Nitric oxide with bromine

The reaction of nitric oxide with bromine to form nitrosyl bromide has not been so thoroughly investigated. 

Bodenstein has, however, shown that the combination of nitric oxide and oxygen 2N0 + 02 = 2N02 is a homogeneous change which is kinetically of the third order, and the same appears to apply to the combination of nitric oxide with chlorine and with bromine f and to the reaction between nitric oxide and hydrogen. J 2NO + C12 = 2NOC1 2NO + Br2 = 2NOBr 2NO + H2 = N20+H20... 

Detection.—Apart from naturally occurring ores of vanadium, vanadium steels, and ferrovanadium, the commonest compounds of vanadium are those which contain the element in the pentavalent state, viz. the pentoxide and the various vanadates. The analytical reactions usually employed are, therefore, those which apply to vanadates. Most vanadium ores can be prepared for the application of these reactions by digesting with mineral acids or by alkaline fusion with the addition of an oxidising agent. When the silica content is high, preliminary treatment with hydrofluoric acid is recommended. Vanadium steels and bronzes, and ferrovanadium, are decomposed by the methods used for other steels the drillings are, for instance, dissolved in sulphuric acid and any insoluble carbides then taken up in nitric acid, or they are filtered off and submitted to an alkaline fusion. Compounds of lower valency are readily converted into vanadates by oxidation with bromine water, sodium peroxide, or potassium permanganate. 

Although glucose has some of the properties expected of an aldehyde, it lacks others. For example, it forms certain carbonyl derivatives (e.g., oxime and cyanohydrin), and can be reduced to the hexahydroxyhexane (sorbitol), and oxidized with bromine to gluconic acid (a monocarboxylic acid). (With nitric acid, oxidation proceeds further to give the dicarboxylic acid, D-glucaric acid.)... 

Aldoses can be degraded by the following two reactions. First the aldehyde is oxidized with bromine water to form a carboxylic acid. Next the carboxylic acid is decarboxy-lated with hydrogen peroxide and ferric sulfate leaving an aldehyde. The new aldose is one carbon shorter. When glucose is degraded in this manner, and the product is oxidized by dilute nitric acid, an optically active compound is formed. 

The constitution of this substance was settled by oxidation with bromine to give a stable 7-lactone, and with nitric acid to give L(+)-di-methoxysuccinic acid.24... 

Trimethyl-D-lyxofuranose was obtained by the hydrolysis of the products obtained by the methylation of methyl D-lyxofuranosides (ttf3 mixture).63 The product (XLVII) on oxidation with bromine, gave 2,3,5-trimethyl-D-lyxonolactone which was hydrolyzed extremely slowly in aqueous solution, and on oxidation with nitric acid followed by esterification methyl meso-dimethoxysuccinate was obtained. 

Show the products of the common reactions of monosaccharides that were presented in this chapter oxidation with nitric acid, oxidation with bromine, reduction with... 

Aldoses oxidized with bromine. Aldaric acid obtained after nitric acid oxidation. Pyridine contained water. Reactions carried out in deuterium oxide. Am-berlite IRA-400 (OH). 

Practice Problem A Show that the following mechanism is consistent with the experimentally determined rate law of rate = A[NO] [Br2] for the reaction of nitric oxide and bromine 2NO(g) + Br2(g)------ 2NOBr(g). 

Tribromoacetic acid [75-96-7] (Br CCOOH), mol wt 296.74, C2HBr302, mp 135°C bp 245°C (decomposition), is soluble in water, ethyl alcohol, and diethyl ether. This acid is relatively unstable to hydrolytic conditions and can be decomposed to bromoform in boiling water. Tribromoacetic acid can be prepared by the oxidation of bromal [115-17-3] or perbromoethene [79-28-7] with fuming nitric acid and by treating an aqueous solution of malonic acid with bromine. 

Cyclooctadiene is reacted with bromine to make fire-retardants. Cyclododecane is oxidized with air and then nitric acid to make a diacid containing 12 carbons. This acid is used to prepare some types of nylon, and its esters are used in synthetic lubricating oils. 

Nitric acid is also useful as an oxidant for the formation of sulphate from sulphones. Two such methods have been developed, firstly the established AOAC method which involves oxidation with a mixture of nitric acid and bromine S and secondly the Carius method. The latter is probably the oldest method used for the determination of sulphones as sulphate. This oxidation procedure involves heating the sulphone with concentrated nitric acid and sodium chloride at 280-300 °C in a sealed tube. The traditional method as described is prone to explosions. This problem may be alleviated by using less nitric acid whilst employing an oxygen atmosphere ". The Carius method is slower than the other oxidation methods described above but it usually yields the best results. 

D-glucose and its lactone from 2,3,6-trimethyl-D-glucose provided conclusive proof that the ring system was not of the hexylene oxide type.142 188 The final evidence necessary to characterize the tetramethylglucose in question as a furanose derivative was provided by Haworth, Hirst and Miller,176 who demonstrated that oxidation of the tetramethylglucose with bromine water and of the resulting lactone with nitric acid yielded dimethoxysuccinic acid and oxalic acid, but not i-zyZo-trimethoxyglutaric acid, the absence of which ruled out a pyranose structure. 

Especial care is required when working with the following much used substances hydrocyanic add, phosgene, dimethyl sulphate, the lower add chlorides, chlorine, bromine, nitric oxide and nitrogen peroxide, carbon monoxide, sodium, and potassium. Large scale operations with these should be carried out in a special room in any case always in a good fume chamber. 

The original procedure for the bromination-oxidation-reduction route used bromine in aqueous potassium hydroxide, followed by oxidation with nitric acid-hydrogen peroxide and reduction with alkaline ethanol. This procedure was improved by using NBS in aqueous sodium bicarbonate for the initial oxime bromination, followed by oxidation with nitric acid and final reduction of the Q -bromonitroalkane with sodium borohydride in methanol. It is possible to convert oximes to nitroalkanes via this procedure without isolating or purifying any of the intermediates. This procedure is reported to give yields of between 10 and 55 % for a range of oxime to nitroalkane conversions. ... 

Bromine reacts with cold nitric oxide forming nitrosyl bromide, NOBr, and nitrosyl tribromide, NOBrs. 

On the other hand, nitrosyl bromide is ineffective. This may be attributed to the fact that the reagent is extensively dissociated to afford nitric oxide and molecular bromine. Furthermore, in the case of some amides, reaction with nitrosyl bromide results in the formation of complex crystalline compounds containing reactive bromine. 

---