Nitronate salts nitration

Determination of nitrate as nitron nitrate Discussion. The mono-acid base nitron, C20H16N4, forms a fairly insoluble crystalline nitrate, C20H 16N4,HN03 (solubility is 0.099 g L 1 at about 20 °C), which can be used for the quantitative determination of nitrates [see Section 11.11(E)]. The sulphate and acetate are soluble so that precipitation may be made in sulphuric or acetic (ethanoic) acid solution. Perchlorates (0.08 g), iodides (0.17 g), thiocyanates (0.4 g), chromates (0.6 g), chlorates (1.2g), nitrites (1.9 g), bromides (6.1 g), hexacyanoferrate(II), hexacyanoferrate(III), oxalates, and considerable quantities of chlorides interfere, and should be absent. The figures in parentheses are the approximate solubilities of the nitron salts in g L-1 at about 20 °C. 

Nitronate salts can react with alkyl halides to yield polynitroaliphatic compounds with varying degrees of success. The main by-products of these reactions arise for competitive 0-alkylation. Alkyl nitrates are formed as by-products when the nitroform anion is used in these reactions. ... 

Nitronate salts and the tautomeric act-form of nitroalkanes, known as nitronic acids, are converted to gem-dinitro compounds on treatment with dinitrogen tetroxide. Novikov and co-workers synthesized phenyldinitromethane by treating phenylnitromethane with dinitrogen tetroxide in ether and later reported the synthesis of some substituted phenyltrinitromethanes from the direct nitration of the nitronate salts of phenylnitromethanes. 

Oxidative nitration, a process discovered by Kaplan and Shechter, is probably the most efficient and useful method available for the synthesis of em-dinitroaliphatic compounds from the corresponding nitroalkanes. The process, which is an electron-transfer substitution at saturated carbon, involves treatment of the nitronate salts of primary or secondary nitroalkanes with silver nitrate and an inorganic nitrite in neutral or alkali media. The reaction is believed ° °° to proceed through the addition complex (82) which collapses and leads to oxidative addition of nitrite anion to the nitronate and reduction of silver from Ag+ to Ag . Reactions proceed rapidly in homogeneous solution between 0 and 30 °C. 

A major drawback of the Kaplan-Shechter reaction is the use of expensive silver nitrate as one of the reagents, which prevents scale up to an industrial capacity. Urbanski and co-workers modified the process by showing that the silver nitrate component can be replaced with an inorganic one-electron transfer agent like ferricyanide anion. In a standard procedure the nitroalkane or the corresponding nitronate salt is treated in alkaline media with potassium... 

Feuer and co-workers extended their studies to the alkaline nitration of a,Nitration with potassium ferf-butoxide and amyl nitrate in THF at —30 °C yields the corresponding dipotassium salt of the a,nitronate salts from these reactions are isolated via methanol-induced precipitation from the aqueous reaction liquors, a process which also separates the product from impurities. These salts undergo hydrolysis on treatment with aqueous potassium hydroxide, and subsequent acidification yields the corresponding Q, y-dinitroalkane. This route has been used to synthesize 1,4-dinitrobutane (27) from apidonitrile (95) in 30 % overall yield. 

Table III. Nitration of Alkyl Nitronate Salts with Nitronium Tetrafluoroborate...

Intensely yellow leaflets from alcohol, solvated needles from chloroform, dec about 189. Practically inso] in water sol in alcohol, benzene, acetone, chloroform, ethyl acetate, dil acids slightly so] in ether. The ale soln undergoes partial decompn, indicated by a ted color, hence shonld be protected from light. Dipole moment in benzene 7,2. Solubility of some Nitron salts in 0,0lJV HCI Nitrate 0.0099%, perchlorate 0.008%, iodide 0.0] 7%, thiocyanate 0.04%, chromate 0.06%, chlorate 0.12%, nitrite 0.19%, bromide 0.61%. 

The racemic salts prepared are the bromide, [Ir en3]Br3.8H20, the nitrate, and the perchlorate. All are colourless crystalline bodies. The bromide yields with sodium d-camphor nitronate, 1-triethylene-diamino-iridium d-camphor nitronate, and from the filtrate after... 

Nitration. The synthesis of gem-dinitroalkanes by reaction of nitronate anions with the combined salts is efficient. 

This occurs readily by reaction of pyridines with nitronium salts, such as nitron-ium tetrafluoroborate. Protic nitrating agents such as nitric acid of course lead exclusively to A/ -protonation. 

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