Bromite

Chlorite ion is oxidized rapidly to chlorine dioxide by ozone at pH 4, yielding one mol CIO2 per mol O3 when chlorite is in excess (k > lO" (39). The oxidation of bromite to bromate by ozone is too rapid to measure. Chlorine dioxide is oxidized rapidly to chlorate. Chlorate, bromate, and iodate ions do not react with ozone. 

Methods for the analysis of hypobromite—bromite mixtures are given (74). 

Boiling the solution speeds the conversion of intermediate hypobromites and bromites to bromate. The less soluble bromate can be separated from the hahde by fractional crystallization. A method that is often more economical is the oxidation of bromides into bromates by hypochlorites in aqueous solution. This can be done by passing chlorine into an alkaline bromide solution (75) ... 

In opocinchenine the hydroxyl group must, therefore, be in the ortho-position relative to the point of attachment of the benzene ring to the quinoline nucleus. The relative positions of the two ethyl groups are determined by the fact that apocincheninic acid ethyl ether on oxidation with lead peroxide and sulphuric acid gives the lactone of hydroxyopo-cincheninic acid ethyl ether (I), which, on oxidation by sodium hypo-bromite, yields quinolylphenetoledicarboxylic acid (II). 

Chlorous acid is the least stable of the oxoacids of chlorine it cannot be isolated but is known in dilute aqueous solution. HOBrO and HOIO are even less stable, and, if they exist at all, have only a fleeting presence in aqueous solutions. Several chlorites have been isolated and NaC102 is sufficiently stable to be manufactured as an article of commerce on the kilotonne pa scale. Little reliable information is available on bromites and still less is established for iodites which are essentially non-existent. 

Crystalline barium bromite Ba(Br02)2-H20 was first isolated in 1959 it can be made by treating the hypobromite with Br2 at pH 11.2 and 0°C, followed by slow evaporation. Sr(Br02)2.2H20 was obtained similarly. 

Generally yields are good. R can be alkyl or aryl. Modern variants of the Hofmann rearrangement use lead tetraacetate" or iodosobenzene instead of hypo-bromite. 

Stage 1 Preparation of 2-Phenyl-2-Methoxy-Ethyl Bromide - 1.3 mols of tert-butyl hypo-bromite is added slowly and with agitation to a mixture of 107 grams (1 mol) of vinyi-benzene (styrene) and 250 mi of methanol (99%), kept at -10°C. When the addition of the reactant is finished, the mixture is allowed to return to ambient temperature, it is washed in water and dried on anhydrous NajS04. Rectification is effected in vacuo in order to obtain a colorless liquid BP,j = 113°C, BPj.j = 84°C, = 1,5429, yield = 76%. 

Treatment with sodium hypochlorite or hypobromite converts primary amines into N-halo- or N,N-dihaloamines. Secondary amines can be converted to N-halo secondary amines. Similar reactions can be carried out on unsubstituted and N-substituted amides and on sulfonamides. With unsubstituted amides the N-halo-gen product is seldom isolated but usually rearranges (see 18-13) however, N-halo-N-alkyl amides and N-halo imides are quite stable. The important reagent NBS is made in this manner. N-Halogenation has also been accomplished with other reagents, (e.g., sodium bromite NaBr02) benzyltrimethylammonium tribromide (PhCH2NMe3 Br3"), and NCS. The mechanisms of these reactions involve attack by a positive halogen and are probably similar to those of 12-47 and 12-49.N-Fluorination can be accomplished by direct treatment of amines °° or... 

The separation in Part a is obvious. Oxidation numbers confirm the other assignments. In Part b, recall that whereas the oxygen atom in H2 O has an oxidation number of-2, the oxygen atoms in H2 O2 have oxidation number -1. In Part c, the oxidation number of the bromine atoms in Br02 is -I3. Among the products, bromine is -H5 in Br03 and -1 in Br. Thus, bromite ions are oxidized to bromate ions in one half-reaction and reduced to bromide ions in the other half-reaction. 

Write formulas for each of the following compounds (a) sodium bromide, (b) sodium bromate, (c) sodium bromite, (d) sodium hypobromite, and (e) sodium perbromate. 

Since aldehydes are notoriously polymerizable and difficult to manipulate, the products of periodate oxidation are oftentimes further oxidized, with hypohalite, to carboxylic acids, or are reduced to the corresponding alcohols. Oxidation has been more usually employed than reduction, since acids frequently form crystalline salts and other conveniently prepared derivatives. A process of oxidation of these aldehydic products by hypo-bromite, in the presence of barium carbonate or strontium carbonate, was developed and used extensively by Hudson and his coworkers.107 110 194-199,90s Their method can best be illustrated by an example the further oxidation of the dialdehyde, VI, shown previously (see p. 16) to be obtained by the oxidation of the methyl a-D-aldohexopyranosides. The isolation of... 

C. 2-Methyl-2-nitrosopropane. A solution of sodium hypo-bromite is prepared by adding, dropwise, and with stirring over a 5-minute period, 57.5 g. (18.5 ml. or 0.360 mole) of bromine to a solution of 36.0 g. (0.900 mole) of sodium hydroxide in 225 ml. of water. The resulting yellow solution, contained in a 1-1. three-necked flask fitted with a mechanical stirrer, a thermometer, and a dry ice-acetone cooling bath, is cooled to —20°. A suspension of 26.7 g. (0.300 mole) of N-i-butylhydroxylamine in 50 ml. of water is added to the reaction flask with continuous stirring as rapidly as possible without allowing the temperature of the reaction mixture to exceed 0°. The reaction solution is... 

When used to treat bromide-ion bearing waste, the process will not produce bromite ion. 

Zum Hofmann-Abbau von aliphatischen und aromatischen Carbonsaure-amiden eignet sich die Umsetzung mit Natrium-bromit in waBrig-alkalischer Losung2 ... 

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