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561.
562.
Methanol has recently attracted significant interest in the energetic field. Current technology for the conversion of methane
to methanol is based on energy intensive endothermic steam reforming followed by catalytic conversion into methanol. The one-step
method performed at very low temperatures (35°C) is methane oxidation to methanol via bacteria. The aim of this work was to
examine the role of copper in the one-step methane oxidation to methanol by utilizing whole cells of Methylosinus trichosporium OB3b bacteria. From the results obtained it was found that copper concentration in the medium influences the rate of bacterial
biomass growth or methanol production during the process of methane oxidation to methanol. The presented results indicate
that the process of methane oxidation to methanol by Methylosinus trichosporium OB3b bacteria is most efficient when the mineral medium contains 1.0 × 10−6 mol dm−3 of copper. Under these conditions, a satisfactory growth of biomass was also achieved.
Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May
2008. 相似文献
563.
Barbara Hefczyc Jan Zawadiak Henryk Janeczek Marek Kowalczuk Beata Orlińska 《Monatshefte für Chemie / Chemical Monthly》2011,288(2):271-276
Abstract
New asymmetrical azo-perester derivatives of tert-butyl and tert-amyl hydroperoxides were obtained by reacting azo acids with hydroperoxides in the presence of N,N′-carbonyldiimidazole. The obtained azo-peresters possess two labile functional groups: the azo group and the perester group. Data from dynamic differential scanning calorimetry (DSC) experiments indicate that the azo groups decompose at somewhat lower temperatures than the perester groups. 相似文献564.
Beata Kolesinska 《Central European Journal of Chemistry》2010,8(6):1147-1171
Review with 101 refs. of progress in synthetic applications and properties of P-acylphosphonium salts including acylation via P-acylphosphonium salts, enantioselective acylation using chiral phosphine ligands, nucleophilic (β)-oniovinylation, and reaction
involving vinyloges of P-acylphosphonium salts formed by treatment conjugated alkenoates or alkynoates with phosphines. 相似文献
565.
This paper focuses on the quantitative determination of the loss of the components from plastic membranes of ion-selective electrodes (ISEs) during contact with aqueous bathing solutions. The leaching processes, which affect the ISE responses, are rarely characterized by independent methods. For this purpose, differential pulse cathodic stripping voltammetry (DP CSV) is used. This method, owing to its high sensitivity, acceptable recovery and accuracy, is a good tool to characterize the kinetics of leakage of the lipophilic salts. Sodium tetraphenylborate (NaTPB) leakage from the PVC-based sodium-selective membrane containing two different plasticizers, o-nitrophenyl octyl ether (o-NPOE) or di(2-ethylhexyl) sebacate (DOS) is presented. Correlation between the rate of leaching of the lipophilic salt and dielectric constants of the plasticizers is observed. The data obtained by DP CSV correlate well with potentiometric and electrochemical impedance responses. The observed outflow of TPB− is associated with decreasing potentiometric sensitivity to sodium and increasing bulk membrane resistance. 相似文献
566.
This study presents the determination of the pseudo-total and available element contents in suspended matter in leachate using stripping voltammetry (DPASV) on a hanging mercury drop electrode and an inductively coupled plasma mass spectrometer (ICP-MS). The following elements were studied: Zn, Pb, As, Sb, Co, Cu, Ni, Cr, Sn, Mo and Cd. To determine the pseudo-total metal contents, we applied microwave digestion using a mixture of HNO3 and HClO4 with a small quantity of HF. To assess the metal availability from suspended matter in leachate, the single extraction procedure with 0.1mol·L–1 acetic acid and 0.01mol·L–1 ammonium acetate was applied. Metal bioavailability based on single extraction with 15% H2O2 was determined. We also estimated the association with particular phases of suspended matter in leachate. 相似文献
567.
