Nitrite salts

Nitrous acid or nitrite salts may be used to catalyze the nitration of easily nitratable aromatic hydrocarbons, eg, phenol or phenoHc ethers. It has been suggested that a nitrosonium ion (NO + ) attacks the aromatic, resulting initially in the formation of a nitro so aromatic compound (13). Oxidation of the nitro so aromatic then occurs ... 

Palladium and Palladium Alloys. Palladium is used in telephone equipment and in electronics appHcations as a substitute for gold in specific areas. Palladium is plated from ammoniacal and acid baths available along with chelated variations as proprietary processes. One typical alkaline bath uses 8 g/L diammine-dinitropalladium, 100 g/L ammonium nitrate, and 10 g/L sodium nitrite. The pH is adjusted to 9—10 using ammonium hydroxide, and the bath is operated at 100 A/m at 50° C. If ammonium sulfamate, 100 g/L, is used in some baths to replace the nitrate and sodium nitrite salts, the bath is mn at lower temperature, 25—35°C, and a pH of 7.5—8.5. A palladium—nickel alloy, 75% Pd, is plated from a bath having 6 g/L palladium from the same salt, 3 g/L nickel from nickel sulfamate concentrate, and 90 g/L ammonium hydroxide. The bath is operated at 20—40°C with 50-100 A/m/... 

The formation of nitrosamines, e.g. n-nitrosodiedianolamine, which are possible human carcinogens, can occur in synthetic or semi-synthetic fluids which contain a nitrite salt and diethanolamine or triethanolamine. 

Tertiary aliphatic amines react in the cold to give nitrite salts and these decompose on warming to give nitrosamines and alcohols ... 

Some exceptions to this general observation were found halide and nitrite salts have unusually high hydrogen-bond basicities (as would be expected), while penta-cyanopropionide, picrate, triflate, and perfluorobezenesulfonate salts not only had unusually low hydrogen-bond basicities (also as would be expected) but also lower s values, perhaps due to the weakening of the Coulombic interactions by delocalization of the charge on the anions. 

When mixed with Na thiosulfate or cyanide salts and heated, violent explns occur. A similar reaction occurs if an ammonium salt is melted with a nitrite salt. NaN02 at 460°F in contact with the fiber drums in which it is shipped undergoes a vigorous decompn reaction producing a proplnt-type burning until the carton is consumed (Ref 6)... 

In classical organic chemistry, nltrosamlnes were considered only as the reaction products of secondary amines with an acidified solution of a nitrite salt or ester. Today, it is recognized that nitrosamines can be produced from primary, secondary, and tertiary amines, and nltrosamides from secondary amides. Douglass et al. (34) have published a good review of nitrosamine formation. For the purposes of this presentation, it will suffice to say that amine and amide precursors for nitrosation reactions to form N-nitroso compounds are indeed ubiquitous in our food supply, environment, and par-... 

Another case of high nitrosamine concentration in chlorinated phenoxy- and benzoic acid herbicides was resolved by the elimination by the manufacturer of nitrite salts in the formu-... 

The first widely used intermediates for nucleophilic aromatic substitution were the aryl diazonium salts. Aryl diazonium ions are usually prepared by reaction of an aniline with nitrous acid, which is generated in situ from a nitrite salt.81 Unlike aliphatic diazonium ions, which decompose very rapidly to molecular nitrogen and a carbocation (see Part A, Section 4.1.5), aryl diazonium ions are stable enough to exist in solution at room temperature and below. They can also be isolated as salts with nonnucleophilic anions, such as tetrafluoroborate or trifluoroacetate.82 Salts prepared with 0-benzenedisulfonimidate also appear to have potential for synthetic application.83... 

See Other NITRITE SALTS OF NITROGENOUS BASES, OXOSALTS OF NITROGENOUS... 

Nitrite salts inhibit the sometimes explosive spontaneous polymerisation of N-vinylpyridine derivatives . 

See entries hydrazinium salts, nitrite salts of nitrogenous bases... 

Heating a mixture of an ammonium salt with a nitrite salt causes a violent explosion on melting [1], owing to formation and decomposition of ammonium nitrite. Salts of other nitrogenous bases behave similarly. Mixtures of ammonium chloride and sodium nitrite are used as commercial explosives [2], Accidental contact of traces of ammonium nitrate with sodium nitrite residues caused wooden decking on a truck to ignite [3],... 

See wood, below also nitrite salts of nitrogenous bases 1,3-Butadiene... 

Diazotization can be carried out without difficulty in 90-96% sulfuric acid, however. Nitrous fumes are given off as soon as aqueous solutions of nitrite salts are added to sulfuric acid of lower concentration, but solid sodium nitrite can be dissolved in 90-96% sulfuric acid at 0-10 °C smoothly and without evolution of gas. Nitrosylsulfuric acid, NO+HS04-, is formed. Directions for the preparation of 2 M nitrosylsulfuric acid are given by Fierz-David and Blangey43, but sodium hydrogen sulfate crystallizes after some time from acid of this strength so that it is best to prepare a stock solution of 1 M sodium nitrite in 96% sulfuric acid, which is quite stable at room temperature. 

Metal nitrites react with salts of nitrogenous bases to give the corresponding nitrite salts, many of which are unstable. 

Ray, P. C. et al., J. Chem. Soc., 1911, 99, 1470 1912, 101, 141, 216 Ammonium and substituted-ammonium nitrite salts exhibit a range of instability, and reaction mixtures which may be expected to yield these products should be handled with care. Ammonium nitrite will decompose explosively either as the solid, or in cone, aqueous solution when heated to 60-70°C. Presence of traces of acid lowers the decomposition temperature markedly. Hydroxylammo-nium nitrite appears to be so unstable that it decomposes immediately in solution. Hydrazinium(l+) nitrite is a solid which explodes violently on percussion, or less vigorously if heated rapidly, and hydrogen azide may be a product of decomposition [1], Mono- and di-alkylammonium nitrites decompose at temperatures below 60-70°C, but usually without violence [2], Individual entries are ... 

POLY(AMINIUM) PERCHLORATES, NITRITE SALTS OE NITROGENOUS BASES... 

Nitric oxide also can be made by reactions of nitric acid, nitrate, or nitrite salts with metals, metal oxides, or sulfates. Several metals react with nitric acid liberating nitric oxide. (See Nitric Acid, Reactions). For example, action of 1 1 nitric acid on copper turnings forms nitric oxide ... 

The U.S. Food and Drug Administration (FDA) regulates the addition of nitrate and nitrite salts to fish products. Maximum permitted levels vary among products and types of fish, with up to 500 ppm residual sodium nitrate or 200 ppm sodium nitrite permitted as a preservative and color fixative in smoke cured sable fish, shad, or salmon (Code of Federal Regulations, 1981a,b Committee on Nittite and Alternative Curing Agents in Food, 1981). 

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