2,4-Dinitrotoluene concentration

The method was used for routine monitoring of dinitrotoluene concentrations in seawater from Dokai Bay, Japan. Both 2,6- and 2,4-dinitrotoluene were detected. Concentrations of 2,4-dinitrotoluene in surface water samples were higher than those in bottom water samples in 8 out of 10 samples. 

FIGURE 2.20 Reduction of 2,4-dinitro-toluene by platinum prior charged in Nal/DMF at a potential of -1.8 V versus SCE. Maximum charge 52 C. Dinitrotoluene (concentration 10 mmol.L ) was dissolved in dry DMF maintained under insert atmosphere (Simonet, J., Unpublished results). 

Toluene, Proceed as for Benzene but use 0-5 ml. of toluene and a mixture of 3 ml. of concentrated sulphuric acid and 2 ml. of fuming nitric acid. Gently warm the mixture over a free flame for 1-2 minutes, cool, and pour into 20 ml. of ice water. Recrystalhse the product from dilute alcohol. 2 4-Dinitrotoluene, m.p. 71°, is obtained. 

Place 18 g. (12 ml.) of fuming nitric acid, sp. gr. 1 5, and 30 g. (16-5 ml.) of concentrated sulphuric acid and a few fragments of broken glass in a 250 or 500 ml. round-bottomed flask. Add gradually, in small portions, 14 g. of p-nitrotoluene do not allow the temperature to rise above 50 and cool the flask, if necessary, by immersion in cold water. Place a small funnel in the mouth of the flask and heat on a water bath at 90-95° for 30 minutes. Allow to cool almost to the laboratory temperature and pour the reaction mixture slowly into about 500 ml. of ice water containing a few small pieces of ice. Filter the crude dinitrotoluene through a Buchner funnel at the pump, wash it thoroughly with cold water, and drain as completely as possible. RecrystalUse from the minimum volume of hot methyl alcohol (flask, reflux condenser, and water bath experimental details as in Section IV,12). The yield of pure 2 4-dinitrotoluene, m.p. 71°, is 12 -5 g. 

Mixtures of HNO, H2SO4, and SO also result in high concentrations of NO/, and toluene can be readily nitrated at —40 to — 10°C as a result (6). At these low temperatures, the formation of the meta-isomer of mononitrotoluene (MNT) is greatiy reduced. Such a reduction is highly desired in the production both of dinitrotoluenes (DNTs) employed to produce intermediates for polyurethane production and of trinitrotoluene (TNT), which is a high explosive. > -MNT results in the production of undesired DNT and TNT isomers (see Nitrobenzene and nitrotoluenes). 

Organic Reactions. Nitric acid is used extensively ia iadustry to nitrate aHphatic and aromatic compounds (21). In many iastances nitration requires the use of sulfuric acid as a dehydrating agent or catalyst the extent of nitration achieved depends on the concentration of nitric and sulfuric acids used. This is of iadustrial importance ia the manufacture of nitrobenzene and dinitrotoluene, which are iatermediates ia the manufacture of polyurethanes. Trinitrotoluene (TNT) is an explosive. Various isomers of mononitrotoluene are used to make optical brighteners, herbicides (qv), and iasecticides. Such nitrations are generally attributed to the presence of the nitronium ion, NO2, the concentration of which iacreases with acid strength (see Nitration). 

Dinitrotoluenes are produced hy nitration of toluene with a mixture of concentrated nitric and sulfuric acid at approximately 80°C. The main products are 2,4- and 2,6-dinitrotoluenes ... 

Nitrobenzene, 2,4-dinitrotoluene and 2,6-dinitrotoluene were determined in water by GC-EC or GC-CLD thermal energy analyzer (TEA) and by EI-MS, CI-MS and NICI-MS455, after solid-phase microextraction (SPME) with polydimethylsiloxane coated fiber. SPME is a technique to concentrate organic compounds dissolved in an aqueous matrix by adsorption on a solid stationary phase immobilized on a fused silica fiber. The analytes were thermally desorbed directly into the GC injector LOD was 9 pg/L for nitrobenzene and 15 pg/L for the dinitrotoluenes456. 

Biological. When 2,4 dinitrotoluene was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, significant biodegradation with gradual acclimation was followed by deadaptive process in subsequent subcultures. At a concentration of 5 mg/L, 77, 61, 50, and 27% losses were observed after 7, 14, 21, and 28-d incubation periods, respectively. At a concentration of 10 mg/L, only 50, 49, 44, and 23% were observed after 7, 14, 21, and 28-d incubation periods, respectively (Tabak et al, 1981). 

During World War II, copious quantities of ordnance were lost into the harbor at Halifax, Nova Scotia. Decades later, these UUXO now present a significant environmental contamination problem. Studies conducted on this ordnance by Sandia National Laboratories [1] suggest that there may be sufficient concentrations of explosive chemical signature compounds emanating from UUXO to enable detection with chemical sensors. Some UUXO in Halifax Harbor have been shown to produce parts-per-billion levels of explosives in the water near the ordnance. In addition to the parent explosive compound (TNT), other explosive-related compounds such as 2,4-dinitrotoluene (2,4-DNT) were detected, as were degradation products of TNT such as 4-amino-2,6-dinitrotoluene (4-ADNT), and... 

The crude diaminotoluene (Note 12) is dissolved in eight times its weight of benzene (212 g.) at 70°, and the solution is filtered quickly through a hot Biichner funnel (Note 13) with moderate suction (Note 14). The filtrate is cooled to 25° and the mother liquor is decanted from the brown crystals. The mother liquor is concentrated to a volume of 25 cc. by distillation under atmospheric pressure, and then cooled to 25°. The mother liquor is decanted from the diaminotoluene and the entire product is dried in the air. The yield is 22.5 g. (81 per cent of the theoretical amount based on the diaminotoluene sulfate used 74 per cent based on the dinitrotoluene used) of a product which melts at 98°. 

The use of iron and a little hydrochloric acid (or alternatively of iron and acetic acid) is to be preferred when the use of the more strongly acidic medium leads to the formation of undesirable by-products nuclear chlorination, for example, often results when tin or zinc is used in association with concentrated hydrochloric acid. A suitable experimental procedure for the reduction of 2,4-dinitrotoluene to 2,4-diaminotoluene has been described.23... 

As Haber and Weiss (1934) suggested, at lower H202 concentrations and fixed Fe2+ the oxidation reaction approaches second order however, when the ratio of H202 Fe2+ increases, the reaction kinetic approaches zero order and the reaction process depends on the competition between hydroxyl radicals and superoxide radicals. If an excess of hydrogen peroxide is present, then the reactions as shown in Equation (6.123) and Equation (6.124) for 2,4-dinitrotoluene are dominant. The amount of H202 was used up quickly in this study, indicating the importance of Equation (6.123). At concentrations of Fe2+ greater than 600 mg/L, the DRE of BTX reached a maximum value at approximately 82% for benzene and toluene and 73% for xylene. 

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