216 research outputs found
New TiO2 based photocatalysts for the degradation of organic pollutants in water
No full textIn the last years a new category of TiO2 based composites prepared by impregnation of bare polycrystalline TiO2 powders with different sensitizers (i.e. phthalocyanines, porphyrins) permitted the improvement of the photocatalytic degradation of 4-nitrophenol (4-NP) under UV1-3 as well as under visible light irradiation.4 On the other hand growing interest devoted to the photodegradation of organic pollutants in water solutions by means of economically advantageous and environmental friendly processes are regarding this topic.
Continuing our research in this area, we report here our recent results concerning: i) the preparation of new TiO2 and TiO2 based photocatalysts containing Fe and Cu species; ii) improvement of the photodegradation processes and conditions.
1. Mele, G.; Del Sole, R.; Vasapollo, G.; García-López, E.; Palmisano, L.; Schiavello, M. J. Catal. 2003, 217, 334. 2. Mele, G. ; Del Sole, R.; Vasapollo, G.; Marcì, G.; Garcìa-Lòpez, E.; Palmisano, L.; Coronado, J. M.; Hernández-Alonso, M. D.; Malitesta, C.; Guascito, R. J. Phys Chem. B 2005, 109, 12347. 3. Mele, G.; García-López, E.; Palmisano, L.; Dyrda, G.; Słota, R. J. Phys. Chem. C, 2007, 111, 6581. 4. Wang, C.; Li, J.; Mele, G.; Yang, G. M.; Zhang, F. X.; Palmisano, L.; Vasapollo, G. Appl. Catal. B: Environ. 2007, 76, 218
Nitrogen-oxygen bond length/stretching frequency relationships in C-nitroso compounds and their coordination complexes
No full textThe mode of coordination of monomeric C-nitroso compds. to metals is discussed. In contrast to previous studies it is proposed that an understanding of the ν(N-O)/r(N-O) and r(C-N)/r(N-O) relationships in the noncoordinated nitroso compds. is of primary importance for assessment of the coordination mode. Both ν(N-O)/r(N-O) and r(C-N)/r(N-O) have linear interrelationships in C-nitroso compds. and the coordination compds. of RNO have the same ν(N-O)/r(N-O) relationship as the noncoordinated monomers. Previous correlations of Δν(N-O) with coordination mode are therefore correlations of r(N-O) with coordination mode. σ-N and σ-O complexes of arom. RNO conform to the same r(C-N)/r(N-O) equation (within a very small error) as the noncoordinated monomers. The extent of deviation from the r(C-N)/r(N-O) relationship for complexes of aliph. RNO is of a similar order of magnitude to that which occurs when C-nitroso monomers form the trans dimer. The coordination mode of aliph. RNO is, with one exception, σ-N. Nitrosobenzene has a variety of coordination modes to transition metals but does not display σ-O coordination. p-Nitrosodimethylaniline undergoes σ-O coordination to d10 metals
Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)
No full textCarbamoyl and alkoxycarbonyl complexes of Pd(II) and Pt(II) of the type (pnp)M(CONHR)Cl [pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M = Pd, R = Ph, p-tolyl, p-MeOC6H4, cyclohexyl, Me3C; M = Pt, R = Ph], (pnp)Pd(CONPr2)Cl, (pnp)M(CO2R)Cl (M = Pd, R = Ph, Me; M = Pt, R = Me) and (pnp)Pd(CO2Me)2 result from reaction of (pnp)MCl2 with CO and amines or alkoxides at room temp. and atm. pressure. The carbamoyl complexes react with bases to give urethane or (PhNH)2CO, depending upon the exptl. conditions
Catalytic reduction of the arene ring, and other functionalities, of organic substrates using formic acid and palladium on carbon
No full textThe arene ring in a variety of compds. with functionalities which contain nitrogen is reduced in good yields using formic acid and Pd/C in methanol. Treatment of nitrobenzene with formic acid and Pd/carbon in methanol gave cyclohexylamine (53% yield) and as byproducts N-phenylcyclohexylamine (34% yield) and dicyclohexylamine (12% yield). The conditions were also applicable to azidobenzene, nitrosobenzene, aniline and azobenzene, or azobenzene oxide
Anthocyanins from bay (Laurus nobilis) L. berries
No full textAnthocyanin composition in the berries of Laurus nobilis L., a perennial tree or shrub typical of the
Mediterranean region, was determined for the first time. The pigments were extracted from the berries
with 0.1% HCl in methanol, purified on a C-18 solid-phase cartridge, and characterized by means of
high-performance liquid chromatography (HPLC)-diode array detection (DAD)-mass spectrometry
(MS) analysis. The major anthocyanins were characterized as cyanidin 3-O-glucoside (41%) and
cyanidin 3-O-rutinoside (53%). Furthermore, two minor anthocyanins were detected and identified
as 3-O-glucoside and 3-O-rutinoside derivatives of peonidin (5%). The two major pigments were
also isolated by preparative HPLC and characterized by H1 nuclear magnetic resonance (NMR)
spectroscopy. The attractive color and the great abundance of the plant in the south of Italy make
Laurus nobilis berries a new and very good source of natural pigments
Crisio of capitalism
No full textThere are some fundamental questions that must be answered if we want to fully understand capitalism, in the various forms that it has been taking in the present phase of its planet-wide expansion: How is the work process organized? How do markets work? What determines the share that goes to profits and the share that goes to wages? What is the role of technology? Why some workers earn more than others? What is a crisis, and when does it takes a structural rather than conjunctural character? What is the connection between the financial crisis and the general economic crisis, and when and how does this last take the character of a systemic crisis? Is it possible to overcome a structural crisis by means of Keynesian policies? What does the passage from the Keynesism of the social state to private, entrepreneurial and military Keynesism means?
