Fátima Mirante

Cloud point prediction of fuels and fuel blends

The cloud point temperature, the temperature at which the first wax crystals appear in solution, is one of the most important specifications associated with the low temperature behaviour of a fuel. A database of about 80 fuels and fuel blends was collected and used to assess the performance of the three predictive local composition models (Wilson, NRTL and UNIQUAC) for cloud point prediction. The results indicates that Predictive UNIQUAC can predict the cloud points of the fuels within the experimental uncertainty of the measurements. It could thus be a useful tool in the production of fuels both in the design of refining process and the blend of fuels to meet the low temperature specifications.

Influence of a porous MOF support on the catalytic performance of Eu-polyoxometalate based materials: desulfurization of a model diesel

An aluminum 2-aminoterephthalate based metal–organic framework (MOF) material was applied for the first time to prepare highly efficient heterogeneous catalysts in desulfurization processes. Sandwich-type [Eu(PW11O39)2]11− polyoxometalate (POM) was supported on Al(III) and Cr(III) MIL-type MOFs, NH2-MIL-53(Al) and MIL-101(Cr), and extensive characterization confirmed the incorporation of the POM on the two supports. The catalytic performance of the two composite materials, POM/MIL(Al) and POM/MIL(Cr), was evaluated in the oxidative desulfurization (ODS) of a model fuel containing some of the most common refractory sulfur compounds in diesel. Both composite materials have shown to be active and robust heterogeneous catalysts for the efficient removal of the sulfur-containing compounds from the model diesel, and the influence of the solid support on the catalytic performance of the active species was further assessed. The POM/MIL(Al) revealed notable catalytic performance, since complete desulfurization was obtained after 2 h of reaction. Furthermore, this remarkable heterogeneous catalyst revealed to be stable and recyclable for various catalytic cycles.

Structural characterisation and DFT studies of (Cr(cyclam)(O-dmso)Cl) 2 : a new precursor complex towards potential DNA intercalators

The synthesis and structural characterisation of the complex [Cr([14]aneN4)(O -dmso)Cl](PF6)2/dmso is reported. The structural studies were carried out in gas-phase by electrospray mass spectrometry (ESMS) and in the solid state by single crystal X-ray diffraction. The metal complex shows a distorted octahedral coordination environment with the macrocycle adopting a folded cis -V conformation. The angle Naxial � /Cr� /Naxial deviates by only 128 from the ideal value of 1808 for a perfect octahedron indicating that there is a good match between the size of the macrocyclic cavity and the size of Cr(III) ion. The ESMS shows that the complex loses a proton with concomitant opening of the [14]aneN4 ring to give the [Cr([14]aneN4-H)(dmso)Cl] � ion with a CH2� /CH� / pendant chain. This group interacts with dmso leading to the loss of this ligand and to the formation of the [Cr([14]aneN4-H)Cl] � ion, which has the highest relative abundance (100%). DFT calculations reproduce the geometry of the paramagnetic complex and are consistent with its electronic spectrum. # 2003 Elsevier Science B.V. All rights reserved.