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71.
Francisco José Aguilar Troyano Frederic Ballaschk Marcel Jaschinski Yasemin Özkaya Dr. Adrián Gómez-Suárez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14054-14058
The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light-mediated, catalyst-free methodology is fast and broadly applicable allowing for the preparation of C−F bonds from (hetero)benzylic, propargylic, and non-activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single-electron oxidation of cesium oxalates—which are readily available from the corresponding tertiary alcohols—with in situ generated TEDA2+. (TEDA: N-(chloromethyl)triethylenediamine), a radical cation derived from Selectfluor®. 相似文献
72.
Fırıncı Rukiye Fırıncı Erkan Başbülbül Gamze Dabanca Mustafa Berk Barut Celepci Duygu Günay M. Emin 《Transition Metal Chemistry》2019,44(4):391-397
Transition Metal Chemistry - Three 1,3-dimethylbarbiturate-enamine derivatives and their symmetrical palladium(II) complexes were prepared and characterized by spectroscopic methods. In addition,... 相似文献
73.
D. Karakaş I. Ölmez S. Tosun G. Tuncel 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(1):187-192
Instrumental neutron activation analysis (INAA), flame atomic absorption spectrometry (FAAS), flame atomic emission spectrometry (FAES), graphite furnace atomic absorption spectrometry (GF-AAS), ion chromatography (IC) and visible spectrometry (VIS) were used to determine the composition of atmospheric aerosols, collected at a rural site in the Western Black Sea Coast of Turkey. A total of 354 daily aerosol samples were analyzed for 46 trace and major elements and ions. Sample preparation, quality control procedures, instrumental operating conditions for INAA and source apportionment work is presented. 相似文献
74.
E. I. Ölmez D. Kut A. N. Bilge I. Ölmez 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(2):227-231
In ambient air, arsenic to selenium ratio (As/Se) is generally found to be less than 1, except in areas influenced by specific
point sources, such as Cu smelters. However, the annual average of this ratio is found to be much higher than unity in Turkey.
This finding is rather unique and may provide a marker for air masses influenced by the coal-related emissions in Turkey.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
75.
α-Aspartame (L-α-aspartyl-L-phenylalanine methyl ester) is increasingly being used in wide variety of commonly consumed food products. This structure contains ester and peptide bonds. The ester linkage may hydrolyze to produce L-α-aspartyl-L-phenylalanine or cyclohydrolyze to produce the corresponding diketopiperazine ring. This ring can open to form L-α-aspartyl-L-phenylalanine and ultimately this compound can hydrolyze to L-phenylalanine and L-aspartic acid. The pH, buffer type, concentration, the presence of water and temperature are other important factors affecting its stability. Because α-aspartame can lose its sweetness under these conditions determination of aspartame and its breakdown products is extremely important for diet foods quality. The optimum mobile phase for the chromatographic separation was found to be acetonitrile-water (20:80, ν/ν) with 5.10?3 M hexanesulfonic acid and a pH of 2.6. 相似文献
76.
G. Buchbauer H. Spreitzer B. Öckher C. Pretterklieber I. Piringer P. Wolschann 《Monatshefte für Chemie / Chemical Monthly》1995,126(4):467-472
Summary Guided by molecular modeling studies, the synthesis of the title compound is described. The organoleptic evaluation proved the predicted real sandal like odour of (Z)-dehydro-homo--santalol.
Aus den Diplomarbeiten von C.P. (1991), I.P. und B.Ö. (1992), Universität Wien 相似文献
77.
Harry J. Whitlow Margaretha Andersson Mikael Hult Leif Persson Mohamed El Bouanani Mikael Östling Carina Zaring Nils Lundberg David D. Cohen Nick Dytlewski Peter N. Johnston Ian F. Bubb Scott R. Walker Erik Johanson Sture Hogmark P. Anders Ingemarsson 《Mikrochimica acta》1995,120(1-4):171-181
Recoil Spectrometry covers a group of techniques that are very similar to the well known Rutherford backscattering Spectrometry technique, but with the important difference that one measures the recoiling target atom rather than the projectile ion. This makes it possible to determine both the identity of the recoil and its depth of origin from its energy and velocity, using a suitable detector system. The incident ion is typically high-energy (30–100MeV)35C1,81Br or127I. Low concentrations of light elements such as C, O and N can be profiled in a heavy matrix such as Fe or GaAs. Here we present an overview of mass and energy dispersive recoil Spectrometry and illustrate its successful use in some typical applications. 相似文献
78.
N. C. van de Merbel M. Stenberg R. Öste G. Marko-Varga L. Gorton H. Lingeman U. A. Th. Brinkman 《Chromatographia》1995,41(1-2):6-14
Summary A two-dimensional, column liquid chromatographic system is used for the determination of the D- and L-enantiomers of amino acids in biological samples. Separation of the amino acids is first on ion-exchange column by gradient elution with a sodium citratesodium chloride buffer. Enantioseparation is by subsequent injection of 3 l heart-cuts of the individual amino acids onto a second column with a chiral crown ether stationary phase. Finally, fluorescence detection is after post-column labelling of the amino acids using ano-phthalaldehyde-2-mercaptoethanol reagent solution. The high separation power and selectivity of the system allow processing of complex samples with hardly any additional treatment and the determination of small quantities of D-amino acids in the presence of excess L-form. Applicability of the system is illustrated by the determination of D- and L-aspartate, serine, glutamate and alanine in various complex biological samples, such as protein hydrolysates, urine and biotechnological and food samples. Data are given on detectability, repeatability and linearity. 相似文献
79.
The thermal behaviours of the Ti(II), Mn(II), Fe(II), Ni(II), Cu(II) and Zn(II) complexes of triethanolamine were studied by means of thermogravimetry, differential thermogravimetry, differential thermal analysis infrared spectrophotometry and elemental analysis. The sequence of thermal stability of the metal complexes, determined by using the initial decomposition temperature, was found to be Ti(II)?Mn(II)>Fe(II)>Ni(II)>Zn(II)>Cu(II). Some of the kinetic parameters, such as the activation energy and order of reaction for the initial decomposition reaction, were calculated and the relationship between the thermal stability and the chemical structure of the complexes is discussed. 相似文献
80.
The applicability of a new leaching method, the HSS (H2O2-Na2SO4-H2SO4) system, in the extraction of uranium from Saricaolu-Bergama Region low grade ore, and the efficiency of Acigol Lake (Denizli)-Turkey water as a natural source of Na2SO4 has been investigated. The effect of H2SO4 concentration, temperature, leaching time, H2O2 and Na2SO4 concentrations and the amount of Acigol Lake water on the extraction of uranium was examined. HSS was found suitable for the extraction of uranium from Saricaolu-Bergama Region samples and it was observed that the acid consumption could be decreased by adding Na2SO4. 相似文献