Pub Date : 2025-02-28DOI: 10.1016/j.ctta.2025.100179
Eduardo I. Concepción
In this work, the refractive indices nD, refractive index deviations Δ nD, molar refractions Rm and excess molar refractions REm were determined over the full range of compositions for the Diglycolamine-water binary mixture. Experimental measurements of these properties were carried out at atmospheric pressure and at temperatures ranging from 293.15 to 333.15 K. Excess molar refractions REm and refractive index deviations Δ nD have been fitted to the polynomial Redlich-Kister equation. The refractive indices have been compared with those predicted by the mixing rules proposed by: Lorentz-Lorenz (L-L), Gladstone- Dale (G-L), Eykman (E), Arago-Biot (A-B), Eyring-John (E-J), Bruggeman (B), and Oster (OS), in order to verify their validity for the Diglycolamine-water binary system. The experimental values of the refractive indices agree well with all the previous relationships, with the relationship of Oster (OS) and Gladstone-Dale (G-L) with which better results are obtained.
{"title":"Refractive indices of binary mixtures of diglycolamine - water at various temperatures","authors":"Eduardo I. Concepción","doi":"10.1016/j.ctta.2025.100179","DOIUrl":"10.1016/j.ctta.2025.100179","url":null,"abstract":"<div><div>In this work, the refractive indices <em>n<sub>D</sub></em>, refractive index deviations <em>Δ n<sub>D</sub></em>, molar refractions <em>R</em><sub><em>m</em></sub> and excess molar refractions <em>R<sup>E</sup><sub>m</sub></em> were determined over the full range of compositions for the Diglycolamine-water binary mixture. Experimental measurements of these properties were carried out at atmospheric pressure and at temperatures ranging from 293.15 to 333.15 K. Excess molar refractions <em>R</em><sup><em>E</em></sup><sub><em>m</em></sub> and refractive index deviations <em>Δ n</em><sub><em>D</em></sub> have been fitted to the polynomial Redlich-Kister equation. The refractive indices have been compared with those predicted by the mixing rules proposed by: Lorentz-Lorenz (L-L), Gladstone- Dale (G-L), Eykman (E), Arago-Biot (A-B), Eyring-John (E-J), Bruggeman (B), and Oster (OS), in order to verify their validity for the Diglycolamine-water binary system. The experimental values of the refractive indices agree well with all the previous relationships, with the relationship of Oster (OS) and Gladstone-Dale (G-L) with which better results are obtained.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100179"},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.ctta.2025.100180
Petr Sysel , Pavla Nekvapilová , Jakub Havlín
This study investigated the preparation and thermal behavior of the polyimide based on the nonaromatic bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride and aromatic 4,4´-(1,4-phenylenediisopropylidene)bisaniline. A significantly greater mass loss was detected in the nitrogen atmosphere than in the air atmosphere by using an isothermal thermogravimetric analysis of this product at 375 °C. This loss in nitrogen was reduced when approximately 1 wt% of the radical inhibitor 2,6-di‑tert-4-methylphenol was added to the polymer, whereas in the case of using an atmosphere containing oxygen, which is one from the most effective radical inhibitors, the presence of 2,6-di‑tert-4-methylphenol had practically no effect. This finding supports the application of a retro Diels–Alder reaction during the decomposition of the structure coming from bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride including radical formation as intermediate products at temperatures above 350 °C, whereby the present oxygen inhibits this process very effectively. The products formed during thermal attack were analyzed via a combination of dynamic thermogravimetry with infrared spectroscopy. Some aspects of fully aromatic polyimides based on 4,4´-oxydiphthalic anhydride and 4,4´-(1,4-phenyleneisopropylidene)bisaniline were compared.
