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1.
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
2.
A. R. Cholach V. A. Sobyanin V. V. Gorodetskii 《Reaction Kinetics and Catalysis Letters》1981,18(3-4):391-396
The adsorption and steady-state decomposition of ammonia on rhenium has been studied. A mechanism for the interaction of ammonia with the Re surface is suggested.
. .相似文献
3.
V. A. Tertykh S. S. Kotlyar V. V. Yanishpolskii K. B. Yatsimirskii T. N. Yakubovich Yu. I. Bratushko 《Reaction Kinetics and Catalysis Letters》1987,33(2):411-416
Porphyrin immobilized on silica and its complex with cobalt have been prepared and identified. Oxidation kinetics is described by the Michaelis-Menten equation.
- . - --.相似文献
4.
The pyrolysis of phenylazoethane has been studied in a stirred-flow system using cyclohexene as carrier gas at sub-ambient pressures, in the temperature range of 380–416°C. The activation energy is examined in relation to the C–N bond dissociation energy and the heat of formation of the phenyldiazenyl radical.
, - 380–416°C. C–N .相似文献
5.
T. Wierzchowski 《Reaction Kinetics and Catalysis Letters》1986,30(2):203-207
The hydrogenation of CO2 has been studied on three different series of catalysts: Fe/MgO, Ni/Ti, Cr/Zn doped with potassium. Reaction was carried out in a conventional flow microreactor system at 15 bar at 250–350°C. Three independent competing reactions: Reverse gas-water shift (RGWS), Fischer-Tropsch (FT) and methanol synthesis were observed.
CO2 : Fe/MgO, Ni/Ti, Cr/Zn . 15 250–350°C. : RGWS, F.T. .相似文献
6.
T. Shakhtshneider E. Ivanov V. Boldyrev 《Journal of Thermal Analysis and Calorimetry》1988,33(2):525-529
The thermal solid-state isomerizations of Copy2Cl2 (py=pyridine), Nien2(NO2)2 and Nien2(NCS)2 (en=ethylenediamine) were studied by thermal analysis, thermomicroscopy, X-ray diffraction and IR-spectroscopy. It was shown that the reactions proceed by nuclear formation and growth. The kinetic-morphological peculiarities of the processes suggest that the process-determining stage is a phase stage, i. e. structural transformation. The topography and kinetics of processes are therefore determined by the crystal structures of the initial material and the reaction product, and by the contact conditions at the interface. The stress relaxation processes affect the morphology of the products and the kinetics of the transformation.
Zusammenfassung Thermische Isomerisierungsreaktionen in fester Phase wurden durch thermische Analyse, Thermomikroskopie, Röntgenbeugung und IR-Spektroskopie an CoPy2Cl2 (Py=Pyridin), Nien2(NO2)2 und Nien2(NCS)2 (en=Ethylendiamin) untersucht. Es wird gezeigt, dass die Reaktionen durch Keimbildung und Wachstum ablaufen. Die kinetischen und morphologischen Charakteristika der Prozesse weisen darauf hin, dass der geschwindigkeitsbestimmende Schritt ein Phasenschritt, d. h. eine Strukturumwandlung ist. Deshalb sind Topographie und Kinetik der Vorgänge durch die Kristallstrukturen des Ausgangsstoffe und des Reaktionsprodukts und durch die Kontaktbedingungen an der Grenfläche bestimmt. Die Spannungsrelaxationsprozesse beeinflussen die Morphologie der Produkte und die Umwandlungskinetik.
, , 2l2, Nien2(NO2)2 Nien2(NCS)2, en= , = . , . - , . , . .相似文献
7.
Only H2S consumption and H2O formation was found in the sulfurization of CoMoK/Al2O3 water gas shift catalyst with H2S/H2, but CO2 was formed first, then CH4, H2O and H2S appeared in the later part of TPS with CS2/H2. Carbon deposition on the catalyst during the sulfurization with CS2/H2 caused a lower activity than the catalyst sulfurized with H2S but could be removed in the run of WGS reaction.
, CoMoK/Al2O3, H2S/H2 H2S H2O, CS2/H2 CO2 CH4, H2O H2S. CS2/H2 H2S, , .相似文献
8.
