- An unusual pathway of the oxidation of diethyl ether by bismuth(V) derivatives
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Di(tert-butylperoxy)triphenylbismuth and the triphenylbismuth-tert-butyl hydroperoxide system transform diethyl ether into ethoxyacetic aldehyde.The latter undergoes further conversions under these reaction conditions to give the corresponding hydroperoxide, ethoxyacetic acid, and bismuth(III) acylates. - Key words: diethyl ether, ethoxyacetic aldehyde, triphenylbismuth, tert-butyl hydroperoxide, oxidation.
- Dodonov, V. A.,Zinov'eva, T. I.,Dolganova, N. V.
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- Photochemical reactions of alkoxy-containing-alkyl phenylglyoxylates: Remote hydrogen abstraction
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A series of alkoxy-containing-alkyl phenylglyoxylates have been synthesized and their photochemical reactions studied. The intention was to probe structural requirements for remote hydrogen abstraction. Products resulting from 1,10- and 1,11-hydrogen abstraction were isolated from the photochemical reactions of 4′-methoxybutyl phenylglyoxylate 3d and 5′-benzyloxypentyl phenylglyoxylate 3h respectively. Products resulting from Norrish Type II and intermolecular hydrogen abstraction reactions were also isolated. Triplet lifetimes of representative compounds were measured by laser flash photolysis.
- Hu, Shengkui,Neckers
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p. 1751 - 1754
(2007/10/03)
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- OH radical initiated photooxidation of 2-ethoxyethanol under laboratory conditions related to the troposphere: Product studies and proposed mechanism
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The products formed by the hydroxyl radical-initiated oxidation of 2- ethoxyethanol (CH3CH2OCH2CH2OH) have been investigated by irradiating synthetic air mixtures containing the substrate, methyl nitrite, and nitric oxide at ppm levels in a Teflon bag reactor at room temperature. The decay of reactants and the formation of products were monitored by gas chromatography and mass spectrometry. The major products ethyl formate [HC(O)OCH2CH3], ethylene glycol monaformate [HC(O)OCH2CH2OH], ethylene glycol monaacetate [CH3C(O)OCH2CH2OH], and ethoxyacetaldehyde [CH3CH2OCH2C(O)H] give a quantitative mass balance with the decay of the substrate molecule. The yields of these products were 34 ± 10%, 36 ± 7%, 7.8 ± 2.4%, and 24 ± 13%, respectively, in terms of percent of 2-ethoxyethanol removed by the OH radical. The product distribution is explained by a mechanism involving initial OH attack at the three CH2 groups in 2-ethoxyethanol followed by the subsequent reactions of the resulting alkyl and alkoxy radicals. The decomposition reactions of the alkoxy radicals from 2-ethoxyethanol, which can take place either by C-C or C-O bond breaking, involve preferential C-C cleavage rather than C-O cleavage. Rate coefficients at room temperature for the reactions of OH radicals with ethoxyacetaldehyde and 2-methyl-1,3- dioxolane (CH3CHOCH2CH2O, a minor product) have been determined to be 16.6 x 10-12 and 9.4 x 10-12 cm3 molecule-1 s-1, respectively.
- Stemmler, Konrad,Mengon, Wolfgang,Kerr, J. Alistair
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p. 3385 - 3391
(2007/10/03)
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- DIASTEREOSELECTIVE ALDOLIZATION TO TETROSES AND PYRANOSES MEDIATED BY RHODIUM
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Rhodium ions bind to oxygen and unsaturated sites in ethane-1,2-diol derivatives to orient and catalyse these molecules for participation in diastereogenic carbon-carbon, carbon-oxygen, and carbon-hydrogen bond formation.
- Deem, M. L.,Romac, E. A.
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p. 4649 - 4652
(2007/10/02)
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- Hydroxyl Radical Induced Oxidation of Diethyl Ether in Oxygenated Aqueous Solution. A Product and Pulse Radiolysis Study
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The reaction of peroxyl radicals derived from diethyl ether were investigated by product analyses and pulse-radiolytic techniques.The products and their G values in the γ radiolysis of diethyl ether (1E-3 M) in N2O/O2-saturated aqeous solutions at 0.43 W kg-1 are acetaldehyde , ethanol , ethyl acetate , ethyl formate , formaldehyde , hydrogen peroxide , 1-ethoxyethyl hydroperoxide , and 2-ethoxyacetaldehyde .Except for the latter, all products have the 1-ethoxyethylperoxy radical (I) as a precursor.It is formed as the major radical by OH abstraction of the α-H atom (96percent) followed by O2 addition.Besides other bimolecular decay processes of I which are also discussed, there is an important route leading to 1-ethoxyethyloxyl radicals and O2: 2I -> 2CH3CH(O*)OEt + O2.The oxyl radical rearrangment in aqueous solutions to the 1-ethoxy-1-hydroxyethyl radical: CH3CH(O*)OEt -> CH3C*(OH)OEt.The latter adds oxygen to give the corresponding peroxyl radical, which eliminates HO2* in a fast spontaneous reaction to give ethyl acetate: CH3C*(OH)OEt + O2 - HO2* -> CH3COOEt.Evidence for the formation of HO2* (O2-* in neutral and basic solutions) according to the above reaction sequence was provided by pulse-spectrometric and pulse-conductometric measurements. 1-Ethoxyethyl hydroperoxide is thought to result from the reduction of I by O2-*.At much lower dose rates (0.0048 W kg-1) an intramolecular H abstraction competes with the bimolecular decay of I.This process leads to a different product distribution and to formation of acidic products.
- Schuchmann, Man Nien,Sonntag, Clemens von
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p. 1995 - 2000
(2007/10/02)
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