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1.
Molecular nitrogen and irradiation temperature are shown to affect the radiationchemical yield of O
st
–
in the radiolysis of N2O adsorbed on alumina with large surface areas and to exert no influence in the case of small surface areas of Al2O3.
, - O st – N2O, Al2O3 .相似文献
2.
A. A. Medvinskii N. N. Bulgakov A. V. Kravtsov L. M. Smolova 《Reaction Kinetics and Catalysis Letters》1979,11(4):331-335
The choice of parameters according to the interacting bond method (IBM)/1/is under discussion for systems containing OH and CO-bond interacting with MgO crystal (100) plane. Various CO2 chemisorption forms on pure and hydroxylated surfaces are compared by a rough estimate of chemisorption heats.
(MBC) (1) ( (100) , OH CO. CO2 , .相似文献
3.
A. Marini V. Berbenni V. Massarotti G. Flor 《Journal of Thermal Analysis and Calorimetry》1988,33(1):337-342
In an attempt to explain how the calibration factor of a heat flux DSC cell depends both on the standard utilized and on the experimental variables, a study has been undertaken of the entire DSC trace.This report deals with the second half of the peak and shows that, other experimental conditons being fixed, the peak area increases with increasing heating rate.This accounts for the observed decrease in the calibration factors with increasing heating rate.
Zusammenfassung Die gesamte DSC-Kurve wurde untersucht, um zu klären, wie der Eichfaktor einer Wärmefluss-DSC vom verwendeten Eichstandard und von den Versuchsbedingungen abhängt. Der vorliegende Teil behandelt den zweiten Abschnitt eines DSC-peaks (vom Maximum an). Es wird gezeigt, dass bei Konstanthalten aller anderen Versuchsbedingungen die peak-Flächen mit steigender Aufheizgeschwindigkeit zunehmen. Das wird als Ursache für die beobachtete Verringerung des Eichfaktors mit steigender Aufheizgeschwindigkeit angesehen.
, . . , - , . .相似文献
4.
The thermal properties of calcium, strontium and barium anthranilates (general formula MA2·n H2O, whsre M='metal, and) were studied. Thermal, chemical and X-ray analysis, as well as infrared spectra, were used to determine the mechanism of decomposition for these compounds. Calcium anthranilate is decomposed in four stages; the final reaction product is calcium oxide. The other anthranilates are decomposed in three stages; the final reaction products are strontium carbonate and barium carbonate.
Zusammenfassung Die thermischen Eigenschaften von Kalzium-, Strontium- und Bariumanthranilat (mit der allgemeinen Zusammensetzung MA2·n H2O, M=Metall, wurden untersucht.Die Zersetzungsmechanismen dieser Verbindungen wurden durch thermische, chemische- und Röntgenanalyse und mit Infrarotspektroskopie ermittelt. Kalziumanthranilat zersetzt sich in vier Stufen. Das Endprodukt ist Kalziumoxyd. Die anderen Anthranilate zersetzen sich in drei Stufen und geben Strontiumkarbonat und Bariumkarbonat als Endprodukt.
, MA2·nH2O, =, , , . . . .相似文献
5.
Adsorption isotherms of n-hexane, methylcyclohexane and benzene on -alumina were obtained in the range of 354–443 K using gas chromatography. The data obtained were corrected for axial diffusion and were found to fit the Freundlich isotherm better than the Langmuir isotherm. Isosteric heats of adsorption were calculated from adsorption data.
-, - 353–443 . , , . .相似文献
6.
V. A. Semikolenov D. Kh. Mihailova Ya. V. Sobchak V. A. Likholobov Yu. I. Yermakov 《Reaction Kinetics and Catalysis Letters》1979,10(1):105-110
Mono-, di- and triphosphine ligands anchored by a Si–C bond to the surface of silica have been synthesized. Complexes of Pd(II) and Pd(O) with these ligands have been obtained. On the basis of elemental analysis and UV spectroscopy, structures of the complexes formed are suggested. The catalytic properties of the above complexes in the selective hydrogenation of cyclopentadiene are compared.
-, - , Si–C . Pd(II) Pd(O) . - . .相似文献
7.
Abstract A series of rare earth transition metal perovskites has been synthesized and the catalytic activity tested for 2-propanol decomposition. The effect of rare earth ions on the catalytic activity can been understood from the correlations obtained between the physico-chemical properties and the catalytic activity of the perovskites.
, , 2-. , - .相似文献
8.
The function of SO2 in CO oxidation on Pd-V catalysts is to transform a rapid heterogeneous-homogeneous process to a slower heterogeneous one. High concentrations of CO also exert the same effect. In the heterogeneous process an increase in the SO2 concentration increasing the degree of catalyst reduction with and without Pd additives, promotes CO oxidation.
CO - SO2 - . CO. SO2, , , CO.相似文献
9.
