Nitration of toluene to TNT

This method, which proved to be more economical than direct nitration of Toluene to TNT, was used in the US until WWII, when Dr l.A. Grageroff introduced the so-called reverse process . This method was twice as rapid. 

On the basis of her own experiments and those reported in the literature Orlova [2a] came to the conclusion that the mechanism of nitration of toluene to TNT in heterogeneous conditions can be depicted in the following terms. 

The nitration of toluene to TNT is carried out by successive introduction of nitro groups. Such a method is justified from the points of view both of safety and economy as it permits the most efficient use of acids and produces a final product of high purity due to the purification of the intermediate products obtained in the separate stages of the process. 

The three-stage nitration of toluene to TNT comprises the following processes ... 

Fig. 85. Diagram of the British continuous nitration of toluene to TNT (according to McNab ([18]).

As stated in Chapter III, the ideal nitration of toluene to TNT would be toluene to 1-2 nitrotoluene, to 1-2-4 dinitrotoluene, to 1-2-4-6 TNT. But this... 

Ihe oxidation reduction process is involved in the formation of the w-tiite compound, a by-product of coniiiuious production of TNT 1541. Ihe formation of tins compound is discussed in the paragraph on by-products of nitration of toluene to TNT. 

During World War I, one stage nitration of toluene to TNT was carried out using a Hough nitrator (Vol. I, p. 157, Fig. 31). Tlie nilrator was filled with... 

The best yield, 95%, was obtained with the K salt (Ref 38). It is formed in small amts during the nitration of toluene to prepare TNT (Refs 37 38), and has been held responsible for exp Ins which have occurred in TNT mfg plants. 

The appropriate mixed acid compns for the nitration processes that produce militarily and industrially important expls will be described in Sections V VI. Typical MA compns for aromatic nitrations contain 110 to 200% nitric acid over the stoichiometric requirement. For the nitration of toluene to MNT DNT, a typical MA compn in round figures is 30% HN03,60% H2S04, 10% H20. For the nitration of DNT to TNT the MA contains no water and is approx 20% HN03, 80% H2S04... 

DNB has been synthesized in small quantities as a by-product in the nitration of toluene to form TNT (Mitchell and Dennis 1982). 

Oxidation leads to the formation of di- and tri-nitrocresols, impurities frequently met with in TNT. Nitrocresols are mainly formed during the nitration of toluene to mononitrotoluene (Noelting and Forel [11]). If they have not been removed from mononitrotoluene by washing with alkalis, they undergo either further nitration to trinitrocresol, or oxidation to oxalic acid. Trinitrocresol may be removed from TNT by mild alkali washing (e.g. with a NaHC03 or a sodium sulphite solution). 

As a simpler example of a complex reaction, consider the nitration of toluene to give TNT, 2,4,6-trinitrotoluene (kindly do this abstractly, not experimentally like the evil professor in Problem 1.13). The reaction is... 

In previous work, we had developed a nitration medium of nitrate salts (such as sodium nitrate and potassium nitrate) In oleum that was stable at 140°C, highly reactive, and nonoxldatlve on the substrate trlbromodinltrobenzene (2). Application of a similar mixture to the nitration of toluene under mild conditions revealed that dinitrotoluene was produced quantitatively In one step at room temperature. Subsequent work on equivalent anhydrous mixed acid systems produced similar results at temperatures as low as -13°C. Only nitration of dinitrotoluene to TNT required elevated temperatures and very strong acid. 

It is prepared by the direct nitration of toluene with a mixture of nitric and sulphuric acids. TNT is a very stable, violent and powerful high explosive, but less sensitive to shock and friction than picric acid. It is widely used as a filling for shells, bombs, etc. often mixed with ammonium nitrate and other high explosives. The lower grades of TNT may contain isomers which under hot storage conditions may give rise to exudation. 

Trinitrotoluene (TNT) is made by nitration of toluene. Display electrostatic potential maps for toluene, 4-nitrotoluene (the first nitration product) and 2,4-dinitrotoluene (the second nitration product). Are the second and third nitration steps likely to be easier or more difficult than the initial nitration of toluene Explain. 

In the production of TNT from the reaction between toluene and mixed acids (nitric/sulfuric), TeNMe forms in amounts between 0.2—0.4% of the total wt of TNT. This TeNMe has been held responsible for several expins which have occurred in TNT plants, causing fatal injuries to personnel and severe damage to facilities. These expins were attributed to the presence of TeNMe in the acid fume lines and the acid storage tanks. Mixts of TeNMe and readily oxidizable materials are known to form very powerful and sensitive expl mixts. Since TeNMe is also isolated from the nitration of Nitrobenzene (NB), the TeNMe formed in the nitration of toluene may arise from the oxidation of the aromatic ring and/or methyl group. In an effort to gain more informa-. tion on the origin of TeNMe from TNT production, radioactive carbon-14 (14C) was used as a tracer to determine the extent to which each of the carbon atoms in the toluene skeleton of the various nitro-substituted isomers contributes to... 

Red Water — which can be almost black at times - also contains dissolved TNT however, it is not an incidental stream like Pink Water it is a major by-product stream from TNT manuf. The mixed-acid nitration of toluene yields not only 2,4,6-trinitrotoluene, the desired product, but also a host of other isomers and by-products amounting to approx 4.5% of the total yield and it is necessary to remove them from the product. They are removed by extraction with a Na sulfite—Na carbonate soln which sulfonates and dissolves them the extract is called Red Water. Red Water is a very complex and somewhat variable mixt containing 15% or so of sulfonated or sellited nitrobodies and a number of inorganic salts. Typical components are w, NajSOj—NaS04, NaN02— NaNOj, sulfonated or... 

Two other derivatives of toluene are the important explosive trinitrotoluene (TNT) and the polyurethane monomer toluene diisocyanate (TDI). TNT requires complete nitration of toluene. TDI is derived from a mixture of dinitrotoluenes (usually 80% o,p and 20% o,o) by reduction to the diamine and reaction with phosgene to the diisocyanate. TDI is made into flexible foam polyurethanes for cushioning in furniture (35%), transportation (25%), carpet underlay (20%), and bedding (10%). A small amount is used in polyurethane coatings, rigid foams, and elastomers. 

Trinitrotoluene (TNT) was the most commonly used conventional military explosive during the twentieth century. Although it had been used extensively in the dye industry during late 1800s, it was not adopted for use as a military explosive until 1902, when the German army used it to replace picric acid. TNT was first used in warfare during the Russo-Japanese War (1904-1905). The US Army began its use in 1912. After an economical process was developed for the nitration of toluene, TNT became the chief artillery ammunition in World War I (1914—1918). The most valuable property of TNT is that it can be safely melted and cast alone or with other explosives as a slurry. 

TNT is the abbreviation of the aromatic nitrated aromatic compound 2,4,6-trinitrotoluene. It is a pale-yellow crystalline solid that was first synthesized in 1863 by the German chemist Joseph Wilbrand (1811—1894), but it was not immediately used as an explosive. TNT is made by nitrating toluene using nitric acid, sulfuric acid, and oleum (a mixture of sulfuric acid and S03). Nitration of toluene occurs in stages, with the nitro units added sequentially in a stepwise process as the reaction proceeds. The last nitro unit is accomplished by using oleum (SO, dissolved in sulfuric acid). After nitration, unused acids are recycled, and the product is washed with sodium sulfite and water to remove impurities. 

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