The mineral stichtite was synthesised and its thermal decomposition measured using thermogravimetry coupled to an evolved
gas mass spectrometer. Mass loss steps were observed at 52, 294, 550 and 670�C attributed to dehydration, dehydroxylation
and loss of carbonate. The loss of carbonate occurred at higher temperatures than dehydroxylation.
Thermal decomposition of borax has been researched by thermal, XRD and FTIR methods as well as SEM microscopy. Study have
revealed that it proceeds according to the mechanism of internal reactions in the structure of the precursor as a medium.
The following stages of the process have been distinguished: (1) dehydration, (2) internal structure reconstitution—formation
of tincalconite, (3) amorphization of crystal structure, (4) gradual dehydroxylation and crystallization of Na2O2B2O3 inside the amorphous matrix.
Authors:R. Frost, J. Kristóf, W. Martens, M. Weier, and E. Horváth
mineral sabugalite (HAl)0.5[(UO2)2(PO4)]2⋅8H2O, has been studied using a combination of energy
dispersive X-ray analysis, X-ray diffraction, dynamic and controlled rate
thermal analysis techniques. X-ray diffraction shows that the starting material
in the thermal decomposition is sabugalite and the product of the thermal
treatment is a mixture of aluminium and uranyl phosphates. Four mass loss
steps are observed for the dehydration of sabugalite at 48°C (temperature
range 39 to 59°C), 84°C (temperature range 59 to 109°C), 127°C
(temperature range 109 to 165°C) and around 270°C (temperature range
175 to 525°C) with mass losses of 2.8, 6.5, 2.3 and 4.4%, respectively,
making a total mass loss of water of 16.0%. In the CRTA experiment mass loss
stages were found at 60, 97, 140 and 270°C which correspond to four dehydration
steps involving the loss of 2, 6, 6 and 2 moles of water. These mass losses
result in the formation of four phases namely meta(I)sabugalite, meta(II)sabugalite,
meta(III)sabugalite and finally uranyl phosphate and alumina phosphates. The
use of a combination of dynamic and controlled rate thermal analysis techniques
enabled a definitive study of the thermal decomposition of sabugalite. While
the temperature ranges and the mass losses vary due to the different experimental
conditions, the results of the CRTA analysis should be considered as standard
data due to the quasi-equilibrium nature of the thermal decomposition process.
Authors:Claudia Aparicio, Libor Machala, and Zdenek Marusak
containing crystalline water are heated, one endothermic effect (always below 200 °C) corresponds to a release of the water molecules. Afterward, the thermaldecomposition occurs at higher temperatures depending on the composition of the starting compound
Authors:M. Navarro, M. Lagarrigue, J. De Paoli, R. Carbonio, and M. Gómez
In order to investigate the formation of the multiferroic BiFeO3, the thermal decomposition of the inorganic complex Bismuth hexacyanoferrate (III) tetrahydrate, Bi[Fe(CN)6]·4H2O has been studied. The starting material and the decomposition products were characterized by IR spectroscopy, thermal analysis,
laboratory powder X-ray diffraction, and microscopic electron scanning. The crystal structures of these compounds were refined
by Rietveld analysis. BiFeO3 were synthesized by the decomposition thermal method at temperature as low as 600 °C. There is a clear dependence of the
type and amount of impurities that are present in the samples with the time and temperature of preparation.
The thermal decomposition of theophylline, theobromine, caffeine, diprophylline and aminophylline were evaluated by calorimetrical,
thermoanalytical and computational methods. Calorimetrical studies have been performed with aid of a heat flux Mettler Toledo
DSC system. 10 mg samples were encapsulated in a 40 μL flat-bottomed aluminium pans. Measurements in the temperature range
form 20 to 400°C were carried out at a heating rate of 10 and 20°C min−1 under an air stream. It has been established that the values of melting points, heat of transitions and enthalpy for methylxanthines
under study varied with the increasing of heating rate.
Thermoanalytical studies have been followed by using of a derivatograph. 50, 100 and 200 mg samples of the studied compounds
were heated in a static air atmosphere at a heating rate of 3, 5, 10 and 15°C min−1 up to the final temperature of 800°C. By DTA, TG and DTG methods the influence of heating rate and sample size on thermal
destruction of the studied methylxanthines has been determined. For chemometric evaluation of thermoanalytical results the
principal component analysis (PCA) was applied. This method revealed that first of all the heating rate influences on the
results of thermal decomposition. The most advantageous results can be obtained taking into account sample masses and heating
rates located in the central part of the two-dimensional PCA graph. As a result, similar data could be obtained for 100 mg
samples heated at 10°C·min−1 and for 200 mg samples heated at 5°C min−1.
Authors:E. M. Schwartz, I. M. Vitola, G. S. Sergeiyeva, G. O. Piloyan, and O. V. Drozdova
The thermal decompositions of dicitratoborates M1[B(C6H6O7)2]·nH2O (n=0–2, M1=Rb, K, Li, NH4) and M11[B(C6H6O7)2]2·8H2O (M11=Co, Ni, Mn, Cu, Zn, Cd) were investigated by means of TG, DTA and DTG methods. It was found that these thermal decompositions involve three successive stages: dehydration, the endothermal decomposition of the ligand, and oxidation of the residual organic component. The volatile products of decomposition in each stage were detected by means of gas chromatography. The method of TG-curve transformation into the curvedm/d T vs.m, wherem is the loss of weight at each moment of time, was used for a more detailed study of dehydration. The optimal conditions for TG-curve modification were found.
Authors:Annamária Krajníková, Katarína Győryová, Daniela Hudecová, Jana Kovářová, and Zuzana Vargová
works we described the preparation, thermal, spectral and biological properties of aliphatic zinc(II) carboxylates [ 13 – 15 ], salicylates and halogenosalicylates [ 16 , 17 ] and benzoates [ 18 , 19 ]. It was found that the thermaldecomposition of
Authors:V. M. Abdul Mujeeb, K. Muraleedharan, M. P. Kannan, and T. Ganga Devi
analysis (TG) is usually adopted to study the kinetics of thermally activated solid-state reactions to obtain thermal stability parameters of solids [ 9 – 13 ]. The kinetics of the thermaldecomposition of inorganic materials could be markedly affected by
Authors:Luiz Carlos Machado, Marcos Tadeu D’Orlando de Azeredo, Hamilton Perez Soares Corrêa, Jivaldo do Rosário Matos, and Ítalo Odone Mazali
) (where Ln = La, Pr, Nd, Sm, Eu, and Gd) have been produced from the thermaldecomposition of hydrated lanthanide sulfates at temperatures >1073 K for 5 h under N 2 or air [ 1 , 8 ]. Subsequent reduction of as prepared Ln 2 O 2 SO 4 under a H 2 flow (3