TNT purification

The most recent UK Royal Ordnance Factory (ROF) continuous process for the manuf of TNT is described by Thomas (Ref 90b). It uses a novel method of achieving continuous counter-current contacting between heavy and light phases in the trinitration section and some of the washing stages . The plant is also designed to operate based on the use of 96—100% sulfuric acid in the trinitration stage instead of the oleum used at Radford TNT Purification. 

Crude TNT produced by either batch or continuous methods requires purification. The ultimate objective of TNT purification is to remove all those products which are more reactive than TNT itself (isomers, nitrocresols, nitro-benzoic acids, etc), or which can easily give oily exudation products, such as isomers or lower nitrated substances... 

Basic Explosives Manufacture. The major quantities and the toughest problems are here. They include a) acid waters, treated with lime or soda ash, chemical washes, spills, washdowns b) Red Water from TNT purification. A complex, brick-red soln of Na nitrate, Na sulfate, Na sulfite, Na nitrite, and about 17% organics which include sulfonated nitrotoluene isomers and complex, unidentified dye-bodies c) dissolved expls, eg, Pink Water which is approx lOOppm TNT in w d) suspended expl particles — dust and chips and e) sometimes solvents such as acet, benz, and dimethyl aniline... 

Ditta Vulcania, Factory in Fascia d oro, near Brescia (Shell Loading, Industrial Explosives, TNT Purification, Compression of Explosives) (Now closed) ... 

Gilbert, Recovery of Organic Values from TNT Purification Waste Water , Propellants and Explosives, (2) (1977), 118-125 68) L.K. 

It has been suggested that complete purification of the TNT is not really necessary in some cases, especially with modern bomb assembly and sealing techniques and the availability of additives to prevent exudation of cast TNT mixts (Ref 6). This proposal merits serious consideration in the light of the problems and energy loss involved in purification as discussed above. The use of low temp during the initial stages of nitration promises to substantially reduce formation of the meta isomers, which will correspondingly facilitate the purification step. This development is discussed under Preparation . Other refs to TNT purification are cited under "Refs (Refs 5,7,10 12)... 

Swedish-Norwegian Chematur and Norsk Spraengstoff industri method Purincation of TNT Purification by cr>stallizatkm Sulphiiation and drying of TNT French method British method German method Continuous method... 

After nitration, the crude TNT requires purification. The uitimate objective of TNT purification is to remove aii those products produced during nitration which are more reactive than TNT or which can easiiy give oiiy exudation products. Oii exudation from TNT is an undesirabie characteristic for the foiiowing reasons ... 

Extensive biodegradation of TNT and red water (a spent-sellite waste solution produced during the TNT purification process) by P. chrysosporium has been observed (29, 81). A large portion of the TNT was mineralized in these studies. The TNT mineralization rates were found to be proportional to the TNT concentration which may be related to the pseudo-first order kinetics observed for free radical mechanisms used by the fungus. This effect has also been observed for AmDNT (56) which suggests a free radical mechanism for the degradation of the AmDNT. When the concentration of TNT in cultures (both liquid and soil) approached that typically found in the environment, i.e., 10,000 mg/kg in soil and 100 mg/liter in water, approximately 20% of the TNT was converted to CO2 and 15% was AmDNT at 90 days (30). In both these cases, the TNT completely disappeared. 

Muraour, Henri (1881—1954). Fr scientist, a specialist in expls (Ingenieur general des poudres) and ballistics. Published more than 200 papers from WW1 thru 1952 (Ref 2) on expls, proplnts, combstn of proplnts, expl phenomena, antiflash agents, purification of TNT, theory of expl reactions, etc, as well as a widely read book (Ref 1)... 

In the purification of TNT the following impurities have to be removed (1) traces of nitric and sulfuric acids (2) unsymmetrical isomers (3) products of incomplete nitration (4) byproducts (tetranitromethane, trinitrobenzene, nitrobenzoic acids, nitrocresols, etc)... 

The first purification step is thorough washing of the TNT with hot water, in washing tanks or by emulsification, followed by neutralization with Na bicarbonate soln. This removes residual acids... 

Modern purification methods employ Na sulfite solns to react with the 0 and 7 -TNT isomers to form water soluble substances which can then be washed out of the desired a-TNT-However, these water washes form a blood-red soln — the bothersome red-water of TNT plants. Modern methods of disposing of red-water will be described in Section X... 

In all, the board submitted 32 recommendations as a result of its investigation. They include additional training for personnel in nitration and purification areas to enable them to cope with such emergency situations. The board also recommended the development of sensing equipment to uncover possible hazardous conditions earlier in the TNT manufacturing process . 

The purification of TNT to remove DNT and other exudation-causing impurities increased the brittleness of TNT-based cast expls. However, since DNT was known to be an effective plasticizer of NC in propint formulations, it was found that Octol + 0.45% plasticized high viscosity NC and Octol +... 

Pyridine Perchlorate is almost as powerful as TNT (Pb block expansion 95% TNT, 87% PA), but is much more sensitive to impact (FI 40% PA), being comparable to PETN in this respect (Refs 4 5). Kuhn (Ref 7) states that it can be detonated on impact, but is normally considered a stable intermediate, suitable for purification of pyridine. Occasionally explns have occurred when the salt was disturbed (Ref 11), which have been variously attributed to the presence of ethyl perchlorate, AP or chlorates. A safer preparative modification is described (Ref 8). It explds on heating to above 335°, or at a lower temp if AP is present (Ref 10). According to Mellor (Ref 9), the salt can expld violently in contact with metals, while Zacherl (Ref 6) describes a lab expln which occurred during the distn of pyridine liberated from its perchlorate... 

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. 

M. Altstein, A. Bronshtein, B. Glattstein, A. Zeichner, T. Tamiri, and J. Almog, Immunochemical approaches for purification and detection of TNT traces by antibodies entrapped in a sol-gel matrix. Anal. Chem. 73, 2461-2467 (2001). 

Iso-Trioil. A product resulting from the purification of crude TNT by recrystallization from nitric acid. This process has been used in Europe on a production scale however, the Sellite purification process was selected for use in the USA. Isotrioil has been found to be a satisfactory substitute for TNT in Dynamite consisting of ... 

Iso-Trioil Resulting from Nitric Acid Purification of Crude TNT , PATR-DB-TR 16-58 (Jan 1959)... 

A) Firm Rag. G. Mangiarotti, ItalP 528927 (1955) CA 53, 3598 (1959) [Purification of a mixture of T4 (RDX) and Tritolo (TNT) can be achieved by dissolving it at 45° in acetone, cooling to 25° and, after decantation, filtration, centrifugation and treatment with C or decolorizing earth, crystallizing in a vertical crystallizer. 

N) Ditto, Vol 3. Supplement Number One to Volume 1 (1943). Chap I (Analysis of acids including i Ilu strati on s of Berl pipette and Weighing pipette used at Keystone Ordn Works, Meadville, Pennsylvania) Chap II (Various laboratory procedures) Chap IV (Analysis of toluene used for manuf TNT) Chap V (Analysis of TNT) Chap VI [Analysis of Sellite (Na sulfite soln) used for purification of crude TNT] Chap VI [Analysis of "soda ash (crude Na carbonate)] Chap VI [Analysis of brimstone (crude sulfur) used for manuf sellite] Chap VII [Analysis of Tri-Oil (crude TNT), yellow waters, and red waters formed during manuf of TNT] ... 

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