Search Results

You are looking at 1 - 10 of 484 items for :

  • "kinetic analysis" x
  • All content x
Clear All

isothermal data. One of prerequisites for this kinetic analysis is to get data of conversion rate of high accuracy. Thus if we observe the non-stoichiometry by changing temperature frequency and extract combined data of conversion and rate of conversion

Restricted access

By means of model calculations it could be shown for an irreversible surface reaction of 1st order that the determination of the activation energy of the desorption of the reactant or, respectively, of the surface reaction is possible by application of the method of variation of the heating rate to the desorption curve of the reactant, according to circumstances whether the ratio of the activation energy of the surface reaction and of the desorption of the reactant is greater or smaller than one.

Restricted access

(activation energy, pre-exponential factor, and conversion function) of each degradation step is one important target of kinetic investigations. Many kinetic analysis methods have been developed, among which isoconversional methods have been widely used [ 1

Restricted access

Computational thermal and kinetic analysis

Complete standard procedure to evaluate the kinetic triplet form non-isothermal data

Journal of Thermal Analysis and Calorimetry
Authors: A. Rotaru and M. Goşa

Abstract  

Advanced software (TKS-SP2.0 version) for thermal and kinetic analysis, for determining the non-isothermal kinetic parameters of heterogeneous processes has been developed. The dynamic handle of conversion degree steps and ranges, heating rates and kinetic models, makes the evaluation of the kinetic parameters much faster, for TG, TPR and dilatometry experiments. The standard procedure for evaluating the kinetic triplet was implemented; several linear isoconversional methods (from generalized KAS to FWO, Li-Tang and Friedmann methods), IKP method, Perez-Maqueda et al. criterion (both by Differential equation) and Master plots method. The software is designed mainly for data processing of experimental files, but may also import other already transformed numeric data.

Restricted access

Abstract  

The thermal decomposition of three new reagent cyclohexylamine-p-tolylglyoxime (L1H2), tertiarybutyl amine-p-tolylglyoxime (L2H2) and secondary butylamine-p-tolylglyoxime (L3H2 and their Co-complexes were studied by both isothermal and nonisothermal methods. As expected, the complex structure of Co-complexes, different steps with different activation energies were realized in decomposition process. Model-fitting and model-free kinetic approaches were applied to nonisothermal and isothermal data. The kinetic triplet (f(α), A and E) related to nonisothermal model-fitting method can not be meaningfully compared with values obtained from isothermal method. The complex nature of the multi-step process of the studied compounds was more easily revealed using a wider temperature range in nonisothermal isoconversional method.

Restricted access

Abstract  

The title polymer was obtained electrochemically by the reduction of 4,4'-bis(dibromomethyl)-2,2'-dimethoxybiphenyl under very smooth conditions. The DSC and TG/DTG curves registered at four different heating rates showed that the polymer is stable in air up to 150C, where smooth degradation starts. Above 300C, decomposition is fast and exothermic (ΔH= –323 J g–1) . The activation energy (1164 kJ mol–1 ) was determined by Ozawa's method.

Restricted access

Thermal and kinetic analysis of uranium salts

Part 2. Uranium (VI) acetate hydrates

Journal of Thermal Analysis and Calorimetry
Authors: Gülbanu Koyundereli Çılgı, Halil Cetişli, and Ramazan Donat

, there is a gap in the academic literature about kinetic analysis of each decomposition stage of uranyl acetate salts. However, the kinetic and thermodynamic findings play an important role in solid-state chemistry. This situation has indicated a need for

Restricted access

Thermal and kinetic analysis of uranium salts

Part 1. Uranium (VI) oxalate hydrates

Journal of Thermal Analysis and Calorimetry
Authors: Halil Cetişli, Gülbanu Koyundereli Çılgı, and Ramazan Donat

literature about kinetic analysis of each decomposition stages. This conflict and deficiency have indicated a need for more studies on the thermal decomposition of uranyl oxalate. In this study, thermal decomposition of UO 2 C 2 O 4 ·3H 2 O compound

Restricted access

Abstract  

In this research, thermogravimetry (TG/DTG) was used to determine the kinetic analysis of different coals and effect of cleaning process on kinetic parameters of raw and cleaned coal samples from Soma, Tuncbilek and Afsin Elbistan regions. Kinetic parameters of the samples were determined using Arrhenius and Coats and Redfern kinetic models and the results are discussed.

Restricted access

Abstract  

In principle, the kinetic analysis of thermal effects has limitations when based on a single measurement. Using a simulated example and the dehydration of Ca(OH)2 , it will be shown that, through the simultaneous application of non-linear regression to several measurements run at different heating rates (multivariate non-linear regression), the difficult problem of determining the probable reaction type can be reliably solved.

Restricted access