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1.
L. Ya. Leitis K. I. Rubina M. V. Shimanskaya V. V. Kharlamov Kh. M. Minachev 《Reaction Kinetics and Catalysis Letters》1985,29(1):175-179
It has been established that zeolites containing Pd and Cu ions catalyze the vapor phase oxidation of methylpyridines. In oxidation of 2-methylpyridine on PdCuNa-mordenite at 375 °C the yield of 2-pyridinecarbaldehyde is 40 % of its theoretical values.
, , Pd Cu, . 2- PdCuNa- 2- 375°C 40% .相似文献
2.
J. V. Sinisterra M. E. Borredon Z. Mouloungui M. Delmas A. Gaset 《Reaction Kinetics and Catalysis Letters》1985,29(1):41-47
The nature of adsorbed sulfonium and phosphonate ylids on a new barium hydroxide catalyst (C-200) is analyzed by IR. The catalytic activity of C-200 in solid-liquid phase transfer conditions is explained by these IR studies.
(C-200) . C-200 - .相似文献
3.
The use of the technique of solution thermochemistry is proposed for the rapid assay for quality control and quality assurance of dosage amounts of some ethical formulations of some antimalarial drugs. The active ingredients are chloroquine, hydroxychloroquine, dapsone, proguanil hydrochloride, and pyrimethamine.Assay is done without the separation of the excipients and without isolation or derivatisation of the analytes. The titrations are done in glacial acetic acid and utilise the catalysed hydrolysis of acetic anhydride by perchloric acid to indicate the endpoint of the reactions.The time taken for a typical assay, of a typical dosage amount is about 3–5 minutes. The reproducibility is of the order of 1% for the milligramme amounts of analyte present in the dosage amounts of the drugs.
We acknowledge the Nigerian Government for the provision of a grant to one of us (S.I.A.). We acknowledge the following for the gifts of samples of the authentic drugs and the tablets assayed in this work: Imperial Chemical Industries plc; May and Baker plc; Winthrop Laboratories plc; Wellcome Foundation (Medical Division). 相似文献
Zusammenfassung Es wird die Anwendung eines lösungsthermochemischen Verfahrens zu Schnellbestimmungen bei der Qualitätskontrolle und — sicherung von Wirkstoffeinsatzmengen einiger rezeptpflichtiger Präparate von einigen antimalarischen Arzneimitteln empfohlen. Die aktiven Bestandteile sind Chloroquin, Hydroxychloroquin, Dapson, Proguanilhydrochlorid und Pyrimethamin.Die Bestimmungen werden ohne jegliche Abtrennung der Bindestoffe und ohne Isolierung oder Derivatisierung der zu bestimmenden Substanzen durchgeführt. Die Titrierungen werden in Eisessig durchgeführt und bedienen sich der katalytischen Hydrolyse von Essigsäureanhydrid durch Perchlorsäure als Endpunktindikation der Reaktion.Die Dauer für eine typische Probe bei einer typischen Wirkstoffmenge beträgt etwa 3–5 Minuten. Die Reproduzierbarkeit liegt in der Größenordnung von 1% für Milligrammengen der zu analysierenden Stoffe im Arzneimittel.
. , , , . - . . 3–5 . 1% , .
We acknowledge the Nigerian Government for the provision of a grant to one of us (S.I.A.). We acknowledge the following for the gifts of samples of the authentic drugs and the tablets assayed in this work: Imperial Chemical Industries plc; May and Baker plc; Winthrop Laboratories plc; Wellcome Foundation (Medical Division). 相似文献
4.
Yu. K. Dolgikh V. K. Ryabchuk L. L. Basov S. G. Grenishin 《Reaction Kinetics and Catalysis Letters》1986,32(1):45-50
Photoinduced adsorption (PIA) of oxygen molecules on AgBr films at 77 K has been experimentally observed and investigated. Lifetimes of PIA centers and desorption activation energies of O2 molecules have been determined. The process is suggested to compete with the ionic step of AgBr photolysis.
- () - AgBr 77 K. - O2. , , - AgBr.相似文献
5.
Electron paramagnetic resonance studies on intermediates and final active catalyst material used for partial oxidation of anthracene to anthraquinone are reported.
, .相似文献
6.
