20633-11-8

To pursue a sustainable and efficient approach for aliphatic nitroester preparation from alcohol, europium-triflate-catalyzed nitration, which directly uses commercial nitric acid, has been successfully developed. Gram scalability with operational ease showed its practicability.

Organic nitric acid esters have been prepared in 89-98% yield by the nitration of the corresponding alcohols and polyols with N2O5 in liquid CO2.

Nitrate-containing 1-alkyl-3-methylimidazolium ionic liquids, [C n-mim]NO3, where n = 4, 6, 8, 12, are synthesized in one step by reacting 1-methylimidazole with alkyl nitrates under various conditions without using AgNO3 and 1-alkyl-3-methylimidazolium halides.

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In the invented process for producing a nitro compound, an organic substrate and nitrogen dioxide are reacted in the presence of oxygen or are reacted in a molar ratio of nitrogen dioxide to the organic substrate of less than 1 to yield a corresponding nitro compound. The reaction may be performed in the presence of N-hydroxyphthalimide or other imide compounds. Such organic substrates include (a) aliphatic hydrocarbons, (b) alicyclic hydrocarbons, (c) non-aromatic heterocyclic compounds each having a carbon atom on a ring, which carbon atom is bonded to a hydrogen atom, (d) compounds each having a carbon-hydrogen bond at the adjacent position to an aromatic ring, and (e) compounds each having a carbon-hydrogen bond at the adjacent position to a carbonyl group. This process can efficiently nitrate an organic substrate even under relatively mild conditions.

High-resolution gas chromatographic separation of all diastereomeric monomethyl-substituted cyclohexyl nitrates is shown on a nonpolar methylpolysiloxane stationary phase, and the first application of this procedure to the environmental diastereomeric analysis of alkyl nitrates is presented.Two characteristic signals in the achiral analysis of atmospheric samples could be assigned to the smallest alkyl nitrate containing two asymmetric carbon atoms, 3-methyl-2-pentyl nitrate.Retention indices in the temperature-programmed separation based on the n-alkanes were determined.The homologous series of 1-alkyl nitrates were found to be useful as ECD-visible n-alkanes.Enantiomeric separation of alkyl nitrates was achieved on heptakis(3-O-acetyl,-2,6-di-O-pentyl)-β-cyclodextrin (LIPODEX-D).The influence of the nitrooxy group and the alkyl chain length on the chiral discrimination on LIPODEX-D is discussed for 25 chiral alkyl nitrates.The absolute configurations of some alkyl nitrates were assigned by asymmetric synthesis of enantiomerically pure references.The complexity of the alkyl nitrate mixtures present in air samoles does not allow a direct chiral separation as the alkyl nitrates partly coelute on the LIPODEX-D column.Column coupling of LIPODEX-D with a polar achiral stationary phase like polyalkylenglocol (PAG) was successfully applied to solve this problem, and the chiral alkyl nitrates present in a typical air sample were separated.A systematic nomenclature for alkyl nitrates is introduced to handle the steadily growing number of branched and long-chain nitrates detected in environmental analysis. - Keywords: analytical methods; alkyl nitrates; chiral resolution; cyclodextrins; gas chromatography

When NO-3 is electrochemically oxidized in the presence of a variety of terminal and 1,2-disubstituted olefins 1 in a mixed solvent system (MeCN:H2O:Et2O = 10:2:1), a radical NO.3 is generated from NO-3 and nitrate esters 3 are formed by a new coupling reaction of the olefin with the radical. The products 3 can be further transformed into the corresponding alcohols 4 and alkyl iodides 5. Under the same reaction conditions, 1,1-di- and 1,1,2-trisubstituted olefins 6 do not give nitrate esters but afford oxazoline derivatives 7. (1S,5S)-(-)-β-Pinene (13) is diastereoselectively transformed into (1S,2R,5S)-(-)-myrtanol (14) by this technique.

Primary and secondary alkyl nitrates free of nitrites were conveniently prepared by treating the corresponding alcohols with potassium nitrate and boron trifluoride 1.25 hydrate. This procedure was also successful for the preparation of 1-adamantyl nitrate.

The yields of alkyl nitrates formed in the NOx-air photooxidations of the homologous series of n-alkanes from ethane through n-octane have been determined at 299 +/- 2 K and 735 torr total pressure for two different chemical systems.Alkyl peroxy radicals were generated by reaction of the n-alkanes with OH radicals (generated from the photolysis of methyl nitrite in air) or Cl atoms (from photolysis of Cl2 in air).The alkyl nitrate yields obtained from the two systems, corrected for secondary reactions, were in agreement within the experimental errors and increased monotonically with the carbon number of the n-alkane, from x-air photooxidations of the large n-alkanes.

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