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1.
The kinetic methods usually employed to determine reaction orders involve some sort of mathematical approximation and provide values approximate and very often discrepant. Three methods are reported to determine accurate reaction orders without introducing approximations.
, , , , . .相似文献
2.
D. Duprez P. Pereira J. Barbier R. Maurel 《Reaction Kinetics and Catalysis Letters》1980,13(3):217-223
Two deactivation factors of Rh/-Al2O3 catalysts in toluene steam dealkylation are examined: deactivation during working and sulfur poisoning. Onstream deactivation is only due to coke deposit. Specific activity per free exposed fraction of the metal is constant. Sulfur is a strong non-selective poison which may hinder coke formation.
Rh/-Al2O3 : . . . , .相似文献
3.
N. M. Vitkovskaya V. G. Bernshtein F. K. Schmidt 《Reaction Kinetics and Catalysis Letters》1986,31(1):167-172
[Cu(-C2H2)2]+, [Cu(-CCH2)2]+ and [Cu(-C2H2) (-CCH2]+ complexes have been studied by the ab initio double-zeta basis set method. It has been established that all calculated compounds are stable to decomposition into two C2H2 molecules and Cu+ cation and into one C2H2 molecules and the respective monocomplex. Calculation results suggest the possibility of intramolecular acetylene-vinylidene rearrangement in the coordination sphere of Cu+.
ab initio : [Cu(-C2H2)2]+, [Cu(-CCH2)2]+, [Cu(-C2H2) (-CCH2)]+. C2H2 Cu+ C2H2 . - Cu+.相似文献
4.
Reduction of V2O5/Al2O3 and V2O5/silica-alumina produced Lewis acid sites which could strongly adsorb CO (heat of adsorption: 90 kJ/mol). Such strong acid sites were not formed in the cases of V2O5/SiO2 and V2O5/MgO. V2O5 loaded on Al2O3 interacted with the basic sites of alumina but not with the acidic sites, while the V2O5 on silica-alumina interacted with the acidic sites of the silica-alumina and decreased its acidity.
V2O5/Al2O3 V2O5/SiO2–Al2O3 , CO ( 90 /). V2O5/SiO2 V2O5/MgO . V2O5, Al2O3, , , V2O5 SiO2–Al2O3 - .相似文献
5.
Ligand exchange between the compounds Co(AA)2Py2 and Co(AA)Clpyx (x=1 or 3) formed in the, system, CO(AA)2–SnR2Cl2(R=Ph, Et) in chloroform with pyridine has been established to be catalyzed by SnR2Cl2. An interpretation of the catalytic action of SnR2Cl2 is suggested.
, Co(AA2py2 Co(AA)Clpyx (x=1 3) (Co(AA)2–SnR2Cl2 (R=Ph, Et) , SnR2Cl2. SnR2Cl2.相似文献
6.
It has been found that the rate of isotope exchange in Ba2YCu3O7–x–O2 system is high. Its kinetics is exponential, first order with respect to dioxygen and the exchange is of the mixed first/third type.
Ba2YCu3O7–x–O2 . -, -, - .相似文献
7.
The anharmonic contribution to the heat capacity of any chalcopyrite semiconductor AIBIIIC
2
VI
or AIIBIVC
2
V
is evaluated. It is shown that the degree of lattice anharmonicity decreases with increasing atomic weight of the constituent atoms of the compounds, and there is no essential difference in the degree of lattice anharmonicity of the two groups of compounds. Except for CdGeAs2, the trend in the Grüneisen constants is the same.
Zusammenfassung Der anharmonische Beitrag zur Wärmekapazität verschiedener Halbleiterverbindungen AIBIIIC 2 VI und AIIBIVC 2 V vom Chalkopyrit-Typ wird bestimmt. Es wird gezeigt, dass die Gitteranharmonizität mit steigender relativer Atommasse der Bestandteile der Verbindungen abnimmt und dass keine wesentlichen Unterschiede in der Gitteranharmonizität beider Gruppen von Verbindungen bestehen. Der Trend der Grüneisen-Konstanten ist der gleiche, ausgenommen bei CdGeAs2.
IIII 2 VI IIIV 2 V . , , , . , CdGeAs2.相似文献
8.