{"title":"Behavior of polyimides based on bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride under thermal treatment","authors":"Petr Sysel , Pavla Nekvapilová , Jakub Havlín","doi":"10.1016/j.ctta.2025.100180","DOIUrl":"10.1016/j.ctta.2025.100180","url":null,"abstract":"<div><div>This study investigated the preparation and thermal behavior of the polyimide based on the nonaromatic bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride and aromatic 4,4´-(1,4-phenylenediisopropylidene)bisaniline. A significantly greater mass loss was detected in the nitrogen atmosphere than in the air atmosphere by using an isothermal thermogravimetric analysis of this product at 375 °C. This loss in nitrogen was reduced when approximately 1 wt% of the radical inhibitor 2,6-di‑tert-4-methylphenol was added to the polymer, whereas in the case of using an atmosphere containing oxygen, which is one from the most effective radical inhibitors, the presence of 2,6-di‑tert-4-methylphenol had practically no effect. This finding supports the application of a retro Diels–Alder reaction during the decomposition of the structure coming from bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride including radical formation as intermediate products at temperatures above 350 °C, whereby the present oxygen inhibits this process very effectively. The products formed during thermal attack were analyzed via a combination of dynamic thermogravimetry with infrared spectroscopy. Some aspects of fully aromatic polyimides based on 4,4´-oxydiphthalic anhydride and 4,4´-(1,4-phenyleneisopropylidene)bisaniline were compared.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100180"},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-27DOI: 10.1016/j.ctta.2025.100178
Misbah Khan , Muhammad Asif Shakoori , Syed Ali Raza
Ethylene glycol (EG) is an organic compound commonly used as an antifreeze agent in automotive applications as a heat transfer fluid. It also has a wide range of applications across several industries, including polymer, chemical, pharmaceutical, etc. The main objective of this study is to test COMPASS-II forcefield to model EG and water for the analysis of condensation behavior and related thermophysical properties. In addition, we also calculate the effects of parameters, such as temperature, pressure, and mass fractions on EG and water. For this, we employ molecular dynamics simulations to investigate the effects of various parameters on condensation time, density, isobaric heat capacity, energies, as well as structural and dynamical properties. Our findings reveal that the density of EG decreases with temperature, increases with the mass fraction of water, and remains stable across varying pressures. Condensation time shows a decrease with pressure and an increase with temperature, and it remains constant with increasing water mass fraction. Additionally, isobaric heat capacity exhibits a trend of initial decrease at low temperatures, followed by an increase at higher temperatures, while decreasing with pressure. Notably, the total potential energy behavior diverges from typical refrigerants, aligning instead with the observed density variations over time. Furthermore, molecular diffusion increases with temperature and decreases with pressure, showing minimal dependence on mass fraction. This study provides insights that could enhance heat transfer efficiency and reduce the viscosity of EG, broadening its application as a heat transfer technology.
{"title":"Condensation and thermophysical properties of ethylene glycol + water using molecular dynamic simulations","authors":"Misbah Khan , Muhammad Asif Shakoori , Syed Ali Raza","doi":"10.1016/j.ctta.2025.100178","DOIUrl":"10.1016/j.ctta.2025.100178","url":null,"abstract":"<div><div>Ethylene glycol (EG) is an organic compound commonly used as an antifreeze agent in automotive applications as a heat transfer fluid. It also has a wide range of applications across several industries, including polymer, chemical, pharmaceutical, etc. The main objective of this study is to test COMPASS-II forcefield to model EG and water for the analysis of condensation behavior and related thermophysical properties. In addition, we also calculate the effects of parameters, such as temperature, pressure, and mass fractions on EG and water. For this, we employ molecular dynamics simulations to investigate the effects of various parameters on condensation time, density, isobaric heat capacity, energies, as well as structural and dynamical properties. Our findings reveal that the density of EG decreases with temperature, increases with the mass fraction of water, and remains stable across varying pressures. Condensation time shows a decrease with pressure and an increase with temperature, and it remains constant with increasing water mass fraction. Additionally, isobaric heat capacity exhibits a trend of initial decrease at low temperatures, followed by an increase at higher temperatures, while decreasing with pressure. Notably, the total potential energy behavior diverges from typical refrigerants, aligning instead with the observed density variations over time. Furthermore, molecular diffusion increases with temperature and decreases with pressure, showing minimal dependence on mass fraction. This study provides insights that could enhance heat transfer efficiency and reduce the viscosity of EG, broadening its application as a heat transfer technology.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100178"},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new solubility model based on enhancement factor concept is proposed to correlate solubility of drug compounds in supercritical carbon dioxide (SCCO2). The correlating ability of the new model is compared with existing solubility model. The proposed model and existing models were tested with twenty nine drug-supercritical carbon dioxide systems reported in the literature. The proposed model correlating performance is indicated in terms of absolute relative deviation percentage. Additionally, Akaike's Information Criterion (AIC) was used to assess the model's performance compared with existing solubility model. The results show the compared to existing solubility model, the proposed model accurately correlates the solubility.The global absolute average relative deviation percentage for the existing model and proposed new model are 22.17 % and 16.11 % respectively.
