Oxidation with dinitrogen oxide

Analogous to the acid catalyzed hydroxylation of phenol on H-ZSM-5 with hydrogen peroxide [92], benzene and chlorobenzene can be oxidized with dinitrogen oxide on HZSM-5 [125-126]. In the hydroxylation of benzene, the selectivity for phenol is high at conversions below 10%, with selectivities in N2O of about 30%. A small amount of ortho-diphenol or catechol was formed. The hydroxylation of chlorobenzene was also ortho-selective (58%). The reaction was proposed to proceed via scheme 7. 

Chemical oxidation with strong acid is reportedly selective at the 6-hydroxyl, either with nitric acid—sulfuric acid—vanadium salts (241) which is claimed as specific for the 6-hydroxyl up to 40% conversion, or with dinitrogen tetroxide ia carbon tetrachloride, with similar specificity up to 25% conversion (242). 

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. 

When ammonia reacts with dinitrogen oxide gas (AH = 82.05 kj/mol), liquid water and nitrogen gas are formed. How much heat is liberated or absorbed by the reaction that produces 345 mL of nitrogen gas at 25°C and 717 mm Hg ... 

The carbide bums incandescently at red heat in contact with dinitrogen mono- or tetra-oxides. 

Arsenic trioxide reacts violently and nitrogen oxide ignites in excess fluorine. Bubbles of sulfur dioxide explode separately on contacting fluorine, while addition of the latter to sulfur dioxide causes an explosion at a certain concentration [1], Reaction of fluorine with dinitrogen tetraoxide usually causes ignition [2], Interaction with carbon monoxide may be explosive. Anhydrous silica incandesces in the gas, and interaction with liquid fluorine at — 80°C is explosive [3,4], Boron trioxide also incandesces in the gas [3],... 

Nitration with dinitrogen pentoxide (N205) has increased in its importance as an environmentally cleaner alternative to conventional procedures. It might become the nitration method of the future. Dinitrogen pentoxide can be produced either by ozone oxidation of dinitrogen tetraoxide (N204) or electrolysis of N204 dissolved in nitric acid.19... 

To the best of the author s knowledge, the only isolated diaza analog of o-benzoquinone is bis-N-oxide 79 and its derivatives. Compound 79 was isolated as orange-colored crystals from a reaction of tetraketo derivative 78 with dinitrogen tetroxide (76TL1703 77AP264). 

In reality, nitration of naphthalene with dinitrogen tetroxide in an aprotic medium is a complex process. The leading role belongs to nitrosyl cation. This species is a strong oxidant acting according to the outer-sphere mechanism (compare with Section 1.7.10) ... 

The nitrolysis of fert-butyl substituted amines with dinitrogen pentoxide in nitric acid solves many of these problems. However, these substrates are not always accessible via the usual condensation routes. The acidic reagents frequently used for these nitrolysis reactions are not always suitable for substrates with acid-sensitive or easily oxidized functionality. 

With less electron-rich pyrroles, hydrochloric acid can be used in the diazotization. The diazo compounds were isolated after neutralization with aqueous ammonia [84H(22)2269]. 3-Diazo-2,5-diphenylpyrrole, although efficiently prepared by diazotization of the 3-aminopyrrole, can also be prepared by oxidation of the 3-nitrosopyrrole with dinitrogen trioxide (60JCS3270). Pyrrole-3-carboxylic acid, with buffered nitrous acid, gave the 3-diazo derivative 295 by displacement of the carboxyl group, together with the 3-diazo-2-carboxylic acid 296, obtained by further hydrolysis (62JCS1638) (Scheme 90). 

The first examples of furazan and furoxan nitrile oxides have been reported in the early 1990s. 4-Aminofurazan-3-carbonitrile oxide (65) was generated from the hydroximoyl chloride with base and its cycloaddition reactions investigated <92KGS687>, and the 4-phenyl analogue (66) is formed via the nitrolic acid derivative by treatment of the aldoxime with dinitrogen tetroxide <93LA44i>. Furazan-3-amidoximes react in the usual way with nitriles to yield 3-(furazan-3-yl)-1,2,4-oxadiazoles <9013941 >. 

The oxidation of benzaldoxime with dinitrogen tetroxide has been recently studied [17). From this reaction, phenylnitrolic acid, diphenyl-furoxane, benzaldehyde and benzaldoxime anhydride N-oxide (XXII) (45 % yield) are obtained. Upon warming in chloroform, this oxide is converted to diphenyloxadiazole. 

Polyolefins are resistant to aqueous solutions of inorganic acids such as hydrochloric, phosphoric, and sulfuric acids. These polymers are also resistant to chromic and nitric acids but react with them as well as with dinitrogen tetroxide at elevated temperatures. Polymers with tertiary hydrogen atoms, such as PP, are more readily oxidized than those with only secondary hydrogen atoms, such as hope. 

When acting with dinitrogen tetroxide on ethylene oxide and homologues followed by hydrolysis a nitric ester of the type (IV) is formed (Pujo etal. [108], Rossmy [75]). 

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