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991.
2,5-Bis(perfluoro-n-heptyl)-, 2-perfluoroalkylether-5-perfluoro-n-heptyl-, and 2,5-bisperfluoroalkylether-1,3,4-oxadiazoles were synthesized and characterized. 2,5-Bis(perfluoro-n-heptyl)-1,3,4-oxadiazole was thermally and hydrolytically stable at 325°C; however, in the presence of air, degradation took place at 235°C. The perfluoroalkylether analogue exhibited thermal and hydrolytic stability at 325°C; it was found to be unaffected by Jet-A fuel and air at 235°C. At 325°C in air some degradation occured as evidenced by volatiles production, oxygen consumption, and 96% starting material recovery.  相似文献   
992.
Complexation of polymeric anion exchangers with transition metals was studied by polarographic and potentiometric titration techniques.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1693–1698.Original Russian Text Copyright © 2004 by Ergozhin, Chalov, Kovrigina, Iskakova, Nikitina.  相似文献   
993.
A new scheme for the synthesis of dibenzodithiacrown ethers is proposed based on the use of substituted phenol derivatives as intermediates, prepared by aromatization of 2-alkylthio(arylthio)cyclohexanes during bromination. 1,7-Dithia-8,9,17,18-dibenzo-18-crown-6 and 1,10-dithia-11,12,20,21-dibenzo-21-crow-7 without isomers relative to position of the sulfur atoms have been synthesized, and also new thiadiazamacroheterocycles — 1,4,7-trioxa-10,19-dithia-13,16-diaza-12,17-dioxo-8,9,14,15,20,21-tribenzoheneicosane and 1,4,7,10-tetraoxa-13,22-dithia-16,19-diaza-15,20-dioxo-11,12,17,18,23,24-tribenzotetracosane.M. V. Lomonosov Moscow State University, Moscow 119899. M. V. Lomonosov Moscow State Academy for Fine Chemical Technology, Moscow 117571. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 121–127, January, 1997.  相似文献   
994.
Y. K. Sawa  N. Tsuji  S. Maeda 《Tetrahedron》1961,15(1-4):144-153
Sinomenine, an alkaloid of the Japanese plant Sinomenium acutum, was converted to the 4-phenylether by the Ullmann reaction in a good yield. The Clemmensen reduction of sinomenine-phenylether and of its derivatives gave (+)-3-methoxy-4-phenoxy-N-methyl-Δx-morphinan.

Hydrogenation and successive sodium-liquid ammonia reduction of (+)-3-methoxy-4-phenoxy-N-methyl-Δx-morphinan gave (+)-3-methoxy-N-methylmorphinan.  相似文献   

995.
J. Tsuji  M. Hara  K. Ohno 《Tetrahedron》1974,30(14):2143-2146
Palladium compounds and metallic palladium combined with phosphine are active catalysts of selective hydrosilylation of terminal olefins. Butadiene and trichlorosilane give a 1:1 adduct and trimethylsilane affords a 1:2 adduct. Special features of the palladium catalyzed hydrosilylation reactions are presented.  相似文献   
996.
Summary In the present investigations, the standardization of vanadium(II) solution against ferric and cupric salts has been described and a few visual indicators have been shown to be applicable in the above titrations. When iron(III) solution is added to vanadium(II) solution neutral red marks the end point for VII to VIII change. This change is also noted when vanadium(II) solution is added to ferric solution in the presence of excess of concentrated hydrochloric acid at an elevated temperature and neutral red and phenosafranine as visual indicators. Under the same conditions, the end point with eupric solution also corresponds to this change.When vanadium(II) solution is added to ferric solution at an elevated temperature in the presence of methylene blue or gallocyanine as visual indicators, the end point marks VII to VIV change. A mixture of iron and copper has also been titrated successfully with the help of visual indicators.
Zusammenfassung Zur Einstellung von Vanadium(II)-lösungen mit Eisen(III)- oder Kupfer(II)-salzen werden als visuelle Indicatoren Neutralrot, Phenosafranin, Methylenblau oder Gallocyanin benutzt. Bei Zugabe von Eisen(III)-lösung zur Vanadium(II)-lösung zeigt Neutralrot den Übergang VII VIII an. Dieser Übergang wird ebenfalls von Neutralrot und Phenosafranin angezeigt, wenn Vanadium(II)-lösung in Gegenwart von überschüssiger konz. Salzsäure bei erhöhter Temperatur zu Eisen(III)- oder Kupfer(II)-lösung gegeben wird. Der Übergang VII VIV wird von Methylenblau oder Gallocyanin angezeigt, wenn Eisen(III)-lösung bei erhöhter Temperatur mit Vanadium(II)-lösung titriert wird. Die Titration eines Gemisches von Eisen(III) und Kupfer(II) wird ebenfalls ausgeführt.


Thanks of the authors are due to the C.S.I.R. authorities for providing a Junior Research Fellowship to one of them (R.K.M.).  相似文献   
997.
Hydrated iron oxide or amorphous-Fe2O3·3.5 H2O (HFeO), hydrated titanium oxide (HTiO) and hydrated thorium oxide (HThO) were synthesized and their applicability for the decontamination of intermediate level liquid wastes (ILLW) was tested. The sorption of a few actinides like plutonium and americium on HFeO, 137Cs and 106Ru on HTiO and 90Sr on HThO was investigated as a function of pH, time and loading capacity of the hydrous oxide with metal ions. The influence of the total dissolved salt content was also monitored. Some of these parameters influenced the sorption behavior significantly. The radiation stability of these inorganic sorbents were studied by irradiating them up to 48 Mrad. Adsorbed actinides and fission products were successfully eluted from HFeO and from the mix-bed of HTiO and HThO by 0.5M nitric acid.The authors wish to thank Shri R. D. Changarani, Chief Superintendent NRG Facilities and Shri P. K. Dey, Head FRD for their valuable advice and constant support.  相似文献   
998.
Standard papers regulating the quality of waters of different types are considered. Procedures for determining water quality indexes are briefly reviewed.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 8, 2005, pp. 886–893.Original Russian Text Copyright © 2005 by Kutseva, Kartashova, Tchamaev.  相似文献   
999.
In previous work (Le Bizec et al., Rapid Commun. Mass Spectrom. 2000; 14: 1058), it was demonstrated that a boar meal intake could lead to possible false accusations of abuse of 17beta-nortestosterone in antidoping control. The aim of the present study was to identify and quantify endogenous 19-norsteroids in boar edible tissue at concentrations that can alter the steroid urinary profile in humans, and lead to excretion of 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE). The samples were analysed in two laboratories. The methodologies used for extraction and detection (GC/MS(EI) and LC/MS/MS(APCI+)) are compared and discussed. 19-Norandrostenedione (NAED), 17beta- and 17alpha-nortestosterone (bNT, aNT), and 17beta- and 17alpha-testosterone (bT, aT) were quantified. The largest concentrations of NAED and bNT were observed in testicles (83 and 172 microg/kg), liver (17 and 63 microg/kg) and kidney (45 and 38 microg/kg). A correlation between the bNT and NAED content of a typical meal prepared with boar parts and the excreted concentrations of 19-NA and 19-NE in human urine was demonstrated.  相似文献   
1000.
We present a density functional scheme for calculating the frequency-dependent linear response of superconductors. The central result is a set of integral equations determining the linear response of the normal and anomalous densities to external perturbations. Analytic solutions of these integral equations are obtained for homogeneous systems with separable effective interactions. For inhomogeneous superconductors, the formalism leads to a scheme for calculating the critical temperature without explicitly solving the gap equation. © 1995 John Wiley & Sons, Inc.  相似文献   
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