{"title":"A new model to correlate solubility of drug compounds in supercritical carbon dioxide","authors":"Amrithaa Raghavan , Ratna Surya Alwi , Geetha Devi M , Chandrasekhar Garlapati","doi":"10.1016/j.ctta.2025.100177","DOIUrl":"10.1016/j.ctta.2025.100177","url":null,"abstract":"<div><div>A new solubility model based on enhancement factor concept is proposed to correlate solubility of drug compounds in supercritical carbon dioxide (SCCO<sub>2</sub>). The correlating ability of the new model is compared with existing solubility model. The proposed model and existing models were tested with twenty nine drug-supercritical carbon dioxide systems reported in the literature. The proposed model correlating performance is indicated in terms of absolute relative deviation percentage. Additionally, Akaike's Information Criterion (AIC) was used to assess the model's performance compared with existing solubility model. The results show the compared to existing solubility model, the proposed model accurately correlates the solubility.The global absolute average relative deviation percentage for the existing model and proposed new model are 22.17 % and 16.11 % respectively.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100177"},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the thermodynamic properties of ternary solutions comprising sodium nitrate/sodium citrate in sodium salicylate solutions at 0.010, 0.020 and 0.030 mol·kg-1 concentrations. Measurements of density and speed of sound were carried out across four temperatures (288.15 to 318.15) K with a gap of 10K at 0.1 MPa. pressure. Key factors like apparent volume per mole , partial volume per mole , and the change in partial molar volume of transfer , were derived from experimental density measurements, while apparent isentropic compression per mole and partial isentropic compression per mole ; were computed using speed of sound measurements. Pair and triplet coefficients were analyzed to unveil solute and solvent and solute-solute interactions. In addition, Relative association (Ra) and relaxation strength () were calculated, showing a decrease in solute-solvent interactions with adding of salts and rising temperature. Further, an FTIR spectroscopic study of the mixtures (sodium salicylate + water) as well as (sodium Nitrate/sodium Citrate+ water) was conducted to provide further insight into the interactions of solutes and solvents. Spectroscopic results offer insights into solutions with implications for chemical engineering and materials science.
{"title":"Temperature-dependent physicochemical interactions and spectroscopic characterization of sodium nitrate/sodium citrate in aqueous sodium salicylate solutions","authors":"Mashahid Hussain Choudhary , Nabaparna Chakraborty , Kailash Chandra Juglan , Abrar H. Syed","doi":"10.1016/j.ctta.2025.100176","DOIUrl":"10.1016/j.ctta.2025.100176","url":null,"abstract":"<div><div>This study investigates the thermodynamic properties of ternary solutions comprising sodium nitrate/sodium citrate in sodium salicylate solutions at 0.010, 0.020 and 0.030 mol·kg<sup>-1</sup> concentrations. Measurements of density and speed of sound were carried out across four temperatures (288.15 to 318.15) K with a gap of 10K at 0.1 MPa. pressure. Key factors like apparent volume per mole <span><math><msub><mi>V</mi><mi>ϕ</mi></msub></math></span>, partial volume per mole <span><math><msubsup><mi>V</mi><mi>ϕ</mi><mn>0</mn></msubsup></math></span>, and the change in partial molar volume of transfer <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mi>V</mi><mi>ϕ</mi><mn>0</mn></msubsup></mrow></math></span>, were derived from experimental density measurements, while apparent isentropic compression per mole <span><math><msub><mi>K</mi><mrow><mi>ϕ</mi><mo>,</mo><mi>s</mi></mrow></msub></math></span> and partial isentropic compression per mole <span><math><msubsup><mi>K</mi><mrow><mi>ϕ</mi><mo>,</mo><mi>s</mi></mrow><mn>0</mn></msubsup></math></span>; were computed using speed of sound measurements. Pair and triplet coefficients were analyzed to unveil solute and solvent and solute-solute interactions. In addition, Relative association (R<sub>a</sub>) and relaxation strength (<span><math><msub><mi>r</mi><mi>s</mi></msub></math></span>) were calculated, showing a decrease in solute-solvent interactions with adding of salts and rising temperature. Further, an FTIR spectroscopic study of the mixtures (sodium salicylate + water) as well as (sodium Nitrate/sodium Citrate+ water) was conducted to provide further insight into the interactions of solutes and solvents. Spectroscopic results offer insights into solutions with implications for chemical engineering and materials science.