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1.
L. Sümegi A. Rockenbauer M. Györ T. Szymanska-Buzar 《Reaction Kinetics and Catalysis Letters》1987,34(2):283-288
Nitroso compounds, well known as spin traps, have not been applied for scavenging free radicals formed in reactions with the contribution of chloranil, so far. In our studies we show that spin traps such as nitrosodurene (ND), 2,6-dichloronitrosobenzene (Cl2NB) react with radicals formed in the reaction between chloranil and durene, yielding stable spin adducts.
, , . , 2,6-, , , , . , , , , .相似文献
2.
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
3.
Ali A. Z. El Fayoumi 《Journal of Thermal Analysis and Calorimetry》1982,23(1-2):135-141
DTA and TG has been used to study the thermal stability of cross-linked epoxidized polydienes. Cross-linking has been achieved using some derivatives of hydroxycarbostyrils, triazines and phthalimide. The new properties of the polymers after curing are interpreted on the basis of the results of DTA and TG.
Zusammenfassung DTA und TG wurden zur Untersuchung der Thermostabilität von quervernetzten epoxidierten Polydienen eingesetzt. Die Quervernetzung wurde unter Verwendung einiger Derivate von Hydroxycarbostyrilen, Triazinen und Phtalimid durchgeführt. Die neuen Eigenschaften der Polymere nach einer Wärmebehandlung wurden aufgrund der Ergebnisse der DTA und TG gedeutet.
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4.
Relative reactivity of o-xylene, o-tolualdehyde, phthalide, and phthalane and the rate of phthalic anhydride formation from them have been determined. The main route of o-xylene oxidation to phthalic anhydride is due to the o-arrangement of methyl groups, proceeding through bicyclic products, such as dihydrobenzofuran (phthalane) and 3,4-benzofuran.
-, - , , . - - : () 3,4-.相似文献
5.
J. Zsakó J. Sztatisz Á. Czégeni G. Liptay Cs. Várhelyi 《Journal of Thermal Analysis and Calorimetry》1987,32(2):463-470
Ten metal and ammonium salts of the acid H2[ReCl6] were obtained by double decomposition reactions, and their pyrolyses in air atmosphere were studied by means of DSC measurements. The kinetic parameters of these reactions were derived and are discussed.
Zusammenfassung 10 Metall- und Ammoniumsalze der Säure H2[ReCl6] wurden durch Doppelzersetzungsreaktionen erhalten. Die Pyrolyse dieser Salze in Luft wurde mittels DSC untersucht. Die kinetischen Parameter dieser Reaktionen wurden ermittelt und diskutiert.
H2[ReCl6]. . .相似文献
6.
A. I. Volkov G. G. Volkova V. K. Yermolaev L. A. Sazonov 《Reaction Kinetics and Catalysis Letters》1982,20(3-4):283-288
Radiolysis of adsorbed N2O is shown to occur due to both the dissociative capture of electrons and direct energy transfer from the excited states of alumina to N2O. One excited state ensures the decomposition of three N2O molecules.
, N2O , N2O, N2O.相似文献
7.
A. D. Efendiev F. G. Abdinov A. G. Agazade A. Sh. Mamedov T. N. Shakhtakhtinskii 《Reaction Kinetics and Catalysis Letters》1991,43(1):37-42
Kinetics and mechanism of the interaction of maleic anhydride with pentachlorinated phosphorus have been studied. Kinetic parameters of a model making it possible to control this reaction have been calculated.
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8.
A Model of polymer decomposition is proposed which formally involves the termination of active centres. It yields reasonable activation energies for the decompositions of polypropylene, polyethylene, polystyrene and polymethyl methacrylate investigated by non-isothermal thermogravimetry. In the value of a formal reaction orders the model reflects the reaction conditions, such as initial sample weight, atmosphere, ventilation conditions, sample holder nature and shape, etc.
Zusammenfassung Ein Modell für Zersetzungsreaktionen von Polymeren wurde entworfen, das auf dem Abbau von aktiven Zentren basiert. Es liefert richtige Aktivierungsenergien für die Zersetzung von Polypropylen, Polyäthylen, Polystyren und Polymethylmethakrylat (bestimmt durch nichtisotherme Thermogravimetrie) und macht es ausserdem möglich, die äusseren Reaktionsbedingungen, wie Einwaage, Atmosphäre, Ventillationsbedingungen, Art und Form des Probenhalters usw. zu berücksichtigen.
, . , , , . «» , , , , . .相似文献
9.
