Nitration Mixture

Methyl m-nitrobenzoate. In a 1 htre round-bottomed or bolt-head flask, fitted with a mechanical stirrer, place 102 g. (94 ml.) of pure methyl benzoate (Section IV,176) support a separatory funnel containing a mixture of 62 -5 ml, of concentrated sulphuric acid and 62 -5 ml. of concentrated nitric acid over the mouth of the flask. Cool the flask in an ice bath to 0-10°, and then run in the nitrating mixture, with stirring. 

Dinitration of toluene results in the formation of a number of isomeric products, and with a typical sulfuric—nitric acid nitrating mixture the following mixture ofisomers is obtained 75 wt % 2,4-dinitrotoluene [121-14-2] 19 wt % 2,6-dinitrotoluene [606-20-2], 2.5 wt % 3,4-dinitrotoluene [610-39-9], 1 wt %... 

Many plants outside of North America pfill or granulate a mixture of ammonium nitrate and calcium carbonate. Production of this mixture, often called calcium ammonium nitrate, essentially removes any explosion hazard. In many cases calcium nitrate recovered from acidulation of phosphate rock (see Phosphoric acid and the phosphates) is reacted with ammonia and carbon dioxide to give a calcium carbonate—ammonium nitrate mixture containing 21 to 26% nitrogen (23). 

The mechanism of the reaction is now well known due to a series of kinetic studies by Katritzky et al. (Table 31). The nature, free base or conjugate acid, of the substrate depends on the substituents in the pyrazole ring and on the acidity of the nitrating mixture. 

The question of what other species can be the active electrophile in nitration arises in the case of nitration using solutions of nitric acid in acetic anhydride. The solutions are very potent nitrating mixtures and effect nitrations at higher rates than solutions of nitric acid in inert organic solvents. Acetyl nitrate is formed in such solutions, and mty be the actual nitrating agent. 

The preeautions with any partieular explosive depends on the hazard. In die UK explosives are elassified as 1 - Gunpowder 2 - Nitrate mixture 3 - Nitro eompound 4 - Chlorate mixture 5 - Eulminate 6 - Ammunition and 7 - Eireworks. 

Pipette 25 mL of an aluminium ion solution (approximately 0.01 M) into a conical flask and from a burette add a slight excess of 0.01 M EDTA solution adjust the pH to between 7 and 8 by the addition of ammonia solution (test drops on phenol red paper or use a pH meter). Boil the solution for a few minutes to ensure complete complexation of the aluminium cool to room temperature and adjust the pH to 7-8. Add 50 mg of solochrome black/potassium nitrate mixture [see Section 10.50(C)] and titrate rapidly with standard 0.01 M zinc sulphate solution until the colour changes from blue to wine red. 

Pipette 25 mL of the bismuth solution (approx. 0.01 M) into a 500 mL conical flask and dilute with de-ionised water to about 150 mL. If necessary, adjust the pH to about 1 by the cautious addition of dilute aqueous ammonia or of dilute nitric acid use a pH meter. Add 30 mg of the xylenol orange/potassium nitrate mixture (see Section 10.50) and then titrate with standard 0.01 M EDTA solution until the red colour starts to fade. From this point add the titrant slowly until the end point is reached and the indicator changes to yellow. 

Pipette 25.0 mL of the 0.01 M calcium ion solution into a 250mL conical flask, dilute it with about 25 mL of distilled water, add 2mL buffer, solution, 1 mL 0.1M Mg-EDTA, and 30-40mg solochrome black/potassium nitrate mixture. Titrate with the EDTA solution until the colour changes from wine red to clear blue. No tinge of reddish hue should remain at the equivalence point. Titrate slowly near the end point. 

Procedure. Pipette 25 mL of the test solution (which may contain both calcium and lead at concentrations of up to 0.01 M) into a 250 mL conical flask and dilute to 100 mL with de-ionised water. Add about 50 mg of methylthymol blue/potassium nitrate mixture followed by dilute nitric acid until the solution is yellow, and then add powdered hexamine until the solution has an intense blue colour (pH ca 6). Titrate with standard (0.01 M) EDTA solution until the colour turns to yellow this gives the titration value for lead. 