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100176"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Annually, the textile industry discharges thousands of tons of non-dissolved dyes into water bodies, presenting significant environmental challenges. Eggshell waste has emerged as a valuable, low-cost, and environmentally friendly adsorbent for addressing these issues. This study investigates the adsorption of Reactive Black 5 dye using eggshell waste supported by Fe2O3, focusing on equilibrium isotherms to evaluate the adsorption capacity. The synthesized adsorbent was characterized using SEM, XRD, FTIR and BET analyses, revealing the spherical morphology and substantial surface area of Fe2O3, which contributed to enhanced adsorption efficiency. XRD confirmed the crystalline structure of the eggshell waste. Adsorption data fit best with the Langmuir isotherm model, demonstrating a maximum adsorption capacity of 250 mg/g for the removal of Reactive Black 5 dye. The combination of eggshell waste with Fe2O3 presents an efficient and sustainable solution for dye removal from wastewater, promoting both environmental protection and the reutilization of waste materials.
{"title":"Adsorption of reactive black 5 dye using eggshell waste supported by Fe2O3: An equilibrium isotherms study","authors":"Akram Fadhl Al-mahmodi , Mahmood Riyadh Atta , Yamuna Munusamy , Baker Nasser Saleh Al-dhawi","doi":"10.1016/j.ctta.2025.100174","DOIUrl":"10.1016/j.ctta.2025.100174","url":null,"abstract":"<div><div>Annually, the textile industry discharges thousands of tons of non-dissolved dyes into water bodies, presenting significant environmental challenges. Eggshell waste has emerged as a valuable, low-cost, and environmentally friendly adsorbent for addressing these issues. This study investigates the adsorption of Reactive Black 5 dye using eggshell waste supported by Fe<sub>2</sub>O<sub>3</sub>, focusing on equilibrium isotherms to evaluate the adsorption capacity. The synthesized adsorbent was characterized using SEM, XRD, FTIR and BET analyses, revealing the spherical morphology and substantial surface area of Fe<sub>2</sub>O<sub>3</sub>, which contributed to enhanced adsorption efficiency. XRD confirmed the crystalline structure of the eggshell waste. Adsorption data fit best with the Langmuir isotherm model, demonstrating a maximum adsorption capacity of 250 mg/g for the removal of Reactive Black 5 dye. The combination of eggshell waste with Fe<sub>2</sub>O<sub>3</sub> presents an efficient and sustainable solution for dye removal from wastewater, promoting both environmental protection and the reutilization of waste materials.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100174"},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1016/j.ctta.2025.100170
Philipp Finster, Judith Jung, Magnus Rohde, Hans Jürgen Seifert, Carlos Ziebert
The heat capacities of liquid ethylene carbonate (EC) and ethyl methyl carbonate (EMC), two important electrolyte components for capacitors and Lithium-ion-batteries, were measured using differential scanning calorimetry in the temperature range from 263 to 500 K in heating mode and from 493 to 273 K in cooling mode for EC. The effect of the supercooled liquid of EC on the heat capacity is discussed. The heat capacity of EMC was determined from 211 to 360 K in heating mode. Based on the obtained heat capacities and the literature data, a simplified Maier–Kelley-fit for the heat capacities is provided. The temperature range of the experimentally determined heat capacity of the liquid state was extended to higher temperatures than previously reported in literature.
