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1.
The isothermal decomposition of zinc hydroxy azides, Zn(OH)2-x(N3)x: follows deceleratory kinetics throughout the temperature range studied. The initial part of the decomposition fits into
unimolecular decay law, log (1-a) = -kt. The contracting volume law satisfactorily describes the data at higher degrees of decomposition. The maximum value ofa upto which the slow decomposition could be recorded was 0.75. The aged form of zinc hydroxy azide decomposes with much lower
rates and slightly different topochemical characteristics. The decrease in the rate of decomposition on ageing has been attributed
to the formation of carbonate on the surface of the compound during storage. The change in topochemical behaviour is traced
to the reported layer structure of zinc hydroxy azide. The effect of pre-heating on subsequent thermal decomposition has also
been discussed. 相似文献
2.
J. Straszko J. Możejko M. Olszak-Humienik 《Journal of Thermal Analysis and Calorimetry》1995,45(5):1109-1116
The paper describes the kinetics of all the recorded steps of thermal decomposition of nickel sulfate hexahydrate in air. The thermal decomposition of the salt in air led to NiO at about 1060 K. The kinetic parameters, the activation energyE and the preexponential factorA, and the thermodynamic parameters, the entropy, enthalpy and free energy of activation were evaluated for the dehydration and decomposition reactions. Tentative reaction mechanisms are suggested for each step of the thermal decomposition. 相似文献
3.
4.
The synthesis of malachite CuCO3·Cu(OH)2 or Cu2CO3(OH)2 was studied through titrations of copper(II) salt solutions with a solution of sodium carbonate at different temperatures. The precipitates were characterized by TG, IR and chemical analysis. The composition varies depending on thepH of the solution and the temperature. Purer malachite was synthesized by simple mixing of a solution of copper(II) nitrate or sulfate with a solution of sodium carbonate at 50°C.The kinetics of the thermal decomposition of synthetic malachite was described by eitherR
3 orA
m(m=1.2–1.4) law, according to TG analysis, both isothermal and nonisothermal. The Arrhenius parameters determined using three different integral methods showed the kinetic compensation effect, which is correlated to the working temperature interval analyzed.The authors thank Mr. H. Takemoto for analyzing kinetics of the thermal decomposition of synthetic malachite. 相似文献
5.
Dana Bogdan J. P. Aycard Mohamed Hnach Elena Volanschi Mihaela Hillebrand V. Badescu N. Dragoe E. Segal 《Journal of Thermal Analysis and Calorimetry》1996,46(6):1729-1740
The thermal behaviour of some compounds derived from 5-phenylfuran-2,3-dione was studied. The thermoanalytical data relating to the decomposition steps and intermediates were completed with mass spectrometric analysis and infrared spectroscopy results. For some of the investigated reactions, the kinetic and structural data correlated satisfactorily. 相似文献
6.
M. C. D Silva M. M. Concei??o M. F. S. Trindade A. G. Souza C. D. Pinheiro J. C. Machado P. F. A. Filho 《Journal of Thermal Analysis and Calorimetry》2004,75(2):583-590
The thermodynamic and kinetic parameters of the thermal decomposition of Zn(S2CNR2)2 complexes (R=CH3, C2H5 and n-C3H7) were determined with the dynamic thermogravimetric method. Superimposed TG/DTG/DSC curves show that thermal decomposition
reactions for chelates with R=C2H5 and n-C3H7 occur in the liquid phase, at temperatures far away from their melting points, whereas for the complex with R=CH3 the thermal decomposition begins at a temperature closer to its melting point, suggesting a rather complex decomposition
mechanism.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Małecka Barbara Drożdż-Cieíla Ewa Olszewski P. K. 《Journal of Thermal Analysis and Calorimetry》2003,74(2):485-490
The kinetics of manganese(II) oxalate thermal decomposition in the helium atmosphere was studied on the basis of isothermal
measurements in the temperature range from 608 to 623 K. Manganese(II) oxide, MnO, was found to be the final product of reaction.
The Avrami-Erofeev kinetic equation was used to describe all the experimental data in the range of decomposition degrees from
0.1 to 0.9. The determined activation energy equals 184.7 kJ mol-1 with standard deviation ±5.2 kJ mol-1. The estimated value of parameter n is 1.9 with standard deviation ±0.01 what suggests that the rate limiting step of MnC2O4 decomposition is the nucleation of new MnO phase and that the rate of nuclei growth is rising during decomposition.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
本文制备了均匀棒状过氧化氢合碳酸钠,化学分析确定其组成为Na2CO3·1.5H2O2,用DTA-TG-DTG技术并辅以X-ray分析研究了它在静态空气、流动氧气和流动氮气气氛中的非等温热分解过程及动力学。 相似文献
9.
Živković Ž. D Živković D. T. Grujičić D. B. 《Journal of Thermal Analysis and Calorimetry》1998,53(2):617-623
This paper presents the results of simultaneous DTA-TG-DTG and DSC studies on the thermal decomposition of Cu(NO3)2·3H2O,
Co(NO3)2·6H2O and Ni(NO3)2·6H2O in an air atmosphere. The mechanism and enthalpies of the investigated processes were determined,
as well as the kinetic parameters of the processes run under non-isothermal conditions by means of Kissinger's method. The
dependence of the activation energy on the ionic radius of the cations building up the crystal lattices of the investigated
compounds was also studied.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
The thermal decomposition reactions of calcitic dolomite were investigated. Simultaneous TG/DTG/DTA were applied under non-isothermal
conditions. From the recorded curves, the activation energies, pre-exponential factors and thermodynamic parameters of activation
were calculated for the two thermal decomposition steps.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献