O nitration

Nitroglycerine (7.6) is prepared by injecting highly-concentrated glycerine into a mixture of highly-concentrated nitric and sulfuric acids at a controlled temperature. 

The mixtures are constantly stirred and cooled with brine. At the end of the reaction the nitroglycerine and acids are poured into a separator, 

Transportation of nitroglycerine and similar nitric acid esters is very hazardous and only permitted in the form of solutions in non-explosive solvents or as mixtures with fine-powdered inert materials containing not more that 5% nitroglycerine. 

The manufacturing method used today for the nitration of cellulose employs a mixture of sulfuric and nitric acids. During nitration of the 

The reaction is able to take place without destroying the fibrous structure of the cellulose. The extent of nitration of the —OH groups is dependent on the reaction conditions, particularly the composition of the acid, the time and temperature of nitration. 

The manufacturing method used today for the nitration of cellulose employs a mixture of sulfuric and nitric acids. During nitration of the cellulose some of the —OH groups in the molecules are replaced by the nitrate groups —ONO2 as shown in Reaction 7.8. 

Millar and Philbin ° reported using dinitrogen pentoxide in methylene chloride at subambient temperatures for the nitrodesily lation of silylamines (33) and silylamides. The methodology, which results in nitramines (34), nitramides and nitroureas in excellent yields, is well suited for the synthesis of energetic materials and we believe it will find wide use in the future. 

Solutions of dinitrogen pentoxide in anhydrous nitric acid are unlikely to find wide use for the industrial synthesis of nitrate esters - synthesis from the parent alcohol is relatively straightforward and so this reagent, which is more expensive than mixed acid, holds few advantages. 

Nitric acid is formed during these reactions and in some cases the addition of sodium fluoride as a base can be advantageous. This is the case with higher carbohydrates like cellulose and 

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The phenomenon has also been observed in the AT-nitration of iV-methyl-2,4,6-trinitroaniline and the O-nitration of alcohols. ... 

Nitration is defined in this article as the reaction between a nitration agent and an organic compound that results in one or more nitro (—NO2) groups becoming chemically bonded to an atom in this compound. Nitric acid is used as the nitrating agent to represent C-, 0-, and N-nitrations. O-nitrations result in esters. N-nitrations result in nitramines. 

O-nitration, in which a nitro group is attached to an oxygen atom to form a nitrate ester,... 

As already mentioned (Section 1), the,prepn of most of the commonly used high expl compds involves one or more nitration reactions. Indeed, except for ammonium nitrate (AN), primary expls, and BkPdr, it is difficult to bring to mind any expl in common use (or even a laboratory curiosity) that was not prepared by nitration. In Table 1, we list the most important military and commercial high expl compds produced by nitration. We have grouped these compds by nitration type, ie C-nitration, O-nitration, and N-nitration. Note that either nitric acid or mixed acid are the nitrating agents principally employed in industry. This will be discussed further in the next section. The Table also gives Encyclopedia references for those compounds already described in previous Encyclopedia volumes... 

Compound Common Name or Abbreviation O-Nitration Usual Nitrating Agent Encyclopedia Reference... 

Modern practice tends to continuous methods, but many nitrated materials are still produced by batch processes. Below, we will describe the technology of manuf of TNT and NM, examples of C-nitmtion NG and NC, examples of O-nitration,... 

Nitric acid also undergoes reactions with organic compounds wherein the acid serves neither as an oxidizing agent nor as a source of hydrogen ions. The formation of organic nitrates by esterification (O-nitration) involves reaction with the hydroxyl group ... 

Ten coordination has also been observed in Pr(H20)6(N03)3 (382). The Pr(III) ion is surrounded by three bidentate nitrate groups and four water molecules in a bi-capped dodecahedral fashion. The average Pr—0(H20) distance (2.47 A) is slightly shorter than the four Pr—O(nitrate) distances (2.73 A). The Pr—0 distances for the third nitrate group are significantly shorter than the rest ( 2.48 A). 

The extractabilities of metal-organic complexes depend on whether inner or outer sphere complexes are formed. Case 1, section 4.2.1, the extraction of ura-nyl nitrate by TBP, is a good example. The free uranyl ion is surrounded by water of hydration, forming U02(H20)f, which from nitric acid solutions can be crystallized out as the salt U02(H20)6 (N03), though it commonly is written U02(N03)2(H20)6. Thus, in solution as well as in the solid salt, the UOf is surrounded by 6 HjO in an inner coordination sphere. In the solid nitrate salt, the distance du.o(nitrate) between the closest oxygen atoms of the nitrate anions, (0)2N0, and the U-atom is longer than the corresponding distance, du-o(water), to the water molecules, OH2, i.e., du.o(nitrate) > 4u.o(water) thus the nitrate anions are in an outer coordination sphere. 

Commercial 70 % nitric acid can be used for the 6>-nitration of low molecular weight alcohols like ethanol and 2-propanol. The nitrate ester products are isolated from the cautious distillation of a mixture of the alcohol and excess 70 % nitric acid. The presence of urea in these reactions is very important for the destruction of nitrous acid and its omission can lead to very violent fume-off. However, this method is not recommended on safety grounds. Using temperatures above ambient for the O-nitration of alcohols, with either nitric acid or mixed acid, is dangerous and greatly increases the risk of explosion. 

The Henry condensation of nitroform and terminal dinitromethyl compounds with formaldehyde and other aldehydes, followed by nitration of the resulting alcohol functionality, has been used to synthesize numerous explosives. The nitrate esters (104), (105), (106) " and (107)155 ij yg ijggjj synthesized from the action of absolute nitric acid on the parent alcohols. In a similar manner, NMHP (109) is synthesized from the condensation of TNHP (108) with formaldehyde, followed by O-nitration with absolute nitric acid. ... 

The presence of one or more nitro groups (with 69.6% oxygen) linked to C or N in an organic compoimd may have a significant effect on the reactivity, oxygen balance and stability of the compoimd. (Compounds with a nitro group linked to O, nitrate esters, are of very much lower stability and are dealt with separately). The class has been subdivided into the separately treated groups ... 

Other pyrimidine substrates to be converted to A, A -dinitro derivatives by loss of N-substituents include the diacyl compounds 503 and 504, and the di-(/ftt-butyl) compound 505 <2000JOC1200>. In the case of the disulfamic acid derivative 506, O-nitration also occurred, to give the trinitro derivative 507 <2000RCB1082>. 

Problem 11.11 Account for the following, (o) Nitration of PhC(CH,), gives only 16% ortho product, whereas PhCH, gives 50%. (ft) Of all the aryl halides, PhF gives the least amount of ortho product on nitration. ... 

O-Nitration Nitroglycerine Nitrocellulose PETN Mixture of nitric and sulfuric acids Mixture of nitric and sulfuric acids Mixture of nitric and sulfuric acids... 

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