In this paper, we present the results of comprehensive thermodynamic study of some functionally substituted triazoles such as 1-benzyl-4-phenyl-1H-1,2,3-triazole, 1-benzyl-4-(m-tolyl)-1H-1,2,3-triazole and 1-benzyl-4-(4‑tert-butylphenyl)-1H-1,2,3-triazole. The temperature dependences of heat capacities of 1-benzyl-4-(m-tolyl)-1H-1,2,3-triazole and 1-benzyl-4-(4‑tert-butylphenyl)-1H-1,2,3-triazole were measured in a wide temperature range of ∼(5 – 370) K using the adiabatic calorimetry. Those of 1-benzyl-4-phenyl-1H-1,2,3-triazole were determined at the range of ∼(5 – 80) K, supplementing the previous measurements at the more elevated temperatures. The melting parameters and thermal stability (melting temperature, enthalpy of fusion, temperature of thermal destruction) of the compounds were determined using the differential scanning calorimetry. Also, the standard thermodynamic functions (absolute entropies, reduced enthalpies and Gibbs energies) were calculated in the temperature range of (0 – Tm) K.
本文介绍了一些功能取代的三唑，如 1-苄基-4-苯基-1H-1,2,3-三唑、1-苄基-4-（间甲苯基）-1H-1,2,3-三唑和 1-苄基-4-（4-叔丁基苯基）-1H-1,2,3-三唑的综合热力学研究结果。采用绝热量热法测量了 1-苄基-4-(间甲苯基)-1H-1,2,3-三唑和 1-苄基-4-(4-叔丁基苯基)-1H-1,2,3-三唑在 ∼(5 - 370) K 宽温度范围内的热容量随温度变化的关系。在 ∼(5 - 80) K 范围内测定了 1-苄基-4-苯基-1H-1,2,3-三唑的热稳定性，补充了之前在较高温度下的测量结果。利用差示扫描量热法测定了化合物的熔化参数和热稳定性（熔化温度、熔焓、热破坏温度）。此外，还计算了 (0 - Tm) K 温度范围内的标准热力学函数（绝对熵、还原焓和吉布斯能）。
{"title":"Heat capacities and thermodynamic functions of three 1-benzyl-4-aryl-1H-1,2,3-triazoles in the temperature range of (0 – Tm) K","authors":"Y.N. Yurkshtovich , A.V. Blokhin , A.G. Labetski , D.I. Shiman , A.A. Notfullin , M.I. Yagofarov","doi":"10.1016/j.tca.2024.179881","DOIUrl":"10.1016/j.tca.2024.179881","url":null,"abstract":"<div><div>In this paper, we present the results of comprehensive thermodynamic study of some functionally substituted triazoles such as 1-benzyl-4-phenyl-1<em>H</em>-1,2,3-triazole, 1-benzyl-4-(<em>m</em>-tolyl)-1<em>H</em>-1,2,3-triazole and 1-benzyl-4-(4‑<em>tert</em>-butylphenyl)-1<em>H</em>-1,2,3-triazole. The temperature dependences of heat capacities of 1-benzyl-4-(<em>m</em>-tolyl)-1<em>H</em>-1,2,3-triazole and 1-benzyl-4-(4‑<em>tert</em>-butylphenyl)-1<em>H</em>-1,2,3-triazole were measured in a wide temperature range of ∼(5 – 370) K using the adiabatic calorimetry. Those of 1-benzyl-4-phenyl-1<em>H</em>-1,2,3-triazole were determined at the range of ∼(5 – 80) K, supplementing the previous measurements at the more elevated temperatures. The melting parameters and thermal stability (melting temperature, enthalpy of fusion, temperature of thermal destruction) of the compounds were determined using the differential scanning calorimetry. Also, the standard thermodynamic functions (absolute entropies, reduced enthalpies and Gibbs energies) were calculated in the temperature range of (0 – <em>T</em><sub>m</sub>) K.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179881"},"PeriodicalIF":3.1,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.tca.2024.179882
Mohamed-Said Chemam, Younes Djouadi, Chaima Khelkhal, Olga V. Ostolopovskaya, Mohammed Amine Khelkhal, Alexey V. Vakhin
In-situ combustion is considered an efficient thermally enhanced oil recovery method. However, the combustion front stabilization remains a challenge for the scientific community. The present study examines the efficacy of copper tall oil (Cu-TO) and copper sunflower oil (Cu-SFO) on heavy oil high-temperature oxidation reactions, which are believed to solve this challenge. We applied non-isothermal differential scanning calorimetry (DSC) analyses combined with an isoconversional kinetic approach in order to calculate kinetic parameters, thermodynamic functions, and the effective rate constant of these reactions. The obtained results demonstrated that both catalysts are able to reduce the activation energies and shift oxidation regions to lower temperatures, with Cu-SFO showing superior performance. Kinetic predictions further supported these findings and revealed that the selected catalysts contributed significantly to decreasing oxidation times across all conversion ranges. Additionally, thermodynamic analyses indicated that Cu-SFO facilitated a more ordered and energetically