Reaction with sodium sulphite

Physical (including thermochemical and explosive) properties Chemical properties of 2,4,6-trinitrotoluene Reaction with sodium sulphite Oxidation of 2,4,6-trinitrotoluene Reduction of 2,4,6-trinitrotoluene Melhylation of 2,4,6-trinitrotoluene... 

Sulphonyl halides, other than fluorides, have also been produced by halide exchange. Thus, sulphonyl chlorides may be made from the fluoride by refluxing with aluminium trichloride622,623. Sulphonyl bromides may be prepared from the sulphonyl chloride by reaction with sodium sulphite and base, followed by bromine (equation 158)624... 

Reaction with sodium sulphite Other reactions Addition products... 

Elucidation of the structure of a-tnniirotolaene Kinetics of the nitration of dinitroioluene to trinitrotoluene Explosive properties of TNT Toxicity of a-trinitrotoluene Metabolism of iriniiroiolucne Uns mmctrical isomers of trinitrotoluenes Physical properties Thermochemical properties Heat of crystallization Heat of combustion and of formation Heat of nitration Chemical properties Reactions With alkalis Reaction with sodium sulphite Effect of light... 

The crude product contains isomers other than that required and also nitrated phenolic compounds resulting from side reactions. The usual method of purification is to treat the crude product with sodium sulphite, which converts asymmetric trinitro compounds to sulphonic acid derivatives, and to wash out the resulting soluble products with alkaline water. The purity of the product is determined by the melting point, the minimum value for Grade I TNT commonly being 80-2°C. Unless adequate purity is achieved, slow exudation of impurities can occur during storage and the TNT then becomes insensitive. 

The carbanions take up 02 and these take up protons to give hydroperoxides in good yields. But because they are explosive in nature, they are not usually isolated and on reduction with sodium sulphite on trialkyl phosphite give alcohols. Alcohols can also be prepared via hydroperoxy molybdenum complexes and alkyl boranes. These reactions are summarized as follows ... 

Reaction of Potassium lodate with Sodium Sulphite in a Sulphate Medium. Pour 20jml of a sodium sulphite solution acidified with sulphuric acid and containing a small amount of starch into a 100-ml beaker. Pour 20 ml of a potassium iodate solution into a second 100-ml beaker. The potassium iodate solution must contain... 

REACTION OF POTASSIUM lODATE WITH SODIUM SULPHITE... 

The action of heat on sulphites varies both with the temperature and with the nature of the metal concerned. With sodium sulphite, Na2S03, the chief reaction at 700° C. in vacuo is... 

General procedure for the reduction of N-chlorosulphonyl /3-lactams with sodium sulphite. A solution of N-chlorosulphonyl /1-lactam dissolved in ether is added slowly to a stirred mixture of about two parts of 25 per cent aqueous sodium sulphite and one part of ether. The aqueous phase is kept slightly basic by addition of 10 per cent potassium hydroxide solution as the reduction proceeds. The reaction course could easily be followed by t.l.c. in which the product has a considerably smaller RF value than the starting material. At the end of the reaction (usually less than 15 minutes) the ether layer is separated and dried and evaporated. The products are of greater than 95 per cent purity as determined by p.m.r. spectroscopy. The reaction may be carried out at 25 °C or at 0°C. 

The second stage is sulphonation with sodium sulphite (Figure 4.13) which adds the sulphonate group across the double bond. This, too, is an exothermic reaction and care must be taken to limit the temperature rise to avoid discolouration of the sulphosuccinate. 

One of the typical reactions of aromatic nitro compounds with two or more nitro groups is that with sodium sulphite. Here one of the nitro groups is replaced by a sulphonic group (as its sodium salt) and sodium nitrate is formed ... 

The reaction occurs particularly readily with nitro groups that are in the 0-and p- position to each other, i.e. with mobile nitro groups . As to meta- nitro groups they react less readily and require a higher temperature. Nitro derivatives of higher homologues of benzene with two or three nitro groups (such as di- and tri-nitro derivatives of m- xylene also react less readily, and trinitromesitylene does not react with sodium sulphite [35a]. 

As m- dinitrobenzene reacts with sodium sulphite with more difficulty, this reaction is now used for removing the o- and p- isomers from commercial dinitrobenzene (pp. 246-248). 

