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Cataldo F.,Actinium Chemical Research | Cataldo F.,University of Tuscia | Iglesias-Groth S.,University of La Laguna
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2014

The DSC (Differential Scanning Calorimetry) analysis of heavy ozonized C60 fullerene (known also as "fullerene ozopolymer"), shows the exothermal decomposition of this compound with a peak at 158°C with a decomposition enthalpy ΔHdec ≈-322 kJ/mol and an activation energy for the decomposition E# = 71 kJ/mol. These experimental facts confirm the secondary ozonide/peroxidic and polymeric nature of fullerene ozopolymer originally suggested by the infrared spectroscopy analysis and solid state 13C-NMR spectroscopy. It is also shown that the secondary ozonide group of fullerene ozopolymer can be reduced selectively by a treatment with hydrogen iodide. © 2014 Taylor & Francis Group, LLC.

Iglesias-Groth S.,Institute of Astrophysics of Canarias | Cataldo F.,Instituto Nazionale Of Astrofisica | Cataldo F.,Actinium Chemical Research | Manchado A.,Institute of Astrophysics of Canarias | Manchado A.,University of La Laguna
Monthly Notices of the Royal Astronomical Society | Year: 2011

The detection of C 60 and C 70 fullerenes in young planetary nebulae and in reflection nebulae suggests that these molecules are more common in certain astrophysical environments than previously thought. The dependence on temperature of the positions and widths of the infrared bands of the C 60 and C 70 fullerenes is needed for a firm qualitative detection of these molecules in space. Furthermore, the integrated molar absorptivity Ψ (in km mol -1) of each infrared absorption band is required for a quantitative determination of the abundance of C 60 and C 70 in space. In this paper, we report on the temperature dependence of the wavelength shift and integrated molar absorptivity of the infrared bands of the C 60 and C 70 fullerenes. The measurements have been made in a KBr matrix in the temperature range between -180°C and +250°C. The experimental data have been extrapolated to derive both the infrared band shift and the integrated molar absorptivity of the C 60 and C 70 fullerenes at absolute zero temperature. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Cataldo F.,Actinium Chemical Research | Cataldo F.,University of Tuscia
Ozone: Science and Engineering | Year: 2015

Highly pure ethyl oleate and ethyl elaidate were ozonized to their secondary ozonides (respectively EO-SOZ and EE-SOZ). The decomposition enthalpies of EO-SOZ and EE-SOZ were determined by DSC (Differential Scanning Calorimetry) and found, respectively, at --266 kJ/mol and --264 kJ/mol, a value much closer to the theoretically calculated upper limit of --278 kJ/mol than the decomposition enthalpy of --243 kJ/mol measured on EO-SOZ prepared from an ethyl oleate sample conforming to the European Pharmacopoeia. Although a considerable amount of heat was liberated, EO-SOZ and EE-SOZ cannot be defined as explosive based on their DSC traces at a heating rate of 10 °C/min. Pure EO-SOZ and EE-SOZ show a decomposition peak at the DSCs of 137 °C and 139 °C, respectively. The thermal decomposition of EO-SOZ and EE-SOZ was studied also by FT-IR spectroscopy showing that the decomposition involves the loss of the ozonide infrared band at 1110 cm−1 and the formation of the expected decomposition products (pelargonic acid, pelargonaldehyde, ethyl azelate, etc.). The kinetics of the photochemical decomposition of EO-SOZ and EE-SOZ were studied by FT-IR spectroscopy, and the relative rate constants were determined. EO-SOZ when overozonized forms a spin adduct with nitrosobenzene and the relative nitroxyl radical was clearly detected by the Electron Spin Resonance (ESR). Secondary ozonation products known as trioxides may be responsible for these adducts. Copyright © 2015 International Ozone Association.

Cataldo F.,Actinium Chemical Research | Cataldo F.,University of Tuscia
Tetrahedron Letters | Year: 2015

The synthesis of a series of 1-alkene secondary ozonides was monitored with Raman spectroscopy which is very effective in the detection of the O-O stretching band of the 1,2,4-trioxolane ring. The 1-alkene secondary ozonides thermal decomposition was studied with DSC (differential scanning calorimetry). For all ozonides studied the decomposition onset was found at about 106 °C and the decomposition peak at about 130 °C. The decomposition enthalpy ΔHdec of the secondary ozonides examined was found in the range of -313 to -347 kJ/mol. Despite the considerable amount of heat evolved, the decomposition was not explosive. The decomposition products of 1-octadecene ozonide were studied by TGA-FTIR (thermogravimetric analysis coupled with FT-infrared spectroscopy) and by GC-MS. The main products detected were formic acid and heptadecanal. © 2015 Elsevier Ltd. All rights reserved.