favorable oxidation process, as demonstrated by increasingly negative entropy values and consistently lower Gibbs free energy. The research highlights the Cu-SFO catalyst exceptional ability to accelerate the transition from low-temperature to high-temperature oxidation while maintaining high catalytic activity. Taken together all these results, this research work contributes to provide comprehensive insights from the kinetic and thermodynamic analysis that reveal unique catalytic effects and reaction mechanisms, presenting an approach to stabilize combustion front and improve heavy oil recovery efficiency, addressing a critical challenge in the field of in-situ combustion.
{"title":"Study of Heavy Oil In-situ Combustion with Copper Biocatalysts: Kinetics and Thermodynamic Aspects of High-Temperature Oxidation Reactions","authors":"Mohamed-Said Chemam, Younes Djouadi, Chaima Khelkhal, Olga V. Ostolopovskaya, Mohammed Amine Khelkhal, Alexey V. Vakhin","doi":"10.1016/j.tca.2024.179882","DOIUrl":"10.1016/j.tca.2024.179882","url":null,"abstract":"<div><div>In-situ combustion is considered an efficient thermally enhanced oil recovery method. However, the combustion front stabilization remains a challenge for the scientific community. The present study examines the efficacy of copper tall oil (Cu-TO) and copper sunflower oil (Cu-SFO) on heavy oil high-temperature oxidation reactions, which are believed to solve this challenge. We applied non-isothermal differential scanning calorimetry (DSC) analyses combined with an isoconversional kinetic approach in order to calculate kinetic parameters, thermodynamic functions, and the effective rate constant of these reactions. The obtained results demonstrated that both catalysts are able to reduce the activation energies and shift oxidation regions to lower temperatures, with Cu-SFO showing superior performance. Kinetic predictions further supported these findings and revealed that the selected catalysts contributed significantly to decreasing oxidation times across all conversion ranges. Additionally, thermodynamic analyses indicated that Cu-SFO facilitated a more ordered and energetically favorable oxidation process, as demonstrated by increasingly negative entropy values and consistently lower Gibbs free energy. The research highlights the Cu-SFO catalyst exceptional ability to accelerate the transition from low-temperature to high-temperature oxidation while maintaining high catalytic activity. Taken together all these results, this research work contributes to provide comprehensive insights from the kinetic and thermodynamic analysis that reveal unique catalytic effects and reaction mechanisms, presenting an approach to stabilize combustion front and improve heavy oil recovery efficiency, addressing a critical challenge in the field of in-situ combustion.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179882"},"PeriodicalIF":3.1,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.tca.2024.179877
Botao Tang , Tao Zhou , Lei Ni , Liang Yin , Juncheng Jiang , Ahmed Mebarki
The safety of self-reactive chemicals has garnered attention due to their immense destructive power. The use of an accelerating rate calorimeter allows for more accurate measurement and understanding of the kinetic parameters and reaction mechanisms of self-reactive chemicals, thereby reducing the occurrence of major accidents. In this study, a new accelerating rate calorimeter is designed and constructed by combining Modelica and a fuzzy Proportional-Integral-Derivative algorithm. The feasibility of the calorimeter data was verified by using two solutions with significantly different reaction rates: 20 % mass fraction di‑tert‑butyl peroxide/toluene and tert-butylperoxy-2-ethylhecanoate. Their thermal hazard characteristic parameters were compared with the literature data. In addition, the risk level of thermal runaway was determined using the Stoessel risk assessment method. These results demonstrate that the accelerating rate calorimeter based on Modelica modeling meets the accuracy of thermal hazard characteristic parameters. It is capable of performing risk assessments for runaway reactions of self-reactive chemicals.