L. A. Sokolova N. M. Popova K. Dosumov 《Reaction Kinetics and Catalysis Letters》1984,26(1-2):193-197
Thermal desorption and IR spectroscopic studies of NO adsorption on disperse Ru-black and Ru/Al2O3 catalysts have revealed that NO is adsorbed as a surface nitrosyl, nitrite and nitrate complex, the stability of which depends on the temperature. A mechanism for the interaction of adsorbed NO with Ru catalysts is suggested.
NO Ru Ru/Al2O3 , NO , , . (II) .相似文献
7.
The Arrhenius expression for reaction 1, CH3CH2COO2NO2CH3CH2COO2+NO2, has been determined to be k=2×1015 exp (–12800/T)·s–1. The free radical mechanism is the exclusive thermal decomposition mechanism of PPN. The main nitrogenous decomposition products of pure PPN are ethyl nitrate, nitrogen dioxide and methyl nitrate. In the presence of NO, ethyl nitrite is the major organitrogen product.
CH3CH2COO2NO2CH3CH2COO2+NO2 : k=2·1015exp (–12800/T) –1. () - . , . NO .相似文献
8.
A. M. Volodin V. S. Zakharenko A. E. Cherkashin 《Reaction Kinetics and Catalysis Letters》1981,18(3-4):321-324
Oxygen photoadsorption on SnO2 is shown to be accompanied by the formation of O
2
–
ion-radicals. Charge separation under irradiation and stabilization of photoinduced centers is mot effective in the presence of physically adsorbed O2.
, SnO2 - O 2 – . . O2.相似文献
9.
Pyridine (py) and acetic acid (Ac) adsorption on dealuminated HY zeolites with Al content in the range of 3.9–58 per unit cell (U.C.) was studied at 553 K by a flow-gravimetric technique. The ratio of the number of adsorbed py and Ac molecules to the number of Al atoms was plotted as a function of the Al content. The plot passes through a maximum for py and a minimum for Ac. The extrema are at about 30 Al/U.C.
(Py) (Ac) HY Al 3,9–58 (U.C.) 553 . Py Ac Al Al. Py Ac. 30 Al/U.C..相似文献
10.
Conversion of paraffins on TsVK and Y zeolites follow a similar mechanism yielding the same intermediates. Low selectivity of Y zeolites with respect to aromatic hydrocarbons is attributed to the strong adsorption of these hydrocarbons on zeolites. It is assumed that the centers of strong adsorption are Al3+ ions in cationic positions in zeolite.
, . . , Al3+ .相似文献
11.
G. D. Chukin A. S. Kulikov S. A. Sergienko 《Reaction Kinetics and Catalysis Letters》1985,27(2):287-291
It has been revealed that in crystalline aluminosilicates the three-coordinated aluminium ion belonging to the lattice is not the Lewis acid center. The latter is the off-lattice aluminium ion compensating the excess of the negative charge in the lattice or acting as cation valence-bonded to the oxygen anion of the SiO4 tetrahedron.
, , , . , , , SiO4-, .相似文献
12.
Interaction of O
s
–
anion radicals stabilized on ZnO surface with ethylene is shown to be accompanied by the formation of polymeric radicals that are stable in vacuum up to 160–180 K and destroyed in the presence of molecular O2 even at 90 K.
, - O s – , ZnO, . 160–180 . O2 90 .相似文献
13.
Piloyan activation energiesE as well as initals of exothermT
D
of sevenN-monoalkyl and fiveN,N-dialkyl-2,4-dinitroanilines were determined. Relationships were found between the TD values and Rf factors as well asE values and those RM functions and also theET
D
–1 term and RM functions.
The authors would like to thank Mrs. Anna Collàkovà for careful DTA measurements, and Dr. Ladislav Smolka for help in treatment of the measured results with the Wang 600 computer. 相似文献
Zusammenfassung Die AktivierungsenergienE nach Piloyan sowie die Anfangswerte der ExothermenT D wurden für siebenN-Monoalkyl- und fünfN,N-Dialkyl-2,4-dinitroaniline bestimmt. Die Zusammenhänge zwischen denT D-Werten und den papierchromatographischenR f-Faktoren der gemessenen Dinitroaniline wurden abgeleitet und erörtert. Desgleichen wurden auch die Zusammenhänge zwischen denE-Werten und denR M-Funktionen der Papierchromatographie abgeleitet und erörtert. Auch zwischen dem AusdruckE ·T D –1 und denR M-Funktionen wurde ein Zusammenhang gefunden.
