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1.
Condensation of triphenylsilane with isopropanol in presence of isopropoxide has been studied in anhydrous medium and the activation parameters have been measured. Dehydration of the medium has been obtained by means of a pre-reaction of triphenylsilane with the residual water in the solvent. In this medium the reaction is extremely slow, moreover, it is inhibited by silanol whose effect would lower the actual catalyst concentration.
. . , .
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2.
The activity of modified Fe/Al2O3 catalysts in the hydrocondensation of CO has been studied in terms of the selectivity for light olefins and of repartition of the hydrocarbon products.
Fe/Al2O3 CO, .
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3.
Hexadiene formation from 2-propanol was investigated in view of acid-base properties of Ca–P–O catalysts with the Ca/P atomic ratio varying from 1.5 to 5.0. The catalytic activity in hexadiene formation increased up to a maximum at Ca/P=2.0, having almost the same amount of weak acidic sites as weak basic sites, and decreased with futher increase in Ca/P ratio.
2- - Ca–P–O Ca/P, 1,5 5,0. , Ca/P=2, , Ca/P.
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4.
    
- () SiAl. , - 125 /–1. SiAl - .
Studies of the acidic and catalytic properties of superhigh silica (SHS) zeolites with different SiAl ratios on a vacuum-circulation reactor indicate that n-hexane cracking is a first order reaction with the effective activation energy of 125 kJ/mol–1. With increasing the SiAl ratio the acidity and activity of SHS-zeolites decrease.
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5.
Water vapour adsorption processes and equilibria on adsorbents with polar surfaces can be well tested with an adsorption method combined with thermal analysis. The first step involves the comparison of isothermal desorption-adsorption curves and thermal curves; in the second step different equilibrium points of the adsorption isotherms are tested by means of thermal analysis.Some examples of building materials are presented to demonstrate the possibilities of the method. The types of adsorption isotherms for the samples were formally equal in all examples; only the complex method presented was able to reveal that formation of the equilibiria was induced by essentially different processes. Such processes are: physical adsorption depending on the structure of the adsorbent and the activity of the external active centres, chemisorption, chemical reaction in the solid/vapour system and chemical reaction in the water phase condensed in the capillaries.
Zusammenfassung Prozesse und Gleichgewichte der Wasserdampfadsorption an Adsorbenten mit polarer Oberfläche können gut mit einer mit thermischer Analyse kombinierten Adsorptionsmethode getestet werden. Der erste Schritt der Methode schließt den Vergleich der Desorptions-Adsorptionsisothermen und der thermischen Kurven in sich ein, im zweiten werden Gleichgewichtspunkte der Adsorptionsisothermen durch thermische Analyse getestet.Am Beispiel von einigen Baumaterialien werden die Möglichkeiten dieser Methode demonstriert. Die Adsorptionsisothermen waren formell in allen Fällen vom gleichen Typ und nur die vorgestellte komplexe Methode ergab, daß die Ausbildung des Gleichgewichtes durch grundsätzlich verschiedene Prozesse erfolgt. Solche Prozesse sind: von der Struktur des Adsorbenten und der Aktivität der aktiven Oberflächenzentren abhängige physikalische Adsorption Chemisorption, chemische Reaktion im Festkörper/Dampf-System und in der in Kapillaren kondensierten wässrigen Phase.

- , . — . — . . , . : , , , — , .
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6.
    
