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1.
The reaction of ( Z, E)-1,5-cyclodecadiene with N-bromosuccinimide in the presence of water or methanol leads to transannular cyclizations producing 4
t
-bromo-1
c
, 9
c
, 10
c
-decalol, and 4
t
-bromo-1
c
-methoxy-9
c
, 10
c
-decalin, resp., in high yields. The stereochemistry of the products has been established by chemical methods, and NMR-techniques.
Mit 1 Abbildung
2. Mitt.: J. Graefe, G. Haufe und M. Mühlstädt, Z. Chem. 16 180 (1976).
Aus der Dissertation zur Promotion A. G. Haufe, Universität Leipzig, 1975. 相似文献
3.
Abstract SUMMARY Palladium was determined spectrophotometrically with sodium ethylene-bis-selenoglycollate in acid medium. The system obeys Beer' law in the range 0.25–0, 3 5 μg.ml ?1 and the molar absorptivity is 2.4 × 10 4 1. mol ?1 .cm ?1. Determination of palladium in the presence of many ions is reported. In spite of the fact that selenium compounds have rarely been used as organic analytical reagents and one finds many palladium determination methods in the literature, this paper fits into the general Purpose reported before 1,2 :systematic comparison of organic sulphur, sellenium and tellurium compounds as analytical reagents in agreement with propositions made some years agp 3,4 In previous work 5 the behaviour of the ethylseleno glycollic (L 1), selenodiglycollic (L 2) and ethylene-bis-selenoglycollic (L 3) anions in acidic solutions of some “soft”, “borderline” and “hard” cations was studied. The results obtained for Pd(II) afforded evidences that its determination could be run with the three mentioned ligands. Nevertheless, L 3 was selected because it provides the most sensitive signal and its synthesis is very simple and its overall yield is excellent 6 From the qualitative study 5 the foreseen selectivity could present some restrictions, but there is little doubt about the usefulness of the method that will be proposed, in various schemes of determination. Similar comments Beamish have been made about EDTA method for Pd(II) determination 8 相似文献
4.
Abstract Compounds of the following structure (R 1O) 2(X)P[sbnd]Y–P(X)(OR 2) 2 (X = O, Y = S n (n = 1–4), R 1 = R 2 = Me, iPr; X = S, Y = S n (n = 1–4), R 1, R 2 = Me, Et, iPr, iBu; X = S, Y = S-Se-S, S-Te-S, R 1 = R 2 = Me were prepared and their NMR spectra were analysed. Depending on the number of sulfur atoms, bonded between the phosphorus atoms, typical ranges of the P-P coupling constants were found for the different sulfanes investigated: 2J PP from-10 to-20 Hz, 3J PP less than 3 Hz, 4J PP from +10 to +13 Hz and 5J PP less than 1 Hz. For the small vicinal coupling constants and the relatively large values of 4J PP different possibilities of their interpretation are given. 相似文献
5.
Abstract A separation and chemical analysis method has been developed of corrosion products forming on aluminum brass surfaces immersed in sodium sulfate solutions at pH= 7.25 (simulating river water) and in sea water at pH= 8.2. This method is based upon a selective solubilization of various oxidation compounds with the aid of proper solvents (i.e. dissolving the metal matrix only to a negligible extent). These analyses can be performed on oxidation films of more than 100 Å thickness. The following solvents were used: 1) Methanol for solubilization of Na +, Cu ++ and Zn ++ chlorides and sulfates; 2) Glycine to solubilize bivalent metal compounds:Cu and Zn oxydes oxysulfates, oxycarbonates, oxychlorides of Cu and Zn; 3) NH 4 OH to solubilize Cu ++ and aluminum compounds. A fair agreement was observed between the formulae derived by stoichiometric calculation applied to chemical analyses and the values obtained by X-ray analysis. Agreement was satisfactory for all compounds, except aluminum, determined by chemical analysis and identified by X-rays only in very thick oxidation films (≥ 10 3 Å). The role of chemical analysis is therefore determinant to finalize the formation mechanism of aluminum brass passivation films. 相似文献
6.