{"title":"Design and implementation of an accelerating rate calorimeter based on Modelica modeling","authors":"Botao Tang , Tao Zhou , Lei Ni , Liang Yin , Juncheng Jiang , Ahmed Mebarki","doi":"10.1016/j.tca.2024.179877","DOIUrl":"10.1016/j.tca.2024.179877","url":null,"abstract":"<div><div>The safety of self-reactive chemicals has garnered attention due to their immense destructive power. The use of an accelerating rate calorimeter allows for more accurate measurement and understanding of the kinetic parameters and reaction mechanisms of self-reactive chemicals, thereby reducing the occurrence of major accidents. In this study, a new accelerating rate calorimeter is designed and constructed by combining Modelica and a fuzzy Proportional-Integral-Derivative algorithm. The feasibility of the calorimeter data was verified by using two solutions with significantly different reaction rates: 20 % mass fraction di‑tert‑butyl peroxide/toluene and tert-butylperoxy-2-ethylhecanoate. Their thermal hazard characteristic parameters were compared with the literature data. In addition, the risk level of thermal runaway was determined using the Stoessel risk assessment method. These results demonstrate that the accelerating rate calorimeter based on Modelica modeling meets the accuracy of thermal hazard characteristic parameters. It is capable of performing risk assessments for runaway reactions of self-reactive chemicals.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179877"},"PeriodicalIF":3.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The thermal stability of zeolitic imidazolate framework-8 (ZIF-8) for poly(vinyl chloride) (PVC) has received attention, but its thermal stabilization mechanism needs further clarification. Herein, the stearic acid-modified ZIF-8 with high specific surface area and large pore volume was effectively synthesized by using zinc stearate as the zinc source for the first time. Modification of stearic acid results in larger adsorption capacity of ZIF-8 for HCl and better thermal stability effect for PVC, especially long-term thermal stability. Moreover, the thermal stability mechanism of ZIF-8 for PVC was demonstrated by experiments and theoretical calculations. In addition to absorbing HCl to eliminate autocatalytic degradation of PVC, ZIF-8 disintegrates and may form 2-methylimidazole-Zn-Cl salt complex instead of free ZnCl2, avoiding the negative zinc burning effect. Furthermore, the Diels-Alder reaction between imidazole ring and degraded PVC prevents the extension of the conjugated double bonds of PVC and delays the deepening of the color of PVC.