{"title":"Heat capacity of ethylene carbonate and ethyl methyl carbonate for the liquid phase at elevated temperatures","authors":"Philipp Finster, Judith Jung, Magnus Rohde, Hans Jürgen Seifert, Carlos Ziebert","doi":"10.1016/j.ctta.2025.100170","DOIUrl":"10.1016/j.ctta.2025.100170","url":null,"abstract":"<div><div>The heat capacities of liquid ethylene carbonate (EC) and ethyl methyl carbonate (EMC), two important electrolyte components for capacitors and Lithium-ion-batteries, were measured using differential scanning calorimetry in the temperature range from 263 to 500 K in heating mode and from 493 to 273 K in cooling mode for EC. The effect of the supercooled liquid of EC on the heat capacity is discussed. The heat capacity of EMC was determined from 211 to 360 K in heating mode. Based on the obtained heat capacities and the literature data, a simplified Maier–Kelley-fit for the heat capacities is provided. The temperature range of the experimentally determined heat capacity of the liquid state was extended to higher temperatures than previously reported in literature.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100170"},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.ctta.2025.100175
Donald Raoul Tchuifon Tchuifon , Lucresse Kora Tioma Nguena , Giscard Doungmo , Sandrale Grace Mokue Mafo , Frank Dorinel Solefack Feudjio , Cyrille Ghislain Fotsop
The thermal degradation of Al-based MOF (CAU-10) were analyzed based on an isoconversional calculation method. The ɤ-Al2O3 formation were characterized using XRD, FTIR, 27Al NMR-MAS and SEM/EDX. The apparent activation energy Ea was evaluated using the iterative isoconversional method. The values of these energies related to the first step (deshydration) and the second step (framework destruction) for the thermal decomposition of CAU-10 reached 35 and 217 kJ/mol, respectively. This indicates that the second step is a complex kinetic process. In addition, the kinetic processes occur in a single step and can be characterized by a unique kinetic triplet (Ea, A, g(α)). For both decomposition steps of CAU-10, the mechanism includes chemical reactions, nucleation, branched nuclei, and three-dimensional diffusion in the first and second phases. According to the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) models in the first step, the Gibbs free energy is between 91.099 kJ/mol and 97.824 kJ/mol; between 242.651 kJ/mol and 244.285 kJ/mol, respectively. This analysis based on thermal measurements combined with structural measurements has highlighted the energetic potential of MOFs synthesis from aluminum exposed to a vapor explosion in a basic context.
{"title":"Pyrolysis kinetics-dependent suitability of Al-based MOFs (CAU-10) for controlling amorphous γ-Al2O3 generation","authors":"Donald Raoul Tchuifon Tchuifon , Lucresse Kora Tioma Nguena , Giscard Doungmo , Sandrale Grace Mokue Mafo , Frank Dorinel Solefack Feudjio , Cyrille Ghislain Fotsop","doi":"10.1016/j.ctta.2025.100175","DOIUrl":"10.1016/j.ctta.2025.100175","url":null,"abstract":"<div><div>The thermal degradation of Al-based MOF (CAU-10) were analyzed based on an isoconversional calculation method. The ɤ-Al<sub>2</sub>O<sub>3</sub> formation were characterized using XRD, FTIR, <sup>27</sup>Al NMR-MAS and SEM/EDX. The apparent activation energy <em>E</em>a was evaluated using the iterative isoconversional method. The values of these energies related to the first step (deshydration) and the second step (framework destruction) for the thermal decomposition of CAU-10 reached 35 and 217 kJ/mol, respectively. This indicates that the second step is a complex kinetic process. In addition, the kinetic processes occur in a single step and can be characterized by a unique kinetic triplet (Ea, A, g(α)). For both decomposition steps of CAU-10, the mechanism includes chemical reactions, nucleation, branched nuclei, and three-dimensional diffusion in the first and second phases. According to the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa <strong>(</strong>FWO) models in the first step, the Gibbs free energy is between 91.099 kJ/mol and 97.824 kJ/mol; between 242.651 kJ/mol and 244.285 kJ/mol, respectively. This analysis based on thermal measurements combined with structural measurements has highlighted the energetic potential of MOFs synthesis from aluminum exposed to a vapor explosion in a basic context.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100175"},"PeriodicalIF":0.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examined the thermal breakdown of Podocarpus falcatus oil (PFO) and its derived biodiesel (BPFO) under dynamic heating conditions. PFO and BPFO were characterized by spectroscopic, computational, and thermo-gravimetric analysis coupled with differential thermo-gravimetric analysis (TGA/DTA). PFO and BPFO's kinetic and thermodynamic properties were examined using Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink isoconversional kinetic models. The conversion limit was restricted from 0.1 to 0.9 at different heating rates of 5, 7 and 10 °C.min−1. The FWO isoconversional model was properly fitted by the TGA/DTA analytical data, with the highest R2 values of 0.941. Average activation energies were 224.50 kJ.mol−1 for PFO and 108.60 kJ.mol−1 for BPFO. Nonspontaneous and endothermic thermal breakdown was confirmed by positive standard enthalpy (∆H) and standard Gibbs free energy(∆G) values. In contrast, the negative standard entropy () indicated a more ordered process. Using density functional theory (DFT) in conjunction with the M05–2X hybrid functional, the computing study was conducted on the two most abundant FAMEs (Fatty acid methyl ester) to achieve the optimum geometry, topology analysis, and electronic properties. There was a good correlation between the computation and experimental results. This study showed that biodiesel's thermal and oxidation stability with regard to time could be accurately predicted using the TGA/DTA approach.
