Search results for "oxidation"
showing 10 items of 1913 documents
Does catalase play a role in Adriamycin induced cardiotoxicity?
1980
Summary Adriamycin causes an increase of lipid peroxidation in mouse cardiac homogenates that is dependent on the concentration of the antiblastic. The same phenomenon is not observed in the hearts of mice treated with an elevated dose of Adriamycin in which, conversely, an increase of the antioxidizing enzyme catalase was noticed. The significance of these findings is discussed with relationship to the hypothesis of an enhanced free radicals formation at the basis of Adriamycin induced cardiotoxicity.
Photoelectrocatalytic selective oxidation of 4-methoxybenzyl alcohol in water by TiO2 supported on titanium anodes
2013
The photoelectrocatalytic partial oxidation of 4-methoxybenzyl alcohol in aqueous solution irradiated by near-UV light was carried out in a three-electrode batch reactor. TiO2 films were either deposited by dip-coating of a TiO2 sol onto a Ti foil and subsequent calcination or generated on Ti plates by thermal oxidation in air at 400-700 degrees C. The effects of the anode preparation method and bias potential values on conversion and selectivity to the corresponding aldehyde were investigated. The photoelectrocatalytic results were compared with the photocatalytic and electrocatalytic ones. The results indicated that no reaction occurred during the electrocatalytic experiments, whereas the…
Modification of Polymers in Supercritical Carbon Dioxide
2003
The interaction of scFluids and polymers are governed by the intermolecular forces between solvent-solvent, solvent-polymer segment, and polymer segment-segment pairs. Because of its symmetry, within reasonable pressure values, CO2 does not have a dipole moment, but it does have a quadrupole moment significant over a much shorter distance than dipolar interactions. The quadrupole moment and the Lewis acidity of CO2 imparts to the carbon dioxide the peculiarity to be a solvent for selected classes of polymers like perfluorinated polyacrylates, polysiloxanes and polyether-polycarbonate diblock copolymers [1–3].
Quercetin as natural stabilizing agent for bio-polymer
2014
The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. Th…
ChemInform Abstract: Oppenauer Oxidation of Secondary Alcohols with 1,1,1-Trifluoroacetone as Hydride Acceptor.
2008
1,1,1-Trifluoroacetone (2a) reacts as a hydride-acceptor in the Oppenauer oxidation of secondary alcohols (1) in the presence of diethylethoxyaluminum. The oxidant allows for selective oxidation of secondary alcohols in the presence of primary alcohols.
Zur C-17-Oxidation von Clavinalkaloiden mit primärer alkoholischer Hydroxylgruppe
1975
Die Oppenauer-Oxidation von 1 mit Cyclohexanon fuhrt zu dem Aldolkondensationsprodukt 4 und der Carbonsaure 3. Analog konnte Lysergsaure (8) in geringer Menge aus 6 gewonnen und im Reaktionsgemisch von 7 nachgewiesen werden. Damit wurden erstmals Clavinalkaloide mit primarer alkoholischer Hydroxylgruppe chemisch zu den entsprechenden Carbonsauren oxidiert. C-17-Oxidation of Clavine Alkaloids with a Primary Alcoholic Hydroxyl Group. 1 is converted by Oppenauer oxidation with cyclohexanone to the aldol condensation product 4 and to the carboxylic acid 3. Lysergic acid (8) was obtained in a small yield by the analogous reaction of 6 and was found in the reaction mixture of 7. Thus clavine alka…
Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home-prepared titanium dioxide
2008
Abstract Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterization of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA convers…
Influence of preparation conditions of nano-crystalline ceria catalysts on the total oxidation of naphthalene, a model polycyclic aromatic hydrocarbon
2007
Abstract Nano-crystalline ceria catalysts prepared by homogeneous precipitation with urea were tested for the total oxidation of naphthalene, a model polycyclic aromatic hydrocarbon (PAH). Systematic variation of preparation conditions, including calcination temperature, calcination time and aging time, resulted in differences in surface area, reducibility, morphology and crystallite size of the CeO 2 catalyst and hence differences in catalytic performance. A combination of high surface area, small crystallite size and high oxygen defect concentration was found to favor the efficiency of the ceria catalysts for the total oxidation of naphthalene. Optimum preparation conditions for this stud…
SiO2-supported vanadium magnesium mixed oxides as selective catalysts for the oxydehydrogenation of short chain alkanes
2001
Abstract Unsupported and SiO 2 -supported VMgO mixed oxides catalysts have been prepared, characterized and tested in the oxidation of propane, n -butane and propylene. Mg-vanadates are observed by XRD, IR and Raman spectroscopy in both pure and supported VMgO catalysts, although the effective Mg/V ratio, in the VMgO phases formed, depends on the silica content. Since SiO 2 reacts partially with MgO during the calcination step, forming Mg 2 SiO 4 , the effective Mg/V ratio depends on the silica content. In this sense, pyro -Mg 2 V 2 O 7 is mainly formed on supported catalysts with Mg/V atomic ratios lower than 4, while ortho -Mg 3 V 2 O 8 is observed on supported catalysts with Mg/V atomic …
An Electronic Perspective On The Electrochemical Changeover In Prussian Blue-Like Materials
2009
Derivative voltabsometric scans together with previous electrogravimetric results allow to distinguish between the different electrochemical processes due to Fe-sites located into the Prussian Blue crystalline framework and other located next to ferrocyanide vacancies. The potassium, proton and hydrated proton counterions involved in these reactions are correlated to changes in near-UV/VIS/near-IR spectra. Potassium counter-ions show two different sites for insertion: one located into the crystalline framework and the other into ferrocyanide vacancies. From the monitoring of electroactive Fe-sites, it is possible to assume that the reduction of all Fe-sites located next to ferrocyanide vaca…