Termogravimetria, termogravimetria derivada (TG,DTG), calorimetria exploratória diferencial (DSC) e difratometria de raios X foram utilizados para estudar o trimetroprim, sulfametoxazol, ampicilina, cloridrato de tetraciclina e rifampicina. Os resultados permitiram obter informações sobre a estabilidade térmica destes compostos e a decomposição térmica em atmosfera de ar.Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC) and X ray diffraction powder patterns have been used to study trimethoprim, sulfamethoxazole, ampicillim, tetracycline hydrochloride and rifampim. The results revealed the extent of their thermal stability and also allowed interpretations concerning their thermal decompositions in air atmosphere.

Coordination compounds of transition metals with norfloxacin (Nor) have potential to improve its effectiveness, as already discussed for some compounds found in the literature. The complexes in the solid state were prepared by precipitation of the respective metal cation (M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) with a norfloxacin sodium salt solution. The thermal behavior under oxidative and pyrolysis conditions was investigated employing thermogravimetry and differential thermal analysis (TG/DTG-DTA) and evolved gas analysis (EGA/TG-FTIR), and the complexes were characterized by elemental analysis (EA), EDTA complexometric titration, infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). By these results, the minimum formula was established as [M(Nor) 2 (H 2 O) 2 ]ÁnH 2 O, where n = 3 (Ni), 2.5 (Mn Co, Zn), or 2 (Cu). The evolved gases identified during thermal decomposition of Ni and Cu complexes were ethylene, CO 2 and CO for Ni; CO 2 and ethane for Cu. Also, antimicrobial activity of the complexes was evaluated by in vitro susceptibility test using the agar diffusion method, and the results were compared with the uncomplexed molecule. It was found that norfloxacin complexation modifies its antibacterial activity. The activity depends on the type of metal ion and microorganism; Mn(II), Co(II) and Zn(II) complexes significantly increased activity against the tested gram-negative bacteria.

Complexes of meloxicam with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were prepared by aqueous precipitation. The compounds were characterized by means of X-ray powder diffractometry, infrared spectroscopy, theoretical calculation, elemental analysis (CNH), differential scanning calorimetry, simultaneous TG/DTG-DTA and evolved gas analysis (EGA). The results obtained from the TG/DTG-DTA curves and elemental analysis made it possible to establish the general formula of these compounds as [M(Hmel) 2 (H 2 O) 2 ]nH 2 O, where M = Mn(II), Co(II), Ni(II); Cu(II) and Zn(II); Hmel = meloxicam and n = 2 (Mn, Co, Ni, Zn) and 1 (Cu). The simultaneous TG/ DTG-DTA data provided previously unreported information about the thermal stability and thermal decomposition of these compounds in dynamic air and nitrogen atmospheres. The EGA showed the remarkable influence of the atmosphere in the thermal decomposition mechanism of these complexes, and it was also possible to identify the main gaseous products of thermal degradation. The lowest energy model structure of the Mn(II), Ni(II) and Zin(II) complexes has been proposed by using the density functional theory at the B3LYP/6-311??G(d) level of theory, and the theoretical spectra were calculated. The antibacterial activity of the compounds was also evaluated in relation to S. aureus by the diffusion method in agar, and the compounds showed little activity. The anti-inflammatory activity of the meloxicam-copper complex was also evaluated in vivo by the rat paw edema method. The compound showed no anti-inflammatory activity, which may have been due to loss of intrinsic activity or poor oral absorption caused by low solubility.

This work aims to determine if thermogravimetry could be used to determine the degree of conversion of soybean oil to biodiesel without knowing the amount of ester in the sample, comparing the results with the values obtained by the standard method, gas chromatography. The syntheses were made using homogeneous and heterogeneous catalysts, and the measures were made in triplicate on both pieces of equipment. The average values (%) obtained were 74.59 ± 0.58, 66.5 ± 1.62, 13.54 ± 0.32 by thermogravimetry and 74.09 ± 0.46, 62.08 ± 2.19, 17.07 ± 0.31 by gas chromatography. These data were statistically compared using F-test, and the result indicated that the thermogravimetry could be used as analytical technique to determine the degree of conversion of biodiesel, with the same reliability as gas chromatography. The thermogravimetry shows more advantages than gas chromatography, because it does not require organic solvent, following the Green Chemistry Principles, and it is already used to determine other thermal properties of biodiesel.

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Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (IR) were used to study amoxicillin trihydrate. The thermal behavior and physical properties of the studied compound were established and coupled TG-IR analyses were used to suggest some decomposition products. 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 09 routine. The theoretical calculations helped us interpret the IR spectra, which supply structural and physicochemical information.

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The biodiesel emerged as a substitute of standard diesel and could be considered a renewable and clean energy source. The transesterification reaction is considered the critical step in biodiesel production. The reaction between a short chain alcohol and chain triglycerides occurs in presence of a catalyst, which could be homogeneous or heterogeneous at reaction system. Trying solving the problems presented by homogeneous catalysis and finds viable applications conditions with heterogeneous catalysts, this work aimed to prepare and characterize a heterogeneous catalyst by chitosan with nickel (metallic complex) and then applies it in biodiesel production in laboratory scale. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) and Fourier Transform Infrared Spectroscopy (FTIR) to characterize the catalyst. To characterize the biodiesel were used Fourier Transform Infrared Spectroscopy and measurements of viscosity and density.