Résumé Après avoir étudié le comportement thermique des principes actifs les auteurs ont établi les diagrammes de phase des mélanges binaires khelline(I)-caféine(I) et khelline(I)-sulfapyridine(I) par thermomicroscopie, analyse thermique et calorimétrique différentielles. Les compositions des eutectiques, du péritectique et du composé défini khelline(I)-caféine(I) ont été déterminées en vue d'une étude physico-chimique, plus particulièrement de solubilité en relation avec la biodisponibilité.
After studying the thermal behaviours of the drugs, the authors established the state diagrams of the binary systems khellin(I)-caffeine(I) and khellin(I)-sulfapyridine(I) by thermomicroscopy, differential scanning calorimetry and differential thermal analysis.Eutectic, peritectic and molecular compound khellin(I)-caffeine(I) compositions were determined for a physico-chemical study, particularly of solubility, in relation with bioavailability.
Zusammenfassung Nach der Untersuchung des thermischen Verhaltens von Wirkstoffen (Drogen) bestimmten die Autoren die Phasendiagramme der BinÄrsysteme Khellin(I)-Koffein(I) und Khellin(I)-Sulfapyridin(I) durch Thermomikroskopie, Thermoanalyse und Differentialkalorimetrie. Die Zusammensetzung der Eutektika, des Peritektikums und der Molekularverbindung Khellin(I)-Koffein(I) wurden zu physikalisch-chemischen Untersuchungen, insbesondere der Löslichkeit im Zusammenhang mit der BiodisponibilitÄt, bestimmt.
, , (II) —(II) (II)- (II). , - - , .相似文献
10.
B. Z. Shalumov A. M. Bessarabov M. V. Mikheev L. A. Gornostaeva B. I. Polyakov 《Reaction Kinetics and Catalysis Letters》1984,25(3-4):177-179
Kinetics of autocatalytic hydrolysis of tetraethyl orthosilicate in the presence of aluminium nitrate has been studied experimentally. According to the suggested reaction mechanism and the proposed mathematical model, kinetic constants have been determined.
. , .相似文献
11.
Yu. V. Mitnik D. O. Oludipe I. Yu. Litvintsev V. N. Sapunov 《Reaction Kinetics and Catalysis Letters》1991,43(2):321-328
Studies of kinetic peculiarities in hydroxylation of phenols by H2O2 in the presence of ferric sulfate have revealed general regularities of this process. A scheme of this process is suggested accounting for the stepwise conversion of Fe3+ into various complex forms. The reaction is suggested to take place in the coordination sphere of Fe3+.
H2O2 . . , Fe3+ .相似文献
12.
A. Kamińska S. Sanyal H. Kaczmarek 《Journal of Thermal Analysis and Calorimetry》1989,35(7):2135-2141
The influence of some irregularities in polystyrene (PS) and polyvinyl chloride (PVC) chains on their thermal stability was investigated. UV irradiation caused an increase in the content of these irregularities in the polymers. It was found that the presence of carbonyl groups and crosslinking of the polymer chains hamper the thermal dehydrochlorination of PVC and the total decomposition of both polymers. On the other hand, weak peroxy linkages (which facilitate degradation processes) and conjugated double bonds decrease the temperature of total decomposition of PS and PVC blends.
Zusammenfassung Es wurde der Einfluß von Unregmlmäßigkeiten in Polystyrol (PS)- und Polyvinylchlorid (PVC)-Ketten auf deren thermische Stabilität untersucht. UV-Bestrahlung verursacht ein Ansteigen des Gehaltes an Unregelmäßigkeiten in den Polymeren. Es wurde festgestellt, daß die Gegenwart von Carbonylgruppen und Querverbindungen der Polymerketten die thermische Dehydrochlorierung von PVC und eine vollständige Zersetzung beider Polymere verhindern. Andererseits senken Peroxidverknüpfungen (die die Degradierungsvorgänge erleichtern) und konjugierte Doppelbindungen die Temperatur für eine vollständige Zersetzung von PS und PVC Gemischen.
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13.
Generalized experimental data for deep and complete oxidation of hydrocarbons on Fe–Cr–O catalysts are presented with calculated kinetic parameters and reactivity of hydrocarbons.
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14.
The specific activity Vsp of ruthenium supported on -alumina (0.084–0.84 wt.%, average particle size 1=1–7 nm) has been investigated for hydrogenation and hydrogenolysis of benzene at 80–320°C and compared with that of Ru powder of 1>1400 nm. A decrease of Vsp with increasing Ru dispersity was found for both reactions, the decrease having been more pronounced for hydrogenolysis. The effect is considered to be due mainly to an influence of dispersity of supported metal on the mode and extent of benze chemisorption.
