Authors:J. Madarász, M. Krunks, L. Niinistö, and G. Pokol
Identification and monitoring of gaseous species released during thermal decomposition of the title compound 1, Zn(tu)2Cl2, (tu=thiourea, (NH2)2C=S) have been carried out in flowing air atmosphere up to 800°C by both online coupled TG-EGA-FTIR and simultaneous TG/DTA-EGA-MS.
The first gaseous products of 1, between 200 and 240°C, are carbon disulfide (CS2) and ammonia (NH3). At 240°C, an exothermic oxidation of CS2 vapors occurs resulting in a sudden release of sulphur dioxide (SO2) and carbonyl sulphide (COS). An intense evolution of hydrogen cyanide (HCN) and beginning of the evolution of cyanamide
(H2NCN) and isothiocyanic acid (HNCS) are also observed just above 240°C. Probably because of condensation and/or polymerization
of cyanamide vapors on the windows and mirrors of the FTIR gas cell optics, some strange baseline shape changes are also occurring
above 330°C. Above 500°C the oxidation process of organic residues appears to accelerate which is indicated by the increasing
concentration of CO2, while above 600°C zinc sulfide starts to oxidize resulting in the evolution of SO2. All species identified by FTIR gas cell were also confirmed by mass spectrometry, except for HNCS.
Analytically pure nickel(II)- and cobalt(II)-acetylacetonate were used to prepare several addition compounds with Lewis-bases (2-picoline-N-oxide, 4-picoline-N-oxide, pyridine-N-oxide) in order to investigate their thermal stability in oxidative atmospheres. Comparison of the thermoanalytical TG-DTA data of the chelates with those on the adducts showed similarities in thermal degradation. A fragmentation pattern observed on simultaneous mass spectrometric investigation is discussed. Elimination of ligand or base molecules corresponding quantitatively to the estimated mass loss values from the TG-curves has been demonstrated.
A recently-developed quadrupole mass spectrometer system specifically designed for thermal analysis studies, has been linked
to a thermobalance and a simultaneous TG-DTA unit, for evolved gas analysis. The performance and applicability of the system
is illustrated by examples from four fields of study
Authors:B. Berger, A. J. Brammer, E. L. Charsley, J. J. Rooney, and S. B. Wirrington
Studies have been carried out on the boron-potassium perchlorate-nitrocellulose pyrotechnic system by DSC, simultaneous TG-DTA-mass spectrometry and chemical analysis. Quantitative measurements have been made on the exothermic pre-ignition reaction which took place above 360°C and the results have been compared with those obtained previously for the corresponding systems containing zirconium and a zirconium/nickel alloy.
complexes were further characterized by spectral and chemical analysis. The halide content in the complexes was determined by Volhard’s method [ 11 ].
TG/DTA–MS studies were carried out using a Rigaku TG-8120
Authors:Imre Miklós Szilágyi, Eero Santala, Mikko Heikkilä, Marianna Kemell, Timur Nikitin, Leonid Khriachtchev, Markku Räsänen, Mikko Ritala, and Markku Leskelä
solutions of PVP and AMT. The annealing process of the PVP/AMT fibers and the product WO 3 nanofibers are characterized by thermal analysis (TG/DTA) and evolved gas analysis with a mass spectrometer (TG/DTA-MS), X-ray diffraction (XRD), scanning electron
Authors:E. L. Charsley, S. B. Warrington, P. Emmott, T. T. Griffiths, and J. Queay
Simultaneous TG-DTA-MS and TG-DSC have been used to investigate the complex reaction which takes place in the region of 300°C when the chlorinated rubber Alloprene is added to pyrotechnic compositions containing equal parts by weight of titanium and sodium nitrate. The results have been compared with those obtained for the titanium-strontium nitrate-Alloprene system.
1,2,4-triazole-3-one (TO) and guanidine nitrate (GN) have the potential to be used as alternative gas-generating agents. To
obtain a better understanding of thermal decomposition properties of TO/GN mixtures, sealed cell differential scanning calorimetry,
thermogravimetry–differential thermal analysis–infrared spectroscopy (TG–DTA–IR), and thermogravimetry–differential thermal
analysis–mass spectrometry (TG–DTA–MS) were carried out. The endothermic peak and onset temperatures of TO/GN mixtures were
lower than those of individual TO and GN. TG–DTA–IR and TG–DTA–MS showed that the mass of TO/GN mixtures decreased with heat
generation and N2 evolved as the major gas during thermal decomposition. The interaction between TO and nitric acid from the dissociation of
GN is proposed for the thermal decomposition of TO/GN mixtures.
Authors:Göktürk Avsar, Hüseyin Altinel, Mustafa Yilmaz, and Bilgehan Guzel
Trifluoromethoxy functionalized copper(II) Schiff base complexes N,N′-bis(5-trifluoromethoxysalicylaldehyde)cyclohexanediiminatodiaquacopper(II) and N,N′-bis(5-trifluoromethoxysalicylaldehyde)phenylenediiminatocopper(II) were synthesized and characterized. Thermal decompositions
of the synthesized complexes were studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition
pathways. Three similar decomposition steps occurred for the two copper complexes. Mass losses and evolved gasses were characterized
by TG/DTA-MS. Kinetic parameters were calculated and the results showed that the values obtained are comparable.
Authors:Margit Bán, J. Madarász, Petra Bombicz, G. Pokol, and S. Gál
Composition and structure of crystals of unknown origin, crystallizing spontaneously from ethylenediamine on standing, has
been determined by elemental analysis, FTIR, 1H and 13C NMR spectroscopy and X-ray diffraction. The crystal with molecular formula C6H14N4 has been found to be a highly symmetric
saturated imino compound with double-ring structure, and unambiguously identified as trans-1,4,5,8-tetraazodecalin by 1H NMR and powder X-ray diffraction based on both its specific AA'BB' spin coupling system and simulated XRD pattern calculated
from available data of previous single crystal structure determination, respectively. Simultaneous TG/DTA measurement shows
one-step degradation of this compound. The volatile decomposition products have been followed by both TG/DTA-MS and TG-FTIR.
Group of the largest fragments (m/z=80, 81 and 82) observed by TG/DTA-MS corresponds to an aromatic 1,4-diazine (pyrazine). In the EGA-FTIR spectrum of released
gaseous species measured at the highest evolution rate by TG-FTIR, ethylenediamine can be identified as another decomposition