Reactions forming nitrosyl compounds

A number of the reactions of nitrous acid, and of nitric acid with more or less extensive contamination by nitrous acid, have been clarified by the recognition that nitrosyl derivatives are involved. Table 9 lists some examples of the intermediates formed with several reactants, together with the concentration terms which appear in the relevant rate equations and some rate coefficients, for the cases in which the nitrous acidium ion is believed to be involved. 

Among earlier studies to which such mechanisms appear relevant are investigations of the reaction of 

RATES OF REACTION WITH THE NITROUS ACIDIUM ION TO FORM NITROSYL 

The reaction with nitric acid was claimed to be second-order. The rate coefficients are reproduced between 20 and 80 °C by the expression 

This reaction is said ° to give up to 99 % conversion in a continuous process operating at 100 °C. 

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Many covalent nitrosyl compounds are effective nitrosating reagents in organic solvents. It is therefore not surprising to find that even low concentrations of nucleophilic anions promote nitrosation in aqueous solutions by forming nitrosyl compounds other than nitrous anhydride (nitrosyl nitrate). Most of the mechanistic evidence for these reagents comes from diazotisation studies either in halogen acids or catalysed by halide ions. We shall therefore confine our discussion to the reactions of nitrosyl halides. 

The organomercury compounds formed in such reactions are not of great synthetic importance, although they do undergo nitrosation reactions with nitrosyl chloride, NOCl. They can also be used as the organometallic component in certain palladium-mediated coupling processes. 

The NO + MF, (except NO -f WF,) reactions proceed spontaneously at 20°. The reactions were followed tensimetrically. Gaseous products were identified by infrared spectroscopy and the solid products were examined by. y-ray powder-photography. Both ReF, and OsF, formed NO+[MF,] (cub.) salts and neither salt could be induced to combine with more NO to yield the quadrivalent (NO),MF, compound. In their reactions with nitrosyl fluoride at 20°, however, the rhenium and osmium fluorides are clearly differentiated ReF, readily forms a thermally stable 2 1 adduct, which is isomorphous with (NOjjWFg, whereas the OsF, -i- ONF reaction is complex. The identification of small quantities of nitrogen oxide trifluoride, in the gaseous product of the reaction, indicate the existence of an... 

Incompatible with strong oxidizers acids, water (slowly decomposes, forming amine and carbon disulfide). Reaction with nitrosating compounds (i.e., nitrogen oxides, nitrosyl chloride, nitrite esters, metal nitrates and nitroso compounds, etc.) can cause the formation of carcinogenic N-nitrosodiethylamine. 

CICLOHEXENO (Spanish) (110-83-8) Forms explosive mixture with air (flash point <20°F/<—7°C. May polymerize from buildup of unstable peroxides. Violent reaction with strong oxidizers. Highly exothermic polymerization reaction with aluminum chloride. Violent reaction with aluminum chloride nitromethane, magnesium perchlorate, nitrosyl fluoride, ozone, peroxyformic acid. Incompatible with aluminum tetrahydroborate, fluorine. Forms explosive compounds with copper(I) perchlorate. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

TIN, TIN FLAKE, or TIN POWDER (7440-31-5) Finely divided material is combustible and forms explosive mixture with air. Contact with moisture in air forms tin dioxide. Violent reaction with strong acids, strong oxidizers, ammonium perchlorate, ammonium nitrate, bis-o-azido benzoyl peroxide, bromates, bromine, bromine pentafluoride, bromine trifluoride, bromine azide, cadmium, carbon tetrachloride, chlorine, chlorine monofluoride, chlorine nitrate, chlorine pentafluoride, chlorites, copper(II) nitrate, fluorine, hydriodic acid, dimethylarsinic acid, nitrosyl fluoride, oxygen difluoride, perchlorates, perchloroeth-ylene, potassium dioxide, phosphorus pentoxide, sulfur, sulfur dichloride. Reacts with alkalis, forming flammable hydrogen gas. Incompatible with arsenic compounds, azochlo-ramide, benzene diazonium-4-sulfonate, benzyl chloride, chloric acid, cobalt chloride, copper oxide, 3,3 -dichloro-4,4 -diaminodiphenylmethane, hexafluorobenzene, hydrazinium nitrate, glicidol, iodine heptafluoride, iodine monochloride, iodine pentafluoride, lead monoxide, mercuric oxide, nitryl fluoride, peroxyformic acid, phosphorus, phosphorus trichloride, tellurium, turpentine, sodium acetylide, sodium peroxide, titanium dioxide. Contact with acetaldehyde may cause polymerization. May form explosive compounds with hexachloroethane, pentachloroethane, picric acid, potassium iodate, potassium peroxide, 2,4,6-trinitrobenzene-l,3,5-triol. 

