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141.
Mass spectra of 1-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain, suggest that the [M? CH3]+ ion is represented partly by an α-hydroxybenzyl fragment. Moreover, the molecular ion loses successively—after scrambling of all hydrogen atoms, except those of CH3? a hydrogen atom and C6H6, generation the CH3CO+ ion. Diffuse peaks, found in the spectra of of 2-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain and in the phenyl ring, show that the molecular ion loses C2H4O, possibly via a four-center mechanism, after an exchange of aromatic and hydroxylic hydrogens. Mass spectra of 1-phenylpropanol-2 and its analogues, specifically, deuterated in the aliphatic chain, demonstrate that in the molecular ion exclusively the hydroxyl hydrogen atom is transferred to one of the ortho-positions of the phenyl ring via a McLafferty rearrangement, generating the [M ? C2H4O]+ ion. Furtherore, an eight-membered ring structure is proposed for the [M ? CH3]+ ion to explain the loss of H2O and C2H2O from this ion after an extensive scrambling of hydrogen atoms. 相似文献
142.
The effects of ultrasonic irradiation on transport and reactions in several flow-injection manifolds are described. The influences of ultrasound on the physical dispersion of the injected plug is considered. Its effects on systems involving homogeneous (catalytic and non-catalytic) and heterogeneous (liquid/liquid extraction, precipitation) reactions are critically evaluated. In general, greater sensitivity is obtained, especially for heterogeneous systems, slow reactions and low analyte concentrations. Finally, practical considerations and potential uses of the combination of ultrasonic irradiation with flow-injection analysis are discussed. 相似文献
143.
Jože Slivnik Mateja Žvanut Borka Sedej 《Monatshefte für Chemie / Chemical Monthly》1968,99(5):1713-1717
Zusammenfassung Die Reaktion zwischen MgCO3 und wässerigen Lösungen von Hydraziniumdifluorid und Flußsäure führt zum Hydraziniumfluoromagnesat. Diese Verbindung ist auch aus Magnesiumchlorid-und Hydraziniumdifluorid-Lösungen herstellbar. Es werden röntgenographische, IR-spektrographische und thermogravimetrische Untersuchungen dieser Verbindung angegeben.
Mit 3 Abbildungen 相似文献
Hydrazinium(+2) fluoromagnesate is formed in the reaction between MgCO3 and hydrazinium difluoride dissolved in hydrogen fluoride. The reaction of magnesium chloride and an aqueous solution of hydrazinium difluoride yields the same product. The results of X-ray diffraction studies, IR spectroscopical studies and thermogravimetrical investigation are given.
Mit 3 Abbildungen 相似文献
144.
L. Moens A. Simonits F. De Corte J. Hoste 《Journal of Radioanalytical and Nuclear Chemistry》1979,54(1-2):377-390
For 13 isotopes, the resonance integral to thermal crosssection ratio was studied. The results of two different methods, applied
in two different laboratories, are compared. One method consists in a direct determination of I0/π0-values from Cd-ratio measurements, the other is based on the evaluation of literature data, using accurately determined k0-factors from two irradiation channels with largely different thermal-to-epithermal flux ratios. 相似文献
145.
一种液晶环氧树脂固化中扩散控制动力学研究 总被引:3,自引:0,他引:3
根据扩散控制反应的基本原理 ,建立了合适的反应模型 ,描述了 4 ,4′ 二 ( 2 ,3 环氧丙氧基 )偶氮苯(DGEAP) / 4,4′ 二氨基二苯甲烷 (DDM)环氧树脂的固化行为 .该模型认为 ,随着环氧基团反应程度的提高 ,基团的反应半径将受到影响 .当体系中出现了介晶基元的有序排列时 ,与之相连的反应基团的分布也受到影响 ,有序区内的局部浓度将变大 ,产生假浓度效应 ,并最终影响扩散控制反应动力学 .通过与普通环氧树脂固化动力学的比较 ,证实了这一效应 . 相似文献
146.