The replacement of triphenylphosphine by triphenylarsine or triphenylbismuthine in the systems -C3H5NiCl–(C2H5)nAlCl3–n-Lig strongly affects the isomerization activity of the catalytic complex and the distribution of hexanes in propylene dimerization. Systems with (C6H5)3As and (C2H5)2AlCl represent the highest isomerization activity and the highest selectivity to 2-methylpentene-2.
, -C3H5NiCl–(C2H5)n–AlCl3–n-Lig . (C6H5)3As (C2H5)2AlCl 2--2.
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7.
A peculiarity of the photocatalytic action of porphyrin molecules with different localization inside lipid bilayers of lecithin vesicles has been studied. The influence of an electrostatic field in the lipid membrane on the efficiency of electron photocatalytic transfer across the membrane is discussed.
, - . . .
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8.
Supported SnO2/SiO2 catalysts have been prepared by the reaction of the surface hydroxy groups of silica gel and gas phase tin chloride (PS method). The catalytic properties have been examined in the reaction of 2-propanol to show the effect of VPS cycles on the amount and nature of the active sites.
SnO2/SiO2 . 2- VPS .
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9.
By TPD it could be shown that hydrogen desorption of a reduced NiY-zeolite stoichiometrically corresponds to the decrease of reduction degree. Therefore, the reason for hydrogen abstraction should be a partial reoxidation of Ni0.
, NiY- . Ni0.
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10.
Infrared studies of the interaction of NO with CuY–A zelites have been made over the temperature range from –100°C to 400°C. Several forms of NO adsorption have been found, in particular, a stable cis-dimer at low temperatures.
- (–100+400°C) NO CuY–A . NO, ë - .
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11.
A simple glass device is described acting as stopcock and winch at the same time. The device is especially suitable for the dislocation of solid sample holders in IR cells.
, . .
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12.
A new molybdenum(VI) complex, Li2[Mo2O6(C2O4)] · 2 H2O (LMO), was prepared and characterized by chemical analysis and IR spectral studies. Its thermal decomposition was studied by using TG and DTA techniques. LMO loses its two moles of water between 75 and 170° to give the anhydrous product, which decomposes in three stages between 240 and 380°. The first two stages occur in the temperature ranges 240–280° and 280–305°, to give intermediates with the tentative compositions Li6[Mo6O19(C2O4)2] and Li6[Mo6O20(C2O4)], respectively. In the third stage, which extends up to 380°, Li6[Mo6O20(C2O4)] decomposes to give the end-product, Li2Mo2O7.
Zusammenfassung Ein neuer Molybdän(VI)-Komplex der Formel Li2[Mo2O6(C2O4)] · 2 H2O (LMO) wurde dargestellt und durch chemische Analyse und IR-spektroskopisch charakterisiert. Die thermische Zersetzung dieses Komplexes wurde mittels TG und DTA untersucht. LMO verliert die zwei Wassermoleküle zwischen 75 und 170° unter Bildung des wasserfreien Produktes, das zwischen 240 und 380° in drei Stufen zersetzt wird. Die in den Temperaturbereich von 240–280° und 280–305° verlaufenden ersten zwei Reaktionsschritte ergeben Intermediäre der tentativen Zusammensetzung Li6[Mo6O19(C2O4)2] bzw. Li6[Mo6O20(C2O4)]. In dem sich bis 380° erstreckenden dritten Reaktionsschritt wird Li6[Mo6O20(C2O4)] unter Bildung des Endproduktes Li2Mo2O7 zersetzt.

Li2[MO2O6(C2O4] · 2 2 . . - 70–170° , , 240–380°. 240–280° 280–305° - Li6[Mo6O19(C2O4)2] Li6[Mo6O20(C2O4)]. - 380° Li2Mo2O7.


The authors are grateful to Prof. S. N. Tandon, Head of the Chemistry Department, for providing the research facilities.  相似文献   

13.
The activity of vanadia/titania catalysts in CO oxidation has been tested and found to be of the same order as that observed for unsupported vanadia; the simultaneous presence of vanadium-sodium compounds cancels the activity, probably because of the elimination of labile V=0 species at surface defects.
V2O5/TiO2 CO, V2O5; - , , V=0 .
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14.
    