(VSp) , - (0,084–0,84 .%, 1=1–7 ), 80–320°C - 1>1400 . VSp , . , -, - .相似文献
15.
J. Tóth 《Reaction Kinetics and Catalysis Letters》1979,12(3):253-257
If the kinetic differential equation of a chemical mechanism is a gradient system, the mechanism is essentially cross-catalytic. Consequently, rather few conservative (in the Horn-Jackson sense) mechanisms have a kinetic differential equation of the gradient type. Relations with thermodynamics are only briefly mentioned.
, , , . ( -) . .相似文献
16.
Acid-base and radical properties of two sets of MgO–Na catalysts have been studied. The catalysts were prepared (I) by impregnation of MgO with NaOH in aqueous solution, and (II) by evaporation of metallic sodium onto a MgO surface. The catalyst prepared by the second method was much more basic than pure MgO (Ho=35) and showed a high activity in olefin isomerization.
- MgO–Na. 1) MgO (NaOH) 2) MgO. , , , MgO(H0=35), .相似文献
17.
On the basis of our own results and literature data it is concluded thatvC=C and the stability of surface -complexes of olefins with transition metal ions are governed by the nature of metal and its valence state.
, C=C - .相似文献
18.
M. A. Vannice T. R. Kiliany M. B. Palmer Jr. 《Reaction Kinetics and Catalysis Letters》1979,12(3):321-326
H2 and O2 uptakes at 296 K on a Pt/Al2O3 catalyst remained constant during repeated H2–O2 titration cycles conducted in a high vacuum adsorption system. Previously reported variations in these uptakes are attributed to adsorption of contaminants during desorption conditions. Also, it was found that nearly 40% of the H2 adsorbed could be removed by degassing at 296 K for 1 hr.
H2 O2 296 Pt/Al/2O3 H2–O2, . . , 40% H2 1 296 .相似文献
19.
V. V. Lavrushko S. A. Lermontov A. E. Shilov 《Reaction Kinetics and Catalysis Letters》1980,15(2):269-272
The1HNMR method and chemical analysis indicate that a complex of Pt(IV) containing a CH3–Pt fragment is formed in the reaction of H2PtCl6+H2PtCl4 with methane at 120 °C in aqueous CF3CO2H. The complex was isolated from the solution as an adduct of Ph3P.
, H2PtCl6 H2PtCl4 CF3COOH 120°C (IV), Pt–CH3. Ph3P , .相似文献
20.
K. Papp É. Kocsárdy A. Kiss T. Lakatos 《Journal of Thermal Analysis and Calorimetry》1977,11(2):249-256
The effect of reduction of pressure on the shapes of the TG, DTG and DTA curves and the mass-spectra of hydroxide and carbonate phases was investigated in some typical Hungarian red muds. The pressure change caused different decomposition rates of the phases and resulted in better separation of the overlapping thermal curves; this led to advantages as regards phase analysis. For phase analysis the red muds were extracted with water, and the extracts and solid residues were identified by IR- and X-ray methods.
Paper presented at the Scientific Session on Thermal Analysis held at Balatonfüred, Hungary, on 14–16 October 1976. 相似文献
Zusammenfassung Die Wirkung der Druckänderung auf die Form der TG-, DTG- und DTA-Kurven, sowie der MS-Spektra der Hydroxid- und Carbonatphasen in einigen typischen ungarischen Rotschlamm-Sorten wurde geprüft. Die Druckänderung verursachte verschiedene Zersetzungsgeschwindigkeiten der Phasen, führte zur besseren Auftrennung der sich überlappenden thermischen Kurven, und war ausserdem auch hinsichtlich der Phasenanalyse vom Vorteil. Zur Phasenanalyse wurden die Rotschlämme mit Wasser extrahiert und die Extrakte und festen Rückstände mittels IR- und Röntgenmethoden identifiziert.
Résumé On a étudié dans quelques espèces typiques de boues rouges de Hongrie l'effet des variations de pression sur la forme des courbes TG, TGD et ATD ainsi que les spectres de masse des phases hydroxyde et carbonate. La variation de la pression entraîne des vitesses de décomposition différentes. Il en résulte une meilleure séparation des phénomènes dans le cas où ceux-ci se chevauchent ainsi que des avantages du point de vue de l'analyse des phases. L'analyse des phases présentes dans les boues rouges a été effectuée par extraction à l'eau. Les extraits et les résidus solides ont été identifiés par spectrométrie infrarouge et par diffraction des rayons X.
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Paper presented at the Scientific Session on Thermal Analysis held at Balatonfüred, Hungary, on 14–16 October 1976. 相似文献