Abstract A direct and fast analytical method for the determination of Lonidamine and its impurity of synthesis, the N 2 alkylated isomer, by UV derivative spectrophotometry, is described. The procedure was defined by regression analysis for a high number of standard solutions. Linear relationships were obtained between mixture composition and maximum amplitude in < 2D at 316 nm for Lonidamine quantitation, and peak trough 4D 226,234 and 4D 323,316 amplitudes by utilising polynomial equation for N 2 isomer quantitation. The method, yielding accurate and precise results, was satisfactorily applied to laboratory mixtures and to a commercial formulation. 相似文献
7.
Abstract The areas treated in this article are: (i) The Haeffner effect; where the light isotope moves towards the anode in all cases so far investigated. (ii) Self diffusion and mutual diffusion. (iii) Shear viscosity of pure isotopes of Li 6 and Li 7. In the course of the discussion, the Haeffner effect is shown to be directly related to electrical resistively at the level of the lowest order Born approximation. Models used for treating isotopic mass effects are then considered; limitations and usefulness being assessed by comparison with experimental data on liquid metals. The marked contrast with low temperature isotope effects is finally commented on. 相似文献
8.
The contents of zinc, copper, lead and cadmium were measured in the dominant species (plants:Scripus triquetor andPhrgrmites australis, macrobenthos:Ilyoplax deschampsin, Helice tridens tientsinensis, Bullacta exarata and Corbicula fluminea, and migrating waders: Calidris ruficollis and C. alpina) of the ecosystem of Yangtze Estuary, China, from 1995–1998. Results show that:
-
(1)
Since the heavy metals stored in plants during growth seasons will be released into the environment in winter, plants are temporary stocks for metals. For the aboveground parts of reeds, about 156.6 kg·ha-1·a-1 of zinc, 369.9 kg·ha-1·a-10 of copper, 32.9 kg·ha-·a-1 of lead and 6.5 kg·ha-1·a-1 of cadmium were released.
-
(2)
The mollusca, especially C.fluminea, are the key species storing and transporting heavy metals on the food chain.
-
(3)
The temporal change in the highest trophic level was studied and found that it was significantly related with metabolic rates. The contents of heavy metals in Dunlin reach the peaks in January and October, which are wintering season and migratory season, respectively, of the bird.
-
(4)
Organisms often show regulation/accumulation mechanisms to different elements of heavy metals. The elements that are widely required, such as zinc and copper, are accumulated at the metabolically active parts. It is quite another thing for the other two elements. Lead was regulated well and scarcely accumulated in the bodies of macrobenthos, but cadmium was absolutely accumulated in the animals.
-
(5)
Heavy metals were found accumulated in some parts of the bodies of these organisms, such as shells and skeletons of macrobenthos and lives and muscles of waders.
-
(6)
All these four elements were accumulated higher in the bodies of waders than in the plants and macrobenthos, which showed a bio-magnification function of the food chain. Overall, besides the physical and chemical processes, biological processes of heavy metal elements in Yangtze Estuarine ecosystem play a very important role in self-purification function of the ecosystem. Measurement of heavy metal contents in plants and animals in the estuarine ecosystem is an efficient technology for monitoring the environmental quality of the estuary.
相似文献
9.
Using p,p'-dimethoxydiphenyldiazomethane (DMDM) as initiator, the polymerization of methyl methacrylate (MMA) in benzene or in bulk was carried out. The initial rate of polymerization, R p, was found to be expressed by the following equation: R p = k[DMDM] 0.53 [MMA] 0.84 The polymerization was confirmed to proceed by a radical mechanism. The over-all activation energy for the polymerization in benzene was calculated as 19.3 kcal/mole. The rate of thermal decomposition of DMDM was also measured in benzene and the rate equation was obtained as follows: k d (sec ?1) = 1.0 × 10 15 exp ( ?29.1 kcal/RT) (for 50-80°C) Explanations of these observations are discussed in connection with those of the preceding papers. 相似文献
10.
