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The thermal decomposition of some mixed uranyl complexes with Schiff bases and DMSO, EtOH or (Ph)3PO as neutral ligand, were investigated and the corresponding activation energy, E*a, and enthalpy of dissociation, ΔHd, values were calculated.
The results obtained indicate that for the same neutral ligand, the thermal stability of the uranyl complexes is influenced by the Schiff base used; for the same Schiff base, the presence of (Ph)3PO results in a greater thermal stability of the mixed complexes than when the other two neutral ligands are present. 相似文献
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L. Abate A. Chisari R. Maggiore G. Siracusa 《Journal of Thermal Analysis and Calorimetry》1983,27(1):139-149
The solid-state syntheses of uranyl acetate adducts with thiourea were attempted directly in a DSC apparatus according to the scheme: UO2Ac2·2 H2O(s)+n thiourea(s) → → UO2Ac2·thiourean(s)+2 H2O(v) (n=1–6), and the correspondingδH values were evaluated. At all stoichiometric ratios the same UO2Ac2·thÌourea product was obtained, to which a pentagonal bipyramidal structure was attributed. Thermoanalytical (TG and DTG) and infrared spectra measurements were also performed and agree with the DSC results. 相似文献
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Roberto Mattioli Daniel Di Risola Rodolfo Federico Alessia Ciogli Francesco Gasparrini Claudio Villani Mario Fontana Anna Maggiore Maria dErme Luciana Mosca Antonio Francioso 《Molecules (Basel, Switzerland)》2022,27(7)
trans-Resveratrol is a natural bioactive compound with well-recognized health promoting effects. When exposed to UV light, this compound can undergo a photochemically induced trans/cis isomerization and a 6π electrochemical cyclization with the subsequent formation of 2,4,6-trihydroxyphenanthrene (THP). THP is a potentially harmful compound which can exert genotoxic effects. In this work we improved the chromatographic separation and determination of the two resveratrol isomers and of THP by using a non-commercial pentafluorophenyl stationary phase. We assessed the effect of natural deep eutectic solvents (NaDES) as possible photo-protective agents by evaluating cis-resveratrol isomer and THP formation under different UV-light exposure conditions with the aim of enhancing resveratrol photostability and inhibiting THP production. Our results demonstrate a marked photoprotective effect exerted by glycerol-containing NaDES, and in particular by proline/glycerol NaDES, which exerts a strong inhibitory effect on the photochemical isomerization of resveratrol and significantly limits the formation of the toxic derivative THP. Considering the presence of resveratrol in various commercial products, these results are of note in view of the potential genotoxic risk associated with its photochemical degradation products and in view of the need for the development of green, eco-sustainable and biocompatible resveratrol photo-stable formulations. 相似文献
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A. Parmaliana A. Mezzapica C. Crisafulli S. Galvagno R. Maggiore N. Giordano 《Reaction Kinetics and Catalysis Letters》1982,19(1-2):155-160
Monolithic supported nickel catalysts were investigated in benzene hydrogenation between 100 and 280 °C. The conversion of benzene to cyclohexane reaches a maximum around 210 °C with a maximum yield at a ratio poH2/poBz=3. The experimental results and some kinetic aspects are discussed.
100 280 °C. 210 °C poH2/poB=3. .相似文献
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S. Galvagno C. Crisafulli R. Maggiore G. R. Tauszik A. Giannetto 《Journal of Thermal Analysis and Calorimetry》1985,30(3):611-618
Ru and Cu samples supported on SiO2, Al2O3 and MgO were studied by the temperature-programmed reduction (TPR) technique. Experiments were carried out both on unreduced impregnated salts and after oxidation of already reduced samples.The TPR profiles were found to be strongly dependent on the support used, indicating different degrees of interaction between the metal and the support, which can be ranked as MgOAl2O3>SiO2. It is suggested that the interaction occurs through the formation of surface complexes difficult to reduce. The decrease in hydrogen consumption observed on the Ru samples with the number of TPR cycles is attributed to the difficulty in oxidizing large Ru particles.
Zusammenfassung Auf SiO2, Al2O3 und MgO aufgebrachte Ru- und Cu-Proben wurden mittels temperaturprogrammierter Reduktion (TPR) untersucht. Experimente wurden sowohl an unreduzierten Salzimprägnierungen als auch nach Oxydation von bereits reduzierten Proben ausgeführt. Die TPR-Profile sind stark vom benutzten Trägen abhängig, was auf unterschiedliche Grade der Wechselwirkung zwischen Metall und Träger hindeutet; die Reihenfolge ist MgOAl2O3>SiO2. Es wird vermutet, daß das Wesen der Wechselwirkung in der Bildung von schwer reduzierbaren Oberflächenkomplexen zu suchen ist. Die bei Ru-Proben mit der Zahl der TPR-Zyklen beobachtete Verminderung des Wasserstoffverbrauchs wird mit der Schwierigkeit, große Ru-Partikel zu oxydieren, in Zusammenhang gebracht.
- () SiO2, l23 MgO. , , , . , , MgO Al2O3>SiO2. , , . , .相似文献
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Galvagno S. Crisafulli C. Maggiore R. Giannetto A. Schwank J. 《Journal of Thermal Analysis and Calorimetry》1987,32(2):471-483
Journal of Thermal Analysis and Calorimetry - Bimetallic Ru-Cu samples supported on SiO2, Al2O3 and MgO were studied by the temperature-programmed reduction (TPR) technique. Experiments were... 相似文献
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Catalytic activity of honeycomb catalysts, I. The benzene-cyclohexane (de)hydrogenation reaction 总被引:1,自引:0,他引:1
A. Parmaliana C. Crisafulli R. Maggiore J. C. J. Bart N. Giordano 《Reaction Kinetics and Catalysis Letters》1981,18(3-4):295-299
Monolithic supported platinum catalysts were investigated with respect to their hydrogenation and dehydrogenation activity towards benzene and cyclohexane, respectively, between 250° and 350°C. Conversion of benzene to cyclohexane is optimal for the volume ratio H2/Bz=5 at lower temperatures. In the cyclohexane dehydrogenation reaction, high temperatures, associated with lower N2/Cy ratios, are beneficial. No byproducts were observed in the two reactions.
, , 250 °C 350 °C. H2/=5. N2/ . .相似文献