P. Cielo 《Journal of Thermal Analysis and Calorimetry》1985,30(1):33-42
The application of thermal analysis techniques directly to the materials being processed could open up new opportunities in the fields of non-destructive testing and process monitoring on the industrial floor. In this paper, a convergent-thermal-wave technique is proposed for the measurement of thermal diffusivity when access to the material is restricted to one side only. Such a technique permits measurement of the thermal properties of samples of large or unknown thickness, as well as coated or stratified materials. A finite-difference numerical model is used to evaluate the possibilities and the accuracy offered by such a technique, and a laser-based experimental apparatus for the non-contact generation and monitoring of annular thermal waves is described.
Zusammenfassung Die direkte Anwendung thermischer Analysenverfahren auf darzustellende Materialien könnte neue Möglichkeiten auf dem Gebiet der nichtzerstörenden Materialprüfung und der industriellen Prozeßüberwachung bieten. In diesem Artikel wird eine Konvergenzthermowellen-Technik zur Messung des thermischen Diffusionsvermögens vorgeschlagen, die auch dann anwendbar ist, wenn das Material nur von einer Seite her zugänglich ist. Diese Technik ermöglicht die Messung thermischer Eigenschaften von Porben unbekannter Größe oder Dicke sowie die von belegten oder beschichteten Materialien. Ein numerisches endliches Differenz-Modell wird zur Bewertung der durch solch eine Technik gebotenen Möglichkeiten und deren Genauigkeit herangezogen. Eine auf Laser basierende Versuchsapparatur zur Nicht-Kontakt-Erzeugung und Aufzeichnung von ringförmigen thermischen Wellen wird beschrieben.
. , . , . . .相似文献
9.
Iv. Dombalov Iv. Gruncharov Y. Pelovski G. Bechev 《Journal of Thermal Analysis and Calorimetry》1987,32(6):1735-1738
The effect of P2O5 on the thermal decomposition of phosphogypsum to phospholime and sulphur dioxide has been studied.
Zusammenfassung Es wurde der Einfluß von P2O5 auf die thermische Zersetzung von Phosphogips zu Phospholim und Schwefeldioxid untersucht.
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10.
Various types of water bonding were studied. e.g. water bound by occlusion, by adsorption, by capillary condensation, by chemisorption and as a solid solution, zeolitic water, interlayer water, crystal water and structural water bound in form of hydroxil groups. The differentiation of these various types of bonding is rather difficult, for on heating water is evolved at various temperatures and in rather wide temperature domains which overlap to different extents. Efforts were made to improve the detection by applying the quasi-isothermal quasi-isobaric measuring technique.
Zusammenfassung Es wurden verschiedene Bindungstypen von Wasser untersucht. Wasser kann unter anderem durch Einschlüsse, Adsorption. Kapillarkondensation, Chemisorption und in Form von Mischkristallen, zeolitisch, schichteingebettetem und Kristallwasser sowie als OH-Form gebunden sein. Die Untersuchung dieser zahlreichen Bindungstypen ist äußerst schwierig, da die Wasserabgabe bei verschiedenen Temperaturen geschieht und die ziemlich breiten Temperaturintervalle mehr oder weniger überlappen. Mittels quasiisothermen und quasiisobaren Meßtechniken wurde versucht, die Möglichkeit der Bestimmung zu verbessern.
. , , , , , , , . , , . , .相似文献
11.
A study has been made of temperature programmed desorption (TPD) of NH3 and H2O from samples of NH4X and CoNH4X zeolites of various degree of exchange. NH3 TPD peaks could be explained by interaction of NH3 with different Brönsted and Lewis acidic centers. Moreover a water peak at high temperatures allowed interpretations of the dehydroxylation, and by reason of the characteristic desorption temperatures a particular state of the Co2+ ions in the CoNH4X zeolites is postulated.
- () NH3 H2O NH4X CoNH4X . NH3 NH3 =qs . . Co2+ CoNH4X.相似文献
12.
A. N. Gartsman A. Ermakova N. I. Rassadnikova 《Reaction Kinetics and Catalysis Letters》1977,6(3):323-327
A solution of the problem of mass transfer in a turbulent boundary layer has been obtained with a first-order chemical reaction occurring in the liquid phase. The dependence of the enhancement factor for absorption and of the mass transfer coefficient on the model parameters can be used for building up a hierarchic model of the gas-liquid reactor.
. .相似文献
13.
S. Nishiyama K. Yoshioka S. Matsuura S. Tsuruya M. Masai 《Reaction Kinetics and Catalysis Letters》1987,33(2):405-410
The H2–D2 exchange activity of Rh powder was enhanced by high-temperature UHV treatment accompanied with an enrichment of the high-index faces of Rh. The thermal decomposition of H2PtCl6·6H2O under UHV condition resulted in an extremely active Pt powder catalyst.
