共查询到20条相似文献，搜索用时 140 毫秒
1.
A. Sayari A. Ghorbel G. M. Pajonk S. J. Teichner 《Reaction Kinetics and Catalysis Letters》1981,15(4):459-465
Kinetic studies of the nitroxidation of isobutene by NO show that the reaction follows a redox mechanism in the temperature range of 300–400°C. This mechanism implies an interaction between dehydrogenated isobutene -allyl radical and atomic nitrogen due to the decomposition of NO by the reduced catalyst, which is then reoxidized.
NO , 300–400°C. - , NO , .相似文献
2.
The compatibility of a lauric fat with several milk fat fractions (MF) was investigated. The enthalpy of crystallization was measured by differential scanning calorimetry (DSC). These values were related to the corresponding values calculated for an Ideal Blend. The different compatibility of the milk fat fractions with the lauric fat could be shown by this method very clearly.
Untersuchungen zur Mischbarkeit/Verträglichkeit von Milchfettfraktionen mit laurischen Fetten
Zusammenfassung Die Mischbarkeit/Verträglichkeit von Milchfettfraktionen mit einem laurischen Fett wurde differenzkalorimetrisch untersucht. Die Auswertung der Befunde bezieht sich auf die entsprechenden Rechnungswerte einer Idealen Mischung. Es wurde nachgewiesen, da sich diese Milchfette deutlich in ihrer Mischbarkeit unterscheiden.
. $ . , $ - . $ .相似文献
3.
T. Chihara M. Shinzawa Y. Yokoyama K. Taya H. Ogawa 《Reaction Kinetics and Catalysis Letters》1989,39(1):181-186
Relative hydrogenation reactivity of the two carbonyl groups of methylcyclohexane-1,4-dione can be estimated beside that of two related compounds, 2- and 3-methyl-cyclohexanones. The reaction is accompanied with hydrogenolysis on Pt and Pd. The less hindered 4-carbonyl group is selectively hydrogenolyzed.
-1,4- , 2- 3-. Pt Pd. 4- .相似文献
4.
G. Karaiskakis A. Lycourghiotis D. Vattis N. A. Katsanos 《Reaction Kinetics and Catalysis Letters》1981,15(4):413-418
Deamination of dicyclohexylamine gives the same final products as those obtained from the respective primary amine on a similar surface. A theoretical rate equation derived permits the calculation of various rate constants from the experimental data. It is concluded that one of the intermediates formed from the two amines must be identical.
, . . , , , .相似文献
5.
T. S. Dzhabiev V. Ya. Shafirovich A. E. Shilov 《Reaction Kinetics and Catalysis Letters》1976,4(1):11-18
Kinetics of the Mn(IV)Mn(III) transition in the oxidation of watet to O2 was investigated at 60–100°C in 6–15 M H2SO4. The reaction is approximately 2-nd order in Mn(IV) concentration in the process of oxidation and 1-st order in initial Mn(IV) concentration. The kinetics is interpreted by the existence of dimeric forms Mn(IV)·Mn(IV), Mn(IV)·Mn(III) and Mn(III)·Mn(III). The suggested mechanism includes O2 formation directly in the coordination sphere of the Mn(IV)·Mn(IV) dimer in a polyelectronic process.
Mn (IV)»Mn (III) O2 60–100°C 6–15 M H2SO4. Mn (IV) I- Mn (IV). [Mn (IV)]2; [Mn(III)]2 Mn(IV)·Mn (III). , [Mn (IV)]2相似文献
6.
The paper deals with the problem of the interactions of the mineral components in clay and argillite samples during the thermal analysis. It is shown that depending on the experimental conditions, the interaction of pyrite and carbonates may cause atypical course of DTA and TG curves. Also the common occurring of sylvine and halite shifts the temperature of their melting to a lower value and this phenomenon occurs in pure salts as well as in the great dilution to some percent in clays.
