- Practical catalytic nitration directly with commercial nitric acid for the preparation of aliphatic nitroesters
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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.
- An, Jichao,He, Pan,Li, Wenhao,Liu, Peipei,Si, Mengyuan,Yang, Bo,Yang, Guanyu
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- Some unusual minor volatile components of tomato
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The identities and possible origins of three minor unusual volatile components of tomato are discussed. These are pentyl nitrate, the first identification of a volatile alkyl nitrate in a fresh vegetable or fruit; 5-ethyl-2(5H)-furanone, which, besides its presence in tomato, was found to be a major autoxidation product of pure (2)-3-hexenal; and 5-ethylcyclopentene-1- carbaldehyde, a likely unusual linolenic acid oxidation product.
- Buttery, Ron G.,Takeoka, Gary R.
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- Alkyl Nitrate Formation from the NOx-Air Photooxidations of C2-C8 n-Alkanes
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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.
- Atkinson, Roger,Aschmann, Sara M.,Carter, William P. L.,Winer, Arthur M.,Pitts, James N.
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- Rate coefficients for the reactions of Cl atoms with a series of C3-C6 hydroxyalkyl nitrates at 296 ± 2 K
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Rate coefficients for the gas-phase reactions of chlorine atoms with a series of C3-C6 hydroxyalkyl nitrates of atmospheric interest have been determined at 296 ± 2 K and atmospheric pressure. The experiments were conducted using the relative rate technique combined with solid-phase microextraction (SPME) sampling followed by gas chromatography (GC) analysis with an electron capture detector (ECD). The experiments were performed in a collapsible 100 L PVF-film (Tedlar) reaction chamber. It is shown that the presence of the hydroxy group enhances the reactivity of the hydroxyalkyl nitrates toward the Cl atom as compared to the corresponding alkyl nitrates and alkyl dinitrates. The Cl atom reactivity toward the hydroxyalkyl nitrates increases with the length of the alkyl chain and with increasing separation between the hydroxy and the nitrooxy groups. Tropospheric lifetimes are calculated using the determined rate coefficients and the atmospheric implications are briefly discussed.
- Treves, Keren,Shragina, Lea,Rudich, Yinon
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- Convenient preparation of alkyl nitrates free of nitrites with potassium nitrate and boron trifluoride hydrate
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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.
- Olah,Wang,Li,Prakash
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- Separation of Diastereomeric and Enantiomeric Alkyl Nitrates - Systematic Approach to Chiral Discrimination on Cyclodextrin LIPODEX-D
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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
- Schneider, Manfred,Ballschmiter, Karlheinz
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p. 539 - 544
(2007/10/03)
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- Pharmaceutical composition and process of treatment
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A process for alleviating proliferative skin diseases such as psoriasis, atopic dermatitis, etc. comprising administering to humans, or domesticated animals, topically and/or systemically a composition comprising a pharmaceutical carrier and at least one active compound selected from the groups, substituted alkyl zanthines, tricyclic antidepressants, organic nitrates, antihypertensives, anti-asthma agents and central nervous system depressants and combinations of certain compounds from specifically named groups of compounds.
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