1- . - n3. 1-.
The free-radical cotelomerization of ethylene and 1-hexene with CCl4 has been studied. Both homo- and cotelomers (n3) are formed. The method of competitive kinetics has been applied to estimate the transfer constants and reactivity ratios for a number of polychloroalkyl radicals with ethylene and 1-hexene.
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15.
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 . -, -, - .
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16.
Chemical oscillatory behavior in the uncatalyzed bromate oxidation of hydroquinone and nitrophenols is reported. The reaction is strongly inhibited by stirring. Effect of one-electron redox couples (EZ catalysts) on the system is described.
. . - ( EZ) .
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17.
The hydrated oxides which are formed by the addition of ammonium bi-carbonate to a solution of Zn(NO3)2 and Fe(NO3)3, and drying the precipitates at 110° are zinc hydroxy carbonate(I) and iron(III) oxide gel(II), respectively. A new, derived derivative thermogravimetric curve along with conventional DTA and DTG methods have been used to study the reaction between (I) and (II) in two components system.A mixture of (I) and (II) subjected to grinding yields about 16% zinc ferrite precursor. In a sample prepared by coprecipitation from the mixed nitrate solution and drying at 110°, nearly 70% precursor is formed. The formation of zinc ferrite spinel reported to take place at low temperature in such cases appears to be related with the formation of the precursor, and reactivity and phase transformation temperature in Fe2O3.
Zusammenfassung Die durch Zugabe von Ammoniumbicarbonat zu einer Lösung von Zn(NO3)2 und Fe(NO3)3 und Trocknung des Niederschlags bei 110° gebildeten hydratisierten Oxide sind Zinkhydroxycarbonat (I) bzw. Eisen(III)oxidgel (II). Eine neue derivierte derivative thermogravimetrische Kurve wurde gemeinsam mit den konventionellen DTA und DTG Methoden zum Studium der Reaktion zwischen (I) und (II) in Zweikomponentensystemen eingesetzt.Das Gemisch von (I) und (II) ergibt beim Mahlen etwa 16% Zinkferrit »Prekursor«. In einer durch Mitfällung der gemischten Nitrate und Trocknung bei 110° erhaltenen Probe wurde fast 70 % »Prekursor« gebildet. Die Bildung von Zinkferritspinell, über dessen Entstehung in solchen Fällen bei niedrigen Temperaturen berichtet wird, scheint mit der Bildung des »Prekursors« verbunden zu sein, sowie mit der Reaktivität und der Phasenübergangstemperatur in Fe2O3.

Résumé Les oxydes hydratés formés lors de l'addition du bicarbonate d'ammonium à une solution de Zn(NO3)2 et de Fe(NO3)2 suivie du séchage du précipité à 110°, sont l'hydroxy-carbonate de zinc(I) et le gel de l'oxyde de fer(III) (II). On a utilisé une nouvelle technique de thermogravimétrie en dérivation, ainsi que les méthodes d'ATD et TGD conventionnelles, pour étudier la réaction entre (I) et (II) dans le système à deux composants.Un mélange de (I) et de (II), soumis au broyage, donne environ 16 p.c. de ferrite de zinc «précurseur», tandis qu'un échantillon préparé par coprécipitation à partir de la solution des nitrates mixtes et séchage à 110°, en donne environ 70 p.c.La formation du spinelle de ferrite de zinc décrite comme ayant lieu, dans des cas similaires, à des températures faibles, paraît être en rapport avec la formation du «précurseur» ainsi qu'avec la réactivité et la température de la transformation de phase de Fe2O3.

Zn(NO3)2 Fe(NO3)3, , 110°, , , (I) (II). , , I II . I II, , 16% , . , 110°, 70% , . « » , Fe2O3.
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18.
Reducibility of Cu–SiO2 catalyst prepared by ion exchange method, being effective for selective dehydrogenation to produce methyl formate from methanol at lower temperatures, has been studied by a TPR technique. The results suggest that easier reduction leads to an increase of dispersity of Cu particles.
, - , , . , , Cu.
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19.
The photolysis products of SO2-pentane-NO mixtures are N2O, H2O and a compound designated as RNO. Kinetic data obtained by OC method confirm the previously proposed scheme of photolysis. Also studied was the photolysis of SO2, NO and cyclohexane mixtures. From comparison of spectral characteristics of RNO and its analog 2-methyl-2-nitrosopropane, the probable structure of RNO is suggested.
SO2--NO N2O, H2O , RNO. , , . SO2 NO . RNO 2--2- RNO.
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20.
The methyl ester and N,N-diethylamide of 2-azido-5-phenyl-4-thiazolecarboxylic acid were obtained by the reaction of the corresponding 4-substituted 2-hydrazino-5-phenylthiazole with NaNO2 in acid media. IR and UV spectroscopy were used to show that the compounds synthesized retain azide form in both the crystalline state and in solution. The reaction of azides with dicarbonyl compounds gave derivatives of 2-[5-methyl-4-acetyl-or 2-[5-methyl-4-ethoxycarbonyl-1,2,3-triazol-1-yl]-5-phenylthiazole-4-carboxylic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 710–714, May, 1993.  相似文献   

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