排序方式: 共有197条查询结果,搜索用时 109 毫秒
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Edward A. Karakhanov Lyusyen M. Karapetyan Yulia S. Kardasheva Anton L. Maksimov Elena A. Runova Vitaliy A. Skorkin Maria V. Terenina 《Macromolecular Symposia》2006,235(1):39-51
Summary: The results of studying a number of reactions catalyzed by several types of soluble macromolecular catalytic systems capable of selectively binding organic substrates, namely, modified cyclodextrins, calixarenes and dendrimers are presented. The use of modified cyclodextrins as components of a catalytic system in the phenol and benzene hydroxylation by hydrogen peroxide allows one both to increase the catalytic activity and to change significantly the chemical selectivity. Phosphorilated calixarene – Rh catalytic systems was found to be catalytically active in hydroformylation of linear alkenes C7–C12. The results of experiments on the oxidation of C7–C16 alkenes show that, when the ligand is the dendrimer molecule, the fraction of forming methyl ketones substantially increases for the substrates C7–C9. For the higher alkenes, this effect is not observed. 相似文献
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Dr. Peter S. Shuttleworth Dr. Vitaliy Budarin Dr. Robin J. White Prof. Vladimir M. Gun'ko Dr. Rafael Luque Prof. James H. Clark 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(28):9351-9357
Understanding of both the textural and functionality changes occurring during (mesoporous) polysaccharide carbonisation at the molecular level provides a deeper insight into the whole spectrum of material properties, from chemical activity to pore shape and surface energy, which is crucial for the successful application of carbonaceous materials in adsorption, catalysis and chromatography. Obtained information will help to identify the most appropriate applications of the carbonaceous material generated during torrefaction and different types of pyrolysis processes and therefore will be important for the development of cost‐ and energy‐efficient zero‐waste biorefineries. The presented approach is informative and semi‐quantitative with the potential to be extended to the formation of other biomass‐derived carbonaceous materials. 相似文献
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Liliya I. Kasyan Stanislav A. Prid'ma Vitaliy A. Palchikov Leonid D. Karat Alexandr V. Turov Olexandr Isayev 《Journal of Physical Organic Chemistry》2011,24(8):705-713
Reactions of 2‐nitro‐, 4‐nitro‐ and 2,4‐dinitrophenylglycidyl ethers with bicyclo[2.2.1]hept‐5‐ene‐endo‐2‐ylmethylamine in isopropanol have been studied. The mixtures of products were chromatographed on silica gel and eluted with ether or ether/2‐propanol (1:1), the structures of individual products have been confirmed by IR spectra, NMR 1H, 13C spectra, using experiments that involve homonuclear and heteronuclear scalar coupling interactions (COSY, TOCSY, HMQC, HMBC), and mass spectrometry. Amino alcohols as the major products of regioselective aminolysis of epoxides (according to the Krasusky rule) have been obtained. The minor products were the compounds with two hydroxyalkyl fragments at the nitrogen atom. In case of dinitrophenylglycidyl ether, it was the minor product of aryl nucleophilic substitution (SNAr). The abnormal course of aminolysis has been confirmed by the results of quantum‐chemical calculations of activation barries and Free Gibbs energies of the competitive reactions of epoxides (at the B3LYP/6‐311 + G(d,p) level of theory). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Vitaliy Chagovets Vladimir Frankevich Renato Zenobi 《Journal of the American Society for Mass Spectrometry》2014,25(11):1991-1994
A new method for measuring the ion velocity distribution using an internal matrix-assisted laser desorption/ionization (MALDI) source Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer is described. The method provides the possibility of studying ion velocities without any influence of electric fields in the direction of the instrument axis until the ions reach the ICR cell. It also allows to simultaneously account for and to estimate not only the velocity distribution but the angular distribution as well. The method was demonstrated using several types of compounds in laser desorption/ionization (LDI) mode. Graphical Abstract
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Rezaeyan Amirsaman Pipich Vitaliy Ma Jingsheng Leu Leon Seemann Timo Rother Gernot Barnsley Lester C. Busch Andreas 《Transport in Porous Media》2022,141(1):201-229
Transport in Porous Media - In geoenergy applications, mudrocks prevent fluids to leak from temporary (H2, CH4) or permanent (CO2, radioactive waste) storage/disposal sites and serve as a source... 相似文献
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Feyer V Plekan O Richter R Coreno M Prince KC Carravetta V 《The journal of physical chemistry. A》2008,112(34):7806-7815
Core level X-ray photoemission spectra (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectra of alanine and threonine in the gas phase have been measured at the carbon, nitrogen, and oxygen K edges and interpreted in the light of theoretical calculations. For the computations, a set of approximations is made which allows sufficiently accurate calculations of several conformers to be performed in reasonable computing time. The accuracy has been checked by comparing results obtained for proline to our previous, higher level calculations. The photoemission spectra at the carbon and oxygen edges are assigned and compared. The nitrogen 1s photoemission peaks show anomalous broadening which we relate to the populations and types of conformers. The carbon K-edge NEXAFS spectra of alanine and threonine are compared with our previous data on glycine and resonances assigned accordingly. The nitrogen K-edge NEXAFS spectra of alanine and threonine do not show measurable effects due to the population of conformers, in contrast to the photoemission results. At the oxygen K edge, the spectra of these amino acids are similar with two prominent peaks assigned to transitions of O 1s electrons from the oxo and hydroxyl groups to vacant pi* and sigma* orbitals and additional intensity for threonine due to the second OH group. Conformer effects are observable in photoemission but appear to be more difficult to resolve in photoabsorption. We explain this by energetic shifts of opposite sign for the core hole states and unoccupied orbitals, which causes partial cancelation in NEXAFS but not in photoemission. 相似文献