G. L. Elizarova T. V. Kim L. G. Matvienko V. N. Parmon 《Reaction Kinetics and Catalysis Letters》1986,31(2):455-459
A way of preparation of dioxygen-evolving catalysts by immobilization of cobalt compounds on ion-exchange resins is proposed. Immobilized cobalt hydroxides are more selective in the reaction of water-to-oxygen oxidation than massive ones and, when prepared as mixture with Al(III), Fe(III), Sn(IV) or Ce(IV), they become even more selective.
. , , Al(III), Fe(III), Sn(IV), Ce(IV) .相似文献
9.
The kinetics of cotelomerization of ethylene and 1-hexene with carbon tetrachloride has been studied. Chain transfer and cotelomerization constants have been calculated for several polychloroalkyl radicals.
I- 303–398 . .相似文献
10.
The effect of fluctuations on the behavior of a simple kinetic model of catalytic reactions allowing a neutral steady-state, is analyzed.
, , .相似文献
11.
M. E. Kassem T. G. Abdel-Malik M. El-Shabasy R. M. Abdel-Latif A. A. Ibrahim 《Journal of Thermal Analysis and Calorimetry》1987,32(5):1531-1537
The influence of chloroacetic acid amide (AC) on the temperature-dependence of the electrical conductivity (), thermal expansion (ij) and specific heat ((C
p) of triglycine sulphate crystals was studied in the phase transition range (T
c=49°). The addition of isostructural AC increased the electrical conductivity, decreased the thermal expansion and changed theC
p peak. The mechanism is discussed on a thermodynamic basis.
Zusammenfassung Der Einfluß der Zumischung von Chloressigsäureamid (AC) auf die Temperaturabhängigkeit der elektrischen Leitfähigkeit, der Wärmeausdehnung ij und der spezifischen WärmeC p von Triglycinsulfat-Kristallen wurde im Phasenübergangsgebiet (T c=49 °C) untersucht. Die Beimischung von isostrukturellem AC erhöht die elektrische Leitfähigkeit und vermindert die Wärmeleitfähigkeit, während derC p-Peak verändert wird. Der Mechanismus kann thermodynamisch diskutiert werden.
(), () ij) () , T c=49°. , , , , C p. .相似文献
12.
The precise stoichiometry of argentic oxynitrate has been elucidated by analytical and thermal analytical techniques. A decomposition path of the oxynitrate has been proposed and values of the enthalpy changes obtained. TG has been used as the criterion of purity of silver(II) oxide and new values for the heat of formation of silver(I) and silver(II) oxide are reported.
The authors wish to thank Mr. J. McEwan and Mrs. I. M. Walker for valuable practical assistance and the United Kingdom Atomic Energy Authority for financial support. 相似文献
Zusammenfassung Die genaue Stöchiometrie des Silberoxynitrats wurde durch analytische und thermoanalytische Prüfung geklärt. Der Zersetzungsvorgang des Oxynitrats wurde verfolgt und die Enthalpieänderungen beobachtet. Die Reinheit von Silber(II)oxyd läßt sich thermogravimetrisch kontrollieren. Es wurden neue Werte für die Bildungswärmen des Silber(II)oxyds und Silber(I)oxyds gefunden.
Résumé Etude de la stoechiométrie précise de l'oxynitrate argentique par les techniques analytiques et thermoanalytiques. On propose un schéma de décomposition de l'oxynitrate et l'on évalue les variations d'enthalpie. Emploi de la TG comme critère de pureté de l'oxyde d'argent(II). Communication de nouvelles valeurs pour les chaleurs de formation des oxydes d'argent (I) et d'argent (II).
. . (II) . (I) (II).
The authors wish to thank Mr. J. McEwan and Mrs. I. M. Walker for valuable practical assistance and the United Kingdom Atomic Energy Authority for financial support. 相似文献
13.
A flow reactor for kinetic studies of heterogeneous catalytic reactions with simultaneous X-ray phase analysis of the catalyst is described. As an example, the correlation between the selectivity of acetylene hydrogenation and the -Pd hydride concentration in palladium catalysts is shown.
, . -Pd .相似文献
14.
The hydrodesulfurization (HDS) of thiophene by nickel-molybdenum catalysts supported on alumina-zirconia has been investigated. The effect of varying the ratios of oxides in the support is to produce a minimum in the activity for HDS, and the coimpregnated catalysts are shown to be more active than the analogous co-precipitated catalysts.
(HDS) -, . HDS. , .相似文献
15.
