P-Nitrotoluene,

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. 

Equip a I litre three-necked flask with a mechanical stirrer and a thermometer, and immerse the flask in a bath of ice and salt. Place 306 g. (283 ml.) of acetic anhydride, 300 g. (285 ml.) of glacial acetic acid and 25 g. of p-nitrotoluene in the flask, and add slowly, with stirring, 42 5 ml. of concentrated sulphuric acid. When the temperature has fallen to 5°, introduce 50 g. of A.R. chromic anhydride in small portions at such a rate that the temperature does not rise above 10° continue the stirring for 10 minutes after all the chromium trioxide has been added. Pour the contents of the flask into a 3 litre beaker two-thirds filled with crushed ice and almost fill the beaker with cold water. Filter the solid at the pump and wash it with cold water until the washings are colourless. Suspend the product in 250 ml. of cold 2 per cent, sodium carbonate solution and stir mechanically for 10-15 minutes filter (1), wash with cold water, and finally with 10 ml. of alcohol. Dry in a vacuum desiccator the yield of crude p-nitrobenzal diacetate is 26 g. (2),... 

AMENDS - AMINES,AROMTATIC - DIAMINOTOLUENES] (Vol2) p-Nitrotoluene [99-99-0]... 

Three products are possible from nitration of toluene o-nitrotoluene, rw-nitro-toluene, and p-nitrotoluene. All ar e formed, but not in equal amounts. Together, the ortho-and para-substituted isomers make up 97% of the product mixture the rneta only 3%. 

One way to assess the relative stabilities of these var ious intermediates is to examine electron delocalization in them using a resonance description. The cyclohexadienyl cations leading to o- and p-nitrotoluene have tertiar y car bocation character. Each has a resonance form in which the positive charge resides on the carbon that bear s the methyl group. 

Often the directing effects of substituents reinforce each other. Bromination of p-nitrotoluene, for exfflnple, takes place at the position that is ortho to the ortho, paradirecting methyl group and rneta to the meta-directing nitro group. 

C-Methylation products, o-nitrotoluene and p-nitrotoluene, were obtained when nitrobenzene was treated with dimethylsulfoxonium methylide (I)." The ratio for the ortho and para-methylation products was about 10-15 1 for the aromatic nucleophilic substitution reaction. The reaction appeared to proceed via the single-electron transfer (SET) mechanism according to ESR studies. 

Preparation of the prototype in this series, procaine (31). i.irts with the oxidation of p-nitrotoluene (27) to the corre-Hiding benzoic acid (28). This is then converted to the acid ll Inride (29) reaction of the halide with diethyl aminoethanol fiI lords the so-called basic ester (30). Reduction by any of a .fl ics of standard methods (e.g., iron and mineral acid, cata-Ivlic reduction) affords procaine (31). ... 

Nitration of toluene is the only important reaction that involves the aromatic ring rather than the aliphatic methyl group. The nitration reaction occurs with an electrophilic substitution hy the nitronium ion. The reaction conditions are milder than those for henzene due to the activation of the ring hy the methyl substituent. A mixture of nitrotoluenes results. The two important monosubstituted nitrotoluenes are o- and p-nitrotoluenes ... 

X. If the directing effects of the two groups reinforce each other, the situation is straightforward. In p-nitrotoluene, for example, both the methyl and the nitro group direct further substitution to the same position (ortho to the methyl = meta to the nitro). A single product is thus formed on electrophilic substitution. 

Influence of the Intensity of Stirring on the Rate of Nitration of p-Nitrotoluene. . . ... 

Fig 7a Influence of temperature on the yield of DNT, Nitration of o- and p-nitrotoluenes in nitrating mixtures with various concentrations of sulfuric acid (Kobe, Skinner and Prindle, Ref 45)... 

As in the case of MNT, agitation is important in increasing the MNT to DNT nitration rate. Orlova s data for the nitration of p-nitrotoluene with 4/74/23% nitric acid/sulfuric acid/water at 70° are shown in Fig 8... 

Fig 8 Influence of the intensity of stirring on the rate of nitration of p-nitrotoluene (Orlova, Ref 62)... 

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