Nitrates formation

Mercurous Nitrate. Mercurous nitrate [10415-75-5] Hg2N20 or Hg2(N02)2, is a white monoclinic crystalline compound that is not very soluble in water but hydrolyzes to form a basic, yellow hydrate. This material is, however, soluble in cold, dilute nitric acid, and a solution is used as starting material for other water-insoluble mercurous salts. Mercurous nitrate is difficult to obtain in the pure state directly because some mercuric nitrate formation is almost unavoidable. When mercury is dissolved in hot dilute nitric acid, technical mercurous nitrate crystallizes on cooling. The use of excess mercury is helpful in reducing mercuric content, but an additional separation step is necessary. More concentrated nitric acid solutions should be avoided because these oxidize the mercurous to mercuric salt. Reagent-grade material is obtained by recrystaUization from dilute nitric acid in the presence of excess mercury. 

Seefeld S, JA Kerr (1997) Kinetics of reactions of propionylperoxy radicals with NO and NOj peroxypropio-nyl nitrate formation under laboratory conditions related to the troposphere. Environ Sci Technol 31 2949-2953. 

In the presence of nitrates, formate and ammonia can be destroyed in another reactor at 150°C, according to the following equations ... 

Decompose salts containing the catalyst precursors such as metal nitrates, formates, oxalates, or acetates. (Oxides are the usual products of the decomposition process.)... 

It was found that the HIV envelope glycoprotein in vitro increases the production of NO by human monocyte-derived macrophages [114]. NO production is increased in patients who have AIDS [115], and the increased concentrations of nitrite in AIDS patients with opportunistic infections is caused by T gondii, Pneumocystis carinii, Mycobacterium tuberculosis, and Mycobacterium avium, whereas nitrite concentrations are normal in symptom-free patients. It was also confirmed that there was increased production of NO in the sera of children with HIV-1 infection, and of circulating cytokines, such as interleukin lp, tumor necrosis factor a, and interferon y. It is postulated that rises in the concentrations of these cytokines may represent a substantial stimulation of NO production [116]. In contrast, it has been shown that there was no altered endogenous nitrate formation in eight patients with AIDS, most of whom had opportunistic infections [117]. It has also been noted that there were high... 

Escherichia coli [NiFe] hydrogenase 3 Membrane-associated component of the formate hydrogen lyase complex H2 production during fermentation H2 uptake under anaerobic conditions Anaerobiosis, carbon source limitation, phosphate limitation, molybdenum, nitrate, formate 7.8... 

The relative importance of the heterc eneous and photochemical nitrate formation pathways can be assessed from recently measured aerosol nitrate profiles. " On humid days, a midmoming nitrate... 

Water extract of the dried seed at a concentration of 2 mg/mL was active on macrophages. Nitrate formation was used as an index of the macrophage stimulating activity to screen effective foods """. Weight-gain inhibition. Seed oil administered subcutaneously to mice at a dose of 0.05 mL/animal was active. Brain weight also decreased after 210 days of dosing " . 

Seefeld, S and J. A. Kerr, Kinetics of the Reactions of Propi-onylperoxy Radicals with NO and N02 Peroxypropionyl Nitrate Formation under Laboratory Conditions Related to the Troposphere, Enriron. ScL Technol., 31, 2949-2953 (1997). 

Nitrous acid/nitrite can also be oxidized in the aqueous solutions found in the atmosphere in the form of fogs, clouds, and particles. Nitrite is well known to be slowly oxidized in the dark to nitrate by dissolved oxygen in the liquid phase. However, it has been reported that the rate of this oxidation increases remarkably during freezing of the solution containing the nitrite (Takenaka et al., 1992, 1996). Figure 7.11, for example, shows the rate of nitrate formation in a nitrite solution at 25°C and in one with the cooling bath at — 21°C (Takenaka et al., 1992). This unusual phenomenon has also been observed with respect to the... 

Tanner, R. L, A. H. Miguel, J. B. de Andrade, J. S. Gaffney, and G. E. Streit, Atmospheric Chemistry of Aldehydes Enhanced Peroxyacetyl Nitrate Formation from Ethanol-Fueled Vehicular Emissions, Environ. Sci. Technol., 22, 1026-1034 (1988). 

However, as expected from the chemistry discussed in Chapter 7.E, simultaneous control of NH3 has a significant effect on particle nitrate formation, since the formation of ammonium nitrate is a major mechanism for conversion of gaseous HN03 to particulate nitrate. Thus, Meng et al. (1997) predict that a 50% reduction in both NO. and NH3 would give about the same reduction in particulate nitrate. 

Kasibhatla, P., W. L. Chameides, B. Duncan, M. Houyoux, C. Jang, R. Mathur, T. Odman, and A. Xiu, Impact of Inert Organic Nitrate Formation on Ground-Level Ozone in a Regional Air Quality Model Using the Carbon Bond Mechanism 4, Geophys. Res. Lett., 24, 3205-3208 (1997). 

Nil, + HN03 NH4N03 Ammonium nitrate formation/ decomposition Dec R9... 

Common Pathways for Loss of Nitric Acid (Without Artifact Particulate Nitrate Formation). Introduction. Loss of HN03 can result from sorption on the surfaces of sampler inlets and inlet lines this situation is common to all collection procedures for atmospheric HN03. Such inlet losses are rarely determined, so it is difficult to assess the accuracy of atmospheric HN03 measurements or to pinpoint the source of bias between methods in intermethod comparisons (e.g., see reference 26). In addition to sampler-associated losses, N03 can be lost from samples during storage. 

A second pathway in this reaction results in organic nitrate formation (9, 17, 18). The size and structure of the organic group controls the yield of reaction 16b relative to 16a. 

Thus, copper and platinum give similar results the nitrite formation is greater with iron, nickel, and cobalt, and the nitrate formation less. The gases were mainly nitrous oxide and nitrogen with a small proportion of oxygen. N. D. Zelinsky and S. G. Krapiwin showed that the decomposition of hydroxylamine into acid and base does not occur in soln. with methyl alcohol as solvent. J. Tafel showed that an aq. soln. of hydroxylamine sulphate in presence of 20-50 per cent, of sulphuric acid is not reduced at a copper cathode. O. Flaschner observed some reduction in dil. sulphuric acid soln. J. Tafel and H. Hahl found that reduction always takes place when the sulphuric acid cone, in the layer of electrolyte in contact with the cathode is reduced beyond a certain point, and when there is no excess of acid in other words, when hydroxylamine sulphate itself is electrolyzed, the reduction is quantitative. These results are most readily accounted for on the view that only free hydroxylamine (produced in this case by partial hydrolysis of the sulphate), but not the hydroxylammonium ion, NH3OH, is reduced at a copper... 

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