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Alkyl phenylsulfinates (Ph-SO-OR) were prepared from thiophenol (or diphenyldisulfide) by electrolysis in acetic acid with alcohols and sodium acetate in satisfactory yields.  相似文献   
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Analytical and Bioanalytical Chemistry - The size-exclusion chromatographic behaviour of 8-hydroxyquinoline (abbreviated as HOx) and its metal(II, III) chelates on Fractogel PVA 2000 in p-dioxane...  相似文献   
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Some trimethylsilylmethyl derivatives of thallium(III) have higher stability and unusual coordination behavior in comparison with simple alkylthallim(III) analogs for steric reasons.  相似文献   
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Summary A combined cation-exchange separation — atomic absorption spectrophotometric method is described for the determination of cobalt in silicate rocks. Silicate is decomposed with a mixture of perchloric acid — hydrofluoric acid. The residue is fed on a Bio-Rad AG 50W, X-8 resin (hydrogen form) column from 0.5 M hydrochloric acid — 0.05 M oxalic acid — 1.5% hydrogen peroxide solution. Polyvalent ions including ferric ions are not adsorbed on the column, while cobalt is retained together with alkaline earths and aluminium. Then, cobalt can be stripped selectively by elution with 1 M hydrochloric acid in 84% acetone solution and can subsequently be determined by AAS. The single column ion-exchange method described allows cobalt to be isolated from complicated matrices with good selectivity, sufficient enough to permit the final determination spectrophotometrically. Quantitative results are presented for the determination of cobalt in international rock standards and iron metal.
Genaue Bestimmung von Cobalt in silicatischen Gesteinen mit Hilfe einer Kombination von Kationenaustauschtrennung und Atomabsorptions-Spektralphotometrie
Zusammenfassung Bei dem beschriebenen kombinierten Verfahren wird die Probe mit Perchlorsäure/Flußsäure aufgeschlossen und der Rückstand in einer Lösung von 0,5 M Salzsäure, 0,05 M Oxalsäure und 1,5% Wasserstoffperoxid auf die Austauschersäule gegeben (Bio-Rad AG 50W, X-8, H-Form). Mehrwertige Ionen einschließlich Eisen werden nicht absorbiert, während Cobalt zusammen mit Erdalkalien und Aluminium zurückgehalten wird. Cobalt kann dann selektiv mit 1 M Salzsäure in 84% Aceton eluiert und anschließend mit AAS bestimmt werden. Das beschriebene Verfahren gestattet die Abtrennung von Cobalt aus komplizierten Matrices mit für die AAS-Bestimmung ausreichender Selektivität. Belegwerte für internationale Standardgesteine und metallisches Eisen werden angegeben.
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Acoustic cavitation generates transient microbubbles with extremely high temperatures and high pressures, which can provide unique reaction routes. The maximum bubble temperature attained is widely known to be dependent on the polytropic index and thermal conductivity of the dissolved gas. Here, we show for the first time experimental evidence that the bubble temperature induced by a high frequency ultrasound is almost the same among different rare gases and the chemical efficiency is in proportion to the gas solubility of rare gases, which would be closely related to the number of active bubbles.  相似文献   
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We discuss exotic meson spectroscopy near open bottom thresholds. Assuming the exotic mesons as ${B^{(\ast)}\bar{B}^{(\ast)}}$ molecular states, we study the interaction among two heavy mesons in terms of the one boson exchange potential model. It is shown that masses of Z b (10610) and Z b (10650) are reproduced as ${B^{(\ast)}\bar{B}^{(\ast)}}$ bound and resonance states. Besides, we also show that ${B^{(\ast)}\bar{B}^{(\ast)}}$ molecular states having various exotic quantum numbers can exist around the thresholds. By contrast, there are no ${D^{(\ast)}\bar{D}^{(\ast)}}$ molecular states having exotic quantum numbers.  相似文献   
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In the previous paper, we described a series of the 2-arylethenesulfonamide derivatives, a novel class of ETA-selective endothelin (ET) receptor antagonists, including the compounds 1a, b. Compound 1a showed excellent oral antagonistic activities and pharmacokinetic profiles, and the monopotassium salt of 1 (YM-598 monopotassium) is in clinical trials. In this paper, we wish to report the investigation of the further details of structure-activity relationships (SARs) of the 2-phenylethenesulfonamide region in 1a. It was found that methyl substitutions at the 2-, 4- and 6-positions of the phenyl group in 1a led to the discovery of the ET(A)/ET(B) mixed antagonist (6s) with an IC50 of 2.2 nM for the ET(A) receptor. We also found that introduction of an ethyl group to the 1-position of the ethenyl group in 1a gave the ET(A) selective antagonist (6u) with an oral endothelin antagonistic activity in rats.  相似文献   
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