Cataldo F.,Actinium Chemical Research
Chemistry and Physics of Lipids | Year: 2010

Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C60 was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C 60 which is converted to an epoxide C60O. Thus, fullerene C60 displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C60 in ethyl oleate has been compared with that of the known antioxidantTMPPD(N,N',N,N,'-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C60 in lipids has been proposed. The kinetics of C60 oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C60 photo-oxidation in lipids have been identified. © 2010 Elsevier Ireland Ltd. All rights reserved.

Putz M.V.,West University of Timișoara | Ori O.,West University of Timișoara | Ori O.,Actinium Chemical Research
Molecules | Year: 2014

This work advances the modeling of bondonic effects on graphenic and honeycomb structures, with an original two-fold generalization: (i) by employing the fourth order path integral bondonic formalism in considering the high order derivatives of the Wiener topological potential of those 1D systems; and (ii) by modeling a class of honeycomb defective structures starting from graphene, the carbon-based reference case, and then generalizing the treatment to Si (silicene), Ge (germanene), Sn (stannene) by using the fermionic two-degenerate statistical states function in terms of electronegativity. The honeycomb nanostructures present ?-sized Stone-Wales topological defects, the isomeric dislocation dipoles originally called by authors Stone-Wales wave or SWw. For these defective nanoribbons the bondonic formalism foresees a specific phase-transition whose critical behavior shows typical bondonic fast critical time and bonding energies. The quantum transition of the ideal-to-defect structural transformations is fully described by computing the caloric capacities for nanostructures triggered by ?-sized topological isomerisations. Present model may be easily applied to hetero-combinations of Group-IV elements like C-Si, C-Ge, C-Sn, Si-Ge, Si-Sn, Ge-Sn. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Putz M.V.,West University of Timișoara | Ori O.,Actinium Chemical Research | Cataldo F.,Actinium Chemical Research | Putz A.-M.,West University of Timișoara | Putz A.-M.,Romanian Academy of Sciences
Current Organic Chemistry | Year: 2013

The ability to derive colored representations of widely employed distance-based topological indices from chemical reactivity electronegativity and chemical hardness has been developed in the novel theoretical tool presented in this work to provide novel, meaningful topo-reactive or structure-reactivity indices with application to polycyclic aromatic hydrocarbons (PAHs). The model, which combines topological and ab initio molecular structural information, relies on the so-called Timisoara-Parma rule for assigning the axial distribution of electronegativity and chemical hardness to a given molecular structure based on a compact finite-difference (CFD) hierarchy, which involves ordering nine forms of electronegativity and chemical hardness derivative-based definitions within conceptual density functional theory (DFT). The results are in good agreement with theoretical and experimental properties improving the predictive power of standard topological indices. The proposed method is suitable for molecular structures with delocalized electrons. © 2013 Bentham Science Publishers.

Cataldo F.,Actinium Chemical Research
Chemistry and Physics of Lipids | Year: 2013

Neat ethyl oleate was ozonized in a bubble reactor and the progress of the ozonolysis was followed by infrared (FT-IR) spectroscopy and by the differential scanning calorimetry (DSC). The ozonolysis was conducted till a molar ratio O3/CC ≈ 1 when the exothermal reaction spontaneously went to completion. A specific thermochemical calculation on ethyl oleate ozonation has been made to determine the theoretical heat of the ozonization reaction using the group increment approach. A linear relationship was found both in the integrated absorptivity of the ozonide infrared band at 1110 cm-1 and the ozonolysis time as well as the thermal decomposition enthalpy of the ozonides and peroxides formed as a result of the ozonation. The DSC decomposition temperature of ozonated ethyl oleate occurs with an exothermal peak at about 150-155 C with a decomposition enthalpy of 243.0 kJ/mol at molar ratio O3/CC ≈ 1. It is shown that the decomposition enthalpy of ozonized ethyl oleate is a constant value (≈243 kJ/mol) at any stage of the O3/CC once an adequate normalization of the decomposition enthalpy for the amount of the adsorbed ozone is taken into consideration. The decomposition enthalpy of ozonized ethyl oleate was also calculated using a simplified thermochemical model, obtaining a result in reasonable agreement with the experimental value. © 2013 Elsevier Ireland Ltd. All rights reserved.

Putz M.V.,West University of Timișoara | Ori O.,Actinium Chemical Research
Chemical Physics Letters | Year: 2012

Recently introduced bosonic quasi-particle 'bondon' is shown in this Letter to account for the emergence of long-range interaction in one-dimensional graphenic nanoribbons opening the door to possible phase-transitions effect. Current simulations also benefit from adopting pure topological potential (used as potential energy in the statistical treatment) that greatly simplify, as usual, the computational tasks without sacrificing the physical information stored in the connectivity of the chemical structures. © 2012 Elsevier B.V. All rights reserved.

Process for the treatment of landfill leachate wastewater having a high COD, said process comprising: taking aliquots of the wastewater from the landfill and mixing them with active charcoal at room temperature, filtering the mixture to obtain an eluate, carrying out a photo-ozonolysis treatment consisting in the simultaneous irradiation with UV-light and saturation with ozone of said eluate.

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