Anhydrid, acetic nitric

RDX. Gilpin Winkler (Ref 38b) measured a heat of nitration of — 88.0kcal/mole of hexa-mine for the reaction of hexamine with 97.5% nitric acid. They also obtained a value of — 140kcal/mole of hexamine for the formation of RDX from hexamine and Bachmann reagents (acetic anhydride, acetic acid, ammonium nitrate and nitric acid). Incidentally, Gilpin Winkler interpret their results to mean that hexamine dinitrate is an intermediate in the direct nitrolysis of hexamine to give RDX, while hexamine mononitrate is an intermediate in the Bachmann process of producing RDX... 

N 42.74% OB to C02 —30.51% cryst (meso), liq (racemic) mp 70—71° (cryst) bp 150° (decompn). Sol in acet and ethanol. Prepn is by nitration of 2,3-diazido-l, 4-butanediol with mixed acid. The procedure involves dropwise addn of 2.58g of the diol to a cooled (0—5°) mixt (1/1) of acetic anhydride/100% nitric acid. The reaction is held to 5—15° and stirred for 30 mins. Several recrysts from ethanol give a (approx) 40% yield. The compd is friction sensitive Qc 682.8 and 671.8kcal/mole Qf 98.8 kcal/mole impact sensy at 50% pt is 6.3cm using a 2kg wt in an Aberdeen Impact App and No 12 tools (PETN=26.7cm) impact sensy of proplnt films (85.15% NC/14.85% diazido compd) is 29—36cm (M2 film=34—36cm) at the 50% pt... 

Ammonium nitrate, Hexamethylenetetraminium acetate, Nitric acid See Nitric acid Acetic anhydride, etc. 

Furazan compound 278 was obtained as a by-product from cholestan-3-one oxime 277 by prolonged heating in an acetic anhydride-pyridine mixture followed by treating with acetyl nitrate prepared from acetic anhydride and nitric acid (Equation 53) <1997T16161>. 

Under the influence of acetic anhydride and nitric acid compound (XXX) gives (XXV) (Marcus and Winkler [68]). 

As the classical method of prepg X-Stoff from acetic anhydride and nitric add was considered very expensive, a new method was developed in Ger during WWII by a Dr Schimmel-schmidt. The procedure developed is essentially... 

Clement and Riviere [59] also reported that cellulose acetate or a mixed ester — a nitrate-acetate — can be obtained by reacting cellulose nitrate with acetic anhydride, acetic acid, and sulphuric acid. According to more recent contributions, e.g. Wolfrom, Bower and Maker [60], the reaction should be performed as follows Cellulose nitrate is dissolved in the cold in a little sulphuric add and acetic anhydride, the surplus of acetic anhydride is then hydrolysed also in the cold, and cellulose acetate is extracted with a suitable solvent, such as chloroform. Other methods of acetylating nitrocellulose consist in reduction, for instance with zinc and hydrogen chloride, which entails denitration of the ester, followed by acetylation with acetic anhydride. All these reactions are carried out in the same vessel. Further, it is possible to synthesize mixed esters, cellulose nitrate-acetates, by subjecting cellulose to the action of a mixture that includes nitric acid, acetic add and acetic anhydride in the presence of sulphuric acid (Kruger [61]). The use of a large amount of nitric acid favours the formation of nitrocellulose only. Mixed esters are formed... 

According to both the NFPA Guide and Bretherick (Refs 5 13), sulfuric acid causes explosions and/or fires when in intimate contact with a large number (over 70) of materials including acetic anhydride, acet and nitric acid, acrolein, alcohols, alcohols and hydrogen peroxide, anun hydroxide, aniline, bromine and metals, carbides, chlorates, cyclopentadiene, ethylene glycol, various hydrocarbons, hydrochloric acid, iron, mercuric nitride, powdered metals, perchlorates, picrates, pyridine, Na carbonate, steel, sucrose, vinyl acetate, and w. Illustrative... 

Acetic anhydride, Hexamethylenetetramine acetate, Nitric acid... 

The process for the production of nitrobenzene from benzene involves the use of mixed acid (Fig. 1), but there are other useful nitrating agents, e.g., inorganic nitrates, oxides of nitrogen, nitric acid plus acetic anhydride, and nitric acid plus phosphoric acid. In fact, the presence of sulfuric acid in quantity is vital to the success of the nitration because it increases the solubility of the hydrocarbon in the reaction mix, thus speeding up the reaction, and promotes the ionization of the nitric acid to give the nitronium ion (N02+), which is the nitrating species. Absorption of water by sulfuric acid favors the nitration reaction and shifts the reaction equilibrium to the product. 

The same compound is formed when acetic anhydride and nitric acid (d = 1.4) are mixed. 