Zusammenfassung Es wird über Zwischenreaktionen der mineralischen Komponenten von Ton und Argillit während der thermischen Analyse berichtet. Von den Versuchsbedingungen abhängend produzieren die Zwischenreaktionen von Pyrit und Karbonat DTA und TG Kurven deren Verlauf nicht charakteristisch ist. Das gemeinsame Vorkommen von Sylvin und Halit verschiebt ihren Schmelzpunkt in Richtung der niedrigen Temperaturen in reinen Salzen ebenso wie bei großer Verdünnung von einigen Prozenten in Ton.
Résumé Les interactions des constituants minéraux des échantillons d'argile et d'argilite pendant l'analyse thermique ont été examinées. Suivant les conditions expérimentales, l'interaction de la pyrite et des carbonates peut provoquer un tracé des courbes ATD et ATG qui s'écarte de l'allure type. La présence simultanée de sylvine et d'halite produit un abaissement de leur point de fusion et ce phénomène apparaít aussi bien avec les sels purs qu'avec ceux fortement dilués, à raison de quelques pour cent, dans les argiles.
, , ., () (). . , .相似文献
7.
《Reaction Kinetics and Catalysis Letters》1979,10(1):43-48
Ni-, Pt-, Pd-, Rh-. , : Rh>Ni>Pt>Pd.
The hydrogenation of citral to citronellal has been studied on Raney nickel, platinum, palladium and rhodium blacks. The selectivity of hydrogenation of the conjugated double bond was found to decrease in the order Rh>Ni>Pt>Pd.相似文献
8.
M. N. Moreno-Carretero J. M. Salas-Peregrín 《Journal of Thermal Analysis and Calorimetry》1985,30(2):377-382
Four Hg(II) complexes, containing as ligands 6-amino-5-nitrosouracil (AH), 6-amino-3-methyl-5-nitrosouracil (BH) or 6-amino-1-methyl-5-nitrosouracil (CH), have been synthesized and their thermal behaviour studied by TG and DSC techniques: Hg3Cl6(AH)4, HgCl2(BH)2· 2 H2O, HgCl2(BH)2 · H2O and HgC2· 2 H2O.The dehydration processes take place in only one step, with enthalpies in the range 40.2–60.0 kJ · mole–1 H2O.Pyrolytic processes start between 200 and 250°, in all cases the thermal stability of the corresponding pyrimidine derivative being lower than that of the free ligand. These processes finish between 600 and 750°, with no residue.
Zusammenfassung Vier 6-Amino-5-nitrosouracil (AH), 6-Amino-3-methyl-nitrosouracil (BH) oder 6-Amino-1-methyl-5-nitrosouracil (CH) als Liganden enthaltende Hg(II)-Komplexe wurden synthetisiert: Hg3Cl6(AH)4, HgCl2(BH)2 · 2 H2O, HgCl2(BH)2 · H2O und HgC2 · 2 H2O. Die Dehydratisierungsprozesse verlaufen in nur einem Schritt mit Enthalpien im Bereich von 40.2–60.0 kJ pro mol H2O. Pyrolitische Prozesse setzen zwischen 200 und 250° ein. In allen Fällen ist die thermische Stabilität der entsprechenden Pyrimidin-Derivate geringer als die der freien Liganden. Diese Prozesse sind zwischen 600 und 750° beendet, wobei kein Rückstand zurückbleibt.
g3l6()4, gl2( )2 · 2 2O, gl2()2 · 2O, g2 · 2 2, — 6- -5-, — 6--3- — 6---5- . , 40.2–60.0 · –1 2. 200 250° 600–750° - . , .相似文献
9.
