F. M. M. Borges

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.

Dehydration and decomposition kinetics of complexes of some rare earth (La, Nd, Dy and Eu) picrates and 2,2'-dithiobis (pyridine-N-oxide)

The dehydration and decomposition behavior of some rare earth complexes is analyzed under a kinetic point of view. The experimental data were obtained thermogravimetrically and the kinetic parameters are calculated by a non-linear method. The results are similar for La, Nd and Dy but different in the case of Eu. The relative mass loss and its first derivative curves as a function of temperature are compared in order to evaluate the quality of the parameters obtained.

Kinetic Study of Thermal Decomposition of the DMIT Complex of Cobalt

In this work, a cobalt complex with dmit (1,3-dithiol-2-thione-4,5-dithiolate) as ligand was prepared and its thermal stability was studied by thermogravimetric analysis and kinetics by means of the Zsakó method and a non-linear method. For both methods, numerical binomial and polynomial filters were used, where points in the central interval were utilized.

Estudo Cinético por TG e DSC da Decomposição Térmica de Alguns Adutos de Haletos de Cádmio

By DSC data, the kinetical parameters Ea , n and A were calculated for the thermal decomposition of the adducts CdCl2.2dmf, CdCl2.dmf and CdBr2.dmf (dmf= dimethylformamide) by using Rogers and Smith method. The found values were : Ea = 85, 176 and 101 kJ mol-1 , n= 0.23, 0.25, and 0.17, A= 2.40x109, 1.89x1019 and 1.07x109 respectively. By TGA data, the kinetical patameters for the thermal decomposition of the adduct CdCl2.1,5 dmeu (dmeu=dimethylethyleneurea) were calculated by using five different methods.

Kinetic study of the thermal decomposition of the compound of terbium(III) trifluoromethanesulfonate and hexamethylphosphoramide (HMPA) employing both Zsakó’s and nonlinear methods

Abstract Terbium trifluoromethanesulfonate compound with hexamethylphosphoramide was synthesized and characterized. Thermogravimetric data with three heating rates were used to obtain kinetic parameters such as activation energy (Ea), reaction order (n) and preexponential factor (k0). The results obtained by two different methods, Zsako’s and a nonlinear one, are compared.

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.

Parâmetros cinéticos da degradação térmica de complexos entre percloratos de terras raras com lactama

Complexes of rare earth perchlorates with 2-azacyclononanone (AZA) were synthesized (molar ratio 1:8) by reaction of hydrated perchlorates in ethanol and triethlylorthoformate by a vapor diffusion method and they were characterized by complexometric analyses with EDTA, CHN microanalytical procedures, IR absorption spectra, thermogravimetry in air and N2 atmosphere and differential scanning calorimetry (DSC) in the N2 atmosphere. The theoretical kinetic study was carried out using the QBASIC program inputting the TG data.