Non-Isothermal Decomposition Kinetics of Hafnium and Zirconyl Hydrogentellurates

IF 1.6 4区化学 Q4 CHEMISTRY, PHYSICAL International Journal of Chemical Kinetics Pub Date : 2024-12-18 DOI:10.1002/kin.21773

Georgi Rusev, Velyana Georgieva, Svetlana Genieva, Ivaylo Tankov

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Abstract

The thermal characteristics of zirconyl and hafnium hydrogentellurates, ZrO(HTeO₄)₂ × 4H₂O (ZrOTe) and Hf(HTeO₄)₄ × 8H₂O (HfTe), were investigated via non-isothermal decomposition kinetics in this paper for the first time. Important kinetic parameters such as activation energy (E_A), pre-exponential factor (A) and g(α) function were determined using Coats-Redfern integral method. The latter was verified by means of z(α) master plots. In addition, plausible decomposition mechanisms for the title compounds were offered. Based on the E_A values, less thermal stability for ZrOTe (633.69 kJ/mol) with respect to HfTe (872.24 kJ/mol) was observed. Thermodynamic functions (ΔS^≠, ΔH^≠, and ΔG^≠) of the activated complexes generated during the thermal decomposition steps were studied as well. A high positive ΔH^≠ value (855.70 kJ/mol) for the thermal decomposition of HfTe indicated formation of high-ordered activated complexes. In contrast, lower ΔH^≠ (612.50 kJ/mol) for ZrOTe suggested easier formation the transition states in that case.

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氢丙酮酸铪和锆基的非等温分解动力学

本文首次采用非等温分解动力学研究了锆基氢正酸盐和铪氢正酸盐ZrO(HTeO4)2 × 4H2O （ZrOTe）和Hf(HTeO4)4 × 8H2O （HfTe）的热特性。采用Coats-Redfern积分法测定了活化能（EA）、指前因子(A)和g（α）函数等重要动力学参数。后者通过z（α）主图得到验证。此外，还给出了标题化合物的合理分解机理。根据EA值，ZrOTe （633.69 kJ/mol）的热稳定性低于HfTe （872.24 kJ/mol）。研究了热分解过程中生成的活化配合物的热力学函数（ΔS≠、ΔH≠、ΔG≠）。HfTe热分解的高正ΔH≠值（855.70 kJ/mol）表明形成了高阶活化配合物。相比之下，ZrOTe的ΔH≠(612.50 kJ/mol)较低表明在这种情况下更容易形成过渡态。

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来源期刊

International Journal of Chemical Kinetics 化学-物理化学

CiteScore

3.30

自引率

6.70%

发文量

审稿时长

3 months

期刊介绍： As the leading archival journal devoted exclusively to chemical kinetics, the International Journal of Chemical Kinetics publishes original research in gas phase, condensed phase, and polymer reaction kinetics, as well as biochemical and surface kinetics. The Journal seeks to be the primary archive for careful experimental measurements of reaction kinetics, in both simple and complex systems. The Journal also presents new developments in applied theoretical kinetics and publishes large kinetic models, and the algorithms and estimates used in these models. These include methods for handling the large reaction networks important in biochemistry, catalysis, and free radical chemistry. In addition, the Journal explores such topics as the quantitative relationships between molecular structure and chemical reactivity, organic/inorganic chemistry and reaction mechanisms, and the reactive chemistry at interfaces.