{"title":"Insights into the thermal stabilization mechanism of zeolitic imidazolate framework-8 for poly(vinyl chloride)","authors":"Shuhang Li, Xianglin Liao, Zhinan Zhang, Xue Chen, Luobiao Hong, Cong Liu, Suilian Luo, Qiong Hou, Yuhai Wang, Guang Shi","doi":"10.1016/j.tca.2024.179880","DOIUrl":"10.1016/j.tca.2024.179880","url":null,"abstract":"<div><div>The thermal stability of zeolitic imidazolate framework-8 (ZIF-8) for poly(vinyl chloride) (PVC) has received attention, but its thermal stabilization mechanism needs further clarification. Herein, the stearic acid-modified ZIF-8 with high specific surface area and large pore volume was effectively synthesized by using zinc stearate as the zinc source for the first time. Modification of stearic acid results in larger adsorption capacity of ZIF-8 for HCl and better thermal stability effect for PVC, especially long-term thermal stability. Moreover, the thermal stability mechanism of ZIF-8 for PVC was demonstrated by experiments and theoretical calculations. In addition to absorbing HCl to eliminate autocatalytic degradation of PVC, ZIF-8 disintegrates and may form 2-methylimidazole-Zn-Cl salt complex instead of free ZnCl2, avoiding the negative zinc burning effect. Furthermore, the Diels-Alder reaction between imidazole ring and degraded PVC prevents the extension of the conjugated double bonds of PVC and delays the deepening of the color of PVC.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179880"},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.tca.2024.179879
Chuchu Song , Qingfeng Guo , Yafang Wang , Libing Liao
Hackmanite has received extensive attention from scholars in recent years. However, there is still no report on the thermoluminescence properties of natural hackmanites under UV irradiation, as well as its relative electron trap and luminescence center. In this paper, the structural defects and thermoluminescence spectroscopic properties of hackmanite are comprehensively characterized by XRD, TL spectroscopy, SEM, EPR, XPS and Raman spectroscopy. The traps depth of TL peaks are calculated by computerized glow curve deconvolution (CGCD) techniques. And the charge transition energy levels of intrinsic defects in Na8Al6Si6O24(Cl,S)2 are calculated by spin-polarized density-functional theory (DFT) in VASP. It shows that the low-temperature TL peaks of hackmanite are associated with Cl vacancies and photochromic properties. The high-temperature peak is caused by marginal oxygen vacancies. The results are conducive to deepening the understanding of structural defects of the hackmanites and linking the thermoluminescence with the phototropy.
{"title":"Thermoluminescence characteristics of UV-irradiated natural hackmanite","authors":"Chuchu Song , Qingfeng Guo , Yafang Wang , Libing Liao","doi":"10.1016/j.tca.2024.179879","DOIUrl":"10.1016/j.tca.2024.179879","url":null,"abstract":"<div><div>Hackmanite has received extensive attention from scholars in recent years. However, there is still no report on the thermoluminescence properties of natural hackmanites under UV irradiation, as well as its relative electron trap and luminescence center. In this paper, the structural defects and thermoluminescence spectroscopic properties of hackmanite are comprehensively characterized by XRD, TL spectroscopy, SEM, EPR, XPS and Raman spectroscopy. The traps depth of TL peaks are calculated by computerized glow curve deconvolution (CGCD) techniques. And the charge transition energy levels of intrinsic defects in Na<sub>8</sub>Al<sub>6</sub>Si<sub>6</sub>O<sub>24</sub>(Cl,S)<sub>2</sub> are calculated by spin-polarized density-functional theory (DFT) in VASP. It shows that the low-temperature TL peaks of hackmanite are associated with Cl vacancies and photochromic properties. The high-temperature peak is caused by marginal oxygen vacancies. The results are conducive to deepening the understanding of structural defects of the hackmanites and linking the thermoluminescence with the phototropy.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179879"},"PeriodicalIF":3.1,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.tca.2024.179878
Xiaohong Wang , Juan Zhao , Xiaoyu Li , Qing Pan , Langhua Gao , Gao Zhang
(C6N2H14) NH4 (ClO4)3 (DAP-4) have attracted an increasing focus recently as an ammoniumperchlorate-based molecular perovskite energetic material with outstanding features. Microscopy, variable temperature X-ray diffraction, in situ infrared spectroscopy, differential scanning calorimetry-thermogravimetry simultaneous thermal analysis coupled with infrared spectroscopy and mass spectrometry (DSC-TG/FTIR/MS) techniques were used to systematically investigate DAP-4 thermal properties from -40 °C to 550 °C. The results revealed that DAP-4 have two solid-solid crystallization phase transitions with a non-characteristic melting process. The generated activation energies of HCN, CO, CH2NH2, CO2 and NO2 gas products are all lower than the macroscopic decomposition's of DAP-4. This finding strongly proves that DAP-4 is easy to form these gas products during thermal stimulus. The two stages decomposition mechanism accompanying a large of CH2NH2 and NH2C2H4 gases and kinetic model of DAP-4 were proposed under the condition of high-purity argon gas. This study provides new insight into the in-depth and accurate description thermal decomposition mechanism of DAP-4 as a potential energetic material.
