A. M. Garrido Pedrosa

Synthesis, structure, and morphology of bifunctional catalysts based on zirconia modified by molybdenum oxide

The preparation of Pt/MoOx-ZrO2 materials has been carried out by polymeric precursor method and with molybdenum loadings in the range 10–20 wt %. The synthesized samples were calcined at 600, 700, and 800°C. The structure and texture of the calcined Pt/MoOx-ZrO2 materials were characterized by x-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, and N2 adsorption measurements. XRD of the calcined samples revealed the formation of crystalline ZrO2, Pt metal, and Zr(MoO4)2. Crystalline Zr(MoO4)2 was also detected by FTIR spectra. A decrease in the specific surface area was observed by nitrogen adsorption experiments when the temperatures of calcination and molybdenum loading increased.

LANTHANIDE TRIFLUOROACETATE COMPLEXES WITH 2-AZACYCLONONANONE Thermal and kinetic studies

Ln(TFA)3⋅3AZA (Ln=La, Sm, Er; TFA=trifluoroacetate and AZA=2-azacyclononanone)compounds were synthesized and characterized by microanalytical procedures, IR spectroscopy, X-ray powder diffraction, and thermal analysis. A kinetic study using La, Sm and Er thermogravimetric curves was carried out aiming to proposing a mechanism for the thermal decomposition of such complexes.

Bis(pentamethylene)urea complexes of the lanthanide nitrates: synthesis, characterization, properties

Lanthanide nitrate complexes of bis(pentamethylene)urea (BPMU) with general formula Ln(NO 3 ) 3 3BPMU, where Ln: La, Nd, Sm, Eu, Ho and Er have been prepared and characterized based on CHN elemental analyses, lanthanide titration with EDTA, molar conductivity, spectroscopic data and thermal studies. The infrared spectra show that ligands (BPMU) are bonded through the carbonyl oxygen, nitrate counter-ions are bidentate linked to the central ions. The structure of the neodymium complex was determined. The crystal is monoclinic, P2 1/c , Z = 4, with the following parameters: a = 10.148(1) A, b = 21.879(2), c = 19.154(2) A, β = 104.11(1)°, V = 4124.3(7) A 3 . The polyhedron is a distorted tricapped trigonal prism, coordination number nine.

Rare earth complexes with 4-methylmorpholine-N-oxide

Complexes of rare earth trifluoroacetates (TFA) with 4-methylmorpholine-N-oxide (MMNO) of composition Ln(TFA)3·3MMNO (Ln=Eu, Dy, Ho, Er, Yb and Y) were synthesized and characterized by elemental analysis data, complexometric titration with EDTA, IR absorption spectra, thermogravimetric analyses and differential scanning calorimetry (DSC) in N2 atmosphere. Infrared spectroscopy data revealed that the MMNO molecules are bound to the central ion through the oxygen of NO groups. These data suggest that the trifluoracetate groups are also coordinated. Thermogravimetric curves indicate that the decomposition of MMNO begins at approximately 350 K and results in Ln2O3 residue at around 1170 K. A theoretical kinetic study was carried out using a QBASIC program with the TG input data for the Dy complex.