The thermal decompositions of the following compounds were studied: Ni(NCO)2(3-Etpy)4. (I), Ni(NCO)2(3-Clpy)4 (II), Ni(NCO)2(3-Brpy)4 (III), Ni(NCO)2(3-NH2py)4 (IV), Ni(NCO)2(3-Clpy)2·2H2O (V) and Ni(NCO)2(3-Brpy)2·2H2O (VI). The release of volatile ligands (3-Rpy and H2O) is a two-step process, Ni(NCO)2(3-Etpy)2 (VII), Ni(NCO)2(3-Clpy)2 (VIII), Ni(NCO)2(3-Brpy)2 (IX) and Ni(NCO)2(3-NH2py)2 (X) being formed as intermediate complexes. The loss of the last molecules of volatile 3-Rpy ligands is accompanied by NCO ligand decomposition. The spectral and magnetic data indicated pseudooctahedral configuration for all complexes I-X.
Zusammenfassung Die thermische Zersetzung der folgenden Verbindungen wurde untersucht: Ni(NCO)2(3-Etpy)4 (I), Ni(NCO)2(3-Clpy)4 (II), Ni(NCO)2(3-Brpy)4 (III), Ni(NCO)2(3-NH2py)4 (IV), Ni(NCO)2(3-Clpy)2·2H2O (V) und Ni(NCO)2(3-Brpy)2·2H2O (VI). Die flüchtigen Liganden (3-Rpy und H2O) werden in zwei Schritten abgegeben, wobei Ni(NCO)2(3-Etpy)2 (VII), Ni(NCO)2(3-Clpy)2 (VIII), Ni(NCO)2(3-Brpy)2 (IX) und Ni(NCO)2(3-NH2py)2 (X) als intermediäre Komplexe gebildet werden. Die Abgabe der letzten Moleküle der flüchtigen 3-Rpy-Liganden geht mit der Zersetzung des NCO-Liganden einher. Die spektrometrischen und magnetischen Daten weisen auf eine pseudooktaedrische Konfiguration aller Komplexe (I-X) hin.
: Ni(NCO)2(3-Etpy)4 (I), Ni(NCO)2(3-Clpy)4 (II), Ni(NCO)2(3-Brpy)4 (III), Ni(NCO)2(3-NH2py)4 (IV), Ni(NCO)2(3Clpy)2·2H2O(V) Ni(NCO)2(3-Brpy)2·2H2O (VI). (3-Rpy H2O) , Ni(NCO)2(3-Etpy)2 (VII), Ni(NCO)2(3-Clpy)2 (VIII), Ni(NCO)2(3-Brpy)2 (IX) Ni(NCO)2(3NH2py)2 (X). . .相似文献
10.
A. A. Shchegolev V. A. Smit S. A. Khurshudyan V. A. Chertkov V. F. Kucherov 《Russian Chemical Bulletin》1977,26(5):1001-1006
Conclusions The conjugated acylation of alkynes in the presence of aromatic derivatives is a universal method for synthesizing various -aryl-, -unsaturated ketones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, pp. 1093–1099, May, 1977. 相似文献
11.
-Alkoxy--phenylbutadienyl salts of heterocyclic bases were synthesized by the reaction of of benzoylacetaldehyde tetraethylacetal with quaternary salts of nitrogen-containing heterocyclic bases in acetic anhydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1378–1381, October, 1971. 相似文献
12.
C. Carfagna P. Iannelli A. Roviello A. Sirigu 《Journal of Thermal Analysis and Calorimetry》1985,30(6):1317-1324
The mesophasic behaviour of the following compounds has been investigated by DSC, X-ray diffraction and optical microscopy methods: CH3(CH2)4-CO-R-A
n
-R-CO-(CH2)4-CH3,n=9 14, 16 CH3(CH2)4-CO-R-B
n
-R-CO-(CH2)4-CH3,n=2, 3A
n=-CO-O-(CH2)n–4-O-CO-,B
n
=-CO-(OCH2CH2)
n
-O-CO-,R=-O-Ø-C(CH3)=N-N=(CH3)C-Ø-O-,Ø=-C6H4
They have been assumed to be low molecular weight models of homologous nematogenic polymers.All the examined compounds exhibit nematic mesomorphism. On complete analogy with the corresponding polymers, the thermodynamic data relative to the nematic-isotropic phase transition show a very reduced, if any, odd-even fluctuation. These data are compared with those obtained for very similar compounds, both polymeric and non-polymeric, containing ester linkages between the rigid and flexible groups, to provide evidence of the reliability of the dimeric compounds as models of the polymeric homologues.
