Dinitrogen tetroxide preparation

Hence dinitrogen tetroxide (sometimes mixed with an organic solvent) can be used to prepare anhydrous metal nitrates (many heavy metal nitrates are hydrated when prepared in aqueous solution, and they cannot be dehydrated without decomposition). 

Outline the laboratory preparation of a sample of dinitrogen tetroxide. Describe and explain what happens when it is heated from 290 K to 900 K. Suggest electronic structures for dinitrogen tetroxide and the other nitrogen-containing molecules formed from it on heating to 900 K. Point out any unusual structural features. 

In solutions of acetyl nitrate in acetic anhydride, prepared from purified nitric acid, the 0 -ratio increases slightly with increasing concentrations of acetyl nitrate (table 5.7, expts. 11,13,16). The use of fuming nitric acid in the preparation of the acetyl nitrate considerably accelerates the rates of reaction and also increases the proportion of o-substitution (table 5.7, expts. 12, 15, 18). These effects resemble, but are much stronger than the corresponding effects in nitrations with solutions of nitric acid in acetic acid contaimng dinitrogen tetroxide. 

Several derivatives of cellulose, including cellulose acetate, can be prepared in solution in dimethylacetamide—lithium chloride (65). Reportedly, this combination does not react with the hydroxy groups, thus leaving them free for esterification or etherification reactions. In another homogeneous-solution method, cellulose is treated with dinitrogen tetroxide in DMF to form the soluble cellulose nitrite ester this is then ester-interchanged with acetic anhydride (66). With pyridine as the catalyst, this method yields cellulose acetate with DS < 2.0. 

Furazan 1 was first prepared and characterized in 1964 by melting glyoxime 2 with succinic anhydride in 57% yield (64JA1863, 65JOC1854). Its A-oxide, furoxan 3, has been in a focus of attention for chemists for more than a century, but was synthesized only in 1994 by oxidation of 2 with dinitrogen tetroxide in dichloromethane in 45% yield (94MC7) (Scheme 1). The A-oxide cannot be prepared by direct oxidation of furazan. 

This procedure for the synthesis of ethyl 3-nitroacrylate is essentially that of Stevens and Emmons.2 Four major changes have been introduced by the submitters rapid introduction of dinitrogen tetroxide no purification of the intermediate nitro iodo ester use of dry, finely powdered sodium acetate for elimination of hydroiodic acid and percolation of the final product through a mat of alumina. With these modifications, the preparation is reproducible and highly efficient (80-90% overall). 

Preparation. It was first prepd by passing a mixt of N monoxide and N dioxide into 72% perchloric ac, the mixt evapd until the temp rose to 140° and dense white fumes were evolved, and cooled. The solid which sepd was found to be a monohydrate of nitrosyl perchlorate which was dried in a vacuum over P pentoxide to give the anhyd salt (Ref 2). More recently it was obtained by the action of an excess of liq dinitrogen tetroxide on anhyd Mg perchlorate (Ref 5)... 

Recently, nitration of organolithiums and Grignards with N204 has been developed for the preparation of certain kinds of nitro compounds (Eqs. 2.14 and 2.15).31 The success of this process depends on the reaction conditions (low temperature) and the structure of substrates. For example, 3-nitrothiophene can be obtained in 70% overall yield from 3-bromothiophene this is far superior to the older method. 3-Nitroveratrole cannot be prepared usefully by classical electrophilic nitration of veratrole, but it can now be prepared by direct o>7/ o-lithiation followed by low-temperature N204 nitration. The mechanism is believed to proceed by dinitrogen tetroxide oxidation of the anion to a radical, followed by the radical s combination. 

A large number of reagents are available for the preparation of nitro PAHs. These include fuming nitric acid in acetic acid (20) or acetic anhydride (13), sodium nitrate in trifluoroacetic acid (21) or trifluoroacetic acid and acetic anhydride (17), dinitrogen tetroxide in carbon tetrachloride (22), sodium nitrate in trimethyl phosphate and phosphorus pentoxide (23), and nitronium tetrafluoroborate in anhydrous acetonitrile (24). Alternative approaches must be used to synthesize nitro PAHs substituted at positions other than the most reactive carbon. For instance,... 

