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- Author or Editor: Anca Mocanu x
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The study on the thermal behavior of some new diazoaminoderivatives was aimed to follow the structure-thermal stability-degradation mechanism correlation by means of the TG-FTIR technique and formation enthalpies. The TG-DTG-DTA curves reveal the thermal degradation in air (30–900 °C) to show two ranges as a function of temperature (time), where the gaseous species resulting by degradation are eliminated: the first, an endothermic one which is identical to that under nitrogen atmosphere and the second, an exothermal one. As made evident by the identification of the individual gaseous species by their characteristic absorbances as well as those obtained by TG-FTIR the compounds C2H2, H2C = NH, SO2, NH3, CO2, H2O, HCl are eliminated in the first domain while CO2, SO2, H2O in the second, which afforded the advancement of the most probable degradation mechanism.
The paper deals with the characterization of three hydrazinic complexes with Ni, Cu and Cr respectively, by means of non-isothermal thermal methods, TG, DTG and DTA, under nitrogen atmosphere in order to investigate the structure-thermostability-thermal degradation mechanism correlation. The thermal analysis made evident the degradation mechanisms characteristic of every sample in accordance with the chemical structure. The quantitative analysis by TG-DTG afforded the estimation of the metal amount in the complex on the basis of the resulting metallic oxide nature as well as of some aspects of the thermal degradation mechanism supported by mass spectral measurements. The melting points given by DTA and confirmed by the Boetius method and the initial temperatures of thermal degradation from TG-DTG-DTA afforded to ascertain the temperature range proper for using and storing the complexes under study which show potential practical applications as drugs.
The article is devoted to a comparative study on the thermal degradation of some new diazoaminoderivatives under both air and nitrogen atmosphere by TG-FTIR analysis. The TG–DTG–DTA curves show the thermal degradation in air to present two temperature domains: an endothermic one identical to the case of the degradation under nitrogen and an exothermic one which is not to be found under nitrogen atmosphere. The identification of the gaseous species released by degradation in air within the endothermic domain made evident the presence of the same components of the degradation in nitrogen atmosphere. In the exothermic domain of the sample degradation in air, the CO2, H2O, SO2 species result by the burning of the molecular residues of the first domain. The obtained results afforded a degradation mechanism to be advanced that coincide for the endothermic domain with that of degradation under nitrogen atmosphere. Due to the importance of these compounds as possible reaction initiators and also as potentially bioactive substances (herbicides, acaricides, fungicides), the study on their thermal degradation could give useful information on the environmental impact of the degradation products resulting by the thermal processing of the plants which could possible retain these compounds, when the initial degradation temperature is exceeded.