The financial assistance of the Ministero Pubblica Istruzione is acknowledged. 相似文献
Zusammenfassung Das mesophasische Verhalten der folgenden Verbindungen wurde mittels DSC, Röntgendiffraktion und optischer Mikroskopie untersucht: CH3(CH2)4-CO-R-A n -R-CO-(CH2)4-CH3;n=914, 16 CH3(CH2)4-CO-R-B n -R-CO-(CH2)4-CH3;n=2, 3A n =-CO-O-(CH2)n-4-O-CO-;B n =-CO-(OCH2CH2)n-O-CO-;R=-O-C6H4-C(CH3)=N-N=(CH3)C-C6H4-O-. Die Verbindungen wurden als Modelle homologer nematogener Polymere mit niedrigem Molekulargewicht angesehen. Alle untersuchten Verbindungen zeigen einen nematischen Mesomorphismus. Analog zu den entsprechenden Polymeren zeigen die sich auf den nematisch-isotropen Phasenübergang beziehenden thermodynamischen Daten eine, wenn überhaupt, sehr reduzierte ungerade-gerade Fluktuation. Diese Daten werden mit denen verglichen, die für sehr ähnliche, sowohl polymère als auch nicht-polymere Verbindungen mit Esterbindungen zwischen den starren und flexiblen Gruppen erhalten wurden, um Beweise für die Zuverlässigkeit der auf dimeren Verbindungen aufbauenden Modelle für polymère Homologe zu erhalten.
, : CH3(CH2)4-CO-R-A n -R-CO-(CH2)4-CH3 n=914,16 CH3(CH2)4-CO-R-B n -R-CO-(CH2)4-CH3 n=2, 3A n =-CO-O-(CH2) n–4-O-CO-;B n =-CO-(OCH2CN2) n -O-COR =-O--C(CH3)=N-N=(CH3)C--O- =C6H4 , . . — , , , - . , , ,
The financial assistance of the Ministero Pubblica Istruzione is acknowledged. 相似文献
13.
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
14.
Take-aki Mitsudo Yukiatsu Komiya Hideki Boku Yoshihisa Watanabe 《Reaction Kinetics and Catalysis Letters》1985,27(2):399-402
In the Fischer-Tropsch synthesis, potassium tetracarbonylhydridoferrate, KHFe (CO)4, supported on HY-zeolite or silica gel exhibited high selectivity to light olefins without following the Schulz-Flory distribution.
, KHFe(CO)4, HY —, — .相似文献
15.
E. K. Poels E. H. van Broekhoven W. A. A. van Barneveld V. Ponec 《Reaction Kinetics and Catalysis Letters》1982,18(1-2):223-228
Reactions of synthesis gas (CO/H2) have been followed on a number of Pd-metal and Pd-alloy catalysts. Formation of methanol is sensitive to the choice of the carrier, but as the literature (and some of the data presented) is indicating, it is not proportional to the Pd-metal surface area. Alloying with Ag does not suppress methane formation substantially. It has been inferred from these results that methane is formed, at least partially, from an oxygen containing intermediate and that Pd ions play a role in the formation of these intermediates.
, -, CO/H2, Pd . , , ( ), Pd. . , , - , , , Pd.相似文献
16.
L. Kotsis J. Argyelán P. Szolcsányi K. Kutics 《Reaction Kinetics and Catalysis Letters》1985,27(1):143-146
The adsorption kinetic characteristics of natural zeolite based adsorbents can be improved significantly by grinding, size fractionation and regranulation. The sorption characteristics of such materials with tridisperse pore-size distributions are discussed here. (Tridisperse structure: the holes of crystallites, the macropore system among crystallites and macropores produced by granulation.)
- , . .相似文献
17.
