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51.
Intraionic C3 reorientation of the anilinium NH+3 group was evidenced by measurements of the temperature dependence of the proton spin—lattice relaxation time, by rotating frame experiments and cw NMR data. Analysis of the results yielded a rotor hindering potential E = 33.6 kJ/mole and τo = 4 × 10−13 s. 相似文献
52.
53.
The method for constructing hybrid orbitals described earlier is now used for the analysis of CNDO/2 wave functions of molecules containing nitrogen atoms in order to get information on the type of hybridization of nitrogen lone pair orbitals in various compounds. 相似文献
54.
The deoxygenation of methyloxirane to propene and its isomerization to oxo compounds on a Ni/SiO2 catalyst were studied in a pulse microreactor, in the presence of H2 as carrier gas, at 473 K. It was found that the deoxigenation leads to the creation of new types of active centers (Lewis acid site-basic site), which cause a change in the direction of ring opening. The differences in regioselectivity observed between Ni and Cu, and Pt and Pd, can be explained by the different affinities of the metals for oxygen. This finding can be generalized to other oxygen-containing compounds.
Part IV: J. Catal. (to be published) 相似文献
=qa Ni/SiO2 473 . , - - , . Ni Cu, Pt Pd . .
Part IV: J. Catal. (to be published) 相似文献
55.
M. Pechál M. Strasák J. Vojtko M. Hrusovský 《Reaction Kinetics and Catalysis Letters》1982,20(1-2):157-161
The oxidation of aliphatic ketones by thallium(III) sulfate in aqueous medium has been studied from the point of view of the temperature effect and the enthalpy-entropy relationship. It has been found that the isokinetic relationship is fulfilled in this case.
(III) - . , .相似文献
56.
Zusammenfassung Eine Halbmikromethode zur Bestimmung der an Kohlenstoff oder Sauerstoff gebundenen Nitro- und Nitrosogruppen in organischen Verbindungen wurde ausgearbeitet. Die Methode beruht auf dem oxydativen Aufschluß der Substanz mit einem Chromsäure—Schwefelsäure-Gemisch, wobei die Nitro- und Nitrosogruppen quantitativ in Salpetersäure übergehen. Diese wird mit Devarda-Legierung in alkalischem Medium zu Ammoniak reduziert, das dann im Stickstoffstrom abdestilliert und acidimetrisch titriert wird.
Summary A semimicro method for determining nitro- and nitroso groups attached to carbon or oxygen in organic compounds has been worked out. The method is based on the oxidative decomposition of the sample with a chromic acid-sulfuric acid mixture, the nitro and the nitroso groups being quantitatively transformed into nitric acid. The latter is reduced to ammonia by means of Devarda alloy in alkaline medium, and is then distilled off in a stream of nitrogen and titrated with a standard acid solution.
Résumé On a mis au point une méthode à l'échelle semimicro pour le dosage dans les substances organiques de groupes nitro et nitroso liés au carbone ou à l'oxygène. La méthode repose sur l'attaque oxydante de la substance par un mélange acide chromique-acide sulfurique, ce qui transforme quantitativement les groupes nitro et nitroso en acide nitrique. Au moyen de l'alliage de Devarda en milieu alcalin, on réduit celui-ci en ammoniac que l'on chasse par distillation dans un courant d'azote et que l'on titre par acidimétrie.相似文献
57.
We demonstrate that a technique is available to investigate glycoprotein synthesis in organ cultures of human breast and prostate surgical specimens where the 3-dimensional epithelial cell arrangement remains intact. Malignant breast and prostate epithelium maintained their capacity to synthesize glycoproteins for at least 3 days as followed by the incorporation of [3H]glucosamine into macromolecules. Over 70% of incorporation was by malignant cells as judged by autoradiography. Labeled glycoproteins were released into glandular lumina and consequently into the culture fluid. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed predominantly one group of macrmolecules released with an apparent molecular weight of 48,000 +/- 6,000 daltons. This glycoprotein was found in all of the breast specimens studied, which included 1 medullary, 1 infiltrating lobular, and 8 infiltrating duct carcinomas. The pattern was independent of the availability of estrogen receptors. A similar glycoprotein was also observed in the culture media from a Grade I and a Grade II well-differentiated infiltrating prostate carcinoma. Incorporation was below the level of detection in 4 of 6 cases of benign prostatic hyperplasia. A more complex pattern of labeled glycoproteins was found in the media of a Grade II and a Grade III poorly-differentiated prostate carcinoma. The established human mammary carcinoma cell line MCF-7 synthesized and released a similar 48,000 molecular weight glycoprotein but additional components with larger molecular weights were also released. An intriguing interpretation that 3-dimensional tissue integrity restricts some glycoprotein synthesis is discussed. Cells grown in 2-dimensional monolayers could escape from such a topographic restriction and express additional families of glycoproteins. 相似文献
58.
The transfer constants (Cs) of the polystyrene radical with some derivatives of phthalic acid have been determined. Among the agents used, tetrachlorophthalanhydride (TCPA) differs distinctly from other compounds by its value of Cs 3·1 × 10?3 for thermal and 3·4 × 10?3 for initiated polymerization of styrene. The values of Cs for phthalanhydride, dimethyl phthalate, and tetrachlorodimethyl phthalate are lower by two decimal orders. The considerable decrease in the degree of polymerization of styrene prepared in the presence of TCPA is mainly attributed to the increased reactivity of chlorine atoms in TCPA induced by the acceptor effect of anhydride ring. Participation of a TCPA-styrene complex in transfer reaction has been assumed but not proved. 相似文献
59.
FT-IR Ar-matrix isolated spectra were studied for dichloro- (Cl2-MB) and tetrachloroderivatives (Cl4-MB) of the ortho Mannich base. The spectra were analyzed based on the DFT calculated frequencies and intensities and compared with those recorded in CCl4 solution in the region of the ν(OH) and ν(OD) vibrations. The matrix-isolated spectra are characterized by narrower ν(OH) and ν(OD) bands with much better resolved fine structure than in solution. The fine structure originates from the anharmonic coupling with the low frequency modes as well as from Fermi resonance. The ν(OD) band shapes can be reproduced exclusively by assuming the Fermi resonance with overtones and summation of the frequencies of modes into which the bridge atoms are involved. The frequency isotopic ratio (ISR) is for both compounds 1.33 while the half-width ratios are equal to 1.82 and 1.94, for Cl2-MB and Cl4-MB, respectively. 相似文献
60.
J. Hladký S. NĚmeček M. Novák A. Prokeš J. Votruba K. -F. Albrecht A. Meyer M. Sachwitz B. N. Guskov V. G. Krivokhizhin M. F. Likhachev I. A. Savin G. Vesztergombi 《Czechoslovak Journal of Physics》1977,27(11):1210-1218
Results of the first elastic K
S
o
regeneration experiment on carbon, using magnetic spark chamber spectrometer, are presented in the beam momentum interval 10p50 GeV/c. The d ifferentia cross section d/dt is reconstructed in the range 0·0025–t0·02 (GeV/c)2 and its slopeB is found to be momentum independent with an average valueB=(65±11) (GeV/c)–2. The results are in agreement with the calculations using the coherent production model. 相似文献