Susan A. Bourne Katherine De Villiers Timothy J. Egan 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o53-o57
The structures of three compounds with potential antimalarial activity are reported. In N,N‐diethyl‐N′‐(7‐iodoquinolin‐4‐yl)ethane‐1,2‐diamine, C15H20IN3, (I), the molecules are linked into ribbons by N—H⋯N and C—H⋯N hydrogen bonds. In N‐(7‐bromoquinolin‐4‐yl)‐N′,N′‐diethylethane‐1,2‐diamine dihydrate, C15H20BrN3·2H2O, (II), two aminoquinoline molecules and four water molecules form an R54(13) hydrogen‐bonded ring which links to its neighbours to form a T5(2) one‐dimensional infinite tape with pendant hydrogen bonds to the aminoquinolines. The phosphate salt 7‐chloro‐4‐[2‐(diethylammonio)ethylamino]quinolinium bis(dihydrogenphosphate) phosphoric acid, C15H22ClN32+·2H2PO4−·H3PO4, (III), was prepared in order to establish the protonation sites of these compounds. The phosphate ions form a two‐dimensional hydrogen‐bonded sheet, while the aminoquinoline cations are linked to the phosphates by N—H⋯O hydrogen bonds from each of their three N atoms. While the conformation of the quinoline region hardly varies between (I), (II) and (III), the amino side chain is much more flexible and adopts a significantly different conformation in each case. Aromatic π–π stacking interactions are the only supramolecular interactions seen in all three structures. 相似文献
147.
A method is described for determining traces of boron in water, fertilizers, geological and biological (reference) materials by isotope-dilution mass spectrometry after separation on an Amberlite IRA-743 borate-selective ion-exchange column. Boron (–250 ng g?1) in water can be determined with an accuracy of 5–20% (computed on a 2s basis). After correction for weighing errors and for moisture, content, which varied from 0 to 8% for the samples tested, 1–35 μg g?1 boron in “dry” fertilizer, biological or geological sample can be assayed with an accuracy of 5–30% (2s). In an IAEA interlaboratory program on a simulated fresh water, the method yielded a value of 24.3 +? 2 μg l?1, compared to the make-up value of 25 μg l?1. 相似文献
148.
149.
The dihydride cluster H_2O_(s_3)(CO)_(10) reacts with ethyne to give a cis-adduct [O_(s_3)H(μ,η~2-CH=CH_2)(CO)_(10)]. The high deuterated cluster D_2O_(s_3)(CO)_(10), the reaction of D_2O_(s_3)(CO)_(10)with ethyne C_2H_2 to form the vinyl product cluster [O_(s_3)D(μ, η~2-CH=CHD)(CO)_(10)], and thereaction of H_2O_(s_3)(CO)_(10) with the deuterated ethyne C_2D_2 to form [O_(s_3)H(μ,η~2-CD=CDH)(CO)_(10)] have been reported primarily in this paper. The two cis-adducts undergo cis-trans-isomerization of μ,η~2-vinyl ligands under a small amount of the nucleophile pyridine. Usingthe combination of deuteration and dynamic ~1H,~2H NMR spectra, we report the experimen-tal evidence determined by the dynamic ~1H, ~2H NMR spectra, mechanism, and kinetic dataof the isomerization. 相似文献
150.
A gas phase electron diffraction investigation of 1-chloro-1-(trichlorovinyl)cyclopropane at 65° showed the existence of one conformer having a perpendicular arrangement of the cyclopropyl- and the trichlorovinylgroup, with torsional angle τ = 91(3)° relative to τ = 180° for the antiperiplanar conformer (CCl-CClanti arrangement). Both the experimental data and a molecular mechanics calculation indicate the lower barrier toward the antiperiplanar form,less than 40 kJ · mol-1. The second barrier was by molecular mechanics calculated to 60 kJ · mol-1. 相似文献