Modular Stereoselective Synthesis of (1→2)‐C‐Glycosides based on the sp2–sp3 Suzuki–Miyaura Reaction 下载免费PDF全文
Beata Oroszova Jan Choutka Dr. Radek Pohl Dr. Kamil Parkan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7043-7047
This work reports a modular and rapid approach to the stereoselective synthesis of a variety of α‐ and β‐(1→2)‐linked C‐disaccharides. The key step is a Ni‐catalyzed cross‐coupling reaction of D ‐glucal pinacol boronate with alkyl halide glycoside easily prepared from commercially available D ‐glucal. The products of this sp2–sp3 cross‐coupling reaction can be converted to glucopyranosyl, mannopyranosyl, or 2‐deoxy‐glucopyranosyl C‐mannopyranosides by one‐ or two‐step stereoselective oxidative–reductive transformations. To the best of our knowledge, we demonstrated the first synthetic application of a challenging sp2–sp3 Suzuki‐Miyaura cross‐coupling reaction in carbohydrate chemistry. 相似文献
568.
A new ruthenium ion imprinted polymer was prepared from the Ru(III) 2-thiobarbituric acid complex (the template), methacrylic acid or acrylamide (the functional monomers), and ethylene glycol dimethacrylate (the cross-linking agent) using 2,2′-azobisisobutyronitrile as the radical initiator. The ion imprinted polymer was characterized and used as a selective sorbent for the solid phase extraction of Ru(III) ions. The effects of type of functional monomer, sample volume, solution pH and flow rate on the extraction efficiency were studied in the dynamic mode. Ru(III) ion was quantitatively retained on the sorbents in the pH range from 3.5 to 10, and can be eluted with 4 mol L?1 aqueous ammonia. The affinity of Ru(III) for the ion imprinted polymer based on the acrylamide monomer is weaker than that for the polymer based on the methacrylic acid monomer, which therefore was used in interference studies and in analytical applications. Following extraction of Ru(III) ions with the imprint and their subsequent elution from the polymer with aqueous ammonia, Ru(III) was detected by electrothermal atomic absorption spectrometry with a detection limit of 0.21 ng mL?1. The method was successfully applied to the determination of trace amounts of Ru(III) in water, waste, road dust and platinum ore (CRM SARM 76) with a reproducibility (expressed as RSD) below 6.4 %. Figure
The new ion imprinted polymer was prepared and used for the separation of ruthenium from water and most complex environmental samples, such as road dust and platinum ore (CRM SARM 76) prior ETAAS determination. 相似文献
569.
D. Wawszczak A. Deptuła W. Łada T. Smoliński T. Olczak M. Brykała P. Wojtowicz M. Rogowski M. Miłkowska A. G. Chmielewski 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(1):243-247
In Poland, there are significant deposits of copper ores. During the copper extraction, large amounts of flotation wastes are produced. In the ores and flotation wastes many other important elements are present. The main goal of this work was analysis of uranium content and to elaborate procedures for recovery of U from these materials. Two types of ores and four types of waste were examined. It has been found that uranium content varies from 4.5 to 25 ppm. The other elements have also been determined in these materials: Cu (4–5 % in ores and 0.3–1.7 % in waste), Ag, Re, Mo, La, Ni, V, etc. For leaching, sulfuric acid and sodium carbonates of various concentrations (temperature, time) were used. The optimum conditions for leaching have been found. The concentration of uranium in the final solution was generally less than 25 μg/mL. The other elements are also present in the leaching solutions. Simultaneous liquid–liquid extraction of uranium with these elements from leaching solution is under study. In our opinion, only such combined procedure for the recovery of uranium together with the accompanying elements could be cost-effective. 相似文献
570.
Detection of Oxidative Damage of Synthetic Oligonucleotides Caused by Thallium(III) Complexes 下载免费PDF全文
Anna M. Nowicka Beata Krasnodebska‐Ostrega Beata Wrzosek Magdalena Jastrzebska Monika Sadowska Marcin Mackiewicz Zbigniew Stojek 《Electroanalysis》2014,26(2):340-350
Biologically important short sequences of DNA were treated with Tl(III) complexes. The chloride complex releases the Tl(III) cation and therefore oxidizes DNA components and at concentrations higher than 50 nM cuts the strands. The cuts are well seen in the EQCM plots. The change in the strand structure is well seen at CD and UV‐Vis spectra. The chelate complexes of Tl(III) do not damage the DNA strands. The SERS spectra were particularly useful in demonstration of the chemical changes and orientation vs. the surface changes of particular groups in the strands after interaction with TlCl4?. 相似文献