Trinitrotoluenes unsymmetrical

Seliwanoff s test analy chem A color test helpful in the identification of ketoses, which develop a red color with resorcinol in hydrochloric acid. s3 liv3,nofs, test sellite liNORG chem A solution of sodium sulfite (Na2S03) used in the purification of 2,4,6-trinitrotoluene to remove unsymmetrical isomers. se,lTt ... 

Chemists at the Naval Air Warfare Center (NAWC), Weapons Division, China Lake, have reported many examples of polynitroarylamine synthesis via Bamberger rearrangements of arylnitramines. " " The nitration of 4-amino-2,5-dinitrotoluene (36) with a mixture of nitric acid and acetic anhydride in glacial acetic acid at room temperature yields the nitramine (37) which on treatment with neat sulfuric acid, provides 4-amino-2,3,5-trinitrotoluene (38) as the sole product. " Nitration of 3,4-dinitroaniline (39) with a solution of nitric acid in acetic anhydride yields A,3,4-trinitroaniline (40) acid-catalyzed rearrangement of the latter in neat sulfuric acid furnishes a 74 % yield of isomeric 2,3,4- (41) and 2,4,5- (42) trinitroanilines in a 4 6 ratio.Accordingly, a mixture of products can be expected when an unsymmetrical arylnitramine has two unsubstituted ortho positions available. 

The action of some inorganic substances on unsymmetrical isomers of trinitrotoluene is mentioned on p. 331, Vol. I. 

Crude TNT contains isomers and nitrated phenolic compounds resulting from side reactions. The usual method of purification is to treat crude TNT with 4% sodium sulfite solution at pH 8-9, which converts the unsymmetrical trinitro compounds to sulfonic acid derivatives. These by-products are then removed by washing with an alkaline solution. Pure TNT is then washed with hot water, flaked and packed. It is important to remove the waste acid and unsymmetrical trinitrotoluenes together with any by-products of nitration as they will degrade the TNT, reduce its shelf life, increase its sensitivity and reduce its compatibility with metals and other materials. Trace amounts of unsymmetrical trinitrotoluenes and by-products will also lower the melting point of TNT. TNT can be further recrystallized from organic solvents or 62% nitric acid. 

For TNT manufacture the presence of m- nitrotoluene in mononitrotoluene is naturally undesirable, as it is a source of unsymmetrical trinitrotoluenes. 

The reaction occurs with more difficulty than the corresponding one with the unsymmetrical trinitrotoluenes and requires a higher temperature or more concentrated solutions of sodium sulphite. The reaction of sulphitation of dinitro-toluene may be used in practice for removing m-nitrotoluene derivatives from mixtures of dinitro-isomers. Thus the sulphitation of trinitrotoluene becomes unnecessary. 

At higher temperatures, however, the a- trinitrotoluene undergoes a more drastic transformation. This is the result of both the action of Na2S03 and of the high pH of the solutions one N02 group is substituted by an S03Na group. Thus the reaction proceeds in essentially the same way as in the case of the unsymmetrical isomers. 

UNSYMMETRICAL ISOMERS OF TRINITROTOLUENE The following unsymmetrical trinitro derivatives of toluene are known ... 

The physical properties of the unsymmetrical isomers of trinitrotoluene are similar to those of a- trinitrotoluene. They are crystalline substances of a pale yellow colour, soluble in most organic solvents, insoluble in water and non-hygroscopic. 

HEATS OF COMBUSTION AND FORMATION OF UNSYMMETRICAL ISOMERS OF TRINITROTOLUENE... 

The unsymmetrical isomers of trinitrotoluene readily react with aqueous solutions of sodium or potasium hydroxide, forming salts of dinitrocresol (Will [37]) ... 

Brady [137] found that a concentrated solution of sodium acetate acted on unsymmetrical trinitrotoluene in a way similar to the action of weak alkalis, giving the corresponding dinitrocresols. Under such conditions less ill-defined amorphous products were obtained than in the reaction with strong alkalis, where they were formed in great quantities. 

Sodium hydroxide gives the following colour reactions with the unsymmetrical isomers of trinitrotoluene (Table 79). 

The unsymmetrical isomers of trinitrotoluene also give specific reactions with sodium carbonate and with lead oxide. The former also affects the ignition temperatures of the isomers. The corresponding data are tabulated below, in Table 80 (after Brunswig [141]). 

SPECIFIC REACTIONS OF THE UNSYMMETRICAL ISOMERS OF TRINITROTOLUENE WITH... 

Brady, Hewetson and Klein [139] studied the action of aromatic amines on unsymmetrical trinitrotoluene. They obtained diphenylamine derivatives, e.g. ... 

Brady, Hewetson and Klein [139] tried to elucidate the mechanism of the reaction of sulphitation of unsymmetrical trinitrotoluenes. They assumed the formation of an addition product of sodium sulphite and the nitro compound in the first stage. 

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. 

According to the British literature of World War I, the optimum temperature of sulphitation is 40-45°C. At higher temperatures a- trinitrotoluene reacts too vigorously, which results in a certain loss of the product. On the other hand, the action of sulphite on the unsymmetrical isomers at lower temperatures is too slow. 

In industrial practice, losses of crude TNT in the sulphitation process amount from 6 to 8%. Out of this 2%-3. 5% is ascribed to the loss of a- trinitrotoluene and 3.5-4.5% to that of unsymmetrical isomers and other impurities, such as tetrani-tromethane (p. 339) and trinitrobenzene which is easily soluble in sodium sulphite, forming addition products. 

The unsymmetrical isomers of trinitrotoluene are affected by light in an apparently similar way, as in the instance of a- isomer, turning brown on exposure to sun. However, the chemical nature of the process has not been investigated. 

Apart from the unsymmetrical isomers of trinitrotoluene, other by-products are formed in the nitration process, owing to oxidation or decomposition processes. 

Another extensive paper on the reaction of unsymmetrical trinitrotoluenes with ammonia leading to aminodinitroioluenes was that by Nielsen. Coon and co-workers [55]. The main purpose of this work was to identify the major com-... 

Unsymmetrically substituted trinitrotoluenes show a splitting of both bands, for example, 2,3.4-trinitrotoluenc show asymmetric 1572, 1558 and symmetric vibration 1360, 1347 cm". Similar bands are given by 2,3,5-, 2,3,6- and 3,4,5-trinitrotoluenes. 

Okamoto and Attarwala [159] brought an improvement to the reaction of Severin, by adding a cationic surfactant (as a phase transfer catalyst) to the reaction medium. They examined the reduction of unsymmetrically substituted -2,4,5- and 2,3,4-trinitrotoluenes by sodium borohydride in methylene dichloride at 23-24 C in the atmosphere of nitrogen in the presence of ethylhexadecyl-dimethylammonium bromide. 

Tfie excellent paper by Chandler, Kohibeck and BoUeter 68bl has drawn attention to the possible formation of the new by-products in the course of sulphitation of crude TNT ( sellite purilication ). The authors noted a high reactivity of sulphonic group in meta position which derives from the sulphitation of unsymmetrical trinitrotoluenes. They explain the formation of 3-mcthyl-2,4,4 6,6 -pentanitrodiphenylmethane (MPDM) fVIll) from 2,4,5-trinitrotoluene by the reactions (II) ... 

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