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Luis Cesar Passoni Alexandre Tadini Cruz Regina Buffon Ulf Schuchardt 《Journal of molecular catalysis. A, Chemical》1997,120(1-3):117-123
The use of heteropolyacids as a reoxidant for palladium in the direct oxidation of benzene to phenol with molecular oxygen was studied as a function of the variables involved. It was shown that the oxidation system is very effective even if a molar ratio of HOAc:H2O of 1:2 is used. After 4 h at 130°C the benzene conversion is 15% and the selectivity for phenol is above 70%. The quantity of palladium acetate can be drastically reduced allowing turnover numbers as high as 800. 相似文献
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Eudes Loren?on Rodrigo G. Lacerda Luiz O. Ladeira Rodrigo R. Resende André S. Ferlauto Ulf Schuchardt Rochel M. Lago 《Journal of Thermal Analysis and Calorimetry》2011,105(3):953-959
Three different forms of carbon, i.e., multi-walled carbon nanotubes (CNTs), single-walled CNTs, and soot, were decorated
with gold nanoparticles by a new method. In this method C10H8
− ions transfer electrons to the CNTs or soot. These electrons on the carbon surface can then reduce Au3+ species to form supported Au nanoparticles with a narrow particle size distribution. Thermogravimetric/differential thermal
analyses (TG/DTA), XRD, Raman, and TEM show that naphthalene molecules remain trapped inside the Au nanoparticles and can
only be removed by treatment at ca. 300 °C. Remarkable effect of the Au nanoparticles on the oxidation of carbon by O2 is also observed by TG/DTA, i.e., on-set oxidation temperature and activation energy (E
a). It is shown that as the Au particle size decreases from 25 to 2 nm a linear decrease of the oxidation temperature is observed.
Au particles larger than 25 nm do not produce any significant effect on carbon oxidation. These results are discussed in terms
of spillover catalytic effect where Au nanoparticles activate O2 molecules to produce active oxygen species which oxidize the different carbon supports. 相似文献
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Preiss A Berger-Preiss E Elend M Gerling S Kühn S Schuchardt S 《Analytical and bioanalytical chemistry》2012,403(9):2553-2561
Groundwater samples collected downgradient from a former municipal solid waste landfill near Berlin, Germany, were analyzed by GC-MS, HPLC-MS, and HPLC-NMR hyphenated techniques to comprehensively characterize the xenobiotic organic compounds (XOCs). The focus thereby was on the detection and identification of the polar XOCs which were analyzed in the extract obtained after separation of the unpolar components by pre-extraction. HPLC-NMR and HPLC-MS runs were used to identify polar XOCs on-line or to obtain preliminary structure information on the other XOCs. These compounds were then isolated by HPLC fractionation and their structures elucidated by off-line NMR and MS investigations. A variety of polar XOCs, products of the dye industry, degradation products of polyethylene glycol, and some heterocyclic compounds could be identified. Furthermore, a semi-quantitative estimation of the identified polar compounds is given. 相似文献
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In the Simmons-Smith reaction, 1,3-dienes are preferentially cyclopropanated at the more electron-rich double bond to afford the trans-vinylcyclopropane; an allylic hydroxyl group increases the reactivity and directs the cyclopropanation to the adjacent double bond. 相似文献
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[Nb]-MCM-41 was synthesized at room temperature by varying the base (tetramethylammonium hydroxide or ammonium hydroxide), the silica source (tetraethyl orthosilicate or tetramethyl orthosilicate), the niobium source (ammonium niobium oxalate, NH4[NbO(C2O4)2(H2O)2] · 3H2O, or potassium niobate, K8Nb6O19) and the order of addition of the niobium source (before or after the silica source). These variations were determinant in the amount of niobium incorporated into the framework and in the structural order of the [Nb]-MCM-41 obtained. Only one method led to the formation of [Nb]-MCM-41 with the desired characteristics and active in the epoxidation of cis-cyclooctene with tert-butyl hydroperoxide leading to 19% conversion and 95% selectivity for cyclooctene oxide after 10 h. 相似文献
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Applied Biochemistry and Biotechnology - Hydrolytic eucalyptus lignin was converted to oils by hydrogenolysis. The lignin was obtained by acid hydrolysis of eucalyptus chips from two... 相似文献
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