- Nitration of alkanes with nitric acid by vanadium-substituted polyoxometalates
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The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium-substituted Keggin-type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H 6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carbon-carbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium-substituted polyoxometalate, for example, [H4PVMo 11O40], decomposes to form free vanadium species and [PMo12O40]3- Keggin anion. The reaction mechanism involving a radical-chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O 40]n-, and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.
- Shinachi, Satoshi,Yahiro, Hidenori,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 6489 - 6496
(2007/10/03)
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- [VO(H2O)5]H[PMo12O40]- catalyzed nitration of alkanes with nitric acid
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[VO(H2O)5]H[PMo12O40], which contains vanadyl counter cations and PMo12O40 3-, can act as a catalyst for the nitration of various alkanes including alkylbenzenes using nitric acid as a nitrating agent in acetic acid at 356 K.
- Yamaguchi, Kazuya,Shinachi, Satoshi,Mizuno, Noritaka
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p. 424 - 425
(2007/10/03)
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- Nitration of alkanes with nitric acid catalyzed by N-hydroxyphthalimide
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Catalytic nitration of alkanes with nitric acid was first successfully achieved by the use of N-hydroxyphthalimide (NHPI) under mild conditions; the key to the present nitration was found to be the in situ generation of NO2 and phthalimide N-ox
- Isozaki,Nishiwaki,Sakaguchi,Ishii
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p. 1352 - 1353
(2007/10/03)
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- NITRATION OR CARBOXYLATION CATALYSTS
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In the presence of an imide compound (e.g., N-hydroxyphthalimide) shown by the following formula (1): ???wherein R1and R2represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group and a cycloalkyl group, and R1and R2may bond together to form a double bond, or an aromatic or non-aromatic ring, and Y is an O or OH, and n denotes 1 to 3;, a substrate is allowed to contact with at least one reactant selected from (i) a nitrogen oxide and (ii) a mixture of carbon monoxide and oxygen to be introduced with at least one functional group selected from a nitro group and a carboxyl group. The nitrogen oxide includes, for example, a compound represented by the formula NxOy(e.g., N2O3, NO2). The substrate includes, for example, a compound having a methine carbon atom (e.g., adamantane), a compound having a methyl group or a methylene group at an adjacent moiety of an aromatic ring. According to such reaction, the substrate can be efficiently nitrated or carboxylated even in a mild or moderate condition.
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- Ozone-mediated nitration of adamantane and derivatives with nitrogen dioxide: Selectivity in the hydrogen abstraction by nitrogen trioxide and subsequent coupling of the resulting carbon radicals with nitrogen dioxide
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In the presence of ozone at -78°C, nitrogen dioxide reacts rapidly and selectively with adamantane at a bridgehead position to give the corresponding nitro derivative as the sole major product. The relative reactivity has been determined for a series of 1-substituted adamantanes, which reveals that electron-withdrawing substituents exert a considerable influence on the ease of substitution at the γ-position as well as the distribution of the N- and O-functionalized products. The results may be rationalized in terms of the initial hydrogen abstraction by nitrogen trioxide, followed by rapid trapping of the resulting adamantyl radicals with nitrogen dioxide.
- Suzuki, Hitomi,Nonoyama, Nobuaki
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p. 2965 - 2971
(2007/10/03)
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- Reactions of 1- and 2-Adamantyl Radicals with Nitrogen Dioxide
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1- and 2-Adamantyl radicals similarly react with excess nitrogen dioxide to form respectively 1-nitro and 1-nitroxyadamane, 2-nitro and 2-nitroxyadamane, which are further nitrated to 1,3-dinitroadamantane, 1-nitro-3-nitroxyadamantane, 1,4-dinitroadamantane, and 1-nitro-4-nitroxyadamantane.
- Barabanova,Medzhinskii,Golod
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p. 1079 - 1082
(2007/10/03)
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