Recently, as the disposal of large volumes of toxic waste waters from the purification of TNT by sulphitation has. become a problem (p. 390), new ways are being sought for the manufacture of TNT free from the unsymmetrical isomers. Apart from the possibility, mentioned above, of the utilization of nitrotoluene obtained by nitrating toluene with a mixture of acetic anhydride and nitric acid, factories TNT are now tending to separate nitrotoluene isomers by methods similar to those applied in the manufacture of dyestuffs intermediates. 

We have reported the use of zeolite HP in conjunction with a mixture of acetic anhydride and nitric acid, which currently offers the best combination of yield and para-selectivity for nitration of simple aromatic compounds.11 For example, this system allows quantitative mononitration of toluene with selectivity for the para isomer of around 80 %. For commercial production of 4-nitrotoluene this would require less than half the toluene or nitric acid needed for the conventional mixed acid method and would generate less than one third of the waste. In general, the system offers excellent possibilities for nitration of substrates of moderate activity. However, it is not very successful with deactivated substrates. One aspect of the work reported here is therefore the modification of this approach so that it accommodates deactivated substrates. 

Normally, nitration of deactivated compounds (and therefore polynitration of toluene) is carried out using aggressive nitric acid - oleum mixtures. Dinitration of toluene with mixed acids produces a 4 1 ratio of 2,4- and 2,6-dinitrotoluenes, from which the former is isolated for manufacture of toluenediisocyanate (TDI) and toluenediamine, both of which are used in the manufacture of polyurethanes. Zirconium and hafnium derivatives catalyse nitration of o-nitrotoluene, but ratios of 2,4- 2,6-dinitrotoluene are modest (66 34).12 Dinitration of toluene using Claycop (copper nitrate on K10 clay), acetic anhydride and nitric acid in the presence of carbon tetrachloride produced dinitrotoluenes in a yield of 85% with a ratio of 2,4- 2,6-dinitrotoluene of 9 1.13 This method, however, requires a large excess of nitric acid, the use of an unacceptable solvent and long reaction times. The direct nitration of toluene to 2,4-dinitrotoluene using nitric acid over a zeolite P catalyst, with azeotropic removal of water, is reported to give a 2,4 2,6 ratio of 14, but full results are yet to be published.14... 

After our success in nitrating moderately active monosubstituted benzenes with acetic anhydride and nitric acid over zeolite p,11 we decided to try the use of trifluoroacetic anhydride and nitric acid over zeolite p for nitration of deactivated substrates. Although trifluoroacetyl nitrate is known to be more active than acetyl nitrate, it has not been widely used in nitration reactions.15 Nitrobenzene has been successfully nitrated using fuming nitric acid and trifluoroacetic anhydride in equimolar proportions at 45-55 °C.16 However, no dinitration of toluene was reported. 

In addition to the sulfuric-nitric acid mixture, acetylnitrate (or a mixture of acetic anhydride with nitric acid) is used quite widely for the introduction of a nitro group into the azole ring. Azoles not containing a pyrrole nitrogen atom are nitrated by acetylnitrate in the same way as by the sulfuric-nitric acid mixture. Data have been published on the nitration of isoxazoles [176,181-183,185,292,293] and thiazoles [203, 206, 215] by acetylnitrate. 1-Substituted pyrazoles [48, 61, 294-301], imidazoles [ 116,133, 302-305], and isoxazoles [306] are nitrated by the nitric acid-acetic anhydride system in the same way as by the sulfuric-nitric acid mixture. 

Dimethyl-4-halogenoisoxazoles also enter into substitutive nitration. Here, only the iodine derivatives react with the sulfuric-nitric acid mixture. Both the bromine and the chlorine derivatives react slowly with a mixture of acetic anhydride and nitric acid [169],... 

Michels and Hayes102 investigated the nitration of a furan and used a mixture of acetic anhydride and nitric acid. The reaction takes place by the addition-elimination mechanism quoted above. They accomplished the nitration in the presence of weak bases, and were able to isolate a crystalline intermediate ... 

Nitration and oxidation. This nitrate (1) is a more efficient and versatile nitrating agent than the well-known acetyl nitrate, generated in situ from acetic anhydride and nitric acid. Oxidation, rather than nitration, is observed with phenols, which are converted mainly into diphenoquinones or o- or p- benzoquinones, depending on the substitution. ... 

The nitration of aromatic ethers leads to a mixture of nitro ethers and nitrophenols in proportions which depend upon experimental conditions. Benzoyl nitrate favors almost exclusively the formation of o-nitrophene-tole however, detailed directions are lacking. Treatment of diphenyl ether with nitric acid in acetic anhydride-acetic acid gives a se[>arable mixture of the ortho and para isomers (86% total). ... 

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