59 research outputs found
Selective oxidation of glycerol catalyzed by iron complexes
No full textIron catalysts promote glycerol oxidatio
Selective oxidation of glycerol to formic acid catalyzed by iron salts
No full textGlycerol is oxidized by hydrogen peroxide to formic acid with excellent selectivity in the presence of iron salts. The oxidation takes place at room temperature inwater; at the end of the reaction the catalytic system is still active and available to restart the oxidation
Microwave-assisted green oxidation of alcohols with hydrogen peroxide catalyzed by iron complexes with nitrogen ligands
No full textOxidation of primary and secondary alcohols, including two diols and glycerol, with H2O2 was catalyzed
by the iron(II) complexes [FeL3](OTf)2 (L 1⁄4 2,20-bipyridine, 2,20-bipyrimidine, 1,10-phenanthroline and
substituted derivatives) and [FeL2](OTf)2 (L 1⁄4 bis(2-pyridinylmethyl)amine, 2,6-di(2-pyridyl)pyridine).
The reactions were performed in acetonitrile, water or mixed solvent (typically water/acetonitrile 4:1) in
a microwawe reactor at low power. Effect of addition of a cocatalyst, which in some cases improved the
yields of the catalytic reaction, was investigated by means of NMR and UVeVisible techniques
Iron complexes with nitrogen bidentate ligands as green catalysts foralcohol oxidation
No full textThe iron(II) complexes [Fe(N-N)3](OTf)2(N-N = 2,2- bipyridine, 1,10-phenanthroline and substitutedderivatives) were employed as catalyst precursors for the oxidation of primary and secondary alcohols,including glycerol. The single-crystal structure of [Fe(bipy)3](OTf)2was determined by X-ray crystallog-raphy.The catalytic reactions were performed using either H2O2or tert-butilhydroperoxide (TBHP) asoxidating agent, in mild experimental conditions: with all catalysts employed, secondary alcohols wereoxidized to the corresponding ketones with up to 100% yields, whereas other substrates gave lowerconversions. Indications on the nature of the catalytically active species, which is probably formed viadissociation of a nitrogen ligand from the iron center, were obtained from NMR and ESI–MS spectra
Mounier educatore: quel mistero chiamato persona
No full textThis article focuses on the philosophy of personalism and its educational applications, especially the author develops a pedagogical analysis on the Mounier’s personalist idea. According to Mounier, we must respect “the inviolable mystery of the person” because the person is the highest value
Mounier educatore: quel "mistero" chiamato persona
No full textThis article focuses on the philosophy of personalism and its educational applications, especially the author develops a pedagogical analysis on the Mounier’s personalist idea. According to Mounier, we must respect “the inviolable mystery of the person” because the person is the highest value
Towards picosecond array detector for single-photon time-resolved multispot parallel analysis
No full textOver the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPADs) for parallel detection of faint ultrafast optical signals. SPADs implemented in CMOS-compatible planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than photomultiplier tubes and they are able to provide very high acquisition speeds. The development of fully-parallel multichannel systems is a challenge both for the detector (with new problems like optical and electrical crosstalk, isolation elements size reduction and the need for higher yields) and for the electronics. The development of a parallel detector must be accompanied by that of the time-to-amplitude converters and analysis electronics necessary in time-correlated single photon counting applications. In this paper we present the fundamental building blocks necessary to develop a parallel picosecond array detector: a new high-performance SPAD detector, compatible with the design of multi-detector systems with a large number of channels, and a new totally integrated system for time-to-amplitude conversion, to allow the simple integration of several channels on a single chip
Alternative intermediates for glycerol valorization: iridium promoted formation of acetals and ketals
No full textThe organoiridium derivatives [Cp*IrCl2]2 (Cp* = pentamethylcyclopentadienyl) and [Cp*Ir(Bu2-NHC)Cl2] (Bu2-NHC = 1,3-di-n-butylimidazolylidene) catalyze glycerol acetalization with several ketones and aldehydes, as well as transacetalization
Design and Use of a High‐Pressure Stirred IR Cell for Operando Studies in Homogeneous Catalysis
No full textThe design and operation of a new kind of high pressure/high temperature stirred IR cell is described. The cell is a stand-alone autoclave made of Hastelloy and effective stirring and gas diffusion are provided by a magnetically driven Teflon shaft. The length of the optical path can be regulated without the need of calibrated spacers and the problem of the sealing of the windows to the cell body has been solved by employing FEP (fluorinated ethylene propylene) encapsulated Viton O-rings, which, upon adapting to the cell when warmed, provide an excellent seal that is also tolerant of all standard solvents. The use of this kind of O-rings allows taking advantage of the chemical resistance of Teflon without needing to mechanically stress the fragile windows as it would be required if bulk Teflon O-rings were employed
La ferita di Medusa. Riflessione pedagogica sulla vulnerabilità umana e sociale
No full textIl presente volume nasce da una ricerca condotta nel settore della vulnerabilità umana e sociale, con particolare attenzione alla riflessione pedagogica e ai processi educativi volti alla promozione della persona. La società odierna manifesta un crescente senso d’insicurezza e profonda incertezza nei confronti del futuro, l’uomo agisce senza il sostegno di legami sociali e familiari certi e vede manifestarsi nuove forme di povertà (non solo materiali ma spesso culturali e relazionali); anche il crescere del precariato lavorativo e le aumentate forme d’indebitamento agiscono nel senso di rafforzare il senso di disorientamento. La riflessione sulla vulnerabilità vuole mostrare tuttavia quanto la vulnerabilità sia in realtà una componente costitutiva della persona, articolando la ricerca lungo tre dimensioni: il corporeo, la relazionalità e la vita morale. La volontà è quella di rileggere il concetto stesso di vulnerabilità per comprendere se nell’antropologia della persona vulnerabile possa esserci già il seme di un rinnovato impegno di solidarietà, di giustizia, di responsabilità, di comunità. Si promuove, a tal proposito, un ritorno alla persona attraverso la proposta di riflessione su di un tema molto attuale, cercando di uscire dal rischio di stabilire nuove categorie d’individui da segnalare ad un servizio sociale specifico, ma indicando possibili percorsi formativi ed educativi in grado di osservare la vulnerabilità come una dimensione umana e sociale che chiede nuove strategie politico-culturali.The aim of the study is to define vulnerability from a pedagogical point of view. First of all, the author affirms that vulnerability can be understood as an anthropological description of the human condition and promotes a return to the meaning of person by proposing to reflect on the vulnerable person faced with an increasing sense of insecurity in today’s society. In fact, this approach suggests the need to develop arguments to support some essential attributes of humanity like vulnerability (see Barcellona’s Declaration) and to discover in them the seed of a renewed commitment to solidarity and responsibility. Therefore the study deals with several aspects of vulnerability: the nature of corporeal vulnerability as a non-eliminable aspect of existence, the ethical dimension of vulnerability and the concept of social vulnerability. In this regard, the author underlines that vulnerability is improperly used to designate particular individuals and populations deprived of their capabilities, because it is a feature of all humanity. Furthermore it explores educational strategies that focus on vulnerability as essential human condition and promote the development of socio-political skills needed for human rights observance
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