{"title":"Thermal properties and decomposition of perovskite energetic materials (C6H14N2) NH4 (ClO4)3","authors":"Xiaohong Wang , Juan Zhao , Xiaoyu Li , Qing Pan , Langhua Gao , Gao Zhang","doi":"10.1016/j.tca.2024.179878","DOIUrl":"10.1016/j.tca.2024.179878","url":null,"abstract":"<div><div>(C<sub>6</sub>N<sub>2</sub>H<sub>14</sub>) NH<sub>4</sub> (ClO<sub>4</sub>)<sub>3</sub> (DAP-4) have attracted an increasing focus recently as an ammoniumperchlorate-based molecular perovskite energetic material with outstanding features. Microscopy, variable temperature X-ray diffraction, in situ infrared spectroscopy, differential scanning calorimetry-thermogravimetry simultaneous thermal analysis coupled with infrared spectroscopy and mass spectrometry (DSC-TG/FTIR/MS) techniques were used to systematically investigate DAP-4 thermal properties from -40 °C to 550 °C. The results revealed that DAP-4 have two solid-solid crystallization phase transitions with a non-characteristic melting process. The generated activation energies of HCN, CO, CH<sub>2</sub>NH<sub>2</sub>, CO<sub>2</sub> and NO<sub>2</sub> gas products are all lower than the macroscopic decomposition's of DAP-4. This finding strongly proves that DAP-4 is easy to form these gas products during thermal stimulus. The two stages decomposition mechanism accompanying a large of CH<sub>2</sub>NH<sub>2</sub> and NH<sub>2</sub>C<sub>2</sub>H<sub>4</sub> gases and kinetic model of DAP-4 were proposed under the condition of high-purity argon gas. This study provides new insight into the in-depth and accurate description thermal decomposition mechanism of DAP-4 as a potential energetic material.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179878"},"PeriodicalIF":3.1,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To utilize chili straw waste (CSW) for energy production and generate higher-quality fuel, the pyrolysis characteristics of CSW under varying particle sizes and heating rates, as well as the effects of different O2/N2 ratios on its combustion characteristics, were investigated using Thermogravimetry-Mass Spectrometry (TG-MS). The gas production performance under three different conditions was also analyzed. Results indicated that the solid yield decreased as particle size increased, with the maximum weight loss rate of 77.79 % occurring at a particle size of 1.25∼1.60 mm. The highest relative pyrolysis rate was 0.77 %/K at a heating rate of 10 K/min, corresponding to a weight loss rate of 74.46 %. Increasing the proportion of oxygen in the atmosphere reduced both the ignition and burnout temperatures of CSW by 9.34 K and 51.89 K, respectively, shifting the Derivative Thermogravimetry (DTG) curve to a lower temperature range. Furthermore, an increase in the heating rate enhanced hydrogen production intensity during CSW pyrolysis, with the peak particle current of H2 rising from 8.7 × 10−10 A to 1.2 × 10−9 A, representing a 0.38-fold increase when the heating rate was raised from 5 K/min to 40 K/min. A kinetic analysis of CSW pyrolysis using the Coats-Redfern (CR) and Achar methods revealed that activation energy (Ea) increases with particle size, indicating higher energy requirements due to heat transfer resistance. The Friedman, Kissinger-Akahira-Sunose (KAS), and Ozawa-Flynn-Wall (OFW) methods showed rising Ea with increasing conversion rates, corresponding to the decomposition of hemicellulose, cellulose, and lignin. In combustion, oxygen concentration significantly influences Ea, raising it for volatile matter and fixed carbon, and also increasing it for lignin at high temperatures. The CR and Achar models provided strong fits, confirming their reliability in describing CSW pyrolysis and combustion.