{"title":"Advanced characterization of biodiesel from Podocarpous falcatus oil via spectroscopy and DFT-based approaches: Thermal degradation kinetics and stability assessment","authors":"Serges Bruno Lemoupi Ngomade , Cyrille Donlifack Atemkeng , Aymard Didier Tamafo Fouegue , Cyrille Ghislain Fotsop , Hilaire Tendongmo , Théophile Kamgaing , Solomon Gabche Anagho , Neeraj Atray","doi":"10.1016/j.ctta.2025.100172","DOIUrl":"10.1016/j.ctta.2025.100172","url":null,"abstract":"<div><div>This study examined the thermal breakdown of <em>Podocarpus falcatus</em> oil (PFO) and its derived biodiesel (BPFO) under dynamic heating conditions. PFO and BPFO were characterized by spectroscopic, computational, and thermo-gravimetric analysis coupled with differential thermo-gravimetric analysis (TGA/DTA). PFO and BPFO's kinetic and thermodynamic properties were examined using Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink isoconversional kinetic models. The conversion limit was restricted from 0.1 to 0.9 at different heating rates of 5, 7 and 10 °C.min<sup>−1</sup>. The FWO isoconversional model was properly fitted by the TGA/DTA analytical data, with the highest R<sup>2</sup> values of 0.941. Average activation energies were 224.50 kJ.mol<sup>−1</sup> for PFO and 108.60 kJ.mol<sup>−1</sup> for BPFO. Nonspontaneous and endothermic thermal breakdown was confirmed by positive standard enthalpy (∆H) and standard Gibbs free energy(∆G) values. In contrast, the negative standard entropy (<span><math><mrow><mstyle><mi>Δ</mi></mstyle><mi>S</mi></mrow></math></span>) indicated a more ordered process. Using density functional theory (DFT) in conjunction with the M05–2X hybrid functional, the computing study was conducted on the two most abundant FAMEs (Fatty acid methyl ester) to achieve the optimum geometry, topology analysis, and electronic properties. There was a good correlation between the computation and experimental results. This study showed that biodiesel's thermal and oxidation stability with regard to time could be accurately predicted using the TGA/DTA approach.</div></div>","PeriodicalId":9781,"journal":{"name":"Chemical Thermodynamics and Thermal Analysis","volume":"18 ","pages":"Article 100172"},"PeriodicalIF":0.0,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.ctta.2025.100173
Sweety Verma PhD , Kavitha Kumari , Juwon Min , In–Hyoup Song PhD , Suman Gahlyan , Sanjeev Maken
Volumetric and optical properties for binary mixtures containing 3–amino-1–propanol (3AP) + isomeric butanol was measured in the temperature range (298.15–318.15) K. Excess molar volume () and deviation in refractive index () were computed using the estimated parameters. The Prigogine–Flory–Patterson (PFP) theory and Graph theoretical approach (GTA), were utilized to analyze the data at 298.15 K, respectively. Furthermore, the molecular species of various components are predicted to exist in both pure and mixed states by the GTA. The excess/deviation in properties was further interpreted in terms of intermolecular interactions. Theoretical and experimental results agree well. The temperature effect on measured properties was also discussed. For the theoretical determination of nD various mixing rules were also used. Furthermore, FT–IR spectroscopy confirmed the formation of hydrogen bonding among the molecules in the components.
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