 359. 

Ravi, V., Mok, Y.S., Rajanikanth, B.S. et al. (2003) Temperature effect on hydrocarbon-enhanced nitric oxide conversion using a dielectric barrier discharge reactor, Fuel Processing Technology 81, 187-99. 

A comparison of catalyst activity and selectivities to hydrocarbon and C02 over the reduced air calcined and nitric oxide calcined 15% Co/Si02 catalysts is shown in Figures 3.1 through 3.4 and Table 3.3. Initial CO conversion at an SV of 10 Nl/g-cat/h over the reduced air calcined sample was 33%, but was significantly... 

These are analogous to the reactions postulated for hydrocarbon systems by Laidler et al.115,176. With certain hydrocarbons there is almost no inhibition region, and the main effect of nitric oxide is to accelerate the rate of decomposition as in the present instance. Further work on this interesting aspect of the decomposition of S2F10 is obviously desirable. In addition, attention should be given to the effects of inert gases on the orders of the individual reactions in the above mechanism, and on the rate of the heterogeneous reaction. 

The oxidation of carbon monoxide, 2CO + 02 — C02 is one of the reactions (apart from reduction of nitric oxides and oxidation of unbumt hydrocarbons) taking place in the car exhaust catalyst. The latter consists of small noble metal particles (Pt, Rh or Pd) on a ceramic support. The reaction proceeds through the following steps [25]... 

The relative importance of these three mechanisms in NO formation and the total amount of prompt NO formed depend on conditions in the combustor. Acceleration of NO formation by nonequilibrium radical concentrations appears to be more important in non-premixed flames, in stirred reactors for lean conditions, and in low-pressure premixed flames, accounting for up to 80% of the total NO formation. Prompt NO formation by the hydrocarbon radical-molecular nitrogen mechanism is dominant in fuel-rich premixed hydrocarbon combustion and in hydrocarbon diffusion flames, accounting for greater than 50% of the total NO formation. Nitric oxide formation by the N20 mechanism increases in importance as the fuel-air ratio decreases, as the burned gas temperature decreases, or as pressure increases. The N20 mechanism is most important under conditions where the total NO formation rate is relatively low [1],... 

A. Ueda, andM. Haruta, Nitric oxide reduction with hydrogen, carbon monoxide, and hydrocarbons over gold catalysts. Gold Bull. 32, 3-11 (1999). 

A very simple and effective method of increasing the intensity of Ti So transitions by several orders of magnitude was introduced by Evans 53-s5) Either the pure liquid or concentrated solutions of an aromatic hydrocarbon in chloroform were saturated with oxygen or nitric oxid at high pressures. The newly appearing absorption bands are proportional to the applied gas pressures from 0—100 atm. The So absorptions are in general well structured and the posi-... 

Diesel emissions contain low concentrations of carbon monoxide and hydrocarbons. The major problem with diesel emissions are nitric oxides and particles as these are the most difficnlt to rednce. 

Alkanes n-butene, isopentane, isooctane Cydoalkanes t dohezane, methylcyclopentane Olefins (sometimes called alkenes ) ethylene, propylene, butene Cydoolefins ( clohezene Alkynes acetylene Aromatics toluene, i ene CHLORINATED HYDROCARBONS ALDEHYDES, RCHO formaldehyde, acetaldehyde KETONES, RCX R " acetone, methylethylketone NITRIC OXIDE, NO ... 

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