{"title":"Investigation of pyrolysis and combustion characteristics of chili straw waste with different O2/N2 ratios and heating rates","authors":"Pengyu Wei , Guoyan Chen , Fubiao Zhi , Anchao Zhang , Haoxin Deng , Xiaoping Wen , Fahui Wang , Chenglong Yu","doi":"10.1016/j.tca.2024.179875","DOIUrl":"10.1016/j.tca.2024.179875","url":null,"abstract":"<div><div>To utilize chili straw waste (CSW) for energy production and generate higher-quality fuel, the pyrolysis characteristics of CSW under varying particle sizes and heating rates, as well as the effects of different O<sub>2</sub>/N<sub>2</sub> ratios on its combustion characteristics, were investigated using Thermogravimetry-Mass Spectrometry (TG-MS). The gas production performance under three different conditions was also analyzed. Results indicated that the solid yield decreased as particle size increased, with the maximum weight loss rate of 77.79 % occurring at a particle size of 1.25∼1.60 mm. The highest relative pyrolysis rate was 0.77 %/K at a heating rate of 10 K/min, corresponding to a weight loss rate of 74.46 %. Increasing the proportion of oxygen in the atmosphere reduced both the ignition and burnout temperatures of CSW by 9.34 K and 51.89 K, respectively, shifting the Derivative Thermogravimetry (DTG) curve to a lower temperature range. Furthermore, an increase in the heating rate enhanced hydrogen production intensity during CSW pyrolysis, with the peak particle current of H<sub>2</sub> rising from 8.7 × 10<sup>−10</sup> A to 1.2 × 10<sup>−9</sup> A, representing a 0.38-fold increase when the heating rate was raised from 5 K/min to 40 K/min. A kinetic analysis of CSW pyrolysis using the Coats-Redfern (CR) and Achar methods revealed that activation energy (E<sub>a</sub>) increases with particle size, indicating higher energy requirements due to heat transfer resistance. The Friedman, Kissinger-Akahira-Sunose (KAS), and Ozawa-Flynn-Wall (OFW) methods showed rising E<sub>a</sub> with increasing conversion rates, corresponding to the decomposition of hemicellulose, cellulose, and lignin. In combustion, oxygen concentration significantly influences E<sub>a</sub>, raising it for volatile matter and fixed carbon, and also increasing it for lignin at high temperatures. The CR and Achar models provided strong fits, confirming their reliability in describing CSW pyrolysis and combustion.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179875"},"PeriodicalIF":3.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.tca.2024.179876
Vera Kalistratova, Arseniy Obedkov, Elena Belova
The kinetic parameters of thermal decomposition of an aqueous solution containing 0.029 mass fractions of hydrazine nitrate and 0.44 mass fractions of nitric acid have been determined: onset temperature and specific thermal effect of exothermic reactions, activation energy, pre-exponential factor, reaction rate and order. Based on the data obtained, a mathematical model of thermal decomposition of nitric acid solutions of hydrazine nitrate has been proposed. It has been found that thermolysis of the solution has a multi-stage nature and can be described by a system of 5 equations of 1st and 2nd order. A comparison of two approaches to creating a mathematical model has been carried out: based on adiabatic calorimetry and differential scanning calorimetry data.
