Nitrogen converters

Sometimes, knowing only the magnitude of the equilibrium constant, it is possible to decide on the feasibility of a reaction. Consider, for example, a possible method for fixing atmospheric nitrogen—converting it to a compound—by reaction with oxygen ... 

In fuel-rich systems, there is evidence [8, 22, 23] that the fuel-nitrogen intermediate reacts not only with oxidizing species in the manner represented, but also competitively with NO (or another nitrogen intermediate) to form N2. This second step, of course, is the reason that NO yields are lower in fuel-rich systems. The fraction of fuel nitrogen converted to NO in fuel-rich systems can be as much as an order of magnitude less than that of lean or near-stoichiometric systems. One should realize, however, that even in fuel-rich systems, the exhaust NO concentration is substantially greater than its equilibrium value at the combustion temperature. 

Nitrogen converters Nitrobacter, Nitrosomonas, and Nitrococcus sp. are nitrifying bacteria that convert ammonia and nitrite to nitrate, causing corrosion and damage to concrete. 

Compound A is an ester but has within it an amine function. Acyl transfer from oxygen to nitrogen converts the ester to a more stable amide. 

This is a small monomeric enzyme (molecular weight around 20000) that catalyses reduction of a double bond between carbon and nitrogen, converting 7,8-dihydrofolate into 5,6,7,8-tetrahydrofolate (Fig. 14). Hydride is transferred from the 4-pro-R position of NADPH to C-6, N-5 acquiring a proton [64-66]. 

In this reaction a chloride migrates between silicon and the ammonium nitrogen, converting a zwitterionic hexacoordinate chelate (58) to a... 

This reaction is one of the most important industrial processes, with over 120 million tons of ammonia produced in 1990 worldwide. However, in spite of metal oxide catalysts introduced in the Haber-Bosch process in 1913 and improved since then, it is also a reaction that requires temperatures near 400° C and 200 atm pressure and that still results in a yield of only 15% ammonia. Bacteria, however, manage to fix nitrogen (convert it to ammonia and then to nitrite and nitrate) at 0.8 atm at room temperature in... 

Other oxidising agents, especially nitric acid and the oxides of nitrogen, convert some elements to oxides. Nitric acid, for example, oxidises sulphur to SO2 and SO3, and germanium and tin to GeOg and SnOg, respectively. 

Owing to the use of excess oxygen, various elemental species from waste convert into their highest oxidation form. For example, carbon converts to CO2, hydrogen converts to H2O, nitrogen converts to HNO3, sulfur converts to H2SO4, etc. Early reactors were simple tube reactors as shown in Fig. 3. 

Variance in the Conversion Percentage. Considerable variance in the fraction of nitrogen converted was observed among repetitions of runs with constant stoichiometry, net power input, and pressure. The data points plotted in Figure 4 include the maximum observed conversion levels for each stoichiometry. Sources of error in the experimental procedure which could have scattered the data down from maximum conversion were ... 

Mixtures of methane and nitrogen can be fed continuously to a thermal argon induction plasma maintained above 10,000 K. A rapid quench of the heated plasma mixture produces HCN, C2H2, and H2. Final yields of HCN, expressed as a fraction of the nitrogen converted, range between 3 and 70%, a function of the input stoichiometry. 

KEYWORDS ultra low sulfur, fuels, on-line process analyzers, thermal oxidation, pyrolysis, electrochemical sensors, nitrogen converters... 

Neutron activation analysis, 181 NIST 1084a, 51 NIST 1085b, 51 NIST 1634c, 51 Nitrogen converters, 152 Nuclear magnetic resonance spectroscopy, 255... 

Nitrosation. Nitric oxide (NO) reacts very slowly with primary or secondary amines unless oxygen is present to convert NO into N2O3 and N2O4. These two oxides of nitrogen convert primary and secondary amines into N-nitrosamines rapidly in either neutral or alkaline aqueous solutions. This reaction is insensitive to the basicity of the amine. Nitrogen oxides are common pollutants and some N-nitrosamines e.g., N-nitrosodimethylamine) are known to be carcinogens."... 

The difference in bonding in pyridine and pyrrole is reflected in their properties. Although both are weak bases, pyridine is 10 -10 times more basic than pyrrole. When pyridine acts as a Br0nsted base, protonation of nitrogen converts an unshared pair (N ) to a bonded pair (N—H) while leaving the aromatic system intact. 

Other experiments have also shown that amino acids disappear rapidly from the blood stream after intravenous injection without significant excretion of amino acids in the urine (23). This must indicate a tremendous avidity for these building stones of protein by all of the tissues. The eventual behavior of amino acids after they leave the blood stream is not known in detail, although it would seem that it probably differs very little basically from the metabolism of amino acids absorbed into the portal circulation. In other words, some are metabolized into nonprotein nitrogenous substances such as creatine, purine, etc. others are deaminized, the nitrogen converted to urea and the rest utilized as carbohydrate or to form other amino acids, the remainder are S3mthe-eized to form tissue or other protein, hormones, etc. That relatively little is lost as urea and that protrin synthesis actually occurs is shown... 

The first is a high pressure liquid nitrogen converter system (as shown on Figure 3), very much similar to the liquid oxygen systems currently in use in all new military iaircraft for airborne breathing applications. In this type of system the gas is stored in liquid form and converted to high pressure gas as... 

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