Nitrites and Nitrates

Nitrates have been formed by reaction of tetra-n-butylammonium nitrate or the nitrate form of Amberlyst A-26 resin with various sulphonate esters. The former report also documented 

It has been suggested that the active species in the ceric 

Peters, and M.A.Prazeres, Reel. Trav. Chlm. Pays-Bas, 1985, 104, 

Brandange and B.Lindquist, Acta Chem. Scand., Ser. B, 1985, 39, 589-H.Suzuki, H.Manabe, and M.Inouye, Chem. Lett., 1985, 1671. 

Sivanandaiah, S.Gurusiddappa, and D.Channe Gowda, Indian J. Chem., 1985, 24B, 1185. 

Nitroglycerin, dynamite, and TNT have now been replaced by simple mixtures of ammonium nitrate and ffiel oil (abbreviated ANFO). While ammonium nitrate and most modern explosives are inert unless set off by powerful detonators, there are 

Detonators are also commonly nitrogen compounds, with the mostwidelyused being lead(II) azide, Pb(N3)2, readily exploded by an electrical current or mechanical shock. The azide ion, Nj, is isoelectronic and isostructural with carbon dioxide. 

Excess amounts of nitrates in surface waters disturb natural equilibria and when present in drinking water, they are also hazardous to human health. In the presence of phosphates, nitrates cause eutrophization overpopulation of aquatic vegetation, which reduces the oxygen content in water during its decomposition, and later leads to the production of ammonia, thus threatening the life of aquatic organisms. 

Numerous cases of poisoning with nitrites from drinking water (mainly from individual sources) are recorded in the literature, many of them with fatal consequences. A content of nitrites above 30 mg 1 is considered as suspect and 40 mg results in methaemoglobinaemia in suckling children. 

Nitrates and nitrites can give rise to other effects. They are, for example, able to decompose carotene. Nitrates affect the activity of the thyroid gland, which plays an important role in the conversion of carotene to vitamin A. The interactions of nitrites with amines are, however, much more dangerous, since they result in the production of jV-nitroso compounds. Many of these compounds damage the liver and exhibit teratogenic and carcinogenic effects [5, 15]. 

Cyanides are among the most toxic substances of wastewaters and they can be leached out into natural waters. They can occur either as simple cyanides (NaCN, HCN), or as complex cyanides of various metals. Simple, water-soluble cyanides readily release hydrogen cyanide even in a neutral medium. HCN is a very weak and water-soluble acid. Hydrogen cyanide acts very rapidly as a poison and it exerts lethal effects even in very low amounts. The toxicity of complex cyanides is much lower than that of simple cyanides, on account of the stability of the complexes. 

The effect of the CN anion is based on blocking the tissue respiration or, more precisely, by blocking the cytochrome. After ingestion, it is rapidly absorbed by the stomach mucous membrane, however, it can also be absorbed by intact skin. It is metabolized mainly to SCN. The course of the acute poisoning depends on the amount of the substance ingested. In man, small doses result in cephalalgias, nausea, dizziness, accelerated 

A substituted 5-formyl-3-hydroxy-2H-l-benzopyran underwent smooth O-nitration at C-3 with fuming nitric acid, and was subsequently 

Kawahata, S.Takatsuto, N.Ikekawa, M-Murata, and S.Omura, Chem. Pharm. Bull., 1986, 21 3102. 

Abramovitch, M.M.Cooper, R.Jeyaraman, and G.Rusek, Tetrahedron Lett., 1986, 27, 3705. 

Kawazoe, Chem. Pharm. Bull., 1986, 34. 2298. 

1360—1340 cm . These are the symmetric and antisymmetric frequencies. A vibrational assignment for sodium nitrite has been given by Tarte [20], and Hafele [41], and Vratny et al. [54] have also discussed the spectra of some crystalline nitrates. 

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Sodium Nitrate and Sodium Nitrite. Nitrates and nitrites ate used in meat-curing processes to prevent the growth of bacteria that cause botulism. Nitrates have been shown to form low, but possibly toxic, levels of nitrosamines in certain cured meats. For this reason, the safety of these products has been questioned, and use is limited (80). 

The carcinogenicity of nitrosamines has created widespread concern over the safety of food products that are significant sources of nitrates and nitrites. Nitrosamines are readily formed by reaction of secondary amines with nitrites at acid pH, conditions which may occur in the gastrointestinal tract. 

Nitrates are found in fairly high concentrations in beets, spinach, kale, coUards, eggplant, celery, and lettuce. AdditionaHy, nitrates and nitrites are commonly used in the curing solutions of bacon, ham, and other cured meats. In cured meats, nitrates and nitrites control the growth of microorganisms, particularly Clostridium botulinum, and also serve as color preservatives. 

T. N. Blumer and co-workers, eds.. Effect of Nitrates and Nitrites in Food as Related to Health, Institute of Nutrition, University of North Carohna, Raleigh, 1973. 

C. Further warming to 65°C forms white iron sulfate monohydrate [17375-41 -6], FeSO H2O, which is stable to 300°C. Strong beating results in decomposition with loss of sulfur dioxide. Solutions of iron(II) sulfate reduce nitrate and nitrite to nitric oxide, whereupon the highly colored [Fe(H20) (N0)] ion is formed. This reaction is the basis of the brown ring text for the quaUtative deterrnination of nitrate or nitrite. 