New and improved routes for the industrial synthesis of dinitrogen pentoxide mean that its use is increasing and for many applications it may replace the use of mixed acid in the near future. Dinitrogen pentoxide can be prepared by (1) ozonolysis of dinitrogen tetroxide, (2) electrolysis of nitric acid-dinitrogen tetroxide solutions, and (3) dehydration of nitric acid. ... 

Barton and Narang" have prepared nitrate esters by treating primary and secondary alky-lamines with dinitrogen tetroxide in the presence of an amidine base like DBU. Wudl and Lee " conducted deamination reactions without any amidine base and reported much lower yields of nitrate ester product. The use of an amidine base is not necessary if the amine substrate... 

Nitramines have been prepared from the reaction of Ai-chloramines with dinitrogen tetroxide. ... 

Phenyl-l,2,4-triazoline-3,5-dione has been prepared by oxidizing 4-phenylurazole with lead dioxide,7 and with ammoni-acal silver nitrate followed by an ethereal solution of iodine.8 The yields are low for both methods. 4-Substituted triazoline-diones can also be made by oxidation of the corresponding urazole with fuming nitric acid9 or dinitrogen tetroxide.10 Oxidation by <-butyl hypochlorite in acetone solution has also been described 1112 it, however, yields an unstable product, even after sublimation. Either dioxane12 or ethyl acetate are preferred as solvents for the reaction, since the product is obtained in a stable form. The latter solvent is superior since... 

The nitrate salt prepared by this method is hydrated. It cannot be dehydrated fully without decomposition. Anhydrous CuNOs may be prepared by dissolving copper metal in a solution of dinitrogen tetroxide, N2O4, in ethyl acetate. Upon crystaUization, an N2O4 adduct of Cu(N03)2 that probably has the composition [NO [Cu(N03)3] is obtained. This adduct, on heating at 90°C, yields blue anhydrous copper(II) nitrate which can be sublimed in vacuum at 150°C and coUected. 

A convenient method of preparing nitryl fluoride is to heat dinitrogen tetroxide with cobalt(III) fluoride at 300°C ... 

In a well-ventilated hood, to a rapidly stirred mixture of 50.2 gm (0.546 mole) of dinitrogen tetroxide and 123 gm (1.5 mole) of anhydrous sodium acetate in 150 ml of carbon tetrachloride prepared at Dry Ice temperature is added, over a 1 hr period, a solution of 46.5 gm (0.546 mole) of 2-pyrrolidone in 50 ml of... 

Aminoferrocene (XXXV) can be prepared in low yield by treatment of O-methylhydroxylamine or O-benzylhydroxylamine with ferrocenyllithium (1, 65). Nitroferrocene (XXXVI), unattainable by direct nitration of ferrocene, can be isolated from the reaction of ferrocenyllithium and either n-propyl nitrate or dinitrogen tetroxide at —70° (30, 36). A similar reaction between ferrocenyllithium and nitrous oxide leads to azoferrocene (XXXVII) (08). 

It was prepared by Berzelius as early as 1812 [50] by treating lead nitrite with ammonium sulphate. Later M. Berthelot [50] obtained it by acting with barium nitrite on ammonium sulphate. Erdmann and Sorensen [50] prepared it by acting with dinitrogen tetroxide on coarsely ground ammonium carbonate near 0°C. Ammonium nitrite cannot be obtained from its aqueous solution, as it decomposes on evaporating. 

Methyl phenyl sulfoxide has also been prepared from thio-anisole by the action of hydrogen peroxide,2,3 lead tetraacetate,4 and dinitrogen tetroxide,5,6 and from methanesulfinyl chloride and benzene with anhydrous aluminum chloride.7... 

Nitrolic acids, which can be isolated from sources such as nitroalkanes and aldoximes, are also probable intermediates in a wide variety of furoxan preparations involving nitric and nitrous acid, and nitrogen oxides. Diacylfuroxans have been synthesized via nitrosation of methyl ketones for example acetone reacts with anhydrous dinitrogen tetroxide or nitric acid/sodium nitrite to give diacetylfuroxan. 

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