{"title":"Kinetic model of thermal decomposition of nitric acid solutions of hydrazine nitrate","authors":"Vera Kalistratova, Arseniy Obedkov, Elena Belova","doi":"10.1016/j.tca.2024.179876","DOIUrl":"10.1016/j.tca.2024.179876","url":null,"abstract":"<div><div>The kinetic parameters of thermal decomposition of an aqueous solution containing 0.029 mass fractions of hydrazine nitrate and 0.44 mass fractions of nitric acid have been determined: onset temperature and specific thermal effect of exothermic reactions, activation energy, pre-exponential factor, reaction rate and order. Based on the data obtained, a mathematical model of thermal decomposition of nitric acid solutions of hydrazine nitrate has been proposed. It has been found that thermolysis of the solution has a multi-stage nature and can be described by a system of 5 equations of 1st and 2nd order. A comparison of two approaches to creating a mathematical model has been carried out: based on adiabatic calorimetry and differential scanning calorimetry data.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179876"},"PeriodicalIF":3.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-06DOI: 10.1016/j.tca.2024.179874
Alexander M. Laptev , Martin Bram
The volatilization of sodium chloride (NaCl) is important for multiple applications, such as energy storage, manufacturing porous parts, and purification and recycling of composites. Until now, only limited information on this feature has been published. To expand the knowledge in this field, we investigated the sublimation and evaporation of two NaCl powders by thermal gravimetry in vacuum and air. The study has shown that the volatilization kinetics of powders with different shapes and sizes are identical. The volatilization of NaCl powders in vacuum occurs mainly by sublimation before melting. In contrast, the volatilization of NaCl in the air is preferentially caused by the evaporation of the melt. In a vacuum, the evaporation of NaCl powder after melting is significantly slower than the sublimation before melting, because of a drastic decrease in the volatilization area. The Hertz-Knudsen relation with an appropriate fitting coefficient satisfactorily describes the mass loss by volatilization in vacuum and air.
{"title":"Sublimation rate of solid NaCl powders and evaporation rate of liquid NaCl upon heating in vacuum and air","authors":"Alexander M. Laptev , Martin Bram","doi":"10.1016/j.tca.2024.179874","DOIUrl":"10.1016/j.tca.2024.179874","url":null,"abstract":"<div><div>The volatilization of sodium chloride (NaCl) is important for multiple applications, such as energy storage, manufacturing porous parts, and purification and recycling of composites. Until now, only limited information on this feature has been published. To expand the knowledge in this field, we investigated the sublimation and evaporation of two NaCl powders by thermal gravimetry in vacuum and air. The study has shown that the volatilization kinetics of powders with different shapes and sizes are identical. The volatilization of NaCl powders in vacuum occurs mainly by sublimation before melting. In contrast, the volatilization of NaCl in the air is preferentially caused by the evaporation of the melt. In a vacuum, the evaporation of NaCl powder after melting is significantly slower than the sublimation before melting, because of a drastic decrease in the volatilization area. The Hertz-Knudsen relation with an appropriate fitting coefficient satisfactorily describes the mass loss by volatilization in vacuum and air.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179874"},"PeriodicalIF":3.1,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-02DOI: 10.1016/j.tca.2024.179873
S. Delsante , G. Borzone , N. Parodi , S. Guerrucci
The present study is devoted to the experimental investigation of homogeneity range and heat of formation (ΔfH° at 300 K) of the cubic L12–HfAl3-xZnx solid solution. A high-temperature direct drop calorimeter has been employed to synthesize and simultaneously determine the ΔfH° of several alloys along the HfZn3–HfAl3 section (25 at. % Hf) whereas X-Ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM) paired with an EDS (Energy Dispersive Spectrometer detector) have been employed to characterize the samples. The performed analysis confirmed that the ternary HfAl3-xZnx alloys were nearly single phase in the range 1 ≤ x ≤ 2.24 having the cubic L12 structure; this in turn helps establish the trend of L12 lattice parameter (at room temperature) with composition. Thanks to the interpolation of our experimental data, the following values of ΔfH° (kJ/mol-atom at 300 K) for the L12–HfAl3-xZnx were determined: -37.1 ± 2.0 (HfAl0.8Zn2.2 corresponding to Hf25Al20Zn55 at. %), -41.7 ± 2.0 (HfAl1.2Zn1.8 corresponding to Hf25Al30.0Zn45.0 at. %), -45.1 ± 2.0 (HfAl1.5Zn1.5 corresponding to Hf25Al37.5Zn37.5 at. %) and -48.5 ± 2.0 (HfAl1.8Zn1.2 corresponding to Hf25Al45.0Zn30.0 at. %). For two pertinent binary intermetallic phases, the following ΔfH° values (in kJ/mol-atom) at 300 K have been obtained: -31.8 ± 3.0 for HfZn3 (unknown structure) and -37.0 ± 2.0 for HfAl3 (tetragonal DO23 – type structure).