Résumé On a déterminé les températures initialesT D de l'effet exothermique ainsi que les énergies d'activationE d'après la méthode de Piloyan, de sept N-mono alcoyl et cinqN,N-dialcoyl-2, 4-dinitroanilines. Une corrélation entre les valeursT D et les facteursR f de la Chromatographie sur papier des dinitroanilines étudiées a été trouvée et discutée, ainsi qu'entre les valeursE et les fonctionsR M de la Chromatographie sur papier. Une relation entre le termeE ·T D –1 et les fonctionsR M a également été trouvée.
E T D N- N,N- -2,4- . D R f , E R M. E. D –1 R M.
The authors would like to thank Mrs. Anna Collàkovà for careful DTA measurements, and Dr. Ladislav Smolka for help in treatment of the measured results with the Wang 600 computer. 相似文献
14.
V. A. Dyachenko E. M. Kuramshin S. S. Zlotskii D. L. Rakhmankulov 《Reaction Kinetics and Catalysis Letters》1987,33(1):63-66
Liquid phase oxidation of cycloalkane diheteroanalogs catalyzed by compounds of Cu2+, Ni2+, Co2+, Cr3+, Fe3+ has been studied. It has been established that these catalysts can be applied to intensify, oxidize and increase the selectivity of this process.
: Cu2, Ni2+, Co2+, Cr3+, Fe3+. .相似文献
15.
4,4-bismaleimidophenyl methane (BM) and 3,3-bismaleimidophenyl sulfone (BS) were blended in solution using weight ratios 31 (MS31), 21 (MS21), 11 (MS11), 12 (MS12) and 13 (MS13). Chain extended bismaleimide resins were also prepared by treating BS/BM with 4,4-diaminodiphenyl ether in molar ratios of 10.3 (BM-E and BS-E resins). These resins were also blended with bismaleimides and the curing characteristics were evaluated by differential scanning calorimetry. Increase in BM content in BMBS blends or increase in chain extended bismaleimide content in BM-EBS or BS-E BM blends resulted in a reduction of melting and curing temperatures. Indication about the extent of cross-linking was obtained from solubility measurements (in DMF) of isothermally cured resins (180 °C, lh and 220 °C, lh in an air oven). Thermogravimetric analysis of samples isothermally cured at 180 °C and 220 °C (lh each) was carried out in nitrogen atmosphere. Improvement in thermal stability of chain extended bismaleimides was observed on blending.
The financial assistance provided by Department of Science and Technology is gratefully acknowledged. 相似文献
Zusammenfassung 4,4-Bismalimidophenyl-methan (BM) und 3,3-Bismalimidophenyl-sulfon (BS) wurden in Lösung in den Gewichtsverhältnissen 31 (MS31), 21 (MS21), 11 (MS11), 12 (MS12) und 13 (MS13) gemischt. Auch kettenpolymerisierten Bismalimid-Harze wurden durch Behandlung von BS/BM mit Diaminodiphenylether im Molverhältnis 10,3 dargestellt (BM-E- und BS-E-Harze). Die Kennwerte der Aushärtung von Mischungen dieser Harze mit den Bismalimiden wurden mittels DSC ermittelt. Eine Erhöhung des BM-Gehaltes in den BM BS-Mischungen oder des Gehaltes der BM-E BS oder BS-E-Mischungen an kettenpolymerisierten Bismalimiden führt zu einer Erniedrigung der Schmelz- und Aushärtetemperaturen. Hinweise über den Vernetzungsgrad wurden aus Löslichkeitsmessungen (in DMF) von Isotherm (je 1 Stunde bei 180 und 220 °C in Luft) gehärteten Harzen erhalten. Die thermogravimetrische Analyse der Isotherm bei 180 bzw. 220 °C 1 Stunde ausgehärteten Proben wurde in Stickstoffatmosphäre ausgeführt. Die thermische Stabilität der Bismalimide wird durch Verschneiden verbessert.