As Muraour [103] found, the reaction of sodium sulphite was not confined to unsymmetrical trinitro derivatives of toluene, a- Trinitrotoluene also reacted with Na2S03 to form dinitrotoluene sulphonic acid, the difference lying in the fact that the reaction proceeds much more slowly than with unsymmetrical isomers. A 3% solution of Na2S03, acting for 1 hr, dissolves at room temperature about 1% of a- trinitrotoluene. 

The reaction of lithium enolates with molecular oxygen has been used for the a-hydroxylation of several substrates. The carbanion generated in the reaction of N,N-dialkylamides or esters with alkyl lithium reagents undergoes rapid oxidation under mild conditions when treated with molecular oxygen. The reaction produces an a-hydroperoxide intermediate which is cleanly reduced with sodium sulphite to the a-hydroxo derivatives" (equation 1). 

The displacement of aromatic amino groups by sulphite, to form a sulphonic acid (or a sulphonate salt), gives rise to the genetic hazard of sulphites. Deamination or dehalogen-ation of the aromatic rings in nucleosides is a very facile reaction in which sulphonic acid salts are produced, either in vivo or in vitro192 199. For example, cytosine reacts with sodium sulphite to form the 6-sulphonate, by deamination, as shown in equation 28. 

Asymmetric dihydroxylation of the side-chain of Z-1-(4-meth-oxyphenyl)-1-(tert-butyldimethylsiloxy)-1-propene to give (R)-l-hydroxyethyl 4-methoxyphenyl ketone in 94% yield (99% e.e.) was effected by addition of the alkene to a stirred mixture of osmium tetroxide, potassium ferricyanide, potassium carbonate, a 9-0-(9 -phenanthryl)ether(PHN) of dihydroquinidine and 1 mole of methanesulphonamide in aqueous tert-butanol (1 1), with reaction during 16 hours at ambient temperature. Then treatment with sodium sulphite prior to work-up to gave the product (ref. 130). Other best ligands were the 9-0-(4 -methyl-2 -quinolyl) ethers (MEQ) of dihydroquinine. 

Reaction of 2.4.6-lriiiitrotoluene with sodium sulphite was extensively studied and reviewed by Cramplon and co-workers 49j. Strauss (50. Buncel and co-workers [51 ]. Bernasconi and co-workers [52). 

As known (Vol. I. p. 332) the reaction ol sodium sulphite with iirisynimetri-cal trinitrotoluenes is a major reaction in the purification of crude I N r. known under the name of Sellitc Process - sellite being the name of sodium sulphite solution. Sodium sulphite solutions have pi I > S.O. It is known how sensitive higher nitrated aromatic compounds are to bases and sodium sulphite (particularly at a temperature, for example, above 40 45 ( ) can produce a damaging effect on TNT. It is therefore advisable to add a certain amount of sodium bisulphite to sodium sulphite to keep the pH value as low as possible. According to Clift and Fedoroff [7 j 0.1 -0.3% NallSOj was added in the U.S.A as a buffer to keep the pi I value down. 

Addition methods were used for the determination of m-saturated compounds and olefins. The methods are based on the additions of bromine to unsaturated bonds, and the waves for the brominated compounds corresponding to the reduction of o, j8-dibromides (involving elimination) are measured. Their heights are proportional to the concentration of the unsaturated compound. Thus vinylchloride and 1,2-dichloroethylene were transformed into l-chloro-l,2-dibromoethane and l,2-dichloro-l,2-dibromoethane, by the action of a 3 M solution of bromine in methanol saturated with sodium bromide. The excess of bromine was removed with ammonia and the polarographic analysis was performed with sodium sulphite or lithium chloride as a supporting electrolyte. On the other hand, acetylene, vinyl-chloride, 1,2-dichloroethylene and 1,1,2-trichloroethylene were determined ) after a 24 hr reaction with bromine in glacial acetic acid (1 1). The excess bromine was removed with a stream of nitrogen or carbon dioxide. An aliquot portion is diluted (1 10) with a 3 M solution of sodium acetate in 80 per cent acetic acid and after deaeration the curve is recorded. 

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