- Mammalian exocrine secretions. XVII: chemical characterization of preorbital secretion of male suni, Neotragus moschatus.
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Gas chromatographic and gas chromatographic-mass spectrometric techniques were employed to identify 83 compounds, including alkanes, alkenes, aldehydes, 2-methylalkanes, carboxylic acids, 1-alkyl formates and alken-1-yl formates, benzoic acid, and cholest
- Stander,Burger,Le, Roux M
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- Electrochemical cross-coupling of biogenic di-acids for sustainable fuel production
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Direct electrocatalytic conversion of bio-derivable acids represents a promising technique for the production of value-added chemicals and tailor-made fuels from lignocellulosic biomass. In the present contribution, we report the electrochemical decarboxylation and cross-coupling of ethyl hydrogen succinate, methyl hydrogen methylsuccinate and methylhexanoic acid with isovaleric acid. The reactions were performed in aqueous solutions or methanol at ambient temperatures, following the principles of green chemistry. High conversions of the starting materials have been obtained with maximum yields between 42 and 61% towards the desired branched alkane products. Besides costly Pt electrodes also (RuxTi1-x)O2 on Ti electrodes exhibited a notable activity for cross-Kolbe electrolysis. As some of the products are insoluble in water, easy product isolation and reuse of the reaction solvent is enabled via phase separation. Several side products have been identified to evaluate the efficiency of the reaction and to elucidate the factors influencing the product selectivity. The yielded alkanes and esters were assessed with regard to their potential as fuels for internal combustion engines. While the longer alkanes constitute promising candidates for the compression-ignition engine, the smaller ester represents an interesting option for the spark-ignition engine.
- Holzh?user, F. Joschka,Creusen, Guido,Moos, Gilles,Dahmen, Manuel,K?nig, Andrea,Artz, Jens,Palkovits, Stefan,Palkovits, Regina
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p. 2334 - 2344
(2019/05/21)
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- Ultrasound promoted Wurtz coupling of alkyl bromides and dibromides
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Sonochemically enhanced Wurtz coupling using lithium metal has been investigated for a number of isomeric alkyl bromides under a variety conditions. The products result from direct coupling of short lived radicals formed at the metal surface rather than the secondary radicals which can be formed during coupling of aromatic halides and thus give rise to a single major product. Coupling has been extended to dibrominated aryl and alkyl compounds as well as showing that aryl-alkyl coupling is possible. Dibrominated alkyls were found to give low molecular weight oligomers although no reaction occurred for 1,2-isomers. The growth of oligomers in THF may be solubility limited. A simple model is proposed to explain these findings.
- Vandenburg, Daniel,Price, Gareth J.
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experimental part
p. 5 - 8
(2012/04/04)
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- Electrocatalytic reduction of organic halides with cobalt bipyridine complexes
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The electrocatalytic reduction of organic halides by the [Cobpy] + complexes coordinationally unsaturated with bpy (at potentials of the first wave) and by the coordinationally saturated [Cobpy2] - complexes (at potentials of the second wave) was observed. The apparent rate constant of the process decreased with an increase in the difference of the reduction potentials of the substrate and catalyst in a large range of the driving force of the process.
- Budnikova,Kafiyatullina,Kargin,Sinyashin
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p. 1702 - 1708
(2007/10/03)
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- New homo-coupling reaction of alkyl, aryl, vinyl, and allyl grignard reagents using trifluoromethanesulfonic anhydride
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Homo-coupling reaction of various alkyl, aryl, vinyl, and allyl Grignard reagents with trifluoromethanesulfonic anhydride provides a simple and straightforward method for the syntheses of symmetrical carbon-carbon coupling products under mild conditions and in moderate to good yields.
- Nishiyama, Tomihiro,Seshita, Takeshi,Shodai, Hiroshi,Aoki, Kazushige,Kameyama, Hideaki,Komura, Kenichi
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p. 549 - 550
(2007/10/03)
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- A new method for preparation of organocalcium halides by cocondensation of calcium vapor with solvents
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Calcium vapor (atom) when cocondensed with various solvents at 77 K was found to be very reactive toward alkyl and aryl halides.A series of organocalcium halides was prepared in good yields by addition of alkyl and aryl halides to the resultant calcium atom-solvent slurries at ambient temperatures.
- Mochida, Kunio,Yamanishi, Takayuki
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p. 247 - 252
(2007/10/02)
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