4,4-- () 3,3-- () 31 (MC 31), 21 (MC 21), 11 (MC 11), 12 (MC 12) 13 (MC13). - / 4,4- 10,3 ( - C-). - . - - - - , . ( 1 180 220°) . . - .
The financial assistance provided by Department of Science and Technology is gratefully acknowledged. 相似文献
16.
The effect of cobalt salicylate on the oxidative degradation and ignition of polystyrene has been studied. It was found that cobalt salicylate sensitizes both the degradation and ignition of polystyrene by facilitating electron-transfer processes in the propagation step. From thermochemical and kinetic studies it was found that the cobalt ion, owing to its ability to exist in variable valence states, promotes electron transfer in the propagation step of polymer degradation, increasing the rate of propagation and consequently the overall rate. Using solid-phase thermal ignition theory, an attempt has been made to explain the sensitization of ignition by the cobalt ion.
Zusammenfassung Die Wirkung von Kobaltsalicylat auf den oxydativen Abbau und die Entzündung von Polystyrol wurde untersucht. Es wurde festgestellt, daß Kobaltsalicylat sowohl den Abbau als auch die Entzündung des Polystyrols durch Erleichterung von Elektrontransferprozessen im Kettenfortpflanzungsschritt begünstigt. Thermochemische und kinetische Untersuchungen ergeben, daß das Kobaltion infolge seiner Fähigkeit, in mehreren Valenzstufen aufzutreten, den Elektronentransfer im Kettenfortpflanzungsschritt erleichtert wodurch die Geschwindigkeit der Kettenfortpflanzung und damit die Geschwindigkeit des Gesamtprozesses erhöht wird. Basierend auf der Theorie der thermischen Festphasenentzündung wird ein Versuch unternommen, Erleichterung der Entzündung durch Kobaltionen zu erklären.
. , , . , , , , . , .相似文献
17.
Thermal behaviour of N3P3Az6 up to 300 °C was studied by means of TG, DTG and DTA methods. It was found that, when heated in small amounts, N3P3Az6 does not undergo decomposition even up to 300 °C. It rather melts at about 150 °C and then polymerizes at higher temperatures with the formation of an insoluble glassy substance. The proposed polymerization mechanism assumes the opening of aziridine rings and combination of the N3P3Az6 units into a three-dimensional structure. The heating of larger amounts of N3P3Az6 leads to its decomposition, due to the considerable amount of heat evolved during the polymerization.
Zusammenfassung Mittels TG, DTG and DTA wurde das thermische Verhalten von N3P3Az6 bis 300 °C untersucht. In geringen Mengen erhitzt erleidet N3P3Az6 bis 300 °C keine Zersetzung. Es schmilzt bei etwa 150 °C und polymerisiert bei höheren Temperaturen zu einer unlöslichen glasigen Substanz. Dem angenommenen Mechanismus nach werden die Aziridinringe geöffnet, die N3P3Az6-Einheiten schließen sich unter Bildung einer dreidimensionalen Struktur zusammen. Beim Erhitzen von größeren Mengen an N3P3Az6 wird die Verbindung wegen der bei der Polymerisation entstehenden beträchtlichen Wärme zersetzt.
, (N3P3Az6) 300°. 300°. 150° , . (N3P3Az6) . (N3P3Az6) , , .相似文献
18.
St. Veleva 《Reaction Kinetics and Catalysis Letters》1988,37(2):281-285
The possibility of preliminary estimation of the oxidation kinetics and mechanism using the quantity to from the exponential kinetic rate equation is discussed.
, to .相似文献
19.
Yu. V. Belokopytov Yu. I. Pyatnitskii Yu. N. Grebennikov 《Reaction Kinetics and Catalysis Letters》1986,31(1):181-185
TPD studies have revealed that benzene and maleic anhydride are adsorbed on different active sites of the V2O5–MoO3 catalyst.
, - .相似文献
20.
Quantum efficiency of the photocatalytic hydrogen evolution upon illumination in the self-and dyesensitized absorption bands of suspended titanium dioxide has been determined. The photocatalytic activity observed upon illumination in the sensitization band is shown to be due to absorption of light quanta by adsorbed molecules of the dye.
. , .相似文献