Pipette 25 mL of the solution containing magnesium, manganese and zinc ions (each approx. 0.02M), into a 250 mL conical flask and dilute to 100 mL with de-ionised water. Add 0.25 g hydroxylammonium chloride [this is to prevent oxidation of Mn(II) ions], followed by 10 mL of the buffer solution and 30-40 mg of the indicator/potassium nitrate mixture. Warm to 40 °C and titrate (preferably stirring magnetically) with the standard EDTA solution to a pure blue colour. 

Influence of the Content of HN03 in Nitrating Mixtures on the Rates of... 

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)... 

Fig 12 Change of nitrogen content in nitrocellulose as a function of water concentration in nitrating mixtures according to Miles (Ref 44)... 

Composition of the nitrating mixture, % Composition of the spent acid, % Cellulose to acid ratio 1 j Nitrogen content of nitrocellulose. %... 

The nature of the electrophile in this nitrating mixture is still not wholly agreed upon whereas kinetic evidence can be interpreted as consistent with nitration by nitronium ion, the fact that substituents with lone pairs of electrons or it-electrons give markedly different ortho para ratios from other nitrating mixtures is usually conceded to be consistent with the electrophile being something other than the nitronium ion. The balance of evidence at present is in favour of pro-tonated acetyl nitrate being the electrophile. 

It is strongly recommended that our procedure1 not be used to prepare guanidine nitrate. Mixtures of ammonium nitrate and organic materials not much different from the mixture in the procedure are now used extensively as commercial explosives. The aqueous mixture of Note 101 is similar to some aqueous mixtures used in sizable quantities for rock blasting a confined mixture of this sort is especially hazardous. Only a few laboratories devoted to explosives research have the barricades and remote control devices needed to run this preparation of guanidine nitrate without risk. 

Caution The nitrating mixture consisting of fuming nitric acid and acetic anhydride is an extremely active one, and combinations of it and organic materials are potentially explosive. The nitration should be carried out behind adequate safety shields. Acetone cyanohydrin nitrate is moderately explosive (Note 6) and all operations with it, but particularly its distillation, should be carried out behind safely shields. 

The nitrating mixture should be colorless at this point. If it is not, 0.5 g. of urea should be added and the mixture air-sparged until colorless. 

The photochemical cyclisation of p.y-unsaturated ketoximes to 2-isoxazolines, e.g., 16—>17, has been reported <95RTC514>. 2-Isoxazolines are obtained from alkenes and primary nitroalkanes in the presence of ammonium cerium nitrate and formic acid <95MI399>. Treatment of certain 1,3-diketones with a nitrating mixture generates acyl nitrile oxides, which can be trapped in situ as dipolar cycloadducts (see Scheme 3) <96SC3401>. 

The internal transport numbers may be measured most accurately and precisely by the Klemm method, which was developed for the purpose of isotope separation. This method has the following merits (1) It is insensitive to a small amount of impurities, such as water. (2) Even in the region of very small concentration of an ion of interest, 12 can be measured accurately. (3) It can be applied to additive ternary systems. An apparatus for the Klemm method of measuring 12 in nitrate mixtures is shown in Fig. I. This cell developed for nitrates by Okada s group has the following advantages compared with other electromigration cells ... 

In the alkali and alkaline earth nitrate mixtures, the internal mobilities have been systematically investigated, the isotherms being shown in Fig. 15. The internal mobilities of the alkali ions as a function of the molar volume are much smaller than expressed by an equation such as Eq. (12). This means that the internal mobilities of the alkali ions, Mju, are modified by the tranquilization effect caused by the divalent cations. The M ik is assumed to be expressed by... 

Figure 15. Isotherms of internal mobilities in alkali-alkaline earth nitrate mixtures. The mobility of the alkali ion is always greater than that of the alkaline earth ion. (Reprinted from T. Koura, H. Matsuura, and I. Okada, "A Dynamic Dissociation Model for Internal Mobilities in Molten Alkali and Alkaline Earth Nitrate Mixtures,"/ Mol. Liq. 73-75 195, Fig. 4, Copyright 1997 with permission from Elsevier Science.)...

A DSC instrument was used to assess the possible consequences of a potential thermal runaway using post-nitration mixtures for evaluations (see Fig. 5.4-65). For the solvent process two minor peaks between 150 and 220 °C appeared, which correspond to thermal effects of -15 kJ/kg and -9 kJ/kg. In contrast, a large thermal effect (-730 kJ/kg) was observed for the reaction mixture from the water process, located between 90 and 160 °C. Based on these data the risk of a thermal runaway for both processes was assessed. 

---