I. P. Olenkova D. V. Tarasova G. N. Kustova G. I. Aleshina E. L. Mikhailenko 《Reaction Kinetics and Catalysis Letters》1978,9(2):221-225
Upon the decomposition of silica-supported ammonium paramolybdate, hexagonal MoO3 is formed at 300–350 °C. Irreversible transformation of hexagonal to rhombic MoO3 is observed with increasing calcination temperature. The hexagonal MoO3 structure is probably stabilized by the insertion of ammonium and silicon ions into the lattice of molybdenum trioxide.
, , 300–359 °C . MoO3 . MoO3, , MoO3.相似文献
10.
The effect of inorganic salts (NaNO3, NaCl, Na2SO4, NaHCO3 and Na3PO4) on the selectivity of competitive hydrogenation of 2-methyl-3-butene-2-ol and 2-phenylpropene at 20 °C and atmospheric pressure on a 5%Pt/act. C catalyst in methanol solution was investigated. The dependence of the selectivity and of the initial rate of hydrogenation of the given equimolar mixture on the amount of sodium phosphate used in the modification of the platinum catalyst was measured.
(NaNO3, NaCl, Na2SO4, NaHCO3, Na3PO4) 2--3--2- 2- 20 °C 5% Pt . Na3PO4 .相似文献
11.
《Reaction Kinetics and Catalysis Letters》1979,11(3):271-275
: -, -. , 50%- , .
The differential heats of n-butylamine adsorption and the catalytic activities in n-hexene cracking have been determined for dealuminated faujasite Y and mordenite with various Si to Al ratios. Dealumination up to 50% increases the catalytic activity but the activity decreases upon further dealumination.相似文献
12.
The use of hydrogen-oxygen titration method to characterize platinum-nickel supported catalysts has shown that the number of oxidized or reduced nickel layers is dependent on the atomic composition. This phenome non involves dynamic changes of the surface probably by a spillover mechanism. A surface reaction scheme based on a previous work is proposed to explain the experimental results.
- - , . , , . , .相似文献
13.
V. A. Zazhigalov Yu. P. Zaitsev V. M. Belousov N. Wüstneck H. Wolf H. Seeboth 《Reaction Kinetics and Catalysis Letters》1986,30(1):47-53
Mechanism of n-butane oxidation of -VOPO4 has been studied in pulse fixed and vibrofluidized catalyst bed reactors by the pulse microcatalytic method. It has been established that the rates of catalysis and reduction are similar, which indicates a reduction-oxidation mechanism for butane conversion and maleic anhydride formation. In the course of catalysis the reaction products are formed largely at the expense of catalyst oxygen and -VOPO4 reduces to (VO)2P2O7.
- -VOPO4. , - . , , , -VOPO4 (VO)2P2O7.相似文献
14.
Various manifestations of the kinetic compensation effect are considered in reactions involving the participation of solid substances under isothermal and nonisothermal conditions, as well as manifestations of other isoparametric correlations. It is shown that isoparametric correlations can be used for the analysis of solid-phase reactions and the exclusion of artefacts in nonisothermal kinetics.
Zusammenfassung Verschiedene Erscheinungen des kinetischen Kompensationseffektes bei unter Beteiligung von festen Substanzen unter isothermen und nichtisothermen Bedingungen verlaufenden Reaktionen werden erörtert, ebenso Erscheinungen anderer isoparametrischer Korrelationen. Es wird gezeigt, daß isoparametrische Korrelationen zur Analyse von Festphasenreaktionen und zum Ausschluß von Artifakten in der nicht-isothermen Kinetik herangezogen werden können.
, , . .相似文献
15.
M. J. R. Loadman 《Journal of Thermal Analysis and Calorimetry》1986,31(5):1183-1192
The temperature regions in which glass transitions (Tg's) occur for a series of blends of polybutadienes with natural rubber and two styrenebutadiene copolymers of different styrene contents have been studied by differential scanning calorimetry. The resulting DSC curves may be used to categorize the polybutadiene, determine the bound styrene content of the styrenebutadiene copolymer and quantify the polybutadiene content of the blends.
Thanks are due to the Board of MRPRA for permission to publish this paper. 相似文献
Zusammenfassung Die Temperaturbereiche, in denen bei einer Reihe von Gemischen von Butadien mit natürlichem Kautschuk und bei zwei Styrol-Butadien-Kopolymeren mit verschiedenem Styrolgehalt Glastransformationen erfolgen, wurden mittels DSC untersucht. Die erhaltenen DSC-Kurven können zur Kategorisierung des Polybutadiens und zur Bestimmung des Gehalts an gebundenem Styrol in Styrol-Polybutadien-Kopolymeren und des Polybutadiengehalts der Gemische verwendet werden.
(g) - . , - .
Thanks are due to the Board of MRPRA for permission to publish this paper. 相似文献
16.