Abstract Palladium(II) forms 1:1 and 1:4 complexes with allyl thiourea. The molar composition of the complexes was determined by molar-ratio and continuous variation methods and confirmed by means of elemental analysis of the compounds isolated from solution. Conformity to Beer's law was observed for up to 12 μg ml ?1 of 4 palladium in strongly acidic medium (molar absorptivity 2.28×10 4 1 mol ?1 cm ?1 at 292 nm);the Sandell's sensitivity of the reaction for palladium is 0.0047 μg cm ?2 per 0.001 absorbance unit. The tolerance of the system to platinum metals and other common cations is satisfactory. A statistical evaluation of the analytical procedure of palladium determination has been undertaken. The infrared spectra of allyl thiourea and of its 1:1 and 1:4 palladium complexes have been measured in the 2.5–50μ region. The absorption bands have been assigned. The spectra reveal that allyl thiourea forms sulphur-to-metal bonds only, rather than nitrogen-to-metal bonds in the complexes studied. 相似文献
11.
Abstract Chloranil (2,3,5,6-teterachloro-p-benzoquinone) reacts with certain aminoglycosoide antibiotics in borate buffer at pH 9.0 to give charge-transfer complexes. The complexes possese an absorption maxmum at about 350 nm with molar absorptivities of 3.78 × 10 5, 4.69 × 10 5, 5.0 × 10 5 and 7.08 × 10 5 for kanamycin, neomycin B, amikacin and tobramycin reepectively, These high intensity of the chargetransfor band and confirmity to beer's law enabled assay of these antibiotics with appreciable sensitivity and good precision. Aminoglycosoide antibiotics have a broad spectrum of activity against both gram-negative and gram-positive bacteria. The official compendia 1,2 recommend the microbiological assay for their evalution. The high experimental errors in microbiological estimation heae been reported 3. Numerous spectrophotometric, fluorometric and chromatographic techniques for their quantitation have been thoroughly reviewed 4,5. Substituted quinones such as 2,5 dichloroquinone 6, 7,7,8,8-tetracyanoqulnone dimethane 7, flouranil 8 are used as TT- acceptors with various electron donors to form charge-transfer(CT) complexes and radical ions 9,10. Some aromatic amines 11,12 and aminoacids have been determined with chloranil 13–15. The present work describes the utility of chloranil for the spectrophotometric determination of kanamycin sulphate, amikacin sulphate tobramycin aulphate, and neorycin B sulphate (framycetine sulphate) either in bulk or in their reepective doaage forms. 相似文献
12.
The rates of electrodeposition of copper plates were determined by measuring cathodic limiting current in the absence and in the presence of carbohydrates (glucose, fructose, mannose, sucrose, lactose, and maltose). It is found that the rate of electrodeposition decreases in the presence of organic additives by an amount ranging from 1.89% to 35.85%, and depending on the types of additives and its concentrations. Our investigation of adsorption isotherm indicates that the inhibition fits both the Langmuir adsorption isotherm and Flory-Huggins adsorption isotherm; we found that the rate of electrodeposition decreases by increasing height and increasing CuSO 4 concentrations. Thermodynamic parameters are given and show that electrodeposition process is diffusion controlled. The rate of deposition and its equations are represented: -
Sh = 0.099Re0.715 Sc0.33 for glucose with average deviation: ±0.158% -
Sh = 0.097Re0.715 Sc0.33 for fructose with average deviation: ±0.058% -
Sh = 0.099Re0.715 Sc0.33 for mannose with average deviation: ±0.108% -
Sh = 0.098Re0.713 Sc0.33 for sucrose with average deviation: ±0.003% -
Sh = 0.099Re0.714 Sc0.33 for lactose with average deviation: ±0.018% -
Sh = 0.099Re0.713 Sc0.33 for maltose with average deviation: ±0.097%. 相似文献
13.
Abstract Dialkyl(aryl)carbamoylmethylphosphine oxides (CMPO), prepared by interaction of tervalent phosphorus acid esters with chloracetic amides R 1R 2P(O)CHR 4C(O)NR 3 2, R 1, R 2, R 3, R 4 = Alkyl or Aryl, can be used successfully for concentrating the transpluto-nium elements. 相似文献
14.