There are also other avenues by which -NO may serve a protective role in ischemia-reperfusion phenomena. Under these circumstances, known to include a high rate of production of oxygen free radicals, -NO can react with Oi to divert Oi through ONOO -dependent (and potentially less damaging) oxidative and decomposition pathways. Nitric oxide may also confer protection by reacting with iron to form iron-nitrosyl compounds. By binding free coordination sites of iron, -NO can limit Fenton chemistry and iron-dependent electron transfer reactions (Kanner etal., 1991 Ignarro,... 

Notes on the addition reactions of nitric oxide. Nitric oxide is an odd molecule, with an odd number of electrons. Probably because of this fact it is unusually active in forming coordination compounds. Examples of such coordination compounds and complex ions are (FeNO)++, [Co(NH3)6NO]++, CuNOCls-, FeNOCls, AINOCI3, Fe(CN)BNO", and the nitrosyl carbonyls, such as Co(CO)3NO. Many of these complexes are unstable and decompose on heating. They appear to be formed by the donation of either one or three electrons from the NO molecule thus in the nitroprusside ion, Fe(CN)5NO , produced by the action of nitric acid on a ferrocyanide, the nitric oxide is considered to contribute three electrons to the iron atom, leaving the latter in the ferrous rather than the ferric condition. Likewise the existence... 

Ketones having an a-methylene group, that is, —CH2 bound to the carbonyl group, can react with nitrous acid, nitrite esters, or nitrosyl chloride to form nitroso compounds and oximes. These reactions are catalyzed by acids or bases. 

Arsenic trifluoride (arsenic(III) fluoride), AsF, can be prepared by reaction of arsenic trioxide with a mixture of sulfuric acid and calcium fluoride or even better with fluorosulfonic acid. Chlorine reacts with ice-cold arsenic trifluoride to produce a hygroscopic soHd compound, arsenic dichloride trifluoride [14933-43-8] ASCI2F35 consisting of AsQ. and AsF ions (21). Arsenic trifluoride forms a stable adduct, 2AsF2 SSO, with sulfur trioxide and reacts with nitrosyl fluoride to give nitrosonium hexafluoroarsenate(V) [18535-07-4] [NO][AsFg]. 

Codeposition of silver vapor with perfluoroalkyl iodides at -196 °C provides an alternative route to nonsolvated primary perfluoroalkylsilvers [272] Phosphine complexes of trifluaromethylsilver are formed from the reaction of trimethyl-phosphme, silver acetate, and bis(trifluoromethyl)cadmium glyme [755] The per-fluoroalkylsilver compounds react with halogens [270], carbon dioxide [274], allyl halides [270, 274], mineral acids and water [275], and nitrosyl chloride [276] to give the expected products Oxidation with dioxygen gives ketones [270] or acyl halides [270] Sulfur reacts via insertion of sulfur into the carbon-silver bond [270] (equation 188)... 

The required nitrite esters 1 can easily be obtained by reaction of an appropriate alcohol with nitrosyl chloride (NOCl). The 3-nitroso alcohols 2 formed by the Barton reaction are useful intermediates for further synthetic transformations, and might for example be converted into carbonyl compounds or amines. The most important application for the Barton reaction is its use for the transformation of a non-activated C-H group into a functional group. This has for example been applied for the functionalisation of the non-activated methyl groups C-18 and C-19 in the synthesis of certain steroids. ... 

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