H2–D2 Rh , - Rh - . H2PtCl6·6H2O Pt .相似文献
14.
B. S. Balzhinimaev V. E. Ponomarev N. P. Belyaeva A. A. Ivanov G. K. Boreskov 《Reaction Kinetics and Catalysis Letters》1986,30(1):23-32
From the analysis of the detailed reaction mechanism and taking into account vanadium complex formation processes, a steady state kinetic equation has been derived to describe experimental data in a wide range of reaction conditions.
, .相似文献
15.
The effect of various inorganic polymers on the catalytic activity and selectivity of platinum in the hydrogenation of 4-chloronitrobenzene and dinitrotoluene has been studied. Platinized iron-containing polycyanogens are less active but more selective catalysts for the hydrogenation of 4-chloronitrobenzene than Pt/C or Pt/BaSO4.
4- . , , , 4-, Pt/C Pt/BaSO4.相似文献
16.
Interaction of carbon monoxide with hydrogen on the surface of rhodium catalysts has been investigated under conditions of pulsed-gas chromatography within the temperature range of –80 to 500 °C. At temperatures up to about 180 °C adsorbed hydrogen was found to be displaced to the gaseous phase as a result of carbon oxide adsorption. At higher temperatures conversion of carbon monoxide and hydrogen to methane takes place.
–80 500 °C. 180 °C . .相似文献
17.
《Reaction Kinetics and Catalysis Letters》1975,3(3):277-283
, , , . 298–366°K. , H+O2+M=HO2+M .
The kinetics of the reaction between fluorine and hydrogen under conditions far from those of self-ignition can be described by a simple scheme of chain reaction over a wide range of concentrations. The probability of formation of fluorine atoms upon collision of F2 molecules with the reactor wall has been determined at 298–366 K. The effectivity of argon, nitrogen and carbon dioxide in trimolecular chain termination, H+O2+MHO2+M, is compared with that of helium.相似文献
18.
The kinetics and intermediates of the permanganate oxidation of trans-crotonic acid have been investigated in the pH range of 0.5–5.0 using the stoppedflow technique. The formation of manganese(III) as a short-lived intermediate has been established. The reaction is first order with respect to both MnO
4
–
and crotonic acid (crotonate). The resolved rate constants at 25°C are 730 and 410 M–1 sec–1 for the acid and the anion, respectively. The reaction mechanism is discussed.
pH=0,5–5,0, . (III) . MnO 4 – , (). 25°C 730 410 M–1 –1 , . .相似文献
19.
J. A. Cusidó A. Isalgué X. Lumbiarres 《Journal of Thermal Analysis and Calorimetry》1986,31(2):279-284
A simple, low-cost apparatus has been designed and constructed for measurement of the thermal conductivities of samples with low cross-sections (10–7 m2). This apparatus has been used to determine variations in the thermal conductivity of the metallic glass Fe80B20 (Metglas 2605) in the crystallization process induced by thermal treatment.In spite of the simplicity, the deviations from the real values of thermal conductivities measured have been lower than 8%, which has proved to be satisfactory for establishing the glass formation, temperature, T8, from changes in thermal conductivity.
Zusammenfassung Eine einfache, billige Apparatur zur Messung der Wärmeleitfähigkeit von Proben mit kleinen Querschnitten (10–7 m2) wurde entworfen und gebaut. Die Apparatur wurde zur Bestimmung von Veränderungen der Wärmeleitfähigkeit des metallischen Glases Fe80B20 (Mctglass 2605) während des durch thermische Behandlung ausgelösten Kristallisationsprozesses benutzt. Trotz der Einfachkeit betrug die Abweichung von den gemessenen tatsächlichen Wärmeleitfähigkeitswerten weniger als 8%, was sich als ausreichend für die Ermittlung der Glasbildungstemperatur 79 aus Veränderungen der Wärmeleitfähigkeit erwiesen hat.
( 10–7 4). Fe80B20 2605) , . , 8%, g .相似文献
20.
The surface of Pt(110) was found to be metastable under the reaction conditions. The necessary condition for the appearance of self-oscillations in the system is the change of platinum surface properties under the action of reaction medium. Self-oscillations in the rate are maintained due to reversibility of these changes.
, Pt(110) . .相似文献