G. Jenner A. Kiennemann E. Bagherzadah A. Deluzarche 《Reaction Kinetics and Catalysis Letters》1980,15(1):103-112
Several effects on the hydrogenation of carbon monoxide in propanol in presence of ruthenium catalysts are examined. The homologation reaction is not observed, only propyl formate and propyl acetate are produced with any ruthenium catalyst. The pH-value is an important parameter: in acid media, the yield of propyl formate is noticeably increased indicating different catalytic active species. The addition of cesium salts is also benefitial for formate formation. This is not the case when water is associated with propanol as solvent. Finally, no ethylene glycol is detected. The process is found to be homogeneous and methanol seems to be the precursor of methyl formate.
, . , . : , . . , . . , -, .相似文献
18.
A. Z. Abyshev P. P. Denisenko D. Z. Abyshev Yu. B. Kerumov 《Chemistry of Natural Compounds》1978,13(5):531-535
Summary From the roots ofSeseli grandivittatum, together with -sitosterol and (–)-3R-decursinol, found in nature for the first time, and its angelate, we have isolated two new compounds which we have called grandivittin and grandivittinol.On the basis of IR, PMR, and mass spectra and chemical transformations, the structure of 3-senecioyloxy-3,4-dihydro-3R-xanthyletin is proposed for grandivittin, and 7-hydroxy-6-(3-hydroxy-2-senecioyloxyisopentyl) coumarin for grandivittinol.Leningrad Sanitary-Hygienic Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 640–646, September–October, 1977. 相似文献
19.
Résumé Nous avons étudié, par absorption infrarouge, trois séries de vanadates du V (V) et leurs produits de transformation au cours du chauffage.Les o-vanadates montrent une structure tétraèdrique simple qui se conserve jusqu'à 950° C au moins.Lesp- etm-vanadates se présentent sous deux formes de structure un peu différente, selon la température à laquelle on les porte.Les pyrovanadates et un certain nombre de métavanadates possèdent une structure formée de chaînes de tétraèdres VO4 liés par un sommet d'oxygène.Les autres métavanadates sont constitués de chaînes de bipyramides triangulaires liées par une arête.
Three series of vanadates of vanadium(V) and their decomposition products, obtained by thermal treatment, were subjected to investigation by infrared adsorption spectroscopy.o-vanadates have a tetrahedral structure which they preserve up to 950°.p-and m-vanadates appear in two slightly different structures depending on the temperature.Pyrovanadates and certain m-vanadates form chains of VO4 tetrahedra which are connected at the apex. Other m-vanadates consist of trigonal bipyramidal chains linked along an edge.
Zusammenfassung Drei Serien der Vanadate des Vanadium (V) und ihrer durch thermische Behandlung erhaltenen Umwandlungsprodukte wurden einer Prüfung durch infrarote Absorptionspektroskopie unterworfen.Die o-Vanadate besitzen eine tetraedrische Struktur, welche sie mindestens bis 950° C beibehalten. Die p- und m-Vanadate erscheinen je nach der Erhitzungstemperatur in zwei wenig unterschiedlichen Strukturen.Pyrovanadate und gewisse Metavanadate bilden Ketten aus VO4 Tetraedern, verbunden an den Sauerstoffspitzen. Die übrigen Metavanadate bestehen aus dreieckigen bipyramidalen Ketten, verbunden entlang einer Kante.
, , .- , 950°. - - , . - VO4, . - , .相似文献
20.
V. E. Agabekov G. V. Butovskaya V. A. Azarko N. I. Mitskevich 《Reaction Kinetics and Catalysis Letters》1982,19(3-4):271-274
Oxidation rates and k2/k6 ratios are given for some acids from propionic to lauric. The k2/k6 ratio is shown to be influenced by the electrostatic effect of the solvent. A linear dependence between the isodielectric values of k2/k6 and the number of methylene groups in the acid molecules is described.
k2/k6 . k2/k6 k2/k6 .相似文献