Some reactors are designed specifically to withstand an explosion (14). The multitube fixed-bed reactors typically have ca 2.5-cm inside-diameter tubes, and heat from the highly exothermic oxidation reaction is removed by a circulating molten salt. This salt is a eutectic mixture of sodium and potassium nitrate and nitrite. Care must be taken in reactor design and operation because fires can result if the salt comes in contact with organic materials at the reactor operating temperature (15). Reactors containing over 20,000 tubes with a 45,000-ton annual production capacity have been constmcted. 

Inhibition of Nitrosamine Formation. Nitrites can react with secondary amines and A/-substituted amides under the acidic conditions of the stomach to form /V-nitrosamines and A/-nitrosamides. These compounds are collectively called N-nitroso compounds. There is strong circumstantial evidence that in vivo A/-nitroso compounds production contributes to the etiology of cancer of the stomach (135,136), esophagus (136,137), and nasopharynx (136,138). Ascorbic acid consumption is negatively correlated with the incidence of these cancers, due to ascorbic acid inhibition of in vivo A/-nitroso compound formation (139). The concentration of A/-nitroso compounds formed in the stomach depends on the nitrate and nitrite intake. 

Nitrate and Nitrite. Nitrate is usually present in trace quantities in surface waters but occasionally occurs in high concentrations in some groundwaters. If present in excessive amounts, it can contribute to the illness infant methemoglobinemia. Nitrate is an essential nutrient for many photosynthetic autotrophs. Nitrite is an intermediate in the reduction of nitrate as well as in the oxidation of ammonia it is also used as a corrosion inhibitor in some industrial processes. 

BS EN 13395 nitrate and nitrite nitrogen flow analysis and spectrometry... 

The reagent is employed for the determination of ammonia in very dilute ammonia solutions and in water. In the presence of interfering substances, it is best to separate the ammonia first by distillation under suitable conditions. The method is also applicable to the determination of nitrates and nitrites these are reduced in alkaline solution by Devarda s alloy to ammonia, which is removed by distillation. The procedure is applicable to concentrations of ammonia as low as 0.1 mgL-1. 

Nitraminoalcohols. See under Aminoalcohols, Nitrated and Nitrited in Vol 1, A179-L to A180-L... 

The oxides of nitrogen are somewhat sol in w, reacting with it in the presence of oxygen to form nitric and nitrous acids. This is the action that takes place deep in the respiratory system. The acids formed are irritants, causing congestion of the throat and bronchi, and edema of the lungs. The acids are neutralized by the alkalies present in the tissues, with the formation of nitrates and nitrites. The latter may cause some arterial dilation, fall in blood press, headache and dizziness, and there may be some formation of methemoglobin. However, the nitrite effect is of secondary importance... 

RC(N02MCH2)nNH(CH2)xC(N02)3 and yield Pb block values of approx 140 (TNT=100) and Ballistic Mortarvalues of approx 140 (TNT=100). See also Amines, Nitrated and Nitrited in Vol 1, A174-Rto A177-R... 

Diverse and sometimes contrasting types of kinetic behaviour have been described for the decompositions of salts in this class, which includes the metal carbonates, sulphates, nitrates and nitrites, phosphates, oxyhalides, permanganates and chromates (Sects. 3.1—3.7, respectively). It is con-... 

Anhydrous nitrates and nitrites are often difficult to prepare and residual water can hydrolyze the reactant with the formation of basic... 

Nitrates and nitrites are first reduced to nitrosyl chloride with thionyl chloride. The volatile nitrosyl chloride then reacts with 4-aminobenzenesulfonic acid to yield a diazonium salt that then couples with 8-hydroxyquinoline to form a colored azo compound. Hence, the coupling reagent is applied to the chromatogram first. 

Nitrate and nitrite ions yield orange-brown to magenta-red chromatogram zones on a pale yellow background immediately on treatment with ammonia these zones are stable for days in an atmosphere of ammonia. 

Note When combined with thin-layer chromatographic separation the reagent provides a specific detection method for nitrate and nitrite. The color development is often completed within a few minutes on silica gel plates. In the absence of ammonia vapor traces of oxides of nitrogen in the laboratory atmosphere can slowly cause the background to become reddish-brown. The simultaneous presence of the following ions in the chromatogram zones interferes with the detection of nitrate/nitrite I , 10J, IO4, MoO and H2PO2. 

Gomez Arrayas R, Adrio J, Carretero JC (2006) Recent applications of chiral ferrocene ligands in asymmetric catalysis. Angew Chem Int Ed 45 7674—7715 Dai LX, Hou XL (2010) Chiral ferrocenes in asymmetric catalysis. Wiley-VCH, Weinheim Rigaut S, Delville MH, Losada J, Astrac D (2002) Water-soluble mono- and star-shaped hexanuclear functional organoiron catalysts for nitrate and nitrite reduction in water syntheses and electroanalytical study. Inorg Chim Acta 334 225-242... 

DiChristina TJ (1992) Effects of nitrate and nitrite on dissimilatory iron reduction by Shewanella putrefaciens 200. J Bacteriol 174 1891-1896. 

This salt is used as an inhibitor for the polymerisation of butadiene. It seems to play its role very well when its concentration is lower than 0.5%. If the concentration is greater than 5%, a black precipitate forms which contains 80% of organic polymer containing nitrate and nitrite groups in the proportions of 2 1. This solid combusts spontaneously at 150 C even when there is no air. 

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