{"title":"Experimental determination of phase stability of the cubic L12 HfAl3-xZnx phase","authors":"S. Delsante , G. Borzone , N. Parodi , S. Guerrucci","doi":"10.1016/j.tca.2024.179873","DOIUrl":"10.1016/j.tca.2024.179873","url":null,"abstract":"<div><div>The present study is devoted to the experimental investigation of homogeneity range and heat of formation (Δ<sub>f</sub><em>H°</em> at 300 K) of the cubic <em>L</em>1<sub>2</sub>–HfAl<sub>3-x</sub>Zn<sub>x</sub> solid solution. A high-temperature direct drop calorimeter has been employed to synthesize and simultaneously determine the Δ<sub>f</sub><em>H°</em> of several alloys along the HfZn<sub>3</sub>–HfAl<sub>3</sub> section (25 at. % Hf) whereas X-Ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM) paired with an EDS (Energy Dispersive Spectrometer detector) have been employed to characterize the samples. The performed analysis confirmed that the ternary HfAl<sub>3-x</sub>Zn<sub>x</sub> alloys were nearly single phase in the range 1 ≤ x ≤ 2.24 having the cubic <em>L</em>1<sub>2</sub> structure; this in turn helps establish the trend of <em>L</em>1<sub>2</sub> lattice parameter (at room temperature) with composition. Thanks to the interpolation of our experimental data, the following values of Δ<sub>f</sub><em>H</em>° (kJ/mol-atom at 300 K) for the <em>L</em>1<sub>2</sub>–HfAl<sub>3-x</sub>Zn<sub>x</sub> were determined: -37.1 ± 2.0 (HfAl<sub>0.8</sub>Zn<sub>2.2</sub> corresponding to Hf<sub>25</sub>Al<sub>20</sub>Zn<sub>55</sub> at. %), -41.7 ± 2.0 (HfAl<sub>1.2</sub>Zn<sub>1.8</sub> corresponding to Hf<sub>25</sub>Al<sub>30.0</sub>Zn<sub>45.0</sub> at. %), -45.1 ± 2.0 (HfAl<sub>1.5</sub>Zn<sub>1.5</sub> corresponding to Hf<sub>25</sub>Al<sub>37.5</sub>Zn<sub>37.5</sub> at. %) and -48.5 ± 2.0 (HfAl<sub>1.8</sub>Zn<sub>1.2</sub> corresponding to Hf<sub>25</sub>Al<sub>45.0</sub>Zn<sub>30.0</sub> at. %). For two pertinent binary intermetallic phases, the following Δ<sub>f</sub><em>H</em>° values (in kJ/mol-atom) at 300 K have been obtained: -31.8 ± 3.0 for HfZn<sub>3</sub> (unknown structure) and -37.0 ± 2.0 for HfAl<sub>3</sub> (tetragonal <em>DO</em><sub>23</sub> – type structure).</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"742 ","pages":"Article 179873"},"PeriodicalIF":3.1,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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