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Solid-state compounds of 2-methoxybenzylidenepyruvate with some bivalent metal ions

Synthesis, characterization and thermal behavior studies

Journal of Thermal Analysis and Calorimetry
Authors: M. Kobelnik, E. Schnitzler, and M. Ionashiro

Abstract  

Solid-state M-2-MeO-BP compounds, where M represents bivalent Mn, Fe, Co, Ni, Cu, Zn and 2-MeO-BP is 2-methoxybenzylidenepyruvate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal stability and thermal decomposition of these compounds. The results led to information about the composition, dehydration, crystallinity and thermal decomposition of the isolated compounds.

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Abstract

Solid-state Ln(L)3 compounds, where Ln stands for trivalent La, Ce, Pr, Nd, Sm, Eu, and L is ketoprofen have been synthesized. Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction powder (DRX) patterns, Fourier transformed infrared spectroscopy (FTIR), and other methods of analysis were used to study solid Ketoprofen of lighter trivalent lanthanides. The results provided information of the composition, dehydration, coordination mode, structure, thermal behavior, and thermal decomposition. The theoretical and experimental spectroscopic study suggests that the carboxylate group of ketoprofen is coordinate to metals as bidentate bond.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Bannach, R. Arcaro, D. Ferroni, A. Siqueira, O. Treu-Filho, M. Ionashiro, and E. Schnitzler

Abstract  

Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction powder (DRX) patterns and Fourier transformed infrared spectroscopy (FTIR) were used to study ketoprofen, ibuprofen, and naproxen. The chemical or physical properties of the studied compounds were established and when possible by X-ray powder diffractometry and/or infrared spectroscopy were used. In this investigation, quantum chemical approach was used to determine the molecular structures using Becke three-parameter hybrid method and the Lee–Yang–Par (LYP) correlation functional. The performed molecular calculations in this work were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FTIR spectra supplying structural and physicochemical parameters.

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Journal of Thermal Analysis and Calorimetry
Authors: L. Lacerda, M. da Silva Carvalho Filho, I. Demiate, G. Bannach, M. Ionashiro, and E. Schnitzler

Abstract  

Corn starch, partially hydrolyzed by fungal α-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.

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Journal of Thermal Analysis and Calorimetry
Authors: E. Schnitzler, G. Bannach, O. Treu-Filho, C. T. Carvalho, and M. Ionashiro

Abstract

Solid-state compounds of general formula ThL4·nH2O, where L represents 2-methoxybenzylidenepyruvate and 2-methoxycynamylidenepyruvate, were synthesized. Complexometric titrations with EDTA, thermogravimetry (TG), differential thermal analysis (DTA), X-ray powder diffractometry, elemental analysis (EA), and infrared spectroscopy have been employed to characterize and to study the thermal behavior of these compounds in dynamic air atmosphere. The results led to informations about the composition, dehydration, crystallinity, and thermal decomposition of the isolated compounds. The performed molecular calculations in this study were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FT-IR spectra supplying structural and physicochemical parameters.

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Abstract  

Solid-state compounds of general formula LnL3⋅ nH2O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and infrared spectroscopy have been employed to characterize and to study the thermal behaviour of these compounds in dynamic air atmosphere. On heating these compounds decompose in four (Gd, Tb, Ho to Lu, Y) or five (Eu, Dy) steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds up to 1200C occurs with the formation of the respective oxide, Tb4O7 and Ln2O3 (Ln=Eu, Gd, Dy to Lu and Y) as final residue. The dehydration enthalpies found for these compounds (Eu, to Lu and Y) were: 65.77, 55.63, 86.89, 121.65, 99.80, 109.59, 131.02, 119.78, 205.46 and 83.11 kJ mol-1, respectively.

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