The answers to the above questions largely depend upon the type of theory we use to interpret economic reality. We have chosen the standpoint of Marx’s critique of political economy. Marxian theory, and then Marxism, does not have the typical characteristics of the so-called “bourgeois sciences”. Marxism interprets the laws of the natural, social and economic sciences as aspects of concrete reality, almost always quite independent from the will of single individuals. Historical facts depend on sets of interconnections, the power relationships between classes and the modalities of the capital – labour conflict in each given historical period.
The profound transformation that the planet has undergone with the so-called globalization of the economic and social processes which characterizes the present imperialist phase of global competition has shown with clarity the limits of many theoretical paradigms. Every economic theory is the outcome of the period in which it was created, and theories that are lucky enough to be dominant are constantly struggling with new approaches.
The scope and aim of this book (which is a compendium of “Trattato di Economia Applicata”, Jaca Book, 2007, by the same author) is delimited in time and space. It is not a work in “pure economics”, but rather a guide to the understanding of the present phase of planet-wise expansion of the social production and reproduction of the capitalist form, and to its structural and systemic crisis. We refer to the theory of the capitalist mode of production as a process. In this sense this is a work of applied economics, although not in the reductive academic meaning of applying economics to, say, the environment, engineering, sociology and so on. To produce an applied economics in our sense we need Marx’s toolkit. Following Marx’s own procedure, we must first appropriate the tools of political economy, in order to then criticize them; this leads us to produce, with a scientific approach, a complex theory that is capable to go beyond political economy and, as a consequence, beyond the capitalist mode of production itself
Extraction and identification of Anthocyanins from Smilax aspera L. Berries
No full textAnthocyanins, present in the berries of Smilax aspera L., a creeping shrub typical of the Mediterranean region, were extracted
and identified for the first time. The pigments were extracted from the skin of the berries with of 0.1% HCl in methanol solution,
purified on a C-18 solid-phase cartridge and characterized by means of HPLC-DAD-MS analysis. From spectral analysis before and
after acid and alkaline hydrolysis, it was noted that pelargonidin 3-O-rutinoside represented about 83% of the total anthocyanin
content in the skin of Smilax aspera berries. A low quantity of cyanidin 3-O-rutinoside (13%) was also found. The attractive colour
and the great abundance of the plant in the south of Italy make Smilax aspera berries a new and very good source of natural
pigments
Determination of Anthocyanins in Ruscus aculeatus L. berries
No full textRed berries of R. aculeatus, a wild shrub typical of Mediterranean Europe and Africa, were investigated for the 1st time to det. the profile of anthocyanins. The pigments were extd. from the skins of the berries with 0.1% HCl in methanol, purified using a C-18 solid phase cartridge, and identified by means of high-performance liq. chromatog. (HPLC)-diode array detection-mass spectrometry anal. Information from HPLC profiles, sapon., and acid hydrolysis of the anthocyanins showed that the major anthocyanins were pelargonidin 3-O-rutinoside (64%), pelargonidin 3-O-glucoside (16%), and pelargonidin 3-O-trans-p-coumarylglucoside (13%). The attractive color of R. aculeatus berries and the great abundance of the plant in the south of Italy make these berries a new and promising source of natural colorants
New alkoxycarbonyl complexes of palladium(II) and their role in carbonylation reactions carried out in the presenceof an alkanol
No full textThe new complexes of general formula trans-Pd(COOR)ClL2 (L = PPh3, R = Et, n-Pr, iso-Pr, n-Bu, iso-Bu, sec-Bu, 2-
ethoxyethyl, cyclopentyl, cyclohexyl; L = Ph2PCH2CH2PPh2, R = Et) are prepd. by reacting trans-PdCl2L2, suspended
in an alkanol under 10-50 atm CO at 50-70°, in the presence of a base such as a trialkylamine or a carboxylic acid anion.
They were characterized by IR, 1H and 31P NMR spectroscopy. The complexes with R = Me and Et show 2 absorption
bands centered at ca. 1650 cm-1, which are probably due to conformational isomers with cis and trans geometry. The
others show only 1 band at ca. 1650 cm-1. The 1H NMR and 31P NMR spectra of all the monophosphine complexes
show that only 1 isomer is present in soln. Instead, for the diphosphine ethoxycarbonyl complex the 1H NMR spectra
suggest that 2 isomers are present in ca. 1:1 ratio, as confirmed by decoupling expts. The 2 isomers may originate from
different orientation of the alkoxycarbonyl ligand with respect to the asym. metal center, because of hindered rotation
around the Pd-C bond due to the partial double bond character. The R group of the alkoxycarbonyl ligand can be
exchanged with a different R' group by reacting the Pd(COOR)Cl(PPh3)2 complex with an excess of R'OH. The reaction
is practically quant. when R is bulkier than R'. The alkoxycarbonyl complexes react with the corresponding alkanol, in
the presence of a base such as a trialkylamine at 90-100° under CO, yielding Pd(0) carbonyl-phosphine complexes with
formation of (MeO)2CO almost quant. They also react with water, giving off CO2 and yielding Pd(0) complexes. The
reaction is promoted by an acid of a non-coordinating anion such as HBF4. Instead, the reaction with HCl yields the
corresponding dichloride of Pd(II), beside CO and the corresponding alkanol. The role of these complexes in catalytic
alkoxycarbonylation reactions is discussed
Palladium-Catalyzed Asymmetric Cyclocarbonylation of Allyl Napthols
No full textThe asym. cyclocarbonylation reaction of allylnaphthol catalyzed by palladium complexes and chiral phosphine is reported. The reaction was performed under syn-gas conditions at relatively mild exptl. conditions (80-100 °C, 300-600 psi (1 psi = 6.895 kPa)) in CH2Cl2 as the solvent
- …