Simultaneous thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA), and evolved gas analysis (EGA) by mass spectrometry (MS) have been used to determine the decomposition path for tetraamineplatinum(II) chloride and cis- and trans-diamineplatinum(II) chloride. Unequivocal identification of the evolved gases was done by direct insertion probe mass spectrometry.The thermal decomposition of (NH3)4PtCl2 occurred in two steps. The first was endothermic loss of two moles of ammonia producing a mixture of cis- and trans-diaamineplatinum(II) chloride. The second step was decomposition of the diamine complex to metallic Pt and N2, HCl, and NH4Cl. Reduction of Pt(II) to metallic Pt was coupled with oxidation of ammonia to molecular nitrogen and protons.
The technical assistance of G. J. Dechert is gratefully acknowledged. 相似文献
Zusammenfassung Simultane Thermogravimetrie (TG), derivative Thermogravimetrie (DTG), Differentialthermoanalyse (DTA) und Analyse der entwickelten Gase (EGA) durch Massenspektrometrie (MS) wurden zur Bestimmung des Reaktionsverlaufs bei Zersetzung von Tetraminplatin(II)-chlorid sowie cis- und trans-Diaminplatin(II)-chlorid herangezogen. Die eindeutige Identifizierung der entwickelten Gase erfolgte durch Massenspektrometrie mit direkter Probeneinführung. Die thermische Zersetzung von (NH3)4PtCl2 erfolgt in zwei Schritten. Der erste ist die endotherme Abspaltung von zwei Mol Ammoniak unter Bildung eines Gemisches von cis- und trans-Diamin-platin(II)-chlorid. Der zweite Schritt ist die Zersetzung des Diaminkomplexes zu metallischem Pt, H2, HCl und NH4Cl. Die Reduktion von Pt(II) zu metallischem Pt ist mit der Oxydation von Ammoniak zu molekularem Stickstoff und Protonen gekoppelt.
-, -, -, - - (II) - (II) . (II). -. (NH3)4PtCl2 . - -(NHN3)2PtCl2. , , . .
The technical assistance of G. J. Dechert is gratefully acknowledged. 相似文献
16.
A. M. Pak E. M. Tsai S. P. Konuspaev O. I. Kartonozhkina D. V. Sokolskii 《Reaction Kinetics and Catalysis Letters》1988,37(1):199-204
Low selectivity of dehydrolinalyl acetate (DeHLA) hydrogenation into linalyl acetate and ester group detachment are predicted in accordance with quantum-chemical data obtained for its homologue dimethyl ethynyl carbinol acetate. Experimental data are confirmed by theoretical calculations. DeHLA hydrogenation produces a variety of products.
, - . . .相似文献
17.
The elementary processes involved in a chemical reaction with phase transformation on a nonporous metallic catalyst are considered. A model of growth for a single bubble and relations to calculate the break-off diameter frequencies are proposed.
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, -. .
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18.
IR spectra of propylene adsorbed in CoO-MgO and CoO-MgO-MoO3 solid solutions show that a surface -complex with Co2+ ions is formed, strongly bonded in the former case and weakly in the latter. Thus, introduction of Mo strongly modifies the catalytic properties of Co2+ active centers. In the presence of oxygen, allylic species, aldehyde and carboxylate complexes appear.
, CoO-MgO CoO-MgO-MoO3 - Co2+, . , Mo Co2+. - .相似文献
19.
A. Abdel Razik M. S. Metwally M. F. El-Hadi M. A. El Wardany 《Reaction Kinetics and Catalysis Letters》1992,48(1):279-290
The rates of hydrolysis of seven acetate esters substituted in the alkyl group have been studied in the presence of a sulfonated cation exchange resin in 70% aqueous acetone solution. the slower hydrolysis rates with increasing size of substituent are related to increasing steric influence, as determined by decreasing values of the steric substituent parameter, Es. The efficiency of the resin catalyst is related to the entropy of substituents. Influence caused by steric hindrance on reaction rates accounts satisfactorily for observed variations of the enthalpies and entropies of activation with alkyl group substituents. The entropy, Sx, values increase in the order: n-octyl-
, , 70%- . , , ES. . , . , S*, : --<-<, .相似文献
20.
The oxidation of methane on supported chromia was studied at temperatures varying between 423 and 743 K and CH4/O2 ratios between 1 and 9 in a differential reactor. The main reaction products observed were carbon monoxide and formaldehyde. The rates of reaction obey a power law expression.
, 423 743 CH4/O2 1 9, . . .相似文献