I. O. Edafiogho J. R. Mulokozi A. M. Mulokozi S. Diete-Spiff 《Journal of Thermal Analysis and Calorimetry》1988,34(1):115-120
In a continuing study of the effect of exposure of chloroquine and its salt derivatives to the sun, the picrate was investigated. The picrate gives a sharp endothermic effect of melting at 209.2 °C, before it decomposes, to give an exothermic peak at 255.6 °C. The endothermic peak of melting at 209.2 °C was found suitable for the quantitative determination of chloroquine picrate in sun-exposed samples.
Zusammenfassung In Fortführung einer Untersuchung über Veränderungen von Chloroquin und dessen Derivaten, wenn diese der Sonne ausgesetzt werden, wurden die Pikrate untersucht. Bei den Pikraten werden ein scharfer, dem Schmelzvorgang zuzuschreibender Effekt bei 209.2 °C und ein mit der Zersetzung einhergehender exothermer Peak bei 255.6 °C beobachtet. Der endotherme Peak bei 209.2 °C erwies sich als geeignet zur quantitativen Bestimmung von Chloroquinpikrat in der Sonne ausgesetzten Proben.
, . 209,2 ° 255,6 ° . , 209,2 ° , .相似文献
17.
J. Kwarciak 《Journal of Thermal Analysis and Calorimetry》1986,31(6):1279-1287
The non-isothermal kinetics of the solid-state reactions taking place in Cu-Al and Cu-Zn-Al alloys were studied by DTA and X-ray measurements. It was found that the degree of conversion, which represents the change in the reacting system, is a function of the area increase in the DTA peak. The kinetic analysis shows that DTA is a useful method for the study of formal kinetic laws. From thef() functions, conclusions on the mechanism of the phase transformations can be drawn.
Zusammenfassung Die nicht-isotherme Kinetik von in Cu-Al und Cu-Zn-Al-Legierungen verlaufenden Festkörperreaktionen wurden mittels DTA und Röntgenmessungen untersucht. Es wurde festgestellt, daß die Zunahme der Fläche des DTA-Peaks abhängig von dem die Veränderungen im Reaktionssystem repräsentierenden Konversionsgrad ist. Die kinetische Analyse zeigt, daß die DTA eine nützliche Methode zur Untersuchung der formalen kinetischen Gesetzmäßigkeiten ist. Aus den Functionenf() können Schlußfolgerungen hinsichtlich des Mechanismus der Phasenübergänge gezogen werden.
, Cu-Al Cu-Zn-Al. , , , . . f() .相似文献
18.
On the basis of experience in liquid crystal research, the optimum conditions are presented for the use of thermo-microscopy and microcalorimetry (DSC) in preliminary investigations of the general chemical, thermodynamic and kinetic behaviour. In the second step, special measurements are necessary to obtain exact results on purities, phase types, temperatures, enthalpies, and kinetic parameters of transitions in stable and metastable states.
Zusammenfassung Ausgehend von den Erfahrungen auf dem Gebiet der Flüssigkristalle wird der optimale Einsatz von Thermomikroskopie und Mikrokalorimetrie (DSC) für allgemein-chemische, thermodynamische und kinetische Voruntersuchungen beschrieben. In einer zweiten Untersuchungsphase sind spezielle Messungen notwendig, um exakte Ergebnisse bezüglich Reinheit und Phasentypen zu erhalten sowie Temperaturen, Enthalpien und kinetische Parameter von stabilen und metastabilen Zustandsänderungen zu bestimmen.
() , . , , , .相似文献
19.
Taichi Sato 《Journal of Thermal Analysis and Calorimetry》1987,32(1):61-70
The thermal decompositions of the crystalline aluminium hydroxides hydrargillite, bayerite and nordstrandite were investigated by thermogravimetry, differential thermal analysis, X-ray diffraction and infrared spectrophotometry. It was found that these aluminium hydroxides undergo thermal decomposition in the following sequences: hydrargillite-1
Zusammenfassung Die thermische Zersetzung von kristallinen Aluminiumhydroxiden, wie Hydrargillit, Bayerit und Nordstrandit, wurde thermogravimetrisch, differentialthermoanalytisch, röntgendiffraktometrisch und IR-spektrophotometrisch untersucht. Es wurde festgestellt, da\ diese Aluminiumhydroxide in der folgenden Reihenfolge zersetzt werden: Hydrargillit-I
, , , , . , :相似文献
20.
Activity and stability of rhodium catalysts in liquid-phase hydrogenation of 3-thiolene-1, 1-dioxide
Activity and stability of rhodium catalysts is found to vary in parallel with metal dispersity. Treatment of reduced samples by air leads to a considerable (3–5 fold) increase of their activity in hydrogenation of 3-thiolene-1,1-dioxide to thiolane-1,1-dioxide.
. (3–5 ) 3--1, 1- -1, 1-.相似文献