Abstract This paper describes the method for the concentration of Cu 2+ by liquid-liquid extraction using Lix 64N solutions in kerosene, followed by back extraction chromatography. It consists of a pass of the organic phase through columns filled with cationic resins (H +) which contains only the water surrounding the grains. The effect of the pH of the aqueous film surrounding the resin grains on the capacity of Vionit CS-3 (-SO 3H) and Vionit CM-14 (-SH) has been established. The loading curves of these resins have been drawn, as the optimum pH of the aqueous film and the resin capacities shown to increase in the order -SH < -SO 3H. The effect of the flow-rate on the loading and the optimum elution conditions have been also determined. A mechanism for the ion-exchange process is proposed. 相似文献
15.
The determination of boron in zirconium by activation analysis using the 10B(d, n) 12C reaction with the chemical separation of 11C is described. The method was applied to industrial zirconium samples as zircalloy.
Collaborateur temporaire de thèse au CEA. 相似文献
16.
Abstract Ruthenium(III) forms a 1:2 complex with allyl thiourea. Conformity to Beer's law was observed for up to 12 pg/ml of ruthenium, in acidic medium. The molar absorptivity of the complex is 1.66E+04 1 mol ?1 cm ?1, at 270 nm; the Sandell's sensitivity of the reaction for ruthenium is 0.0061 μg cm ?2 per 0.001 absorbance unit. The tolerance to diverse ions is quite satisfactory. The infrared spectra of allyl thiourea and of its ruthenium complex, recorded in the 2.5 - 50 μ region, reveal that only sulphur-to-ruthenium bonds are present in the complex. A comparison with the main, most recent, spectrophotometric reagents for ruthenium is reported. The present method has the advantages of simplicity and reasonable sensitivity. 相似文献
17.
Abstract A rapid and specific high-pressure liquid chromatography method for determination of clonazepam in human plasma is described. The analysis is linear for concentrations ranging from 5 to 100 ng. ml -1 plasma for clonazepam. The method is applicable to quantitation of clonazepam in human plasma of subjects receiving 0.05 at 0.20 mg.kg -1 orally, with satisfactory accuracy and precision. 相似文献
18.
Zusammenfassung Die polarographische Bestimmung von organischen Hydroperoxiden in Lösung ist im Konzentrationsbereich von 10 –2 bis 10 –6 m in verschiedenen Grundelektrolyten leicht durchzuführen. Die Eichkurve ist über den ganzen Konzentrationsbereich linear.
Summary Organic hydroperoxides can be determined by polarography in different solvents and supporting electrolytes without difficulties. A linear relationship exists between the diffusion current and the concentration in the range of 10–2 to 10–6 moles per liter.
Mein Dank gilt Herrn Prof. Dr. W. Kern für die freundliche Unterstützung dieser Arbeit.
I. Mitt.: Dulog, L.: diese Z. 202, 192 (1964). 相似文献
19.
Abstract Values for the protonation constants of myo-inositol hexakis(phosphate) have been determined at 25°C and 0.1 M ionic strength by potentiometry in media containing two different concentrations of Li +, Na +, K + and Cs + salts. The Alog K yHM values, which correspond to the differences between the constants obtained with and without alkali-metal cations, are considered as being related to the binding ability of the ligand towards these cations. Their relative behaviour is then analysed and some conclusions are drawn about the conformations which might be adopted by the complexes in different pH regions. 相似文献
20.
Abstract A new heterogeneous Mn(II) ion selective coated wire electrode (CWISE) based on tetrapyridine Mn(II) thiocynanate as electroactive material has been described. the working pH range of the electrode is 2.3 to 8.8. the electrode shows a linear response in the concentration range 1.0×10 ?1M to 1.0×10 ?6M. the response time of the electrode is 35 sec. the selectivity coefficient for different cations determined by mixed solution method are: Fe 2+(0.05), Cd 2+(0.05), Ni 2+(0.01), Co 2+(0.5), Pb 2+(0.5), Hg 2+(0.05), Sn 2+(0), Zn 2+(0) The electrode can be used for the electrometeric determination of Mn(II) ion. 相似文献
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